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1. 5 EEGFUC N E E E 5 Variables ilatina e aae aa aA aaa ias ita 6 Value Assignment iicet rc e tp R R E A R ip R 6 P Variables campistas 8 Array Capabilities eite ttti ist die fat utes beige tea Le tidad 8 Special Use P Variable is etie Co tel poet p HH ees 9 O VU arable S 9 Alloiting Q Variables ute A ii diia Gide 9 Addressing a Q Variable Seti tio ddr ito 10 Array GCapabiliti S iii 10 Special Use Q Vartables ai loo desee ti Ree bois 12 M Variabl s lesen aee Ri ote tee aie ten e t ab e Nt toi to eee Meese 12 M Variable Definitions seite i eerte tie lotto t 12 Limita I a 13 Using MV o pia 13 Operas A 14 ATIINMETC Oper s SEDE 14 reae am 14 Logical Operator s sie tete Rep ei cerei dp AE te ete Free A A E E T E R 14 duree 14 SIN odes 14 COS RE 15 TAN m A 15 ACOS E 15 ATAN OA 15 PETA p 16 NA e E 16 RN 16 UR ERE 17 A ie LU DUE 17 Mu EE 17 EXPIESSION Seat cio pai trial nta rt 17 Dae ors M M MH 18 Variable Value Assignment Statement sese enne nennen eret eene enne tnnt tete teneret tren trennen 18 I Variable Default Value Assignment
2. Clearly there is a value of 00 for address bits A31 A24 7F for address bits A23 A16 A0 for bits A15 A8 and 00 for bits A7 AO Now write these values into the appropriate PMAC registers using the PMAC Executive Software or an suitable terminal communication program The register values would then be PMAC Address Value X 5 0783 39 X 0784 04 X 5 0785 00 X S0786 7F X 0787 A0 X 50788 02 X 50789 Al X SO78A 00 X 9078B 60 X 078C 10 A simple write command followed by a save command to PMAC will put these values into their appropriate registers and make them permanent WX 0783 39 4 0 7F A0 02 A1 0 60 10 SAVE Writing a Host Communications Program PMAC User Manual Remember that these values must be saved and then the card reset with the command the INIT input line pulled low or power cycled before these new values will take effect If using the PMAC Executive Program set up these registers using the ConfigurelV ME Communications menu Setting Up VME Dual Ported RAM Option 2V If Option 2V is installed on the PMAC VME then configure its starting address This setup is done entirely through software in a manner similar to that of setting up the PMAC VME mailbox registers There is no hardware setup or connections for the Option 2V DPRAM on the PMAC VME or PMAC2 VME It is factory installed on the PMAC
3. WHILE M11 1 Cut as long as input is true TM 585 9375 Cut move time X10000 Actual cut move DELAY 500 Hold part of 1953 125 msec return TM 953 125 Return time part of 1953 125 msec X0 Actual return move DELAY 500 Hold part of 1953 125 msec return ENDWHILE Triggered Time Base The time base techniques discussed so far keep the slave coordinate system locked perfectly to the master but they do not provide a way of synchronizing automatically to a particular point on the master Thus the slave cycle can be out of phase with the master cycle and some special technique usually involving position capture from a registration mark must be used to bring the cycles in phase with each other 15 8 Synchronizing PMAC to External Events PMAC User Manual Many time base applications do not require the master and slave cycles to be in phase with each other for instance cutting blank sheets of paper to length rather than printed pages and others have to be continually re registered due to stretching slippage or uneven spacing These types of applications can use the standard time base function However applications that do need to be in phase with the master and in which a registration procedure to do this is difficult or impossible can use the triggered time base feature of the conversion table This technique permits perfect synchronization to the position of the master that is captured by a trigg
4. m 14 Using ini User Prora NEED a a e E ER E a E E 14 Offset from Motor Posiflon esminiai oa ae a a e iaai e enne 14 Position Compare Functions EE 15 Required M Variables eese sees eee entente eene enn RRA RR RR RRE then trennt trennt te ete Ran e tnee trennen innen enne 15 Preloading the Compare Position eee e eese ro none enne nennen eene E trennen ene nena nennen enne trennen 15 Offset from Motor Position ii e pete de eR ipe ode Rho eet de E aee E tue e ta tee dide dud 16 Synchronous M Varlable Assignmelit eed npe tiber he HE EO DE te ERE oa e ERR ape RE E ERE e Sanata 17 Table of Contents 15 i PMAC User Manual 15 ii Table of Contents PMAC User Manual SYNCHRONIZING PMAC TO EXTERNAL EVENTS Features To Help Synchronize Motion PMAC has several powerful features to help in synchronizing the motion under PMAC control to external events These include position following commonly known as electronic gearing time base control commonly known as electronic cams position capture which is very useful for registration applications and position compare which can be used for precision scanning and measurement applications Each of these areas is covered in this section Position Following Electronic Gearing PMAC has several methods of coordinating the axes under its control to axes not under its control The simplest method is basic position following This
5. E B Programmed P Path OC2 Line Tool Center Tool Center a Path T y Path f NEN E S Line to Line Line to Arc Are Programmed cel CC2 Path eee gt Arc 222 Arc Tool Center ba Path F Tool cener V Ea NS Y Arc to Line Arc to Arc Figure 45 Cutter Compensation Change of Direction However if there is no intersection between the two compensated move paths the change is introduced linearly over the next move Cutter Compensation Change of Direction No Intersection Programmed Change Through an Arc CC2 Programmed Path Line Change Through a Line Change in Reversal Figure 46 Cutter Compensation Change of Direction No Intersection How PMAC Removes Compensation PMAC gradually removes compensation over the next LINEAR or CIRCLE mode move following the CCO command that turns off compensation This lead out move starts at a point one cutter radius away from the intersection of the lead in move and the first fully compensated move with the line from the programmed point to this compensated endpoint being perpendicular to the path of the first fully compensated move at the intersection Writing Programs for PMAC 14 30 PMAC User Manual Note that few controllers can make their lead out move a CIRCLE mode move This capability permits releasing contact with the cutting surface very gently important for fine finishing cuts Inside Corner If the last fully compe
6. Flag Isolation These inputs can be kept isolated from other circuits If supplied from the analog supply voltage A 15V and tied to analog ground AGND they will be isolated from the PMAC digital circuitry If supplied from a digital supply voltage 12V and tied to digital ground GND they will be isolated from the PMAC analog circuitry If supplied from a separate supply OPTO V 12 to 24V and tied back to the supply s own ground they will be isolated from both the digital and analog circuitry The setting of jumpers E89 and E90 controls which power the flag circuitry and therefore which circuit s it is isolated from Dedicated Digital Output Flags MACH JEQU Ports PMAC has two dedicated digital outputs for each channel in the hardware configuration the Amplifier Enable Direction line AENA DIRn and the Compare Equals line EQUn Amplifier Enable Direction Output The AENA DIRn output is an optically isolated output tied to the same circuit as the dedicated digital inputs It can be kept isolated from the PMAC digital computation circuitry from the PMAC analog circuitry or both Amplifier Enable Disable Use These outputs are typically used as enable disable lines for the amplifiers commanded by PMAC This control function is very important for safety reasons to make sure the amplifier can be completely shut down when needed It is not a good idea to rely on a zero analog output voltage offsets can easily build 6
7. motor 1 125 correction at 2000 8 250 counts is 125 DAC bits 50 Correction at 500 counts is 50 DAC bits 83 Correction at 750 counts is 83 DAC bits 97 Correction at 1000 counts is 97 DAC bits 60 Correction at 1250 counts is 60 DAC bits 43 Correction at 1500 counts is 43 DAC bits 129 Correction at 1750 counts is 129 DAC bit 0 Correction at 2000 counts and 0 is 0 DAC bits 7 34 Setting Up a Motor PMAC User Manual the correction applied at 600 counts would be Correction 50 600 500 750 500 50 Setting Up a Motor E PMAC User Manual 7 36 Setting Up a Motor PMAC User Manual 9 Setting Up PMAC Commutation Table of Contents SETTING UP PMAC COMMUTATION eese esee tette that t tuse ta tuse ta sns tn sens enses esto stes suse tasse tassa enses suse tn sosta snae 1 leni M EE 1 Incremental Encoder Feedback Requirement ccccceesceescessceeeceseceseceneceaesaeceaecaeecaeeeaeeenesceeeeeseeeseenseeeaeenaeenneeaes 1 Phase Referencing 5 oen rp iei EE E A EE 1 Two Analog Output Requirements e Roe EUR egeo rede suerte ltd dee ened ae 1 Basic Parameter Specific a io Ratt E E toco dal 2 Counts per Commutation Er ne 2 Angle Between PRASES E 2 Permanent Magnet Brushless Motor Commutation essent nennen ene nnne 3 Getting th Polanyi de 3 Poweron Phasing Search nie 3 Phasing Referenced to
8. HK PLC2 4 Background PLC 2 cont HK Comm PLC3 Background PLCO Move Planning 4 RTI Move Planning cont PLC3 cont 4 RTI Background PLC 3 cont HK PLC 1 x Background PLC 0 PLC 1 cont RTI PLC 1 cont HK Comm Background Comm Communications Line Processing v Servo Interrupt RTI Real Time Interrupt Task Start of RTI Figure 24 PMAC Multitasking Example 13 4 Computational Features PMAC User Manual Examples 1234 3 03 leading zeros OK 27 656 0 001 001 leading zero not required S 00 interpreted as hexadecimal Reporting Values PMAC reports numerical values to the host computer as part of response lines in decimal ASCII text form although address values can be reported in hexadecimal ASCII form if I922 or 3 see the Addresses 47 14 section below The value reporter is limited to passing values in the range of i or 1 41 x 19 Values outside of this range are truncated to the maximum or minimum values of the range Addresses PMAC uses the Motorola DSP56001 as its processor The 56001 has dual 16 bit address spaces of 24 bit data for memory and I O The I O in PMAC is memory mapped it does not have a separate I O space as the PC does When specifying an address in PMAC one must state which half of memory X or Y or both halves L for a long 48 bit word followed by an optional colon followed by the numerical address itself The numerica
9. Note Remember that if any I variables are changed during this setup use the SAVE command before powering down or resetting the card or the changes that were made will be lost Alternatively use the I variable pages under the Configuration menu to view and change these variables in a more user friendly fashion 2 8 Getting Started with PMAC PMAC User Manual Encoder I Variables Several I variables are linked to particular encoder inputs regardless of which motor the encoder is assigned to These control how the encoder signal is interpreted They are numbered in the 900s I900 1904 belong to Encoder 1 1905 1909 belong to Encoder 2 and so on to 1975 1979 belonging to Encoder 16 Initially we will only concern ourselves with the first encoder I variable 1900 1905 1910 Etc These control the decoding of the encoder signal into counts Quadrature x1 x2 and x4 plus pulse and direction decode are all possible PMAC is shipped with counterclockwise x4 decode set up 1900 1905 T Check this value for Encoder 1 1900 and change it to 7 if it is different 1901 1906 1911 etc Encoder digital filter disable This controls whether the digital delay filter for noise spike elimination is turned on PMAC is shipped with the filters on 1901 1906 0 1902 1907 1912 etc Encoder position capture control This controls which transitions of those associated encoder signals trigger a position capture
10. The switch may be normally open or normally closed open is high 1 and closed is low 0 The polarity of the edge that causes the home position capture is programmable with Encoder I Variables 2 and 3 1902 and 1903 for HMFL 1 Amplifier fault signal FAULTn This input can take a signal from the amplifier so PMAC knows when the amplifier is having problems and can shut down action The polarity is programmable with I variable Ix25 1125 for motor 1 and the return signal is analog ground AGND FAULT1 is pin 49 With the default setup this signal must be actively pulled low for a fault condition In this setup if nothing is wired into this input PMAC will consider the motor not to be in a fault condition Software Setup for a Motor PMAC has a large set of Initialization parameters I variables that determine the personality of the card for a specific application Many of these are used to configure a motor properly Once set up these variables may be stored in non volatile EAROM memory using the SAVE command so the card is always configured properly PMAC loads the EAROM I variable values into RAM on power up Run the PMAC Executive Program on the PC The value of an I variable may be queried simply by typing in the name of the I variable For instance typing 1900 CR causes the value of the I900 to be returned The value may be changed by typing in the name an equals sign and the new value e g I900 3 lt CR gt
11. USER MANUAL PMAC DELTA TAU Data Systems Inc NEW IDEAS IN MOTION Single Source Machine Control Power Flexibility Ease of Use 21314 Lassen Street Chatsworth CA 91311 Tel 818 998 2095 Fax 818 998 7807 www deltatau com Copyright Information 2003 Delta Tau Data Systems Inc All rights reserved This document is furnished for the customers of Delta Tau Data Systems Inc Other uses are unauthorized without written permission of Delta Tau Data Systems Inc Information contained in this manual may be updated from time to time due to product improvements etc and may not conform in every respect to former issues To report errors or inconsistencies call or email Delta Tau Data Systems Inc Technical Support Phone 818 717 5656 Fax 818 998 7807 Email support deltatau com Website http www deltatau com Operating Conditions All Delta Tau Data Systems Inc motion controller products accessories and amplifiers contain static sensitive components that can be damaged by incorrect handling When installing or handling Delta Tau Data Systems Inc products avoid contact with highly insulated materials Only qualified personnel should be allowed to handle this equipment In the case of industrial applications we expect our products to be protected from hazardous or conductive materials and or environments that could cause harm to the controller by damaging components or causing e
12. X Words Y words 1 Intermediate data Sign extended most 1 Source and process significant word Bits 0 15 Address of source data Y word if 20 conversion X word if 60 conversion Bits 16 23 20 for Y word source 60 for X word source 2 Converted data 2 Bitenable mask Bits 0 4 Fractional Bits Bit 1 to use corresponding bit from source Bits 5 23 Integer Bits word Bit 0 not to use corresponding bit from source word 7 20 Setting Up a Motor PMAC User Manual Filtered Parallel Data Conversion X Words Y words 1 Intermediate data 1 Source and process Raw data reading Bits 0 15 Address of source data Y word if 30 conversion X word if 70 conversion Bits 16 23 30 for Y word source 70 for X word source 2 Intermediate data 2 Bit enable mask Sign extended most significant word Bit 1 to use corresponding bit from source word Bit 0 not to use corresponding bit from source word 3 Converted data 3 Filter value Maximum permitted change in Bits 0 4 Fractional Bits counts servo cycle Bits 5 23 Integer Bits Uses This unshifted format is intended for very high speed very high resolution applications typically with parallel laser interferometer feedback With the normal shifted format the PMAC internal velocity registers saturate when the counts sec Ix08 exceed 256M 268 435 456 With the unshifted format this limit is 32 times hig
13. 078B must have a value of SEO to enable the DPRAM chip installed on the PMAC VME and modify the value in location X 078C the address width register by adding 80 to the existing value For this example the PMAC register values would be PMAC Address Value X 0783 39 X 0784 04 X 0785 00 X 0786 7F X 0787 A0 X 0788 02 X 0789 Al X 078A 10 X 078B EO X 078C 90 Note This dynamic addressing scheme provides the capability for addressing up to 1M byte of DPRAM in 16K byte blocks by changing the value of base 121 on the fly However PMAC VME currently utilizes only a single 16 Kbyte block 8K x 16 so the base 121 register only has to be written to once every time PMAC is powered up or reset The shaded registers above contained the values changed from previous example to enable DPRAM A simple write command followed by a SAVE command to PMAC will put these values into their appropriate registers and make them permanent WX 0783 39 4 0 7F A0 02 A1 10 E0 90 SAVE Remember that these values must be saved with the SAVE command and then the card reset with the command the INIT input line pulled low or power cycled before these new values will take effect After writing 3F to 7FA121 base 121 the dual ported RAM is ready to be used See the PMAC Dual Ported RAM User Manual for more information Talking to PMAC VME Through
14. 51 and 53 to analog ground pin 58 or disable the limit function in software refer to variable Ix25 below Getting Started with PMAC 2 7 PMAC User Manual Note The direction polarity of the limit pins is the opposite of what many would consider intuitive That is the limit switch at the positive end of travel should be wired into the LIM input and the limit switch at the negative end of travel should be wired into the LIM input If the direction input of the encoder is ever changed the wiring of the limit switches must be changed as well It is important to check and re check the direction sense of the limit inputs Amplifier Enable Signal AENAx DIRn Most amplifiers have an enable disable input that permits complete shutdown of the amplifier regardless of the voltage of the command signal PMAC AENA line is meant for this purpose If not using a direction and magnitude amplifier or voltage to frequency converter use this pin to enable and disable the amplifier wired to the enable line AENA1 DIR1 is pin 47 This signal is an open collector output and requires a pull up resistor to A 15V For early tests this amplifier signal may be under manual control The polarity of the signal is controlled by jumper s E17 The default is low true conducting enable Home Flag Signal HMFLn A home switch can be wired between this pin HMFL1 is pin 55 and analog ground AGND or if powered from the bus to digital ground GND
15. 760 decimal Baud Rate Error Bookmark not defined Set up the baud rate counter in the host computer to match the PMAC baud rate which is determined by the master clock and jumpers E40 E43 The baud rate counter must be given a value equal to 115 200 divided by the baud rate e g for 9600 baud the value is 115 200 9600 12 The following program segment illustrates how this can be done outportb combase 3 131 Put COM port in setup mode baud count 115200 baud Calculate counter value outportb combase baud count Write to low byte of counter outportb combase 1 baud count 256 Write to high byte of counter outportb combase 3 3 Put COM port back in normal mode with 8 bits 1 stop bit The command outportb is a byte write command combase is the base address baud is the baud rate in bits per second Itis a good idea in the initial set up to compute a timeout value related to both the baud rate and the host computer s speed As the host polls PMAC to see if it is ready to communicate a counter increments if the counter exceeds the timeout value the host should give up on this attempt to talk to PMAC Depending on the circumstances it should either just try again later as when waiting for some asynchronous communications or assume there is an error condition A good equation for the timeout value is timeout 7 speed baudcount 100 where speed is 1 or 2 for a PC
16. Alternatively the desired characteristics of the band reject and band pass filters can be specified individually and PMAC will compute the coefficients to achieve those characteristics and download them to PMAC Refer to the PEWIN Software User Manual for more details Manual Notch Specification To compute the notch filter coefficients manually consider the continuous transfer function for a notch filter s 42 e 02 G s gt z nz ne s 26 oO 0 p np np Start with five parameters for the filter On the natural frequency of the zeroes in radians second not in Hertz amp the damping ratio of the zeroes e e e o the natural frequency of the poles in radians second not in Hertz e the damping ratio of the poles e T the servo loop sampling period in seconds not in msec To compute radians second from Hertz multiply by 2x 6 283 To compute the sampling period in seconds from the sampling rate in kHz first multiply the rate by 1000 to get Hz and then take the reciprocal Remember that the sampling period is equal to 1x60 1 times the servo interrupt period Closing the Servo Loop 9 7 PMAC User Manual First compute the following intermediate values 2 T nz sS 2 T np s a 1 2 0 T 0 Z z nz s a 1 2 o T 0 p p nps Then compute the filter coefficients gt 2 0nTs 2 1x36 az 1 Ix37 2 a 2E oT 2 1x38 l PEREA a y 1 Ix39 a p
17. CONTROL O character to PMAC over the serial port The bootstrap firmware interprets this as a signal to prepare for downloading of new operational firmware All subsequent bytes received over the serial port will be considered as binary coded bytes of machine code firmware and will be written into the flash memory Note Before attempting to upgrade PMAC operational firmware make sure all of PMAC configuration has been stored to disk If the new firmware provides a different user memory map PMAC will clear memory on power up after new firmware has been loaded Even if this is not the case the easiest way to establish a new firmware checksum reference value is to send the command which clears the buffers The host computer should wait at least five seconds after the CONTROL O command before starting to download the operational firmware This delay ensures that the flash memory is ready to be written to After downloading the PMAC should be powered down No other communications should be attempted with PMAC at this time After turning off power to PMAC the E51 jumper should be removed When power is re applied to PMAC it should operate normally with the new firmware The user settings stored in other segments of the flash memory with the SAVE command are not affected by the downloading of new firmware unless the new firmware has a different user memory map 4 12 Talking to PMAC PMAC User Manual The PMAC Exe
18. Communications ccccccccessseceeseececeeseececsesaececseceeceesaeeecsesaececsesesesaeeecseaaeeeseneeeeeeaaee 3 HOST POrESTUCTULO CE 3 Base Address Selection eee aara enea ne teen teen RARA treten eret enne teeth tn enne tren rennen nnne trennen 3 Register FUNCTIONS p 3 Registers for Simple Polled Communications eee esee een tenente nennen trennen trennen 3 SEMIN GUD A E E E 4 Sending a Character A 4 Reading d Characters i ac Ute pee mne eek REOR ERE DATAE RERNE electi aD eene a a Ke OEE ES eek eed qp ERR OA 4 Using the PMAC PC STD to Interrupt the Host Computer sseeseeseeeeeereneeneeee nennen nennen rennen rens 4 What Signals Can Be Used eese eene nennen ennenne nennen trennt tr RR Ran Ran nen anne nena trennt ne ene tnen nen 4 Selecting a Host Interrupt Line PMAC PC or Lite esses ene enne nennen tenens 6 Selecting a Host Interrupt Line PMAC STD ccococicococonaconononononnnnnnnnnnonnncnnnon ono eene rennen enne nnee trennen teste en rennen 6 PARAT OTI Testo Cm 6 A EP dai ista 9 Finding an Open Interrupt Linesin anisini etes se tton teet ens oa e te ace eden Ains Le dob in RE ott Denn eani donans 9 Hardware Considerations untada ii 9 Initializing the POS PIC sais di 10 VEciornmo eii ediles die 10 Setting up the Host Request Function eese eene eene cane cre cnn enn n teet etre nne nnne trennen tre
19. Conversion Instructions Address Feedback Process 8 Address Raw Data Signals Feedback Data Processed Feedback Data RAM Encoder Counters 8 Timers Latches ADC s Figure 8 Encoder Conversion Table Process Setting Up a Motor 7 13 PMAC User Manual Conversion Table Structure The Encoder Conversion Table has two columns one in the X memory space of the processor and one in the Y memory space The X column holds the converted data while the Y column holds the addresses of the source registers and the conversion methods used on the data in each of those source registers Basically set up the table by writing to the Y column and PMAC uses the Y column data to fill up the X column each servo cycle File Edit Configure Status Window Plot Options Backup Help PMAC Terminal PC Bus PROM 1 15F an Configure Encoder Conversion Table Ce Lena or rante rst Enry CEE 1 T extension of incremental encoder E C8B8 Encoder 1 Figure 9 Configure Encoder Conversion Table Editing Screen Conversion Methods The chart below lists the possible conversion formats To do a conversion the 8 bit format is matched with a 16 bit address to fill the 24 bit Y word in the conversion table If there is more than one row for a given conversion type the other Y words are further setup parameters for the conversion The conversion result is placed in the last highest address X word and the other X words hold interm
20. Dedicated Digital Output Flags JIMACH JEQU Ports essere enne nnne nn cn nein enne enne enne eene tenene 6 Amplifier Enable Direction Output eee ee esee eene nette ennt enne the tnenne the RR tret e tnee trennen trennt te ete teen eene enne tn nnne 6 Amplifier Enable Disable Use esee esee eene enne enne teen te etr ennethetne teste tnee tee tn ete tnet nete trennt trennen nnne 6 Jp M 7 ADS wa D 7 Sourcing Drivers Ar EOS sadvaygennegubadiedevayevoeluctiiuaendsrsutesiy 7 DPolarity CORITOL ir A ye uu tat ud ci e d tetto Sue dv epu SU ub DES 7 Direction DU m An 7 General Purpose EE T amp Compare Equals Outputs te eaeoe ie A E E E E A E E E Mb ede ERES a HERR hae E E ae tes ss Optically Isolated Analog Outputs JMACH Port esses nono neon eren eene ne tret tenete en trennen nr cn nennen 8 CONME rM 8 A annon e e E ies ERE E a eaa a EE E a E 9 Drive Capability M 9 GENETAI PUPPOSE USE E E 9 General Purpose Digital Inputs and Outputs JOPTO Port sese nennen trennen trennen 9 ADV ACCESS EE 9 Standard Sinking Outputs EH A 9 Optio
21. If the position counted down 1172 should be set to 85 for a 3 phase motor or 64 for a 4 phase motor If the position counted up 1172 should be set to 171 for a 3 phase motor or 192 for a 4 phase motor Before continuing make sure to set the offset parameters 1129 and 1179 back to 0 Induction Motors If this motor is an induction motor check the polarity by trying to run the motor with both polarities settings of 1172 and seeing which produces satisfactory results Type lt CR gt to initiate the phasing of the motor Now type O10 lt CR gt open loop output 10 and see if the motor spins well even if it does not accelerate quickly The position should be counting up Next kill the output temporarily with K CR and change the output polarity by giving 1172 a new value e g if it was 85 change it to 171 Now type O10 lt CR gt again and observe the response Kill the motor again and set 1172 to the value that gave decent response If there is no movement with either setting check the troubleshooting guide immediately above Non PMAC Commutated Motors If PMAC is not doing the commutation for a motor make sure that the servo feedback and output polarities match Do this by giving the motor an open loop output command and seeing which way the position counts Type O10 CR open loop output 10 The position counter should count up If it counts down there is a polarity mismatch Now type O 10 lt CR gt The position counter should cou
22. If utilizing an external feedrate override signal and the override should be disabled during RAPID mode set the time base source address variable back to its default value and away from the external source e g 1193 2054 Alternately this variable could be set to another external source if the machine had a separate rapid override setting The section of the file to implement G00 would look something like CLOSE OPEN PROG 1000 CLEAR To erase old version when sending new RAPID First actual line of program 1193 2054 RET G01 Linear Interpolation Mode Typically this code is implemented in PMAC through use of the LINEAR command The simplest implementation of this is NO1000 LINEAR RET If feedrate override is desired and it could have been disabled in RAPID mode the subroutine should set the time base source address variable to the register containing the external information e g 119321833 G02 2D Clockwise Arc Mode Typically this code is implemented in PMAC through use of the CIRCLE1 command The simplest implementation of this is NO2000 CIRCLE1 RET If feedrate override is desired and it could have been disabled in RAPID mode the subroutine should set the time base source address variable to the register containing the external information e g 119321833 G03 2D Counterclockwise Arc Mode Typically this code is implemented in PMAC through use of the CIRCLE2 command The simplest implementation of this is
23. In general for a rotation of angle 0 about a point x y the displacement vector required is xo 1 cos yo sin xo sin yo 1 cos 0 14 36 Writing Programs for PMAC PMAC User Manual To implement this in PMAC code assuming that Q40 through Q48 are as in the above rotation example we add Q50 P1 1 COS 15 P2 SIN 15 Q51 P1 SIN 15 P2 1 COS 15 Q52 0 AROT40 Create 15 degree rotation ADIS50 Create proper displacement Current Position Transformation When a coordinate system is transformed it is important to realize that the starting positions for the upcoming move are transformed and this has an effect on an axis not explicitly commanded in this upcoming move In absolute mode any axis not explicitly commanded implicitly receives a command to its existing position in this case the transformed position For example if the absolute move X1Y0 is followed by a 45 rotation this position is transformed to X0 707Y0 707 If this is followed by an absolute X2 move command this is equivalent to an X2YO 707 command not to an X2YO command Entering A Motion Program The motion program statements are entered one program buffer at a time into PMAC For each program buffer the first step is to open the buffer for entry with the OPEN PROG n command where n is the buffer number with a range of 1 to 32 767 Next if there is anything currently in the buffer that should not be kept it
24. L5 11 AND P1 P2 OR L1 0 Examples of illegal condition statements IF L50 P1 WHILE L75 10000000 IF L1 P2 0 Optimization for Speed and Memory L Variables that are 24 bit signed values are the fastest to read and write Unsigned 1 to 20 bit variables without offset are next fastest and signed 1 to 20 bit variables and those having an offset from bit 0 are the slowest The slower the operation the more PLC program memory is used However 24 bit L variables will use more data memory than the smaller width ones Because speed is more of a concern than data memory in most compiled PLC applications usually all L variables that do not have to be short to point to a particular portion of a word such as all the general purpose L variables in the user buffer are 24 bits wide even if they do not require the full range A read or write operation on a signed 24 bit L variable takes three DSP instruction cycles to execute and two program memory locations to store A read operation from a less than 24 bit 1 to 20 bit signed L variable takes from six to eight DSP instruction cycles and from five to seven program memory locations A read operation from a less than 24 bit 1 to 20 bit unsigned L variable takes from 7 to 9 DSP instruction cycles and from six to eight program memory locations A write operation to a less than 24 bit 1 to 20 bit signed or unsigned L variable takes 12 to 14 instruction cycles and 10 to 12 p
25. MO to M1023 and as with other variable types the number of the M variable may be specified with either a constant or an expression M576 or M P1 20 when read from the number must be specified by a constant when written to M Variable Definitions The definition of an M variable is done using the defines arrow gt composed of the minus sign and greater than symbols Generally a definition only needs to be made once with in an on line command because it is stored in battery backed RAM or saved to flash memory The M variable thus defined may be used repeatedly An M variable may take one of the following types as specified by the address prefix in the definition to 24 bits fixed point in X memory to 24 bits fixed point in Y memory 48 bits fixed point across both X and Y memory 48 bits floating point across both X and Y memory DP 32 bits fixed point low 16 bits of X and Y for use in dual ported RAM F 32 bits floating point low 16 bits of X and Y for use in dual ported RAM TWD Multiplexed BCD decoding from Thumbwheel port TWB Multiplexed binary decoding from Thumbwheel port TWS Multiplexed serial I O decoding from Thumbwheel port TWR Multiplexed serial resolver decoding from Thumbwheel port No address definition uses part of the definition word as general purpose variable If an X or Y type of M variable is defined also define the starting bit to use the number of bits and the format decoding method h
26. PMAC reads the motor commanded positions in open loop commanded positions are always equal to actual positions and converts them to axis positions by effectively executing a PMATCH command inverting the axis definition equations If the LEARN command specifies which axes are to be learned e g LEARN A B C only those axis commands will be added to the program If the LEARN command does not specify any axes commands for all nine axis names are added to the motion program The LEARN function can only add axis move commands to the program Any other parts of the motion program including math logic move modes and move times must be sent to the open motion program buffer directly Motion Program Structure Typically PMAC motion programs are combinations of movement specification statements calculation statements and logic statements The movement specification statements are used to generate commanded trajectories for the axes according to the rules explained in the Program Trajectory section of this manual The calculation statements can be used to determine the parameters for the movement specifications and the logic statements can be used to determine which movement statements get executed and when Basic Move Specifications The simplest motion programs just contain movement specifications For example F5000 X10000 DWELL1000 x0 Remember that in entering this program surround these statements with the buffer contr
27. actual performance of linear and transition point moves between 113 0 mode and 11320 mode is virtually imperceptible unless the feature sizes of the moves are in the same range as the 113 time PVT Mode Moves For the user who desires more direct control over the trajectory profile PMAC offers Position Velocity Time PVT mode moves In these moves the axis states are specified directly at the transitions between moves unlike in blended moves This requires more calculation by the host but allows tighter control of the profile shape For each piece of a move specify the end position or distance the end velocity and the piece time Mode Statement PMAC is put in this mode with the program statement PVT data where data is a constant variable or expression representing the piece time in milliseconds This value should be an integer if it is not PMAC will round it to the nearest integer The piece time may be changed between pieces either with another PVT data statement or with a TA data statement The program is taken out of this mode with another move mode statement e g LINEAR RAPID CIRCLE SPLINE Move Statements A PVT mode move is specified for each axis to be moved with a statement of the form axis data data where axis is a letter specifying the axis the first data is a value specifying the end position or the piece distance depending on whether the axis is in absolute or incremental mode respective
28. information Analog Circuit Jumpers On PMAC the analog output circuitry can be optically isolated from the digital logic circuitry for noise reduction purposes PMAC is shipped from the factory with the circuits optically isolated E85 E87 and E88 OFF It is recommended that the card be used in this configuration but it is possible to jumper the bus supply voltage 12V over to the analog circuitry by putting these jumpers ON defeating the optical isolation but eliminating the need for an separate power source Isolated Setup With the optical isolation in effect it is necessary to provide separate power supply to the analog output circuitry On the JMACH connectors the A 15V analog supply should be brought in on pin 59 the A 15V analog supply on pin 60 and the analog ground AGND on pin 58 Jumper E89 should be ON and Jumper E90 should connect Pins 1 and 2 to permit this 15V to pull up the limit switch and other optically isolated inputs which is required for PMAC to command motion PMAC is shipped with E89 and E90 in this configuration Most amplifiers provide supply outputs for this purpose Alternatively an external supply may be used Non Isolated Setup The 12V and 12V bus supplies may be used to power the analog output circuitry by jumpering them across to the analog side with E85 12V E87 Analog GND and E88 12V however this defeats the isolation and connects the whole computer electrically to the amplifier
29. long as the tasks from the previous RTI have been completed PLC 0 is potentially the most dangerous task on PMAC as far as disturbing the scheduling of tasks is concerned If it is too long it will starve the background tasks for time The first thing to notice is that communications and background PLC tasks will become sluggish In the worst case the watchdog timer will trip shutting down the card because the housekeeping task in background did not have the time to keep it updated Computational Features 13 1 PMAC User Manual e Motion Program Move Planning Motion program move planning consists of working through the lines of a motion program until the next move or dwell command is encountered and computing the equations of motion for this next part of the move sequence Every time PMAC starts executing a new move it sets an internal flag indicating it is time to plan the next move in the program This planning occurs at the next RTI e VME Mailbox Processing Reading or writing a block of up to 16 characters through the VME mailbox registers is the fourth highest priority in PMAC The rate at which this happens is controlled by the host This never takes a significant portion of the PMAC computational power Background Tasks In the time not taken by any of the higher priority tasks PMAC will be executing background tasks There are three basic background tasks command processing PLC programs 1 31 and housekeeping The freque
30. lt ACK gt or BELL Therefore read all 16 mailbox registers to obtain the first 16 characters of the PMAC response and then write 00 to mailbox register 1 in this case at 7FA003 to allow PMAC to put the next chunk of data in the mailbox registers PMAC interrupts again with vector A1 and the remainder of the characters in the mailbox registers are Address 7FAO001 7FA003 7FA005 7FA007 7FAO0ID 7FAOIF Mailbox 0 4 5 14 15 Character 5 CR 2 3 4 Now we read again the mailbox registers looking for CR lt ACK gt or BELL The fifth character we read in mailbox 4 7FA009 happens to contain a CR so we stop reading and write 00 into mailbox register 1 Because PMAC still has to send the final lt ACK gt character it interrupts us again with vector A1 and we see in the mailbox registers Address 7FA001 7F A003 7FA005 7FA007 7FAO0ID 7FAO1F Mailbox 0 4 5 14 15 Character lt ACK gt lt CR gt 2 3 4 Now stop at the first character lt ACK gt which serves as the end of transmission character and again write 00 into mailbox register 1 Since PMAC does not having any more data to be read for now there will not be another interrupt until another command is sent or one of our executing PLC or motion programs puts out data via the CMD or SEND command The diagram on the following page summarizes communicatio
31. nonsensical results because the P and Q variable access always treats the register as a floating point number For general purpose integer variables the L variables will probably replace what was previously done with P variables in the program Since L variables must be defined to a specific address it is important to find open areas of PMAC memory to hold these variables To make this easier declare a User buffer on PMAC with the DEFINE UBUFFER size command where size represents the number of 48 bit words of PMAC memory to be reserved for this buffer The buffer starts at address 9FFF and continues back toward the start of memory for the specified number of words For example the 16 8 Writing a PLC Program PMAC User Manual command DEFINE UBUFFER 256 reserves addresses 9F00 to 9FFF both X and Y registers for user use including L variables A user buffer cannot be created if there is already any buffer in PMAC that was created with a DEFINE command rotary program leadscrew comp etc It is easiest to create the user buffer immediately after re initializing the card with a command Debug these programs using integer M variables assigned to user buffer registers as the general purpose variables instead of P variables This will make the changeover to compiled integer form easier If there are just a few general purpose L variables use the open memory areas 0770 to 077F and 07FO0 to 07FF both X and Y re
32. not line numbers even though they are specified by number A line does not require a label and the labels do not need to be in numerical order These line labels are used only to specify the jumps in GOTO GOSUB and CALL commands all discussed below GOTO Command PMAC provides a GOTO data command in its motion program syntax which causes a jump to line label N data in the same motion program without return In general the use of GOTO commands is strongly discouraged because of the tendency to build up programs that are very hard to decipher However when the data in a GOTO command is a variable or expression e g GOTO P20 it can be used to build the equivalent of a structured CASE statement creating a multiple pronged branching point Adding Variables and Calculations Motion programs can be made a lot more flexible with the use of variables and mathematical calculations The above example program will command the same moves with the same timing every time it is executed If any parameter for the program would need to be changed the entire program would need to be re entered or a different program used However if we use variables in place of the constants we only need to change variable values to change the action of the program F P2 P1 0 WHILE P1 P3 X P4 DWELL P5 x0 DWELL P5 P1 P1 1 ENDWHILE The variables P2 P3 P4 and P5 could be set by the host with on line commands e g P2 2000 by a
33. so Ix78 would be set to 1 048 576 with the default setting Ix83 Set the phase address parameter to 42 for motor 1 7E for motor 2 BA for motor 3 F6 for motor 4 132 for motor 5 16E for motor 6 1AA for motor 7 and 1E6 for motor 8 Using the Motor Once the motor is set up use it just as any other PMAC motor In fact because it is working off internal feedback this motor can be programmed and tested without any physical motor attached User Written Commutation Algorithm For the sophisticated user with unusual and or difficult commutation needs PMAC provides the hooks for custom user written commutation phasing algorithms These routines are written in Motorola 56000 assembly language code usually on a PC or compatible and cross assembled for the 56000 Delta Tau provides the information about where to pick up the needed information where to leave the output commands and where to store the algorithm itself The writing and download procedure is as for the user written servo algorithm Note This is not a task for the inexperienced user To attempt this the user should be well acquainted with both motor theory and assembly language coding Setting Up PMAC Commutation 8 15 PMAC User Manual The user written commutation algorithm is enabled by setting Ix59 to 2 or 3 for Motor x Ix59 3 also enables the user written servo PMAC will only select between the standard commutation algorithm and the user wri
34. the Q variable values do not have to be assigned three per command line but this is for program readability Rotation Example To rotate the coordinate system 15 degrees about the origin in the XY plane Set up the matrix as follows TSEL 2 Select Matrix 2 Q40 2COS 15 Q41 SIN 15 Q42z20 Variables for first row Q43 SIN 15 944 COS 15 045 0 Variables for second row 046 0 047 0 Q48 1 Variables for third row AROT 40 Assign these values to the rotation portion This transformation rotates the points 15 degrees counterclockwise in the XY plane relative to fixed XY axes when viewed from the Z axis in a right handed coordinate system i x j k Alternately stated it rotates the XY axes 15 degrees clockwise in the XY plane relative to fixed points when viewed from the Z axis in a right handed coordinate system Displacement Example To offset the Y and Z axes by five units and 2 5 units respectively leaving the X axis unchanged Set up the matrix as follows TSEL 3 Select Matrix 3 0191 20 First variable Q192 5 Second variable Q193 2 5 Third variable ADIS 191 Assign these values to the displacement portion Second Rotation Example To rotate the coordinate system 15 degrees in the XY plane as in the first rotation example but about an arbitrary point P1 P2 instead of the origin In this case the rotation matrix is the same as for a rotation about the origin but a displacement vector is also required
35. the value that multiplies the difference between the current source data and the last source data Setting its value usually requires some computation this subject is covered in the Time Base Control section of Coordination Features of this manual Converted Data The last source data word is stored in the first X word of the entry in the table and the net result is stored in the second X word The value of the net result is 2 Scale factor New source Old source To use this value to control the time base of a coordinate system enter this address as the value of Ix93 Time Base Source Address for the coordinate system 7 22 Setting Up a Motor PMAC User Manual DEC HEX X Register Y Register 1824 720 00 CO00C Interpolated Cts n 1827 ina T 1 1 Enc 4 counter 1832 728 Interpolated Cts n 1 40 0723 Time Base Int Enc 4 Result 1833 729 u Scale factor 1193 1833 Result 2 S F Interp Cts n Interp Cts n 1 2 Z RTIF 2 IF 110 22 110 IF RTIF Figure 11 Conversion Table Example for Time Base Entry Triggered Time Base Conversion Entries For those applications where it is necessary to synchronize exactly to the position of the master encoder the conversion table provides the capability to freeze the time base while calculating the first moves of the synchronized sequence Then have the time base start up referenced exactly to the mas
36. where filename is the name of the machine code file without the LOD suffix CODE will generate a file called filename PMC that can then be sent to PMAC Closing the Servo Loop 9 11 PMAC User Manual Step 3 Execute the PMAC Executive Program and select the Editor menu with mouse lt ALT E gt or lt F10 gt B Select the Download File to PMAC option and type in the name of the file in response to the prompt PMC is the default suffix Once ENTER is pressed the Executive Program will download the file automatically to the proper PMAC memory location where it will be held indefinitely by the battery backed RAM Step 4 Enable the user written filter for each desired motor by setting Ix59for that motor to 1 or 3 If x59 is 0 or 2 for a motor the default it will use the standard servo algorithm Memory Space Software Interface and Program Restrictions The program space allocated for a user written servo is e Program code starting address P B800 P 9C00 in V1 14 and older e Maximum allowed program length is 1K 24 bit words P B800 to P SBBFF or P 9C00 to P 9FFF in V1 14 and older Usable Data Spaces The data spaces available for variables used in the user written servo are Zero value initialized user registers L 0770 to L 077F Uninitialized user registers L 07F0 to L 07FF These registers retain the last values written to them before power down reset in battery backed PMACs they power up
37. 1 1P lt CR gt has been sent PMAC of course will respond with data containing position information of motor 1 Motor 1 is currently at position 19 2 To read the mailbox registers to obtain this information PMAC has waiting The first thing to do is to send the command line and service the interrupt PMAC generates using an interrupt vector of A0 as an acknowledgment After PMAC has processed the command and put data into the mailbox registers PMAC interrupts a second time with an interrupt vector A1 Remember this second interrupt is sent because PMAC has just now placed data in the mailbox registers now ready to be read Service this second interrupt and note that the accompanying interrupt vector is A 1 read the data in the mailbox registers Actually these registers can be read in any order but it is best to read these characters beginning with the first mailbox until either e a CR signifying the end of that line or e a lt ACK gt valid command line received is encountered or 17 20 Writing a Host Communications Program PMAC User Manual a lt BELL gt invalid command line received is encountered or e all 16 mailbox registers from 7FA001 to 7FAOIF have been read These mailbox registers may be read as many times as needed because PMAC will not write new data into the mailbox registers if PMAC has more data to send until a value of 00 is written to mailbox 1 in this case at 7FA003 In this exa
38. 1 uses DACI by default Pulse and Direction Output PMAC can command drives that accept pulse and direction inputs stepper drives and stepper replacement servo drives The analog output from PMAC is converted to a pulse train through a voltage to frequency converter on the ACC 8D Opt 2 board The PMAC output must be set in sign and magnitude mode by setting bit 16 of Ix02 to 1 The pulse train can be fed back to PMAC for a simulated servo loop or an actual encoder can be used Selecting the Position Loop Feedback Variable Ix03 determines from which register Motor x gets its actual position information to close its position loop every servo cycle The value of Ix03 is the address of the register Usually this is a register in the Encoder Conversion Table that contains processed information from a feedback device With the default setup of the Encoder Conversion Table the default value of Ix03 is the register address of processed data from Encoder x e g Motor 3 uses Encoder 3 by default Selecting the Velocity Loop Feedback Variable Ix04 determines from which register Motor x gets actual position information to close its velocity loop every servo cycle The value of Ix04 is the address of the register Usually this is a register in the Encoder Conversion Table that contains processed information from a feedback device With the default setup of the Encoder Conversion Table the default value of Ix04 is the register address of processed
39. 100 program lines ahead of the execution point in a four axis application where it is using constant values for position e g X1000 Y1200 Z1400 A1600 there should be at least 400 Writing Programs for PMAC 14 51 PMAC User Manual words of memory in the buffer so it would be a good idea to allot 500 or 600 words for the rotary buffer e g DEFINE ROT 600 Required Buffer State for Defining In order for PMAC to be able to reserve room for the rotary buffer there can be no data gathering buffer and no rotary program buffer for a higher numbered coordinate system at the time of the DEFINE ROT command Therefore delete any data gathering buffer first and define the rotary buffers from high numbered to low numbered For instance DELETE GATHER amp 3 DEFINE ROT 200 amp 2 DEFINE ROT 1000 amp 1 DEFINE ROT 20 Preparing to Run To prepare to run a rotary program in a coordinate system use the BO command go to Beginning of program zero the rotary program when addressing that coordinate system This must be done when no buffers are open or it will be interpreted as a B axis command Once prepared this way the program is started with the R command This command can be given either with the buffer open or closed If the R command is given for an empty rotary buffer the buffer will simply wait for a command to be given to it then execute that command immediately Opening for Entry The OPEN ROT command opens all of the rotary
40. 10000 00Y 1 arc min exaggerated Motor 41 10 000 E Figure 23 PMAC Coordinate Definition Setting Up a Coordinate System 12 5 PMAC User Manual What Is Coordinate System Time Base Each coordinate system has its own time base that helps control the speed of interpolated moves in that coordinate system The PMAC interpolation routines increment an elapsed time register every servo cycle While the true time for the servo cycle is set in hardware for the card by jumpers E98 E29 E33 and E3 E6 and does not change the value of time added to the elapsed time register each servo cycle is just a number in a memory register It does not have to match the true physical time for the cycle The units for the time base register are such that 2 8 388 608 equals 1 millisecond The default value for the time base register is equal to the value of 110 The factory default value for 110 of 3 713 707 represents the default physical servo cycle time of 442 microseconds If the value of the time base register is changed from 110 interpolated moves will move at a different speed from that programmed Many people call this capability feedrate override The physical time does not change so servo loop dynamics remain unchanged Each coordinate system has a variable Ix93 that contains the address of the register that the coordinate system uses for its time base With the default value of Ix93 the coordinate system gets its time base informatio
41. 1170 1 issue the command 1175 475 If 1170 2 issue the command I1752 950 Setting Up PMAC Commutation 8 7 PMAC User Manual Final Preparations To finish the preparation for the absolute phasing read a few more things must be done Remove the remaining phase offset by setting Ix79 back to 0 prevent any phasing search move by setting Ix73 and Ix74 to 0 and or removing the phasing search PLC program define the address for the absolute phase position read by setting Ix81 and decide whether to enable the motor immediately on power up reset by setting Ix80 To continue the example 179 20 Remove phase bias or set to bias for zero current 17320 Disable phasing search 17420 Disable phasing search 180 21 Enable motor immediately on power up reset 181 020100 Read R D at location 2 02 of multiplexer address 0 0100 for initial phase position or 181 10FFDO Read 16 bits 10 of parallel data from Port A of 1st ACC 14 SFFDO for initial phase position Trying Absolute Phasing Now try the setup by issuing the motor reset command If the phasing works well the motor should move easily in both directions with small open loop commands If the servo loop has been tuned reasonably the motor can now job in both directions as well but poor jogging performance could be due to a poorly tuned servo loop especially if the open loop commands work well Saving
42. 16 count In a jog until trigger the distance is specified by the 11 6 Basic Motor Moves PMAC User Manual second value in the jog command the value after the arrow in units of counts In a motion program move until trigger the distance is specified by a second value in the axis command the value after the arrow in user axis units In many cases in these types of moves the Ix69 command output should be set to a lower value representing the torque or force limit to ensure that this limit is not exceeded at any time during the move before or after the trigger Notice that if the warning following error status bit is true at the start of the move the trigger will occur almost immediately Merits of Dual Trigger It is common practice to use a combination of a homing switch and the index channel as the home trigger condition The index channel of an encoder while precise and repeatable is not unique in most applications because the motor can travel more than one revolution Typically the homing switch while unique is not extremely precise or repeatable By using a logical combination of the two uniqueness from the switch and precision and repeatability from the index channel can be achieved In this scheme the homing switch is effectively used to select which index channel pulse is used as the home trigger Although the homing switch does not need to be placed accurately in this type of application it is important
43. 20 Table of Contents 17 1 PMAC User Manual Examples o da a nd 21 Dual Ported RAM Communications ccoocncccnnonconnnononnnocnno nono nononn nono none en teen RR Dn r en eene nn E teneret trennen nen 22 Uses o DBRAM iiie aii uere petes ai vss casnedsieau beni dendo ded reso ueste voee me ee PER dge y 22 Using Multiple PMAC VME Cards On the VME bus essent enne trennen ener nn 23 Data Integrity Checks eise le Alda 25 Data Gathering A 27 Real Time Data Gathering Through Dual Ported RAM esee eerte eene eene nenne 28 17 2 Table of Contents PMAC User Manual WRITING A HOST COMMUNICATIONS PROGRAM Communicating From a Host Computer If communicating from a host computer to PMAC in the actual application write a host communications program The PMAC Executive program that was used in development is not intended as a host program for an actual application it was designed simply as a development tool At a fundamental level the host communications routines that are written send and receive strings of ASCII coded characters to and from PMAC Create some low level routines to send and receive individual characters and text lines these will be called repeatedly specifying the different text strings to read or write The basic concepts of communications are covered in the Talking to PMAC section of this manual Communications to the PMAC will take place over one of three P
44. 256 AND M137 lt 256 The simple conditions contained within a compound condition on a single line must not be separated by parentheses For example IF P1 gt 20 AND P1 lt 20 is an illegal condition and will be rejected for illegal syntax Single Line Condition Actions In PMAC motion programs but not in PLC programs the action s to be executed on a true condition can be put on the same line as the condition itself In this case no ENDIF or ENDWHILE is required to mark the end of the conditional action and none may be used the end of the line is automatically the marker for the end of the conditional action Examples of this form are IF P1 lt 0 P1 0 WHILE M11 0 DWELL 10 In PMAC rotary program buffers single line condition actions are the only types of conditional statements permitted Multiple line conditions are not permitted because it cannot be guaranteed that the line that must be jumped to will be in the rotary buffer at that time Multiple Line Conditions In PMAC PLC programs but not in motion programs compound conditions over several program lines are allowed The first line of the condition must start with IF or WHILE following lines of the condition must start with AND or OR Simple and compound conditions within a program line are always evaluated before the conditions on separate lines are combined Between the conditions on multiple lines AND takes precedence over OR PMAC will stop evaluating a multi line AND
45. 39H8nos HO 2 YyACIAIG ovWd AON3nO3HJ 32019 19313S kin o alo o a SHOL2313S LNIOd 3 953 ZHW OZ ATOS a ds a avno a v o l LUJAN ee eee nl e 1X3 9 pa A Lia bz Y H31Nh02 H3000N3 8 v I SjueuiaJoul HOL1V1OdH3ANI gt ze anv H3ZINOHHONAS XVIN ZHIN OL avno a v HO LV1 Viva a g Y 4 4881 De sna viva dH 32019 JO 3903 43 NVHOO SNISIH NO GSHOLW1 HadooNa NIT 38 OL SLNAdLNO TIV a31v70d Y3LNI DVI IWOH lt AIF yO lt Hal3WOH3JH3lNI gS LINVA S18 S y3sv1 SLNAWSYONI ZE OLNI 31V 1OdH3LNI v 31V9 dsa ar 06 S118 HAGOONA 4 NOILISOd Q3 1V IOdH31NI S IHNNVHO 000 HOJ TANNVHO NJA S OVINd NO SLAdNI 3S3HL ASN H3aO9N3 HOH NOILV TOdH3ANI LI8 ONISN NAHM TOHLNOO HO SIXV c AINO JANVH NVI OVINd SIXV v V LON Figure 7 Interpolated Encoder Feedback 7 7 Setting Up a Motor PMAC User Manual Parallel Absolute Feedback When using an absolute encoder as the feedback device the data is presented to PMAC in parallel form All lines must be presented together no high word low word select schemes are permitted With the absolute nature of the device the power on reset position is not automatically zero For this type of device PMAC can use the Ix10 parameter to read the absolute power on reset position up to a width of 48 bits If Ix10 is set to O
46. A 18 How They Work ininaraina di 20 Added Piece lab a 21 Quantifying the Position Adjustment esee eee enint niss inadina in trennen ennt 21 Point Spline COPPECHON a oet tates titia DU cete eate a tie Coe e gea ind A 21 Non Unif orm Split eee ire i ei Nee echte ate n ie tee bine cidade 21 Cutter Radius Compensation reat esed paie ee bee pr eter ei er eed e rct e eres Sleeves 22 Defining the Plane of Compensation eese eese enne enne then e Ran Rene one enn ren nette tnte treten trennen 22 Defining the Magnitude of Compensation eese eese eene creen eene ener ener nente trennen 23 Turning ON CompehsQllOn sitis tasti pe rtis E eid EU terree bete iia 23 Turning Off Compensation a tee petet aii 23 How PMAC Introduces Compensation eese esee ee eee eene teen nennen nenne teen teet enne trennen steer nne trennen 23 Treatment of Compensated Inside Corners eese enne enne nennen nemen trennen trennen rennen 25 Writing Programs for PMAC 14 i PMAC User Manual Treatment of Outside COMES e UU ee NRBIS ede dei 26 Treatment of Full Reyersal iu o A HU ees E bete ex sede Wn e e end tee A 28 Note ON Kull Circles RE 28 Speed of Compensated MOVE Sieisen Hatha ete E e e entero ue ee eain tb e c uon 29 Changes in COMPENSADA dias 29 How PMAC Removes Compensation esee eene enne tnnt RR RR Rae RR RR RR RR e RR ren eene tne tenete trennen 30 Failures in Cutter Compensat
47. AP F gt time lt TA bie TA be TA gt Figure 30 Linear Mode Trajectories Sheet 3 of 4 Writing Programs for PMAC 14 9 PMAC User Manual Changing acceleration times vA gt 4 TM or AP F gt lt TM or AP F gt time TA1 TA2 gt i TA2 gt V A TMor AP F 9 TM or AP F time TA1 gt 4 TA2 i TA2 b vA gt lt TA1 gt TA2 actual gt id TA2 specified 9 time TA2 specified VAS AAA i gt 4 TM1 Pid TM2 gt time 4 TA1 4 TA2 TA2 gt Figure 31 Linear Mode Trajectories Sheet 4 of 4 14 10 Writing Programs for PMAC PMAC User Manual Feedrate Axes If a multi axis move is specified by feedrate and not time there is further flexibility by specifying which axes control the vector feedrate using the FRAX command on line or buffered and velocity is apportioned among these axes so that their vector combination root of sum of squares is the specified velocity PMAC calculates the move time as the vector distance of the feedrate axes divided by the programmed feedrate There is no need to compute each axis velocity individually for each different angle of movement If a simultaneous move is requested of a non feedrate axis that move is completed in the same time as that computed for the f
48. AT type computers Different versions of so called compatible computers use these interrupts for different things consult the users manual for your own model to see what interrupt line is used for what function Below is a table of standard uses for these interrupt lines It is often possible to borrow a COM or LPT interrupt for the duration of a PMAC interfacing program if that port will not be used Hardware Considerations Once the line is chosen the electrical properties of the interrupt line must be considered Also here is an area where compatible PCs often are not really compatible Some use no pull up resistors for these lines on the backplane and those that do use pull up resistors use different values PMAC PC is shipped standard with a 470 ohm pull down resistor connecting D3 and R25 just above the AT connector While this is sufficient to achieve an adequate low state on most PCs and clones on some varieties with low value pull up resistors a lower value pull down may be required to get a valid low state Obviously probing of the interrupt line may be required to verify proper operation extender cards are a big help in this regard Writing a Host Communications Program 17 9 PMAC User Manual Standard Uses for Open Interrupt Lines Line Int PC Use PC AT Use IRQ2 OAH LPT2 IRQ8 15 IRQ3 OBH COM2 COM2 IRQ4 OCH COMI COMI IRQ5 ODH Hard Disk LPT2 IRQ7 OFH LPTI LPTI IRQ10 7
49. Compiled PLC Programs It is possible to compile PMAC PLC programs for faster execution The faster execution of the compiled PLCs comes from two factors first from the elimination of interpretation time and second from the capability of the compiled PLC programs to execute integer arithmetic Floating point operations in compiled PLC programs run 2 to 3 times faster than in interpreted PLC programs integer including boolean operations run 20 to 30 times faster in compiled form Note The size of the compiled code mentioned here refers to the space that the actual compiled code will occupy in the PMAC memory It does not refer to the size of the compiler s output file on the PC s disk drive PMAC does not perform the compilation of the PLC programs itself The compilation is done in a PC the resulting machine code is then downloaded to PMAC PMAC can store and execute up to 32 compiled PLC programs as well as 32 interpreted uncompiled PLC programs for a total of 64 PLC programs 15K 15 360 24 bit words of PMAC memory are reserved for compiled PLCs or 14K 14 336 words if there is a user written servo as well No other task may use this memory and compiled PLCs may not use any other memory A compiled PLC program is labeled PLCC n PLC Compiled n on PMAC This distinguishes it from an interpreted PLC which is simply labeled PLC n There is no special relationship between the interpreted and compiled PLCs of the same numb
50. DWELL commands in between moves will temporarily turn of compensation at the point of the DWELL Also a looping structure such as the HILE condition WAIT or a WHILE loop with no motion commands will temporarily turn off compensation Axis Transformation Matrices PMAC provides the capability to perform matrix transformation operations on the X Y and Z axes of a coordinate system These operations have the same mathematical functionality as the matrix forms of the axis definition statements but these can be changed on the fly in the middle of programs the axis definition statements are meant to be fixed for a particular application The matrix transformations permit translation rotation scaling mirroring and skewing of the X Y and Zaxes They can be useful for English metric conversion floating origins making duplicate mirror images repeating operations with angle offsets and more The basic mathematical operation that the matrix operation performs is as follows X R11R12 R13 X DI Y R2 R22R23 Y D2 Z R31R32 R33 Z D3 The base X Y and Z coordinates are those defined by the axis definition statements Those statements may or may not incorporate a matrix relationship between the axes and motors If there is a matrix relationship in the definition statements these matrix operators will act on top of that relationship Setting Up the Matrices The first thing that must be done is to define a buffer space for the t
51. EQU7 E56 EQU3 E57 INT e e e e e e e e e e PMAC E 6E77E78E79E80 470 ohm E81E82E83E84E86 0 Y 1 rca POL IRQ15 PC AT Ar IRQ3 IRQ14 uy i IRQ4 IRQ5 uc IRQ IRQ2 IRQ10 v vv vy Y Y v v vy y PC AT 8259 PIC PC 8259 PIC 80x86 CPU Figure 54 PMAC PC PMAC Lite Interrupt Structure Writing a Host Comm unications Program PMAC User Manual IR6 FEt gt IR7 SOFTWARE BREQ IRS Pos 4 1R2 HOST REQUEST IR1 4 BOARD EXITING RESET IE PUSHED BUTTON IRO__ BOARD ENTERING RESET IE WATCHDOG TIMEOUT y INT o o o w3 w2 Wi e o e PMAC INTRQ2 STD32 INTRQ1 INTRQ v y y PC 8259 PIC gt 80x86 CPU Figure 55 PMAC STD Interrupt Structure 17 8 Writing a Host Communications Program PMAC User Manual In PMACINT C note the setup particularly unmasking and vectoring the PC interrupt properly the interrupt service routine and the restoration of the old interrupt setup and the end of the program Note PMAC can also perform interrupt based communications with the PC over the serial data port RS 232 on the PC This interrupt capability is inherent in the PC s RS 232 port and does not rely on the PMAC PIC in any way but from the PC end it can be treated very much like the bus communications interrupt scheme Fi
52. If the motor is not commutated by PMAC this command creates a constant DC voltage on the single DAC output for the motor If the motor is commutated by PMAC this command sets the magnitude of the signal that is sinusoidally commutated onto the two DAC outputs for the motor To do a variable O command define an M variable to the filter result register X 003A etc command an OO to the motor to put it in open loop mode then assign a variable value to the M variable This technique will even work on PMAC commutated motors The PMAC Executive Program tuning section uses the open loop moves to allow the user to diagnose and tune amplifier response 11 14 Basic Motor Moves PMAC User Manual 12 Setting Up a Coordinate System Table of Contents SETTING UP A COORDINATE SYSTEM eeeeees eese etes thats tuse ta tuse tasse to senten sees sus tasse ea sonata sess sos enses snae 1 Coordinating Multiple Motion nat bo mre Ee m Eno ERE EF HO RR lan HERE o ERR Fea EL E FERE a EHE DR ds Loco els 1 What 1s a Coordinate NAI E 1 Wh at 18 at AA Merete 1 ONCHO ONE MGICHINEG m 1 B Igor P 1 Phantont AXES nasales caidos n eee subo bean uec E deis see Exc peeoe E E E e NR Ese rIE TE 2 Axis Definition Statements coonononononononnonenenonennoranonon cone keia nennen nne nik aeran aaa Ra kE ean eaaa tn nai niaan an hikaia 2 Matching Mo
53. It goes true when the encoder position matches the pre loaded position compare register value If not using the position compare feature for an encoder have the PMAC command this bit from a motion program or PLC program using an M variable by changing its polarity with the EQU out invert enable bit bit 13 of the DSPGATE status control word Mx13 in the suggested M variable definitions thus allowing PMAC software to generate an interrupt for the PC AXEXPO and AXEXPI bring in EQUn inputs from the PMAC Accessory 24 Axis Expansion Board Jumpers on the ACC 24 control which EQUn line is brought in on the line These also may be set in PMAC software MI and MI2 are PMAC Machine Inputs 1 and 2 which usually come from the system under control Software This line in the PMAC STD can be toggled from a PMAC program after assigning an M variable to bit 7 of Y register FFED e g M10 Y FFED 7 1 Setting this M variable to 1 triggers the interrupt setting it to O clears it Selecting a Host Interrupt Line PMAC PC or Lite Use one and only one of the PMAC PC or PMAC Lite jumpers E76 to E84 and E86 to select which of the PC s interrupt input lines IRQn will receive the signal generated by the PMAC PIC Jumpers E81 E84 and E86 are for IRQ lines on the original PC connector jumpers E76 E80 are for IRQ lines on the AT connector which PC XTs and their clones do not possess These lines feed into an 8259 PIC in the PC itself each line
54. K 1 by describing a vector parallel to the Z axis in the negative direction specifies the XY plane with the normal right left sense of the compensation NORMAL K1 would also use the XY plane but invert the right left sense This same command also specifies the plane for circular interpolation NORMAL K 1 is the default The compensation plane should not be changed while compensation is active Other common settings are NORMAL J 1 which specifies the ZX plane for compensation and NORMAL I 1 which specifies the YZ plane These three settings of the normal vector correspond to RS 274 G codes G17 G18 and G19 respectively If you are implementing G codes in PMAC program 1000 you could incorporate in PROG 1000 N17000 NORMAL K 1 RETURN N18000 NORMAL J 1 RETURN N19000 NORMAL I 1 RETURN 14 22 Writing Programs for PMAC PMAC User Manual Defining the Magnitude of Compensation The magnitude of the compensation the cutter radius must be set using the buffered motion program command CCR data Cutter Compensation Radius This command can take either a constant argument e g CCRO 125 or an expression in parentheses e g CCR P10 0 0625 The units of the argument are the user units of the X Y and Z axes In RS 274 style programs these commands are often incorporated into tool data D codes using PMAC motion program 1003 Negative and zero values for cutter radius are possible Note that the behavior in changing betwee
55. M1 0 Turn off Machine Output 1 Computational Considerations When PMAC is doing calculations in a PLC program motion program or on line it uses its 48 bit floating point format for the intermediate form of the calculation This gives PMAC the ability to automatically convert between its different numerical formats and enables it to do bit wise operations on its P and Q variables although they are floating point values The process of converting a number to 48 bit format is fast and will not be noticeable in most PMAC applications However skipping the conversion step can help increase the PMAC speed and efficiency for computationally demanding applications In such applications using P Q and L long format M variables skip the conversion step they are already in 48 bit format and are computed faster than other variable types When PMAC is doing calculations with L variables in a compiled PLC program PLCC it uses a 24 bit fixed point format for the intermediate form of the calculation This gives PMAC the ability to perform the calculations extremely fast L variable calculations are about ten times faster than equivalent floating point calculations Computational Features 13 23 PMAC User Manual 14 Writing Programs for PMAC Table of Contents WRITING PROGRAMS FOR PMAC e eeeeee eese teens enses tassa thats tassa suse tasse to sens ene ta sens tn sess suse tasse ta sense en sonata snae 1 Writing A Motio
56. Manual G95 Inches Millimeters per Revolution Mode This code sets up the program so that F values feedrate are interpreted to mean length units inches or mm per spindle revolution In PMAC this requires that the time base for the coordinate system be controlled by the spindle encoder Feedrate is still interpreted as length per time but with external time base time is interpreted as proportional to input frequency and hence spindle revolutions giving an effective length per revolutions feedrate The subroutine implementing G95 must therefore cause the program to get its time base from the spindle encoder and get the constants of proportionality correct Actually some or all of these constants may be set up ahead of time This external time base function is performed through a PMAC software feature known as the Encoder Conversion Table which is documented in detail in the Feedback Features section of the manual Instructions for setting up an external time base are given in detail in Chapter 15 Synchronizing PMAC to External Events Briefly a scale factor between time and frequency must be set up in the conversion table that defines a real time input frequency RTIF The motion program then can be written as if it were always getting this frequency In our case we will take a real time spindle speed that is near or greater than our maximum For example we use 6000 rpm 100 rev sec as our real time spindle speed In real
57. NO2000 CIRCLE2 RET If feedrate override is desired and it could have been disabled in RAPID mode the subroutine should set the time base source address variable to the register containing the external information e g 119321833 14 44 Writing Programs for PMAC PMAC User Manual G04 Dwell Command This code requires the use of the READ command Different dialects of G codes have the dwell time after a P or after an X PMAC can handle either just use a READ P ora READ X as appropriate the P value would be placed in Q116 and the X value would be placed in Q124 The units of time must also be considered PMAC dwell units are in milliseconds If the G04 units are seconds the value passed must be multiplied by 1000 A typical implementation would be NO4000 READ P DWELL Q116 1000 RET G09 Exact Stop In some dialects of G code this code causes a stop between two moves so that no corner rounding blending between the moves is done In PMAC this can be implemented simply by executing a short dwell A typical implementation would be NO9000 DWELL10 RET G17 G18 G19 Select Plane These codes select the plane in which circular interpolation and cutter radius compensation will be done G17 selects the XY plane G18 selects the ZX plane and G19 selects the YZ plane In PMAC this is performed by the NORMAL command which specifies the vector normal to this plane and is not limited to these choices The standard PMAC imple
58. PLC program as a result of inputs and or calculations or even by another motion program With calculations inside the motion program we can get even more sophisticated General mathematical expressions can be built in a PMAC motion program using constants variables functions and operators see Computational Features The calculations can be done in separate program statements assigning the calculated value to a variable then using the variable in another statement Alternately the expression can be used directly in a motion specification statement in which case the value of the expression is not retained after the statement is executed 14 40 Writing Programs for PMAC PMAC User Manual Subroutines and Subprograms It is possible to create subroutines and subprograms in PMAC motion programs to create well structured modular programs with re usable subroutines The GOSUBx command in a motion program causes a jump to line label Nx of the same motion program Program execution will jump back to the command immediately following the GOSUB when a RETURN command is encountered This creates a subroutine The CALLx command in a motion program causes a jump to PROG x with a jump back to the command immediately following the CALL when a RETURN command is encountered If x is an integer the jump is to the beginning of PROG x if there is a fractional component to x the jump is to line label N y 100 000 where y is the fractional part of
59. PMAC STD these signals are brought out on connector J6 JEQU on each of the piggyback boards They are open collector sinking outputs with internal 1 kQ pull up resistors rated to 5V On PMAC STD1 5 these signals are brought out on connector J8 JEQU optically isolated from the digital circuitry referenced either to analog ground AGND or an external flag supply ground As shipped from the factory they are open collector sinking outputs with a ULN2803A driver IC rated to 24V and 100mA each They may be changed to open emitter sourcing drivers by replacing this chip in U54 with a UDN2981A driver IC and changing jumpers E101 and E102 Optically Isolated Analog Outputs JMACH Port PMAC provides high precision analog outputs on the JMACH machine connectors that are generally used to command servo amplifiers as a velocity command a torque command or phase current commands in pairs Each channel of PMAC provides complementary DAC and DAC outputs operating from 16 bit digital to analog converters Each output has a range of 10V to 10V providing a resolution of 300uV bit Connections If the amplifier has a single ended input DACn should be used as the command line and AGND as the return If the amplifier has a differential input DACn should be used as the command line and DACn as the return The common of the amplifier input should still be tied to the PMAC AGND in this case 6 8 Input Output Connecting PMAC to the Ma
60. PMAC User Manual TALKING TO PMAC Basic Aspects Of Communicating With PMAC This section covers basic aspects of communicating with PMAC from a host computer At this level there is a program for the host computer that processes these communications The PMAC Executive Program Accessory 9D is the most common of these programs If there will be a host computer in the final application communications routines must be written for the host computer as part of the front end software for the application That is a more advanced topic and it is covered in the Writing a Host Communications Program section of this manual This section concentrates on the actual communications At a basic level PMAC can communicate to a host dumb terminal either over the serial RS 422 or the parallel bus interface The communications mostly consists of lines of ASCII characters sent back and forth Of course most of the time the host will be a computer with considerably more intelligence but at root it will talk to the card as if it were a terminal The PMAC Executive PC program has a terminal emulator mode to do this directly Communications Ports Each version of PMAC can communicate either over its serial port or its parallel bus port The main difference between the different hardware versions of PMAC is the type of bus interface PC STD or VME Note It is important not to command PMAC simultaneously from both ports the characters can
61. S 1 e g M60 gt L 1400 Next define a second M variable to point to the lowest twelve bits of the first M variable s definition word which is in Y register BC3C e g M70 gt Y BC3C 0 12 defines M70 to the low 12 bits of the definition word for M60 To point to the definition word for MO use Y register BC00 for M1 Y BCO1 for M50 Y BC32 32 hex is 50 decimal and for M1023 Y BFFF Now by giving a value to the second M variable it changes which Q variable the first M variable points to In the example the command M70 1024 17 makes M60 point to variable Q17 of C S 1 Q Pointer Offsets Note the offset of 1024 for C S 1 each coordinate system has its own required offset to make the value in the M variable definition match the Q variable number for that coordinate system The offsets are C S 1 1024 C S 5 1152 C S 2 1536 C S 6 1664 C S 3 1280 C S 7 1408 C S 4 1792 C S 8 1920 Once the first M variable has been pointed to a particular Q variable giving a value to this M variable writes that value into the addressed P variable Continuing our example the command M60 3 14 writes a value of 3 14 to Q17 of C S 1 Example To create a table of square roots of values from 0 0 to 9 9 in Q variables QO to Q99 of C S 2 use the following program segment which assumes the use of M60 and M70 as set up above 010020 WHILE Q100 lt 100 M70 1536 0100 M60 SQRT Q100 10 Starting value for array index Loop until done P
62. The Mailbox Registers Communicating with PMAC over the VME bus is different than talking over the RS232 422 port When reading and writing to PMAC VME over the VME bus make use of the 16 mailbox registers Mailbox registers are simply a set of 16 8 bit registers which are addressable from the VME bus beginning at the base address of the PMAC VME card plus 1 That is if a PMAC base address of 7FAO000 is selected the first mailbox register mailbox register 0 can be accessed at location 7FA001 The second mailbox register mailbox register 1 is located 7FA003 the third at 7FAO005 and so on up to 7FAOIF for the 16th mailbox register mailbox register 15 The mailbox registers are located at odd addresses beginning with the base address plus one of PMAC Writing a Host Communications Program 17 17 PMAC User Manual Note Almost all PMAC VME users purchase the Option 2 DPRAM and use the ASCII communications feature of the DPRAM rather than the ASCII mailbox communications described in this section The ASCII DPRAM communications is easier and faster Refer to PMAC Option 2 Dual Ported RAM User manual for details Sending Commands to PMAC VME Through Mailbox Registers When sending commands to PMAC write to these mailbox registers This is relatively straightforward although two rules must be followed 1 Never write to mailbox register 1 this would be location 7FA003 in the example above when sending commands to
63. The PMAC Executive program editor as part of its Upload function appends these commands to the returned program The advisable format to use when working in a text editor is A CLOSE DELETE GATHER OPEN PROG n CLEAR program statements CLOSE Writing Programs for PMAC 14 37 PMAC User Manual After the program has been downloaded and the buffer closed a coordinate system that is to execute this program must be pointed to the program with the B command For example B6 would point the addressed coordinate system s program counter to the beginning of motion program 6 This can be confirmed with the PC program counter query command which should return P6 0 if it is pointing to the top of program 6 If it returns a BELL character it is not pointing to any valid program Once the coordinate system is pointing to the top of the program execution can be started with the R command The B and the R commands can be combined into one command line such as B6R Learning a Motion Program It is possible to have PMAC learn lines of a motion program using the on line LEARN command In this operation the axes are moved to the desired position and the command is given to PMAC PMAC then adds a command line to the open motion program buffer that represents this position This process can be repeated to learn a series of points The motors can be open loop or closed loop as they are moved around At the time of the LEARN command
64. These routines are to be written in Motorola 56000 assembly language code usually on a PC or compatible and cross assembled for the 56000 Delta Tau provides the information about where to pick up the needed information where to leave the output commands and where to store the algorithm itself Note This is not a task for the inexperienced user To attempt this the user should be well acquainted with both servo theory and assembly language coding What is Needed to Write the Filter The user written filter will be written on host computer using a cross assembler Motorola provides 56000 cross assembler programs for IBM PC and compatibles SSP56000CLASa Macintosh II SSP56000CLASb Sun 3 workstations SSP56000CLASc and DEC VAX computers SSP56000CLASd Almost all will work on the IBM PC because the file will have to be converted to DOS format anyway Typically the routine will be written using a simple screen editor then converted to 56000 machine code with the cross assembler The machine code file should have the DOS suffix LOD for the steps below Download and Enable Procedure Step 1 Assemble the user written filter into a DOS file with an LOD suffix Step 2 Execute the IBM PC conversion program CODE EXE that is provided by Delta Tau to convert the machine code file into a format acceptable by PMAC Do this by typing at the DOS prompt CODE filename ENTER 9 10 Closing the Servo Loop PMAC User Manual
65. This is not recommended and should only be done for low power systems To power the flags from the bus 12V supply as well Jumper E90 must be moved to connect Pins 2 and 3 so the 12V can pull up the limit switch and other optically isolated inputs Re initialization Jumper If the card powers up or resets with jumper E51 in its default state OFF for PMAC PC Lite and VME ON for PMAC STD PMAC will go through its normal reset cycle utilizing the setup parameters such as I variables that were previously saved in EAROM Standard and Option 5 PMACs If a PMAC with the Standard or Option 5 CPU powers up or resets with E51 in the non default state ON for PMAC PC Lite and VME OFF for PMAC STD PMAC will re initialize as it resets utilizing the factory default parameters Usually this setting will be used only if the card software and parameters are so confused that even basic communications is impossible For startup make sure this jumper is in its default state PMAC with Options 4A 5A and 5B If the jumper E51 is ON when a PMAC with the Option CPU executes its reset cycle PMAC enters a special re initialization mode that permits the downloading of new firmware In this mode the PMAC can communicate over the serial port only at a baud rate of 38 400 regardless of the setting of the baud rate jumpers Bus communications is also possible on PMAC with bootstrap version 1 01 and newer most PMAC have one of these versions To verify
66. To utilize this feature access the position compare register itself and several status and control bits For Encoder 1 declare M103 gt X C003 0 24 S 24 bit position compare register M111 gt X C000 11 1 Compare flag latch control bit M112 gt X C000 12 1 Compare output enable bit M113 gt X C000 13 1 Compare output invert control bit M116 gt X C000 16 1 Compare equals flag Preloading the Compare Position To preload a compare position simply assign a value to M103 such as M103 1250 This value can be between 8 388 608 and 48 388 607 To obtain the position capture register read from the same address The command can be given from a PMAC motion program a PMAC PLC program or from the host This is the encoder position to reference it to motor zero position the homing offset must be know Synchronizing PMAC to External Events 15 15 PMAC User Manual Compare Control Bits There are three control bits to set up the format of the equals signals The flag latch control bit M111 in our example controls whether the compare equal signal is transparent true only when the positions are actually equal or latched true until actively reset The signal is transparent if this control bit is zero and latched if the control bit is one To clear a latched flag take the control bit to zero then back to one This compare equal signal is always copied into the compare equal flag M116 in our example that i
67. Values Once confirmed that the proper phasing can be reached with the command save the parameters into permanent memory with the SAVE command and do a full card reset with the command If Ix80 was saved as 1 the motor should be enabled and in closed loop position control immediately after the reset although if the servo loop has not been tuned it may not be very stiff Regardless good response should be received from open loop commands If Ix80 was saved as 0 the absolute phase position will have been done during the reset but the motor will be left in the disabled killed state It can be enabled with either open loop or jog commands A command will also enable the motor closed loop doing another absolute position read in the process If the motor performs open loop commands well in both directions at this point the commutation setup is finished and the motor is ready for servo loop tuning Phasing Referenced to Hall Effect Sensor PMAC can use hall effect commutation sensors or their equivalent for an approximate phase referencing on power up This phase referencing is good to 30 of the commutation cycle which is enough to get reasonable torque and reasonable smoothness without any phasing search The final phase reference can then be done when the index pulse is found Usually the index pulse is part of the home position trigger so after the homing search move is done the phase position is adjusted based on a measurement
68. XT 3 or 4 for a 286 based computer 5 to 6 for a 386 based computer and 7 to 9 for a 486 based computer Sending a Character In polled communications the host must see two status bits write ready bits in the serial interface registers become one before it may write a character to the serial output port These two bits are Bit 5 of base 5 and Bit 4 of Base 6 A sample C code segment to do this is i 0 Reset counter while i timeout amp amp inportb combase 5 amp 32 0 Loop until bit true while i lt timeout amp amp inportb combase 6 amp 16 0 Loop until bit true if i lt timeout outportb combase outchar Send character unless timed out Sending an entire line simply involves repeated calls to this routine with a different outchar each time 17 2 Writing a Host Communications Program PMAC User Manual Reading a Character To read a character from the serial port the host must prepare the port to read it may want to do this for an entire line then poll a status bit read ready bit in a serial interface register when this becomes one the character may be read A sample C code segment to do this is i 0 Reset counter outportb combase 4 2 Set port for input while i lt timeout amp amp inportb combase 5 0 Loop until bit true if i lt timeout inchar inportb combase Get char unless timed out disable Disable interrupt
69. a 2D table and the value before the decimal point specifies the number of columns or points for the first source motor the value after the decimal point specifies the number of rows or points for the second source motor In operation PMAC computes the compensation for a given location in the plane of the two source motors as the weighted average of the four specified compensation values surrounding that location Refer to the description of the 2D DEFINE COMP command in the PMAC amp PMAC2 Software Reference Manual 3A0 602705 363 for details 7 30 Setting Up a Motor PMAC User Manual 2D Planar Compensation Tables Az f x y DEFINE COMP 20 15 1 2 3 20000 15000 Table colla Table rows 1st source motor 2nd source motor Target motor 1st motor span in counts 2nd motor span in counts Figure 13 PMAC Compensation Tables S1 L1 N k L1 S2 L2 M St MN C SOURCE 1 POSITION ROWS SHOULD MATCH COLUMNS SHOULD MATCH Chien MN M 1 MN M 2 MN M N 1 MN M N SOURCE 2 POSITION Figure 14 Two Dimensional Compensation Table Setting Up a Motor 7 31 PMAC User Manual Backlash Compensation PMAC can perform sophisticated backlash compensation for all motors On reversal of the direction of the commanded velocity a pre programmed backlash distance is added to or subtracted from the commanded position This backlash distance can be constant over
70. a move command At this point PMAC invokes the double jump back rule and lets the last programmed move come to a stop It does this to prevent the possibility that it might be caught in an indefinitely true set of loops with no movement which could mean that it would not have the next move equations ready in time It resumes calculations when this move has finished and will start up the next sequence of moves in the inner loop To blend all of these moves together continuously pull the last move of the inner loop outside of the inner loop This way two ENDWHILE statements will never be encountered between move commands SPLINE1 TA20 P1 0 WHILE P1 lt 10 P2 0 WHILE P2 359 Note that loop 14 56 Writing Programs for PMAC PMAC User Manual Stops earlier X Pl SIN P2 P2 P2 1 ENDWHILE X P1 SIN P2 Last move from inner loop P1 P1 1 ENDWHILE Looping to Wait There are several methods for holding program execution while waiting for a certain condition to occur Usually this is done with a WHILE loop but what is done inside the loop has an effect on responsiveness and calculation load The fastest execution is the WHILE condition WAIT loop As soon as the WAIT command is encountered motion program calculations are suspended until the next real time interrupt at which time they will re evaluate the condition The motion program effectively becomes like a one line PLC program If the next RTI has already occu
71. a phasing search so 1173 and 1174 are irrelevant For Motors Not Commutated By PMAC If PMAC is not performing the commutation for the motor set Ix01 to 0 so that the commutation routines are disabled and only one analog output is used In the example using motor 1 set 1101 to 0 This is the default DAC Output Address If not commutating from PMAC Ix02 must be set to the register address of the single analog output used to command the amplifier Define the output register address for motor 1 using 1102 In order to send the motor 1 output command to the DACI pin connected set 1102 address C003 49155 decimal This is the default value If the amplifier is expecting sign and magnitude input set 1102 to 1C003 instead For All Types of Motors Regardless of whether PMAC is commutating the motor or not several variable values must be established to tell PMAC where to get its servo loop information Position Loop Load Feedback Address Variable Ix03 defines the register to be used for the position loop servo feedback Typically this reads a processed encoder value from what is known as the encoder conversion table To have motor 1 read the processed input from Encoder 1 1103 must be set to 1824 720 This should be the value preset at the factory 2 10 Getting Started with PMAC PMAC User Manual Velocity Loop Motor Feedback Address It is possible to have separate motor and load feedback encoders this can allow good cont
72. adding integral gain check the integration limit parameter 1163 If this is low 100 000 or less it will limit what integral gain can do If this is the problem set this parameter to its default value by typing 1163 lt CR gt Power Up Mode For future power up reset cycles set 1180 so power up is done in the mode wanted If 1180 is zero Motor 1 will power up killed OV output AENA signal false It will not attempt to control until a servo command is given usually J A or CTRL A for a non PMAC commutated motor or a command for a PMAC commutated motor This I variable must be stored in non volatile memory with the SAVE command to be effective at the next power up reset cycle Homing Search Move To do a homing search move first check the position capture I variables I902 and 1903 in the example Make sure they are set up to capture the position where the home position should be With a bare motor only use the third channel of the encoder Set I902 to 1 to force a capture on the rising edge of the third channel Next set the homing speed with 1123 in units of counts millisecond Changing the sign of I123 changes the direction of the homing move Homing accel decel is controlled by 1120 and 1121 which also affect jog moves Now command a homing move with the HM command and the motor will move as specified until the proper signal edges is found then decelerate to a stop and come back to the position of the trigger plus o
73. an axis moves toward the target position at a designated speed accelerating to and decelerating from this speed in a controlled fashion If more than one move is specified in succession with no pause in between the first move will blend into the second with the same type of controlled acceleration as is done to and from a stop Linear blended move mode is the default mode for motion programs If in another move mode the program can be put into this mode with the LINEAR statement The program can be taken out of LINEAR mode with another move mode statement e g CIRCLE1 CIRCLE2 RAPID PVT SPLINE It is good programming practice to declare the LINEAR mode in each program and not rely on the default The LINEAR statement is equivalent to the RS 274 G Code G01 Acceleration Parameters The acceleration to and from velocity can be constant providing trapezoidal velocity profiles it can be linearly varying and yielding S curve velocity profiles or it can be a combination of the two Specify the time for the full acceleration TA default parameter is coordinate system I variable Ix87 and the time in each half of the S TS default parameter Ix88 If the specified TA time is less than twice the specified TS time the TA time used will be twice TS to get pure S curve acceleration set TA to 0 PMAC can only use integer values for TA and TS If a non integer value is specified PMAC will round it to the nearest integer before using it in tr
74. and PMAC STD motion control cards have the capability of interrupting the host PC for any of a number of reasons This capability can give additional speed power and flexibility in the system but using interrupts properly is one of the more demanding programming tasks on a PC It requires substantial programming experience and a lot of patience Once done the rewards can be substantial in increasing the efficiency of the system These PMACs have an on board Intel 8259 Programmable Interrupt Controller IC PIC This IC has eight inputs that can cause it to send an interrupt signal to the PC With a combination of hardware and software what signals if any can be selected that will cause an interrupt to the PC What Signals Can Be Used The eight inputs to the PIC are labeled IRO to IR7 IRO has the highest priority IR7 the lowest The PMAC design brings a variety of different signals into these inputs on some of the inputs what signal is brought to the input is chosen with jumpers 17 4 Writing a Host Communications Program PMAC User Manual The following table shows which signals match to each input on the PMAC PC and PMAC Lite Those signals marked with an asterisk are not available on the PMAC Lite IPOS is the coordinate system in position signal If the control panel is enabled 12 0 it reflects the panel selected coordinate system by FDPn lines If the control panel is disabled 12 1 it reflects the host addressed
75. application The PMAC was shipped with jumpers configured for the needs of a typical user so it can be started initially without changing any jumpers However we will check a few jumpers here to make sure they are correct before we start In the Hardware Reference manual for the version of the board is a map of the jumper locations and a detailed description of each jumper s function Check the jumpers according to the instructions and refer to the map For more detailed instructions on changing any setting than what is given below refer to the detailed jumper descriptions Card Number Jumpers The PMAC was preset in the factory at card number software address O by the jumper configuration of E40 E43 on the PMAC PC Lite and VME which should all be ON for the PMAC STD this 1s controlled by DIP switches SW1 1 to SW1 4 which should all be OFF The card number is important for two reasons First if several cards are daisy chained together on the serial interface it is the software addressing that determines which card should send data and receive commands Second card O creates its own servo clock signal all the other cards receive the servo clock signal from the outside as a synchronizing signal If they do not receive it they will shut down Each set of synchronized PMAC cards must have one and only one card 0 For the initial setup with PMAC it is advised that the card be set at software address O If this must be changed refer t
76. be intermixed and the commands garbled Active Response Port Either the serial port or the bus port is the active response port where PMAC will send its responses to the commands PMAC powers up resets with the serial port as the active response port However any command received over the bus port makes the bus port the active response port this happens immediately in most bus host applications so is transparent to the user Further responses are returned to the bus port A subsequent command from the serial port does not automatically make the serial port the active response port again so it is possible that PMAC will respond to a command over the serial port by sending data to the bus port This will probably confuse both host computers To make the serial port the active response port again you must send a CTRL Z character to PMAC Caution If using a bus based system with an auxiliary computer over the serial port to do some diagnostic work such as data gathering or tuning with the PMAC Executive Program it is important to stop bus communications Serial Interface The hardware configuration for the PMAC serial interface port is slightly different on different versions of PMAC Talking to PMAC 4 1 PMAC User Manual Hardware Configuration PMAC PC VME PMAC PC and VME have an RS 422 interface on a 26 pin IDC connector J4 This port connects directly to a standard DB 25 connector on a host computer with a st
77. bit hardware counter is software extended to over 36 bits 64 billion counts A software parameter Ix27 allows position rollover at a user specified value this is especially useful for rotary axes Any unused encoder counter in a DSPGATE IC may be utilized as a hardware timer refer to 1900 description 1 T Sub count Interpolation There are two optional methods on PMAC for achieving sub count resolution with incremental feedback The first is called 1 T decoding Each encoder channel has two timer registers associated with it The first register holds the time between the last two encoder transitions Velocity is estimated as being inversely proportional to this time a very accurate estimation particularly at low speeds The second timer holds the time since the last transition Fractional distance traveled since the last transition is estimated as the value of the second timer divided by the value of the first timer see figure 7 3 This interpolation provides added smoothness to low speed moves but it does not provide accurate interpolation at rest 1 T decoding requires the 00 conversion format see below Parallel Sub count Interpolation The second method of interpolation allows PMAC to read up to five bits of parallel fractional information to supplement the integer quadrature count Usually this information is derived from analog sine cosine quadrature signals of encoders or interferometers through analog to digital converter circ
78. brushless motor for these purposes the sensor should be treated as an incremental sensor See Phasing Referenced to Absolute Sensor in the Commutation section of this manual and the descriptions of Ix75 and Ix81 for information on power on phasing If power on absolute position of a system is desired without any rollover of the position the rollover point s of the absolute sensor must be outside the range of travel If treating the absolute position information as an unsigned quantity the rollover points are the zero positions of the sensor If treating the absolute position information as a signed quantity the rollover points are half way in between the zero positions Each Motor x on PMAC has the variables Ix10 I9x and I8x to support the absolute power up position read Ix10 specifies the register address in PMAC of the absolute sensor and the method for reading it 19x and I8x are used to specify second and third resolvers if a geared resolver system is used to determine power on position 7 10 Setting Up a Motor PMAC User Manual Parallel Data Position Ix10 can specify two types of feedback If the absolute position data is presented to PMAC as a parallel word usually through an ACC 14 I O board then the address specified in the low 16 bits of Ix10 is the address of the Y PMAC register that holds this data e g SFFD1 The high eight bits of Ix10 specify the number of bits to use at this register and potentially the nex
79. changes these names into PMAC legal variable names during the download process Computational Features 13 5 PMAC User Manual I Variables I Variables initialization or setup variables determine the personality of the card for a given application They are at fixed locations in memory and have pre defined meanings Most are integer values and their range varies depending on the particular variable There are 1024 I variables from IO to 11023 and they are organized as follows 10 I79 General card setup I80 I99 Geared Resolver setup I185 1199 Coordinate System 1 setup 1200 1284 Motor 2 setup 1285 1299 Coordinate System 2 setup 1800 1884 Motor 8 setup 1885 1899 Coordinate System 8 setup 1900 1979 Encoder 1 16 setup 1980 11023 Reserved for future use Value Assignment Values assigned to an I variable may be either a constant or an expression The commands to do this are on line immediate if no buffer is open when sent or buffered program commands if a buffer is open Examples 1120 45 1120 I1204P25 3 Limited Range For I variables with limited range an attempt to assign an out of range value does not cause an error The value is rolled over automatically to within the range by modulo arithmetic truncation For example I3 has a range of 0 to 3 four possible values The command 13 25 would actually assign a value of 5 modulo 4 1 to the variable Power Down Sto
80. command input on the amplifier Connect the amplifier s command signal return line to PMAC AGND line pin 58 In this setup leave the DACI pin floating Do not ground it Differential Command Signal For a differential command using PMAC channel 1 connect DAC1 pin 43 to the plus command input on the amplifier Connect DACI pin 45 to the minus command input on the amplifier PMAC AGND should still be connected to the amplifier common Sign and Magnitude Command Signal If the amplifier is expecting separate sign and magnitude signals connect DACI pin 43 to the magnitude input Connect AENAT DIRI pin 47 to the sign direction input Amplifier signal returns should be connected to AGND pin 58 This format requires some parameter changes on PMAC refer to variable Ix02 and Ix25 below Jumper E17 controls the polarity of the direction output this may have to be changed during the polarity test Motor Commutated by PMAC If using PMAC to commutate the motor use two analog output channels for the motor Each output may be single ended or differential just as for the DC motor The two channels must be consecutively numbered with the lower numbered channel having an odd number e g use DAC1 and DAC2 for a motor or DAC3 and DACA but not DAC2 and DAC3 or DAC2 and DACA For motor 1 example connect DAC1 pin 43 and DAC2 pin 45 to the analog inputs of the amplifier Do not worry about the phasing polarity yet it will be checked l
81. controller s derivative gain Sinusoidal Input Amplifiers A relatively new type of amplifier for brushless motors both permanent magnet and induction that does not do the commutation itself relying on a controller such as PMAC to do it expects two analog phase current commands from the controller At a constant velocity and load these commands will be sinusoidal waveforms so these amplifiers are sometimes called sinusoidal input amplifiers The amplifier still closes current loops on these phases and it generates the third and fourth phase commands if necessary through simple balance loops To the PMAC servo loop this type of amplifier looks like a torque mode amplifier the magnitude of the sinusoids is proportional to the torque command The servo algorithm produces a single torque command however instead of writing this command value directly to an analog output PMAC processes it through the commutation algorithm to produce two analog outputs There are several advantages to this type of amplifier First it permits use of the PMAC high performance commutation algorithms which often provide superior performance to amplifier commutation Second for synchronous motors permanent magnet and switched reluctance it allows the use of less expensive incremental position sensors because of the PMAC power on phasing search capabilities Third it reduces wiring because only the controller needs position feedback not the amplifier C
82. data from Encoder x e g Motor 3 uses Encoder 3 by default Dual Feedback Systems In most systems this register is the same register that is used for closing the position loop which means that Ix03 equals Ix04 However the concept of dual feedback is becoming increasingly popular in motion systems today In such a system there are position sensors on both the motor and the load 7 2 Setting Up a Motor PMAC User Manual CP FE PI LOW 16 BITS 4 HEX DIGITS SPECIFY THE ADDRESS WHEN HIGH 8 BITS ARE ZERO ADDRESS IS USED IN NORMAL MODE I9 2 OR 3 PMAC REPORTS VARIABLE VALUE IN HEX MODES ADDRESS Peet SR e mo ux 01C 00 3 BINARY 00 0000011100000 00000 0011 Figure 5 Address I Variables Ix02 DAC output address Ix03 POSITION loop feedback address Ix04 VELOCITY loop feedback address S N DAC Locations 1x02 AP e cv lea DACn AMP 4 e DACn 1 D e tM n Y C002 C03B LOAD AV ENC MOT Encoder Table a LIN ENC 1x04 e e m ENCn e e ENCn 1 X 0720 0739 1x03 Figure 5 PMAC Pulse and Direction Output Setting Up a Motor 7 3 PMAC User Manual Accuracy vs Stability A sensor on the load often a linear sca
83. description section for the functions of individual variables 13 6 Computational Features PMAC User Manual 0000 00FF 0100 17FF 1800 BBFF BC00 BFFF C000 CO3F D000 X Memory 23 1615 87 0 23 Y Memory 1615 8 7 Fixed Use Calculation Registers User Buffer Storage Space User Written Servo Storage DFFF E000 F000 FFFF VME Setup Registers M Variable Definitions M ailbox Reg isters Figure 25 PMAC Memory Mapping Internal DSP Memory External Static RAM Battery Backed DSP Gate Registers Dual Ported RAM VME bus registers 1 0 Registers Computational Features 13 7 PMAC User Manual P Variables P variables are general purpose user variables They are 48 bit floating point variables at fixed locations in the PMAC memory but with no pre defined use There are 1024 P variables from PO to P1023 A given P variable means the same thing from any context within the card all coordinate systems have access to all P variables contrast Q variables which are coupled to a given coordinate system This allows for useful information passing between different coordinate systems P variables can be used in programs for any purpose desired positions distances velocities times modes angles intermediate calculations etc Array Capabilities Array Reading It is possible to use a set of P variables as an array To do this when reading fro
84. essentially the same as for linear blended program moves The differences are that the move parameters must be specified by I variables and that the moves themselves are started by on line commands not by motion programs These moves are specified directly to the motor specified by number rather than the axis specified by letter The moves are described in unscaled units all based on counts and milliseconds Jogging Move Control Jog Acceleration Jog home acceleration time is specified by Ix20 for motor x and the S curve time by Ix21 If Ix20 is less than two times Ix21 the acceleration time used will be twice Ix21 The acceleration limit for jog home moves is set by Ix19 in counts msec2 If Ix20 and Ix21 are so small that Ix19 would be exceeded Ix19 controls the acceleration time without changing the profile shape To always specify the acceleration by rate instead of time simply set the acceleration time parameters small enough that the limiting acceleration rate parameter is always used To specify the acceleration by rate do not set both acceleration time parameters Ix20 and Ix21 to zero This will cause a division by zero error in the move calculations that could cause erratic movement The minimum acceleration time setting should be Ix20 1 and Ix21 0 Jog Speed Jogging speed is specified by Ix22 which is a magnitude of the velocity in counts per millisecond Direction is specified by the jog command itself Jog Command
85. for other motors it is also useful to test quickly whether the required performance can be obtained on all motors with a slower servo update in addition it can be used slow the update rate below 1 kHz However it is generally more efficient to slow down the update rate for all motors using the jumpers Reasons to Increase Rate How fast should the servo loops be updated in the system For most applications the default setting of a 442 usec update can be retained There are two basic reasons to change this time First if not getting the dynamic performance required speed up the servo update rate decrease the update time In most systems a faster update rate means that a stiffer and more responsive loop can be closed resulting in smaller errors and lags Reasons to Decrease Rate Second if the routines of lower priority than the servo loop are not executing fast enough consider slowing down the servo update rate increasing the update time The system may be updating faster than is required for the dynamic performance needed If so processor time is being wasted on needless extra updates For example doubling the servo update time from 442 usec to 885 usec virtually doubles the time available for motion and PLC program execution allowing much faster motion block rates and PLC scan rates There are some systems that get better performance with a slower servo update rate Generally these are systems with relatively low encoder resolut
86. for that encoder This must be used for homing moves It can also be used for other purposes It specifies an edge of the encoder third channel the edge of one of the encoder flags or the edge of a logically combined signal from both If it uses a flag also set the next variable The default value for this variable is 1 specifying the rising edge of the third channel 1903 1908 1913 etc Encoder flag select control This controls which of the encoder flags is used to trigger a position capture if the previous I variable has specified that a flag be to be used This is almost always set to O to specify the home flag HMFL n Motor I variables PMAC can be attached to up to eight motors called 1 to 8 A motor is defined in PMAC by setting up I variables that tell the I O addresses of the input and output data where to look for the feedback position and where to send the output command The I variables for motor 1 are in the 100s 1100 1184 for motor 2 in the 200s and so on to the 800s for motor 8 As a shorthand to refer to a particular variable independent of a particular motor the hundreds digit is replaced with the letter x For instance Ix20 refers to I120 for motor 1 or I220 for motor 2 and so on In this example set up motor 1 In preparation disable motor 1 by cutting power to the amplifier Motor Activation The first thing to do in the software setup of a motor is to activate the software algorithms for the m
87. has been pressed to escape the Found Not Found window the program should be in terminal emulation mode so that the PC is acting as a dumb terminal to PMAC Check to see if a response is received by typing 110 CR lt CR gt means carriage return the Enter or Return key PMAC should respond with a six or seven digit number Now type III CR PMAC should respond with a beep signifying an unrecognized command and the error code ERROO3 if the I variable I6 is set to its default value of three For more information on the error codes refer to the explanation of I Variable I6 in PMAC and PMAC2 Software Reference Manual 3A0 602705 363 Next if satisfied that communications with the card is at a basic level type a P CR case does not matter This command requests a position PMAC should respond with a number probably a 0 Now type a CONTROL F Eight numbers one for each axis should appear since CONTROL F requests following error from all eight motors some or all may be 0 Note Even with encoder counts as read out no scaling PMAC position is displayed with fractional counts Connecting PMAC to the System Once the basic operation of the card and the host communications have been established it is time to connect PMAC to the amplifier motor and feedback device Of course most PMAC systems will have more than one motor attached The process described here can be repeated for multiple motors As our example here
88. incremental encoder counters are set to zero during the reset cycle At the end of the reset cycle all activated motors that have Ix80 set to 1 are enabled with the commanded position set to the actual position Other motors are left in the killed state these require a command to enable them at a future time PMAC Re initialization Actions Standard CPU If Jumper E51 is in its non default state on a PMAC with the standard CPU section ON for PMAC PC Lite and VME OFF for PMAC STD PMAC performs a re initialization during the reset cycle Instead of copying saved values of parameters from EEPROM into active memory it copies the factory default values from the firmware PROM into active memory Talking to PMAC 4 11 PMAC User Manual Typically this re initialization procedure is necessary only if the card has been locked up due to errant software or parameter settings and communications are impossible to establish The most common instances of this type are PLC programs with accidentally repeating SEND or CMD statements try sending a CTRL D before re initializing or a fast servo time with too many motors activated PMAC Re initialization Actions Flash CPU If the jumper E51 is ON when a PMAC with the Flash CPU executes its reset cycle PMAC enters a special re initialization mode that permits the downloading of new firmware In this mode the PMAC can communicate only over the PC STD bus port or over the serial port at a bau
89. input frequency that can be accepted without saturation is 32 2 25 72 cts msec If the system could operate to 100 cts msec the choice of RTIF 32 cts msec would not be acceptable but a choice of RTIF 64 cts msec would be acceptable 100 64 1 5625 lt 2 25 A choice of RTIF greater than the maximum input frequency is always acceptable e If PVT or SPLINE mode moves are used the segment times at the RTIF must be an integer number of milliseconds This means that the RTIF must be chosen so that the total cycle time at the RTIF is an integer number of milliseconds e Sometimes this will not be possible unless the resolution of the master encoder is a power of 2 For this reason it is suggested that the master encoder resolution be selected as a power of 2 e g 1024 lines rev instead of 1000 lines rev e For example with a 1000 line rev encoder 4000 cts rev on a spindle motor an RTIF of 200 cts msec corresponds to a speed of 50 revs sec 3000 rpm or exactly 20 msec rev However it yields a TBSF of 655 36 which is not an integer e With this encoder an RTIF that yields an integer TBSF 256 cts msec yields 512 or 204 8 cts msec yields 640 corresponds to a cycle time that is not an integer e However with a 1024 line rev encoder 4096 cts rev an RTIF of 204 8 cts msec corresponds to a speed of 50 rps 3000 rpm for a revolution time of 20 msec and it yields a time base scale factor of exactly 640 In this case the time base functi
90. is the voice coil motor The important question here is whether or not PMAC does the commutation If the commutation is done inside the motor as in brush motors or in the amplifier PMAC does not need to do the commutation and Ix01 must be set to O If this is the case only one analog output is required for the motor and it does not matter what the settings of the commutation I variables Ix70 Ix83 are If PMAC is to perform the commutation for the motor Ix01 must be set to 1 In this case two analog outputs are required for the motor and Ix70 Ix83 must be set up to commutate the motor properly Refer to the Setting Up PMAC Commutation section in this manual Address l Variables Each motor has several address I variables These pointer variables contain the address in the PMAC memory and I O space of a register where PMAC will read or write data automatically These variables include Ix02 Ix03 Ix04 Ix05 Ix10 Ix25 Ix81 and Ix83 Because PMAC has a 16 bit address bus it takes 16 bits four hexadecimal digits to specify an address However the address I variables are 24 bit values and the upper eight bits can be used to specify alternate modes for using the designated register If all of the upper bits are zero the register is used in the default fashion Refer to the individual I variable descriptions in the PMAC amp PMAC2 Software Reference Manual for details on the alternate usage modes for each of these I variables Settin
91. is utilizing it This allows several coordinate systems to use the same program for instance containing the line X Q1 25 Y Q2 but to do have different values in their own Q variables which in this case means different destination points Allotting Q Variables There are a total of 1024 Q variables If you are only using a single coordinate system Coord Sys 1 specified as amp 1 you may use all of these Q0 to Q1023 The Q variables of Coordinate System 2 amp 2 overlap these QO of amp 2 is the same thing as Q512 of amp 1 and Q511 of amp 2 is the same thing as Q1023 of amp 1 The Q buffer is actually rotary so Q512 of amp 2 is the same thing as QO of amp 1 and Q1023 of amp 2 is Q511 of amp 1 Thus both coordinate systems have 512 unique Q variables QO to Q511 There is no protection against overwriting another coordinate system s Q variables It is the user s responsibility to keep Q numbers within the proper range Coordinate System 3 s QO is the same thing as the Q256 of amp 1 Coordinate System 4 s QO is the same thing as Q256 of amp 2 and as Q768 of amp 1 QO of amp 5 is equivalent to Q128 of amp 1 QO of amp 6 is equivalent to Q128 of amp 2 and to Q640 of amp 1 QO of amp 7 is equivalent to Q128 of amp 3 and to Q384 of amp 1 QO of amp 8 is equivalent to Q128 of amp 4 and to Q896 of amp 1 See the table below for clarification The bold numbers denote the sequentially numbered Q variables that can
92. issued simultaneously Serial Communications However if serial communication is being used RS 232 or RS 422 the daisychaining of PMAC does not permit separate hardware addressing so there must be a software addressing scheme PMAC cards equipped with PROM version 1 13 and higher are capable of daisychained communication using the RS 422 port PMAC Lites and PMAC STDs cannot use daisychained communication with the RS 232 port the RS 422 port is required Option 9L for PMAC Lite Up to 16 PMAC cards can be connected and synchronized using serial port communications To do this however a few hardware and software set up procedures must be followed Connections When using serial communications to multiple PMACs from a single host serial port the connection is made through a single multi drop daisy chained cable At one end is the connector for the host computer usually a DB 25 connector At the other end of the cable is one connector drop for each PMAC on the chain Each strand of the cable is brought out on the same pin of each connector Talking to PMAC 4 7 PMAC User Manual Multi Drop Cable The PMAC STD has both a RS 232 port and a RS 422 port If daisy chaining is desired the RS 422 port must be used Delta Tau does not provide this cable The ACC 3D cable provides serial connection to the RS 422 port of a single PMAC PC or PMAC VME and each ACC 3E ordered with it provides an extra drop for an additional PMAC PC or PMAC V
93. lt Max_change Out n Out n 1 Max_change In Out and K are all signed 24 bit numbers range 8 388 608 to 8 388 607 The difference In n Out n 1 is truncated to 24 bits to handle rollover properly 23 The time constant of the filter in servo cycles is 2 K The lower the value of K the longer the time constant No shifting action is performed Any operations such as 1 T interpolation should have been done on the data already so the source register for this filter is typically the result register of the previous operation The output value of the exponential filter is placed in the X register of the third line of the conversion table entry An operation that uses this value should address this third register for example Ix05 for position following or the source address for a time base conversion table entry to keep position lock in time base this filter must be executed before the time base differentiation not afterward 7 24 Setting Up a Motor PMAC User Manual Entry Format Exponential Conversion X Words Y Words 1 Intermediate data 1 Source and process Bits 0 15 X address of source usually a converted position register Bits 16 23 D0 2 Intermediate data 2 Maximum permitted change in output value expressed in LSBs per servo cycle 3 Filtered result unshifted from source 3 Exponential filter gain K where filter equation register data is Out n Out n 1 K 223 In n Ou
94. lt CR gt could lead to contention as both cards try to send position data neither card starts to process the command until it sees the CR character Talking to PMAC 4 9 PMAC User Manual Power Up State With the cards set up for daisy chained communications i e I1 2 or 3 saved in EAROM card QO comes out of the power up reset cycle as the addressed card ready to respond to commands all other cards come out of the power up reset cycle not addressed so they will ignore alphanumeric commands until they are addressed Control Character Commands Control character commands that do not require a data response are always addressed to all cards on the chain The commands in this class are lt CTRL A gt Abort all programs and moves lt CTRL D gt Disable all PLC programs lt CTRL I gt Repeat last command line tab lt CTRL K gt Kill all motors CTRL M Feed hold all coordinate systems CTRL Q Quit all motion programs CTRL R Run all coordinate systems lt CTRL S gt Step all coordinate systems CTRL W Take command line from bus port dual ported RAM lt CTRL X gt Erase command and response queues lt CTRL Z gt Make serial port the active response port CTRL M CTRL M The carriage return character causes the command line just transmitted to every card in the chain to be accepted by that card and processed This allows separate command lines to be sent to each card but processed simultaneousl
95. meets these constraints and uses this equation for interpolation The segment time may not be changed on the fly in SPLINE1 mode If the segment time is changed in the middle of a sequence of moves PMAC will bring the early part of the sequence to a stop automatically and then start up the following section with the new segment time If the segment times are small this can be a very rough operation Added Pieces At the beginning and end of a series of splined moves PMAC automatically adds a zero distance segment of TA time for each axis and performs the spline between this segment and the adjacent one This results in an S curve acceleration to and from a stop Quantifying the Position Adjustment The difference between the splined commanded position and the pre splined program line commanded position for an axis at the end of segment n can be calculated according to the simple equation Diff ET where Dist n is the programmed distance for segment n of the spline whether in absolute or incremental mode and Dist n 1 is the programmed distance for segment n 1 5 Point Spline Correction In contouring applications it is often desired to pass through the series of points as closely as possible In these applications the error introduced by the standard spline algorithm may be too large to tolerate However a very simple pre compensation can dramatically reduce the splining errors For each point X n in the spline replace with a p
96. most common of these situations is the case in which it is not known on which side of the home trigger when powering up In this case move into one of the limit switches to make sure the position is at one end of travel this can be done by homing into the limit much as in the above example Then doa homing move the other direction into the real home trigger A sample Motion Program routine that does this is 11 10 Basic Motor Moves PMAC User Manual CLOSE OPEN PROG 102 CLEAR 1223 10 1225 2C004 1226 0 1907 2 1908 1 HOME2 1223 10 1225 C004 1907 11 1908 0 HOME2 CLOSE Home speed 10 cts msec positive direction Disable LIM2 as limits No home offset Capture on rising edge of a flag Use LIM2 as flag positive end limit Home into limit Home speed 10 cts msec negative direction Re enable LIM2 as limits Capture on flag low and index channel high Use HMFL2 home flag as trigger flag Do actual homing move A sample PLC Program routine that does this is CLOSE M233 gt X 0079 13 1 M245 gt Y 08D4 10 1 OPEN PLC 11 CLEAR 1223 10 1225 2C004 1226 0 1907 2 1908 1 CMD 2HM WHILE M245 1 ENDWHILE WHILE M233 0 ENDWHILE 1223 10 1225 C004 1907 11 1908 0 CMD 2HM WHILE M245 1 ENDWHILE WHILE M233 0 ENDWHILE DIS PLC11 CLOSE Desired Velocity Zero bit Home complete bit Home speed 10 cts msec positive direction Disable LIM2 as limits No home offset Ca
97. motor in the coordinate system be jogged in both directions If not review that motor s setup e Have any motors been assigned to the coordinate system that are not really set up yet Every motor in the coordinate system must have its limits held low even if there is no real motor attached Troubleshooting 5 3 PMAC User Manual Troubleshooting PMAC User Manual 6 Input Output Connecting PMAC to the Machine Table of Contents INPUT OUTPUT CONNECTING PMAC TO THE MACHINE eerte eee ee eene sts tn seta tuse tn sins tn sens tasses suse ta conose 1 Capabilities and Features 4 6 eto ede e e dede eA a ih eit ete i Ie A e bre e tee Pe ERR 1 Quadrature Encoder Inputs IMACH Port 15 eren deter teet rcu iE eenah i EAS K eS SEEE EAEE EESK AEEA AEE KEERA 1 Single Ended vs Differential ctc t dte decet i ii s etre x ce ai 1 Differential Encoder adas ac 3 ANGLO E En SEE 3 Power Supply and LS ANA A 4 Wiring LECH QUES MINE A Ai tits 4 Encoder Signal Sampling aae daa 4 Digtal Delay Filter arso E em 2 Error DelectiOni asset esee ek ai Dnus 5 Optically Isolated Dedicated Digital Input Flags JMACH Port nennen enne ennemi emere nenne 5 Flag UT E S 6 SITZ a TBI IU Tm 6 Home Flas Input sirieni E 6 AMPL RE Fault Input En 6 PLAS SOLA E 6
98. move and incremental vector specification the program would be NORMAL K 1 XY plane F10 CIRCLE1 Clockwise circle X20 Y20 I20 JO Arc move I 20 0 20 J 0 0 0 LINEAR X40 Y20 CIRCLE1 X20 YO IO J 20 Arc move 1 40 40 0 J 0 20 20 Radius Size Specification If the radius method of locating the arc center is used the radius is the number after the letter R in the move command This value always represents the distance from the move starting point With radius specification it is also necessary to specify whether the arc to the move endpoint is the long route 22180 degrees or the short route 2180 degrees The PMAC convention is to take the short arc path if the R value is positive and the long arc path if R is negative R values are not modal A value must be specified on each move command line It is not possible to do a full circle in a single move command with a radius specification the circle must be broken into at least two parts A typical circular move command with a radius specification is X1000 Y2000 R750 Example To do the same moves as in the above example except with radius center specification the program would be NORMAL K 1 XY plane F10 CIRCLE1 X20 Y20 R20 Arc move 180 deg X40 Y20 Automatically linear X20 YO R 20 Arc move 180 deg Do not use the R radius specification if using the axis transformation matrices for scaling purposes with the AROT or IROT statemen
99. not need to be ready to run a motion program Can only home motors defined in the C S running the Can home any motor not defined in a C S running a program program Motors can be homed simultaneously one after another Motors can be homed in any order This includes or any combination of the two starting one motor in the middle of another motor s home move The motion program must be started by an on line The PLC can be started by an on line command a PLC command a PLC program or another motion program program another motion program or automatically at power up or reset Zero Move Homing To declare the current position the home position without commanding any movement use the HOMEZ on line or HOMEZn motion program command These are like the HOME command except that they immediately take the current commanded position as the home position The Ix26 offset is not used with the HOMEZ command Note If the following error is received when giving the HOMEZ command the reported actual position after the HOMEZ command will not be exactly zero it will be equal to the negative of the following error Homing into a Limit Switch It is possible to use a limit switch as a home switch However you must first disable the limit function of the limit switch if you want the move to finish normally if you do not do this the limit function will abort the homing search move Even so the home position has been set
100. of differential encoder signals The first has simple open collector drivers or equivalent on both the main and complementary channels For this type of encoder the jumper must be set up for differential mode to provide pull up resistors on both inputs Differential Line Drivers The second type of differential encoder format and the one that is strongly recommended is the differential line driver on both signals For this type of encoder it does not matter what the jumper setting is most will leave the jumper in the default setting Termination Resistors When driving the encoder signals over a long cable 10 meters or more to reduce the ringing on transitions add termination resistors between the main and complementary lines PMAC provides sockets for resistor packs for this purpose The optimum value of the termination resistor is system dependent but 330 ohms is a good starting point Analog Encoders PMAC can take analog voltage source encoder inputs into its differential line receivers if the drivers have enough capability to work against a 470 ohm pull up resistor and the maximum differential voltage the line receiver sees is between 2 and 12V For a single ended analog signal the complementary channel should be tied to GND to provide proper transitions as the voltage signal goes positive and negative It is better but not required to jumper the input for single ended For a differential analog encoder the two signals for each
101. on rising edge of index pulse WY 072A A0COOC 800 Add triggered time base entry to end of default conversion table process A0 is triggered time base running post trigger C00C points to ENCA registers Scale factor is 800 decimal M199 gt Y 072A 16 8 Process bits of conversion table entry amp 1 Address Coordinate System 1 1 gt 83 33333333A Motor 1 is A axis in C S 1 3 x 2500 x 4 cts rev 360 deg rev 15 10 Synchronizing PMAC to External Events PMAC User Manual Motion program CLOSE OPEN PROG 12 CLEAR 1193 072B Time base source address is triggered DWELLO time base conversion in table 2nd line M199 90 Freeze the time bas line before should be a DWELL LINEAR Linear move mode INC Incremental move specification TA10 36 degrees of master is 10 msec TSO No S curve DELAY12 5 45 degrees of master is 12 5 msec TM50 36 144 deg of master is 50 msec A360 One full revolution of slave axis CLOSE PLC Program CLOSE OPEN PLC 10 CLEAR IF M199 90 Has time base been frozen M199 BO Then arm for trigger ENDIF CLOSE Synchronizing PMAC to Other PMACs When multiple PMACS are used together inter card synchronization is maintained by passing the servo clock signal from the first card to the others With careful writing of programs this permits complete coordination of axes on different cards PMAC provides the capability for p
102. only L variables and integer constants the intermediate format is signed 24 bit integer Refer to the section on compiled PLCs under the Writing a PLC Program section of this manual for more details The general floating point format is 48 bits long with a 36 bit mantissa and a 12 bit exponent This 204 616 provides a range of 35 E or 43 233 x 10 which should provide sufficient range for any foreseeable uses on the card Receiving Values Constant values sent from the host as part of command lines are sent as ASCII text either as decimal values or hexadecimal values Hexadecimal values must be preceded by a character they must be unsigned and they cannot include fractional values Decimal values can be positive or negative and can include fractional values The PMAC value interpreter does not support exponential notation and it is 35 10 limited to passing through values in the range 2 or 3 43x 10 Values outside this range are truncated to the maximum or minimum values of the range Computational Features 13 3 PMAC User Manual CT CT CT CT CT CT CT CT 1 1 1 1 1 1 1 1 2 3 Servo 2 3 Servo 2 3 Servo 2 3 Servo 2 3 Servo 2 3 Servo 2 3 Servo 2 3 Servo CT Conversion Table n Motor n Servo Update HK Housekeeping 4 4 4 4 4 4 4 4 PLC 0 PLC 1 A RTI Background PLC 1 cont
103. pass filter somewhat greater than the resonant frequency to reduce the high frequency gain of the filter itself For those familiar with control theory not necessary to use the notch the form of the PMAC notch filter system is Nz 1 NIz Nx D z 1 DI271 D2272 where the numerator N z is the band reject filter and the denominator D z is the band pass filter The notch filter acts on the output of the PID filter itself PMAC uses four I variables to specify the full notch filtering system two Ix36 N1 and Ix37 N2 for the band reject filter and two Ix38 D1 and Ix39 D2 for the band pass filter These I variables represent the actual coefficients used in the difference equations for the notch These I variables have a range of 2 0 to 42 0 they are 24 bit values with one sign bit two integer bits and 21 fractional bits Before implementing a notch filter in the PID Plus algorithm tune the PID parameters somewhat to get at least minimal performance even if control of oscillations is poor Automatic Notch Specification With the PMAC Executive Program set up a notch filter this can be done without the need to understand how a notch filter works The easiest way is to enter the frequency of the mechanical resonance that to control The Executive Program will compute automatically the desired characteristics of the band reject and band pass filters calculate their coefficients and download them to PMAC
104. per channel or differential two signal lines main and complementary per channel A jumper for each encoder E18 E21 and E24 E27 permits customized configurations as described below The differential line receivers can accept up to 12V between main and complementary inputs and 12V between either input the GND reference voltage Typically O and 5V levels are used Single Ended Encoders With the jumper for an encoder set for single ended the differential input lines for that encoder are tied to 2 5V the single signal line for each channel is then compared to this reference as it changes between O and 5V Input Output Connecting PMAC to the Machine 6 1 PMAC User Manual quvoag AJOSSIDIV Lo Sinan F gt Lig 9L r DOTNY p X A pay NOILV IOSI OLdO sna ssaqdaav gt lt gt SNa VLVG bp me v ova la A Y NOLN10Say 59VO e Lig 91 A SINALNO DOTVNV Y v 4 eu A A Y 4 1 OVQ 4 b 1 noa v L VN3V t L Lins t L LINTT v L LIWIT t L SINOH Tga lid vz TOHINOY Inda Xn un y43009N3 b TOHLINOO 32012 DOTVNV Y IP v H3d0O09N3 d po x NI VLVG v SHSLSIDS
105. port with an IBM PC or compatible using the supplied PMAC Executive program Instructions for setting up the VME bus interface are given in the Writing a Host Communications Program section of this manual Talking to PMAC 4 3 PMAC User Manual Giving Commands to PMAC PMAC is fundamentally a command driven device unlike other controllers that are register driven PMAC will do things if it is issued ASCII command text strings Generally PMAC provides information to the host in ASCII text strings PMAC Processing of Commands When PMAC receives an alphanumeric text character over one of its ports it does nothing but place the character in its command queue It requires a control character ASCII value 1 to 31 to cause it to take some actual action The most common control character used is the carriage return CR ASCII value 13 which tells PMAC to interpret the preceding set of alphanumeric characters as a command and to take the appropriate action Note If using the Option 2 dual ported RAM command PMAC by writing values to specific registers in the DPRAM PMAC can provide information by placing binary values in these registers but the ASCII commands must have been sent already to PMAC that cause it to take the proper action when these values are received and to place the values in these registers Control Characters Other control characters cause PMAC to take an action independent of the alphanumeric characte
106. process Bits 0 15 Y Address of source data Bits 16 23 50 2 Converted data 2 Bias Term 1 256 bit of 16 bit ADC Bits 0 4 Fractional Bits Bits 5 23 Integer Bits Uses of Integrated Analog There are several possible uses of this format First an analog velocity sensor such as a tachometer could be used to provide position like information to the PMAC servo loop remember that the velocity loop expects position information For example consider an axis that has a motor with a tachometer a linear encoder on the load for accuracy and a current loop amplifier for high responsiveness It is difficult to get stability using just the linear scale for both position and velocity loop because there is no direct information about what the motor is doing The tachometer can be connected to an A D converter on an ACC 28 e g ADC1 Then this conversion table entry can integrate the A D value into what is effectively position information for the servo loop to use The source and process word would be 50C006 the bias term would be set empirically to hold the integrated value constant when the motor is still Ix04 for the motor would point to the second line of the entry to use the integrated value Second this makes it possible to do cascaded loops inside PMAC The outer loop which could be a force or tension loop acting around a normal position loop would put out a command value that is a velocity correction to the inn
107. program 10n0 to which operation will jump this value is multiplied by 1000 to specify the number of the line label When a return statement is encountered it will jump back to the calling program For example G17 will cause a jump to N17000 of PROG 1000 G117 will cause a jump to N17000 of PROG 1010 G973 1 will cause a jump to N73100 of PROG 1090 M codes are the same except they use PROG 10n1 T codes use PROG 10n2 D codes use PROG 10n3 Most of the time these codes have numbers within the range 0 to 99 so only PROGs 1000 1001 1002 Writing Programs for PMAC 14 43 PMAC User Manual and 1003 are required to execute them To extend code numbers past 100 PROGs 1010 1011 etc will be required to execute them The manufacturer s task is to write routines for motion programs 10n0 to 10n3 to implement the codes in the manner desired Once this is done the method of implementation is invisible to the part programmers and machine operators Standard G Codes These are the issues involved in implementing some of the more common G codes G00 Rapid Point to Point Positioning Typically this code is implemented in PMAC through use of the RAPID command Many will have only RAPID RETURN as the implementation of this code Since this is a call to NO of PROG 1000 and the NO label is implied automatically by the beginning of any motion program do not explicitly add an NO this routine must be at the very top of PROG 1000
108. program buffers that have been defined Program lines following this are sent to the buffer for the host addressed coordinate system amp n Most users of rotary program buffers will have only one coordinate system so this will not be of concern to them but it is possible to switch coordinate systems on the fly and use several rotary buffers at once It is important to realize that after the OPEN ROT command PMAC is treating as many commands as possible as buffered commands even if it is executing them immediately some commands mean one thing as an on line command and another thing as a buffered command For instance an I100 command is a request for a value of I variable 100 when buffers are closed but it is a command to do a full circle with a 100 unit radius when a motion program buffer is open the I value is the X axis component of the radial vector since no axis positions are given they are all assumed to be the same as the starting point Staying Ahead of Executing Line The key to the handling of a rotary program buffer is knowing how many lines ahead the program is that is how many program lines have been loaded ahead of the program line that PMAC is executing Typically load ahead until a certain number of lines ahead is reached and then wait until the program catches up to within a smaller number of lines ahead A real time application may work one line ahead of the executing line an application doing periodic downloading of a
109. program when it gets a CLOSE command The OPEN CLOSE and CLEAR commands are not actually part of the program they are on line commands to control the program buffer operation Starting the PLC Program Now type I5 2 lt CR gt This permits PLCs 1 to 31 to be enabled Next type ENABLE PLC 1 This should actually start operation of the PLC program The variable P1 should be incrementing steadily Verify this by repeatedly typing P1 CR The reported value should be greater each time If it is not recheck the value of I5 the listing of the program and try re enabling the PLC Other things can be happening in between cycles of the PLC program Reset the value of P1 by typing P1 0 lt CR gt PMAC will execute this command and then PLC 1 will start incrementing the value again from that point Motion programs can be run simultaneously Re run the motion program and notice that P1 keeps incrementing during the operation of the motion program Stopping the PLC Program To halt operation of the PLC program type DISABLE PLC 1 Note that repeated queries of P1 s value yield the same answer ENABLE PLC 1 will re enable operation of the program Each time a PLC program buffer is opened for editing the program is automatically disabled Closing the buffer does not automatically re enable the program When working on a PLC program with the program editor follow the CLOSE command with an ENABLE PLC 1 command so that this command does not need to be
110. radius will not scale with the axes Use the IJK center vector specification instead Calculation Implications It takes one to two milliseconds to perform the matrix transformation for every move involving the X Y or Z axis This will decrease the maximum block execution rate for the motion program A two axis system that was capable of 400 blocks per second without matrix transformation will be capable of only about 250 blocks per second once matrix transformation has been activated with the TSEL command To disable the matrix transformation calculations use TSELECTO which deselects all matrices and stops the matrix calculation overhead Examples These concepts are probably best illustrated with some simple examples In actual use much more sophisticated things may be done with the matrices especially with the inclusion of math and logic Writing Programs for PMAC 14 35 PMAC User Manual Scaling Example If the axis definition statements scaled the axes in units of millimeters but it should be programmed in inches at least temporarily set up the matrix as follows TSEL 1 Select Matrix 1 Q11225 4 012 20 Q13 0 Variables for first row Q1420 0Q15 25 4 016 20 Variables for second row Q017 0 Q18 0 0Q19 25 4 Variables for third row AROT 11 Use Q11 Q19 for matrix Notice that pure scaling uses only the primary diagonal of the matrix The scaling is done with respect to the origin of the coordinate system Of course
111. re typed every time the edited PLC program is downloaded to PMAC Getting Started with PMAC 2 17 PMAC User Manual 2 18 Getting Started with PMAC PMAC User Manual 3 PMAC Features Table of Contents PMAC FEATURES T Executing Motion Programs Executing PLC Programs NR H Commutation Update Housekeeping ete rie e Petre eR ra pase Pee Ree Re DERE ea bees Pe Yee PS eve vestre E Rusa Ee e ERR NER ee Fee Lets EE Communicating With the Host Task Priorities Table of Contents 3 1 PMAC User Manual 3 2 Table of Contents PMAC User Manual 1 PMAC FEATURES Executing Motion Programs The most obvious task of PMAC is executing sequences of motions given to it in a motion program When told to execute a motion program PMAC works through the program one move at a time performing all the calculations up to that move command including non motion tasks to prepare for actual execution of the move PMAC is always working ahead of the actual move in progress so it can blend properly into the upcoming move if required Refer to the Writing Programs for PMAC section of this manual for more details Executing PLC Programs The sequential nature of motion program suits it well for commanding a series of moves and other coordinated actions however these programs are not good at performing actions that are not directly coordinat
112. register It is executed totally in hardware without the need for software intervention although it is set up and later serviced in software This means that the only delays in the capture are the hardware gate delays negligible in any mechanical system so this provides an incredibly accurate capture function Setting the Trigger Condition The position capture register can be used both automatically as in homing routines where the firmware handles the register directly and manually where the user program must handle the register information Regardless of the mode the event that causes the position capture is determined by Encoder I variables 2 and 3 1902 and 1903 for Encoder 1 Encoder I Variable 2 defines what combination of encoder third channel transition and encoder flag transition triggers the capture it also allows software trigger If it says to use a flag Encoder I variable 3 determines which flag almost always set to zero to specify the home flag Using for Homing When using this feature for homing a motor the motor flag address I variable Ix25 for motor x must point to the proper set of flags this has to be done to address the limit flags properly For instance the default value of 1125 is 49152 C000 pointing to the first set of flags Then Encoder Flag I variable 2 e g 1902 and Encoder Flag I variable 3 e g 1903 define the transition within this encoder and flags to cause the position capture Once these
113. section of this manual Encoder Jumpers PMAC can take either non differential single ended A B C or differential inputs A A B B C C from encoders As shipped from the factory the card is set up for non differential encoders individually selectable by jumpers E18 E21 not available on PMAC Lite or PMAC STD and E24 E27 In this setup with pins 1 and 2 of each E point connected the main signal line is pulled up to 5V with a 470 ohm resistor and the complementary lines are held at 2 5V with 1 kohm pull up and pull down resistors allowing them to be a steady comparison point for the signal lines If using single ended encoders leave the complementary lines A B and C floating so PMAC can hold them at 2 5 V Do not ground these inputs If using single ended encoders have the jumpers set up for non differential If using differential encoders with open collector drivers on each channel this is rare have the jumpers set up for differential pins 2 and 3 connected providing an effective 500 ohm pull up on the complementary line If using encoders 2 2 Getting Started with PMAC PMAC User Manual with differential line drivers the jumpers can be set either way although it is preferable to have them set for differential to balance the lines Note If not using a certain encoder input it is better to leave it jumpered for single ended input otherwise it is much more likely to pick up extraneous noise as count
114. separate download of this PLC after each compile download cycle All other commands are passed through the compiler to the output file unchanged The compiler will tells how many words of PMAC memory the compiled code will occupy it will note an error if the compiled code exceeds the maximum permitted 15360 words of PMAC memory If using a user written servo in PMAC ascertain that the compiled code does not exceed 14336 words Downloading the Compiled Code to PMAC The single output file from the compiler can be downloaded to PMAC by any program or routine that can send files to PMAC such as the PMAC Executive program s Download file to PMAC menu selection In the CNC Executive program the download occurs automatically after the compiling The act of downloading any new compiled PLC programs deletes all of the existing compiled PLC programs in the PMAC active memory automatically No other commands need to be used to delete these In PMACS with battery backed memory the compiled PLC programs are retained by the battery automatically through power down cycles until they are explicitly deleted by the DELETE PLCC command or by the downloading of a new set of compiled PLCs In PMACs with flash memory backup the SAVE command must be used after downloading in order for the compiled PLCs to be retained through a power down or reset of the card The SAVE command copies the programs from active memory to the non volatile flash memory At power up r
115. serial port connector J4 on PMAC PC Lite and VME J1 on PMAC STD s bottom board Delta Tau provides cables for this purpose Accessory 3D connects PMAC PC or VME to a DB 25 connector ACC 3L connects PMAC Lite to a DB 9 connector and ACC 3S connects PMAC STD to a DB 25 connector Standard DB 9 to DB 25 or DB 25 to DB 9 adapters may be needed for a particular setup If using the ACC 26 Serial Communications converter connect from the PC COM port to ACC 26 with a standard DB 9 or DB 25 cable and from ACC 26 to PMAC using the cable provided with ACC 26 Since the serial ports on PMAC PC and PMAC VME are RS 422 this accessory can provide the level conversion between RS 232 and RS 422 communications is possible without this conversion but at reduced noise margin Because the conversion is optically isolated the accessory also helps prevent noise and ground loop problems Note If the PMAC is not plugged into a bus it will need an external 5V supply to power its digital circuits The 5V line from the supply should be connected to pin 1 or 2 of the JMACH connector usually through the terminal block and the digital ground to pin 3 or 4 Installing the PMAC Executive Program The initial communications to the card will be done with Delta Tau s PMAC Executive program PE or the accompanying PMAC Setup PS program which are provided on a diskette ACC 9D or 9W The diskette contains an Install utility to make this easy Refer to the
116. set 1170 to 1 and set I171 to the value If the value is not an integer for example a 6 pole motor and a 1024 line encoder figure out the integer multiplier required to make it an integer usually 3 In this case set I170 to the multiplier and I171 to the multiplied integer value Angle Between Phases If it is a 3 phase motor set 1172 to 85 This tells PMAC that the two phases are 85 256 1 3 cycle apart This may be changed later to 171 if the polarity of the signals are wrong If it is a 4 phase motor set 1172 to 64 64 256 1 4 the may be changed later to 192 Phase Search Parameters Now if using a brushless DC synchronous AC motor establish the parameters for the power up phase finding search Initially set 1173 the magnitude of the phase finding output to 8192 which is one quarter of full output Next set I174 the time for each half of the phase finding routine to 5 servo cycles These can be optimized later Now make sure the induction motor parameters 1177 and 1178 are set to 0 so PMAC will not think this is an induction motor Slip Gain and Magnetization Current If using an AC induction motor do not worry about power up phase finding Set 1173 and I174 to 0 Also set 1177 magnetization current and 1178 slip gain Initially set 1177 to 3200 1 10 full current and 1178 to 2500 for a low slip motor or 5000 for a high slip motor These can be optimized later The fact that 1178 is greater than zero prevents
117. should be adjusted for some deadband to assure that OV in creates no frequency also jumper E73 should be left OFF to make sure no glitches get into the sign bit of the counter On PMAC Lite the pulse and direction signals may be output on the CHA4 and CHB4 pins respectively of the JMACHI connector These can be used to command a stepper motor driver The DACA output can be wired into the WIPER input which provides both the feedback that the servo loop requires and the command signals to the driver This permits the PMAC Lite to drive one stepper motor without a special accessory board Software Processing The encoder conversion table can then take the difference in the counter each servo cycle and scale it providing a value proportional to frequency and therefore to the input voltage Usually this is used for feedrate override time base control but the resulting value can be used for any purpose Refer to the Time Base Control section in this manual Status Outputs There are five dedicated low true outputs on the JPAN connector usually used to light LEDs They are BRLD buffer request LED IPLD in position LED EROR Error condition LED F1LD 1st warning following error LED and F2LD which goes true when the watchdog timer trips BRLD ERLD and F2LD are global status lines IPLD and F1LD are coordinate system specific status lines If I2 0 they refer to the panel selected coordinate system by FDPn If I2 1 they re
118. should be emptied with the CLEAR command Existing lines cannot be edited or new lines cannot be inserted between existing lines However new lines can be appended to the end with of course the option of clearing the whole buffer first Typically in program development the editing will be done in a host based text editor such as the PMAC Executive Program editor and the old version of the PMAC program buffer is cleared every time the new version is downloaded to the card After the last of the program statements is downloaded a CLOSE command should be sent to the card to close the program buffer It is a good idea to issue a few commands before the OPEN PROG n command to make sure the buffer space is ready for the program statements First you want to make sure that no motion programs are currently executing except for rotary programs The A for the addressed coordinate system or CTRL A for all coordinate systems abort command can be used to make sure execution has stopped Also make sure that no other buffer is open use the CLOSE command for this Next to make sure that all the open buffer space has not been taken up with a data gathering buffer use the DELETE GATHER command for this All of these on line commands can be included in the editor file with the actual motion program statements even though they are not part of the actual program They would not be reported as part of the program if PMAC were asked to LIST PROG n
119. still has more data to be read Example Again assume that the command to ask for the contents of memory locations X 1000 through X 1002 has been sent RHX 1000 3 CR These three locations contain the values 123456 789012 and 345678 To go and read the mailbox registers send the above command line and service the interrupt PMAC generates using an interrupt vector of A0 After PMAC has processed the command and put data into the mailbox registers PMAC interrupts a second time with an interrupt vector A1 Remember this second interrupt is sent because PMAC has just now placed data in the mailbox registers which is now ready to be read Service the second interrupt and note that the accompanying interrupt vector is A1 Read the data in the mailbox registers In this example PMAC will have 22 characters to be read 123456 789012 345678 CR lt ACK gt with the first 16 of them in the mailbox registers Assume that I variable I3 is set to 2 again The data will be in the registers as follows Address 7FA001 7FA003 7FA005 7FA007 7FA0ID 7FAOIF Mailbox 0 1 2 3 14 15 Character I 2 3 4 3 4 Writing a Host Communications Program 17 21 PMAC User Manual Read the mailbox registers beginning with the first one until a CR lt ACK gt BELL is encountered or all 16 registers have been read In this case the first 16 characters PMAC has does not contain a CR
120. that its triggering edge remain safely between the same two index channel pulses Also the homing switch pulse must be wide enough to always contain at least one index channel pulse Action on Trigger In the homing search move as soon as the PMAC firmware recognizes that the hardware trigger has occurred it takes several actions It reads the position at the time of capture usually the hardware capture register and uses it and the Ix26 home offset parameter to compute the new motor zero position As soon as this is done reported positions are referenced to this new zero position plus or minus any axis offset in the axis definition statement If the axis definitions is H1 gt 10000X 3000 the home position will be reported as 3000 counts If software overtravel limits are used Ix13 Ix14 not equal to zero they are re enabled at this time after having been disabled automatically during the search for the trigger The trajectory to this new zero position is then calculated including deceleration and reversal if necessary The motor will stop under position control with its commanded position equal to the home position If there is a following error the actual position will be different by the amount of the following error Note If a software limit is too close to zero the motor may not be able to stop and reverse before it hits the limit Home Command The homing search move can be executed either through an on line command whi
121. the CTS handshaking so the host cannot hold off characters from a PMAC typically this is undesirable Addressed Card Actions The addressed card at any time can accept alphanumeric commands and respond to them Only it tries to control the communications and handshake lines back to the host computer The cards not addressed at a given time ignore alphanumeric characters sent over the serial port and their communications and handshake outputs are tri stated so as not to interfere with those of the addressed card The cards not addressed still can respond to certain control characters not those querying a card below and of course are listening to see if the addressed card number changes Simultaneous Addressing It is possible to address all cards simultaneously for alphanumeric commands with software addressing In this case all cards will accept alphanumeric characters Card 0 will provide the handshake response characters Query commands are not permitted in addressing If the host sends such a command in this mode card 0 will respond with the BELL character Handling Data Response When sending commands that require a data response it is important to ask for data from only one card per command line a command line is terminated by the CR character and to accept the response before querying another card Otherwise more than one card may try to control the lines at once when responding For example the command string 1P 2P
122. the Servo Loop sections of this manual for more details 3 2 PMAC Features PMAC User Manual 4 Talking to PMAC Table of Contents TALKING LONG TEX o 1 Basic Aspects Of Communicating With PMAC sessi nennen nennen nenne nre nennen ne tnenn nnne ener enne 1 COMMUNICATIONS AAA A A Ex ehe PE Ebene Denken 1 Active Response POL 1 NA nia AA E 1 OA ssis anaes iine iaee E r A E E EER EEE AE E 3 VEDRA OD AA E A EE 3 VME bus A e AA tee n E a aea aE a E E LL E AS 3 Giving Commands to PMAC sssssssssesseeeeeeeene ene oa teen REPERES SEE ER aE E EEn TECIE tnnt no R Ra ERE o Esie 4 PMAC Processing of Commands eee eee eese esee entente nennen nete trennen tren etn en etre trennen enne trennen 4 Command Acknowledgement iie decidi Re ied a ia elle tbe lei eed ie deett idad 4 Data Responses aia totidem tt bete hd dtt 4 DOIG Tie ey sei tU tb tt ubt pM ba etie itt tn hot e est itiuten 4 Data Response FOMA aurais E ttu A erotica GRE CQ desde dit 5 On Line immediate Commands eiat ee cerea e dhs tee a e ER ETE RE E EE PR THER eR de Pu dnd 5 Types of On Line Commands tette te ta ote Ett Leber rete cessed tese feine glos denote eee isis 5 Motor Specific Commands sny nannaa ii dis J Coordinate System Specific Commands eee ee esee nn none enne tenente trennt teet nnet ne tnne trenne
123. the absolute power on reset position read function is disabled and the power on reset position is set to zero regardless of the setting of the sensor and subsequent position readings are incrementally referenced to this zero position For more information refer to the Absolute Power Up Position section in this manual and to the Ix10 description in the Software Reference manual Sensor Rollover If the overall travel for the axis is more than the range of the absolute device PMAC will automatically extend the position in software to handle rollover In this case however the device should be considered a parallel incremental device see next section A device can be considered absolute for commutation purposes so no power on phasing search is required set Ix81 0 if PMAC is doing the commutation but still incremental for overall machine positioning functions In most systems single turn resolvers and absolute encoders have this functionality Refer to the Phasing Referenced to an Absolute Sensor in Setting Up PMAC Commutation section in this manual for more information on this type of setup It is important with this type of feedback device to perform a PMATCH position match function before the first programmed move after power up reset Usually this is done automatically by having I14 equal to 1 If this is not done PMAC will calculate the first move for the motor assuming a starting point of Zero instead of the true position leading to un
124. the bootstrap version type the command VER while communicating to PMAC in bootstrap mode To bypass the download operation in this mode send a CONTROL R character to PMAC This puts PMAC in the normal operational mode with the existing firmware Factory default values for I variables Getting Started with PMAC 2 3 PMAC User Manual conversion table settings and bus addresses for DPRAM and VME are copied from the firmware section of flash memory into active memory The saved values of these values are not used but they are kept in the user section of flash memory For more information on PMAC bootstrap mode and downloading new firmware refer to the PROM Update Specification sheet included with the PROM Connecting PMAC to the Host Computer Bus Connection Caution With the board plugged into the bus it will pull 5V power from the bus automatically In this case there must be no external 5V supply or the two supplies will fight each other possibly causing damage With computer power off plug the PMAC into an open bus slot The PMAC Lite requires one slot on the bus the PMAC PC requires 1 1 2 slots permitting a half size board in the next slot the PMAC VME requires two slots one double slot and the PMAC STD requires two slots for the 4 channel version and three slots for the 8 channel version Serial Port Connection For serial communications use a serial cable to connect the PC s COM port to the PMAC
125. the lead in move is a CIRCLE mode move this compensated tool path will be a spiral Then a circular arc move with radius equal to the cutter radius is added ending at a point one cutter radius away from the intersection of the lead in move and the first fully compensated move with the line from the programmed point to this compensated endpoint being perpendicular to the path of the first fully compensated move at the intersection 14 24 Writing Programs for PMAC PMAC User Manual Introducing Compensation Outside Corner Arc Tool Center id Path Programmed Path Tool Center a pam Aro Line to Line ive y Arc Tool Center f Path Programmed Path P Tool Center Ar 7 Palt gt ine Arc to Line Arc to Arc Figure 39 Compensation Outside Corner The behavior for lead in moves is different from changing the compensation radius from zero to a non zero value while compensation is active An arc move is always added at the corner regardless of the setting of I89 This ensures that the lead in move never cuts into the first fully compensated move Treatment of Compensated Inside Corners Inside corners are still subject to the blending due to the TA and TS times in force default values set by coordinate system I variables Ix87 and Ix88 respectively The longer the acceleration time the larger the rounding of the corner The corner rounding starts and ends a dist
126. the more significant word MSW amp 4095 multiply by 16 777 216 and add to the masked less significant word This forms the mantissa of the floating point value Now take the next 12 bits MSW amp 16773120 of the more significant word This is the exponent to the power of two which can be combined with the mantissa to form the complete value 24 BITS BIT 23 16 15 87 0 PMAC WORD S Byte2 Byte 1 Byte 0 DPRAM 0 Byte 0 BYTE 1 Byte 1 NO 8 25 S Byte2 RELATIVE 255555588 S Sign bit SIGN EXTENSION 48 BITS BIT 4 23 16 15 87 0 PMAC Y WORD S Byte2 Byte 1 Byte 0 PMAC X WORD S Byte5 Byte 4 Byte 3 0 Byte 0 1 Byte 1 DPRAM 2 S Byte2 BYTE 3 S S S S S S S S NO A SIGN EXTENSION Byte 3 RELATIVE 5 Byte 4 6 S Byte5 g P 7 5 5 55 5 5 5 S First word sign bit S Second word sign bit SIGN EXTENSION E Exponent for floating point Figure 57 Dual Ported RAM Data Gathering Formats 17 30 Writing a Host Communications Program
127. the reciprocal of the notch DC gain If Ix30 was 100 000 before implementing the notch to keep the same stiffness set Ix30 227000 100 000 2 27 Play with Ix30 some more now to modify loop stiffness without affecting the characteristics of the notch Indeed one of the important reasons for introducing a notch is to be able to increase the stiffness of the loop without going unstable Other Uses of the Notch Filter The notch filter is really a generalized second order digital filter that can be put to uses other than creating a notch This can give great flexibility in tailoring the performance of the servo algorithm Lead Lag The notch filter can be used as a lead lag filter if the roots are real rather than imaginary A lead lag filter is similar in performance to a PID filter it is useful when filter settings are determined analytically rather than experimentally When a basic lead lag servo filter is desired all servo gains Ix31 to Ix35 should be set to zero Ix30 is used as the generalized gain term Low Pass Filter It is also possible to use this filter component as a low pass filter if reducing roughness of operation is more important than high system bandwidth This can be accomplished by setting the D1 term Ix38 to a positive value between 0 0 and 1 0 The larger the value the lower the cutoff frequency of the filter The DC gain of this filter is 1 1 D1 so the proportional gain needs to be increased by a factor of 1 D1
128. the travel of the motor or it can be a function of motor position The rate at which the backlash is introduced or removed is programmable as is the magnitude of the reversal required for backlash to be introduced or removed Constant Backlash Ix86 for motor x is the constant backlash distance parameter When the direction of the motor s commanded movement changes from positive to negative this value is introduced into the active backlash compensation register which is subtracted from the nominal commanded position When the direction of the motor s commanded movement changes from negative to positive the value of the backlash compensation register is reduced to zero Note A positive value of Ix86 adds extra distance to the travel of the motor on reversal which is what is desired to compensate for true physical backlash The units of Ix86 are 1 16 of a count so the value should be 16 times the number of counts of backlash compensation required Backlash Take Up Rate Ix85 controls the rate at which backlash is introduced or removed upon reversal for motor x This helps to optimize for swift but smooth backlash compensation When reversal is detected each background cycle between each scan of each PLC an amount equal to Ix85 is added to or subtracted from the active backlash compensation register as appropriate until a value Ix86 or 0 in that register is reached In general the highest value of Ix85 that produces smooth transitions
129. thing executed after the automatic power up reset cycle effectively extending what is done in this cycle The last line in this program should be DISABLE PLC 1 which prevents repeated execution of the program A simple file for such a program could be CLOSE OPEN PLC 1 CLEAR M55 0 Spindle Off P92 3000 Maximum spindle RPM P95 1000 Max spindle accel in RPM sec M70 0 English measurements DISABLE PLC 1 So this is only executed once CLOSE Rotary Motion Program Buffers The rotary motion program buffers allow for the downloading of program lines during the execution of the program and for the overwriting of already executed program lines This permits continuous execution of programs larger than the PMAC memory space and also real time downloading of program lines equivalent to SMCC s MDI mode Defining a Rotary Buffer Each coordinate system can have a rotary program buffer To create a rotary buffer for a coordinate system address that coordinate system amp n and send the DEFINE ROT constant command where constant is the size of the buffer in memory words Each value in a program e g X1250 takes one word of memory The buffer should be sized to allow enough room for the distance ahead of the execution point you wish to load Since most applications utilizing rotary buffers will not strain the PMAC memory requirements it is a good idea to oversize the buffer by a good margin For instance to load
130. time one spindle revolution takes 10 msec so we want our feedrate to be in units of length per 10 msec which we achieve by setting Ix90 feedrate time units to 10 If we have 4096 counts per spindle revolution after decode our RTIF would be 4096 x 100 2 409 600 cts sec 409 6 cts msec The equation for the conversion table scale factor SF is SF 131 072 RTIF cts msec 131 072 409 6 320 This value must come out to an integer for true synchronization without any roundoff errors Usually it is easy if the spindle encoder has a resolution of a power of 2 If not the real time spindle speed in rps should be a power of 2 and Ix90 would not be an integer This scale factor would be written to the appropriate register in the conversion table In general this would not have to be done every time G95 is executed rather it would be part of the system setup The typical subroutine for G95 would consist of setting Ix93 and Ix90 for the coordinate system N95000 1190 10 PMAC F is length 10 msec 1193 1833 Time base source is external RET G96 Constant Surface Speed Mode Enable This code sets up the programs so that the spindle is put in constant surface speed CSS mode In this mode the spindle angular velocity is varied in real time so that its surface speed past the tool tip remains constant Essentially this means that the angular velocity of the spindle is inversely proportional to the radial distance of the tool ti
131. to keep the overall loop gain the same Extended Pole Placement Servo Filter For systems with more difficult dynamics such as multiple resonances and low frequency resonances the extended servo algorithm purchased with PMAC Option 6 can be used instead of the PID filter When Option 6 is purchased all motors on the PMAC must use the extended algorithm instead of the PID no mixing is possible With Option 6 the meanings of I variables Ix30 Ix69 are different from the standard PMAC refer to the manual for the extended servo algorithm for these meanings Because the extended algorithm is expressed in pole zero form instead of gain form it is not an intuitively tuneable filter like the PID is For this reason usually the ACC 25 Servo Evaluation Package must be used to tune this filter properly Closing the Servo Loop 9 9 PMAC User Manual Figure 20 Extended Control Alogorithm Block Diagram mj S ie r z hoshi 1 27 KS kg Haz 1M Liz teo z E TS la Haz V id 32xba8 x b 8 SZ s hee l 1 AP 1 69 RS 0 1438 rZ te Haz aa OY 515 to output 940 32 x hOB cai Feedback Encoder 2 Loop 1 GS go ai 1 Z Encoder 1 Feedback x Ix 4 a Encoder 2 Laoni User Written Servo Filter For the sophisticated user with very unusual and or difficult dynamics PMAC provides the hooks for custom user written servo algorithms
132. to PMAC through the RS232 422 port using of course an RS232 422 cable connected from the computer s COM port to the PMAC J4 connector on the front bezel Within the PMAC memory there is a section of 10 registers or memory locations which contain the VME bus base address information address modifier and don t care bits information interrupt level and vector number and the VME bus base address for dual ported RAM if used These memory locations start a the PMAC X memory location X 0783 and continue up through location X 078C Write values to these registers based upon the addresses and modes of operation selected for the PMAC VME through the RS232 422 port by using either the PMAC write memory command W or by using the VME Bus Address Configuration menu option in the PMAC Executive Software Before going through an example the above registers need to be explained in some detail 17 12 Writing a Host Communications Program PMAC User Manual Address Modifier The address modifier AM is simply a 5 bit code sent out on the bus by the host computer or master device each time a read or write is performed This AM informs slaves cards on the VME bus listening to the master what type of address is being sent i e whether it is a short 16 bit standard 24 bit or extended 32 bit address for more information consult a VME bus specification manual Tell PMAC the slave what AM to use The factory default for this
133. update among the different phases of the motor This task occurs automatically without the need for any explicit commands Refer to the Setting Up PMAC Commutation section of this manual for more details Housekeeping PMAC regularly and automatically performs housekeeping tasks that make sure the system is in good working order These tasks include the safety checks such as following error limits hardware overtravel limits software overtravel limits and amplifier faults They also include the update of the watchdog timer If any problem in hardware or software keeps these tasks from executing the watchdog timer will trip and the card will shut down Refer to the Making Your Application Safe section of this manual for more details PMAC Features 3 1 PMAC User Manual Communicating With the Host PMAC can communicate with the host at any time even in the middle of a sequence of motions PMAC will accept a command and take the appropriate action putting the command in a program buffer for later execution providing a data response to the host starting a motor move etc If the command is illegal it will report an error to the host Task Priorities These tasks are ordered in a priority scheme that was optimized to keep applications running efficiently and safely While the priority levels are fixed the frequency at which various tasks are performed is under user control Refer to the Setting Up PMAC Commutation and Closing
134. use a WHILE loop but instead of incrementing a variable use an on board timer PMAC has four 24 bit timers to write to and count down once per servo cycle These timers are at registers X 0700 Y 0700 X 0701 and Y 0701 Usually a signed M variable is assigned to the timer a value is written to it representing the desired time in servo cycles multiply milliseconds by 8 388 608 110 then the PLC waits until the M variable is less than 0 With M70 gt X 0700 24 S M70 P1 8388608 I10 Set timer to 500 msec WHILE M70 gt 0 Loop until counts to zero ENDWHILE Exit PLC program here when true For more timers probably the best technique to use is in memory address X 0 This 24 bit register counts up once per servo cycle Store a starting value for this then in each scan subtract the starting value from the current value and compare the difference to the amount of time to wait By subtracting into another 24 bit register handle rollover of X 0 gracefully First define the following M variables with on line commands M0 X 0 24 Servo counter register M85 gt X 07F0 24 Free 24 bit register M86 gt X SO7F1 24 Free 24 bit register Then we write as part of our PLC program M85 M0 Start of timer M86 M0 M85 Time elapsed so far WHILE M86 P86 Less than specified time M86 M0 M85 Time elapsed so far ENDWHILE Exit PLC program here when true Writing a PLC Program 16 5 PMAC User Manual
135. valid transmission of data including serial parity checking framing error checking serial full duplex communications and bi directional checksum computation on both serial and bus communications For more details on how these techniques work refer to the Writing a Host Communications Program section in this manual Making Your Application Safe 10 7 PMAC User Manual 10 8 Making Your Application Safe PMAC User Manual 11 Basic Motor Moves Table of Contents BASIC MOTOR MOVES RR 11 1 Commanding Some Basic Moves for the Motor oooonooncccoconocononononononcnnoncnnnonnonnnnnnn nono conc enne enne eene trennen trennt 11 1 eras pasto eid e C BP 11 1 JOG ACCEL ALON ENS MESE 11 1 SOLID ada 11 1 Jog COMMONS EE aa 11 1 Homing Search Move Control cinco ii old dildo aii dla cat daa 11 5 Homing Acceleration e ERREUR Ee Ine dde 11 5 Homne Speed RESERVED Fa e E a lap neo bote Os ote U UR CE 11 5 Home Irigs r Condition e eoe RR id 11 5 Specify Flag DM ws 11 5 Software Capture Optiot siie ia 11 5 Tig ser Sisnal s amp Edo 5 RE Rer od nas 11 6 lorque Mode THESE 11 6 Home Command P nmt 11 7 IIA AA 11 7 A AE NM rm 11 8 Homing from a PLC Program cistina iaa iga a nn trennen EE N E EE ENE etre ECE enne trennt 11 8 nto cue uv url 11 9 VA BD E 11 9 Homing into a Limit Switch AAA 11 9 Multi Step Homing Procedures eese essent nee then then then enne
136. velocity segments to create whatever overall profile is desired PVT mode can create any profile that any other move mode can The following diagram shows common velocity segment profiles Writing Programs for PMAC 14 17 PMAC User Manual AP 1 2 Vt AP 1 3 Vt t Time t Time Vel Vel AP 2 3 Vt APzVt t Time t Time Vel Vel Vi AP 1 6 Vt 2 AP 1 2 V V t 1 2 t t 2t Figure 33 PVT Mode Contouring Hermite Spline Use in Contouring PVT mode provides excellent contouring capability because it takes the interpolated commanded path exactly through the programmed points It creates a path known as a Hermite Spline LINEAR and SPLINE modes are second and third order B splines respectively which pass to the inside of programmed points Compared to the PMAC SPLINE mode PVT produces a more accurate profile Its worst case error can be estimated as _vitt met 384R 384 where V is the vector velocity T is the segment time R is the local radius of curvature and is the subtended angle Splined Moves PMAC can perform two types of cubic splines cubic in terms of the position vs time equations to blend together a series of points on an axis Its SPLINE1 mode is a uniform non rational cubic B spline and its SPLINE2 mode is a non uniform non rational cubic B spline It can of course do either spline for all of the axes simultaneously Splining is particularly suited to odd non cartesi
137. we will discuss the setup of motor 1 The procedure is parallel for any other motors There are many combinations of amplifier types motor types and feedback device types that can be connected to PMAC each requiring a somewhat different procedure The easiest connection is that of a DC motor and amplifier with an incremental encoder That is what is described first here Other options will be discussed later or in other sections Getting Started with PMAC 2 5 PMAC User Manual Typically connections are made to a terminal block that is attached to the JMACH connector by a flat cable Acc 8D or 8P The pinout numbers on the terminal block are the same as those on the JMACH connector for PMAC PC Make sure PMAC is unpowered while the connections are being made Leave any loads disconnected from the motor at this point Machine Connectors The primary machine interface connector is JMACH1 J8 on PMAC PC J11 on PMAC Lite P2 on PMAC VME J4 on PMAC STD top board It contains the pins for four channels of machine I O analog outputs incremental encoder inputs and associated input and output flags plus power supply connections These four channels can be used for two to four motors depending on the configuration Our example will use this connector The next machine interface connector is JMACH2 J7 on PMAC PC P2A on PMAC VME J4 on the middle board of an 8 channel PMAC STD not available on a PMAC Lite It is essentially identical
138. with the last values saved to flash memory in flash backed PMACs e Registers reserved with the DEFINE UBUFFER command from L 9FFF with decreasing address values to the declared length of the buffer Interface to Other Firmware The following software interface format is used for the PMAC firmware in order to communicate with a user written filter e On entry the B accumulator contains a 48 bit integer representing desired position DPOS in units of 1 Ix08 32 counts e On entry the X register contains a 48 bit integer representing actual position APOS in units of 1 Ix08 32 counts e Onentry the A accumulator contains a 48 bit integer representing desired velocity DVEL in units of 1 1x08 32 counts servo cycle e Onentry the Y1 register contains the value of Ix08 On entry the R1 register contains the address of the servo status register for the motor whose loop is to be closed 003D for Motor 1 0079 for Motor 2 etc This information can be used when servoing multiple motors to distinguish motor specific registers e On exit the upper 18 bits of Al should contain the control effort for the motor If the motor is not commutated by PMAC Ix01 0 this value will be loaded directly into the DAC register If the motor is commutated by PMAC this value will be used by the phasing routines to create two DAC outputs e The user written filter algorithm must end with a JMP instruction to location P 0023 9 12 Closing
139. 0 before trying to do final optimization GAT O10 Start data gathering open loop 10 command ENDG Stop data gathering o0 Open loop 0 to stop motor Do not issue the ENDG command until the motor has stopped accelerating Upload the data to the PC by pressing the F10 key e Plot the velocity vs time graph on the screen Calculate an acceleration value from the slope of the curve as it leaves zero velocity e Decrease the Ix78 slip gain by 10 and repeat steps 3 and 4 If the acceleration from zero velocity is greater than the first plot continue decreasing slip gain If the acceleration is less than the first plot increase Ix78 from the initial value by 10 and repeat steps 3 and 4 e Continue modifying Ix78 slip gain until honing in on a value that provides the maximum acceleration When close use progressively smaller changes to Ix78 until noticing that there is no significant change in the motor response e Multiply the values of Ix77 and Ix88 together This product is optimum for the motor at least at its present temperature Setting Up PMAC Commutation 8 13 PMAC User Manual e Notice the maximum velocity on the plot that provides maximum acceleration The acceleration stopped because of the back EMF of the motor which is proportional to your Ix77 magnetization current matched the supply voltage To get to a higher speed than this decrease the Ix77 value in inverse proportion to the desired increase in s
140. 06 OFF OFF OFF ON Q7 ON ON ON OFF 08 OFF ON ON OFF 09 ON OFF ON OFF OA OFF OFF ON OFF OB ON ON OFF OFF C OFF ON OFF OFF D ON OFF OFF OFF E OFF OFF OFF OFF F 4 8 Talking to PMAC PMAC User Manual Switch Address Control For PMAC STD SWI 1 SWI 2 SWI 3 SWI 4 Card Address Default OFF OFF OFF OFF Q0 Q0 ON OFF OFF OFF Q1 OFF ON OFF OFF 2 ON ON OFF OFF 03 OFF OFF ON OFF 4 ON OFF ON OFF 5 OFF ON ON OFF 6 ON ON ON OFF 7 OFF OFF OFF ON 8 ON OFF OFF ON 9 OFF ON OFF ON A ON ON OFF ON B OFF OFF ON ON C ON OFF ON ON D OFF ON ON ON E ON ON ON ON F Multi Card Mode Variable When talking to multiple cards over a single daisy chained connector variable I1 should be set to 2 or 3 usually 2 on every PMAC on the chain for proper communications usually I1 is set to 0 sometimes 1 if it is the only card on the connecting cable If this setting has not been made already as would be the case on the initial connection simply set I1 to 2 as the first command to the cards then immediately address one of the cards For example the command string I1 2 0 lt CR gt could be used to set up all the cards for daisy chained communications and then address card 0 Once this setting has been made and stored with the SAVE command it is not necessary to issue this command but it will not hurt to do so Setting I1 to 3 rather than 2 disables
141. 0930 gt v INIL vz LL vz pVHO J A za INnOO INnOO ZHM 082 OL O A0L OLO e UNO oud Q31V 10dH31NI H3931NI NIVH 3STMd on JAS INTIVA er NOL a3aiAoud uasn TWNOILdO Figure 4 Using the PMAC Control Panel Analog Wiper Input 6 13 Input Output Connecting PMAC to the Machine PMAC User Manual 6 14 Input Output Connecting PMAC to the Machine PMAC User Manual 7 Setting Up a Motor Table of Contents SETTING UP A MOTOR c 1 What 18 8 MOtOn oi EE 1 Defining the MOtOE ee iaa 1 Motor TeV Griddles ias 1 Activatne the Mot da 1 Does PMAC Commutate This Motor cocina dae ea 1 AAULESSAEV AD ld 1 Hex vs Decimal Reporta 2 Selectitig the Outpult s etr RH EEE ONEEN Ea NUR erre Dy eb equ enp A MEE DU ER sane 2 Selecting the Position Loop Feedback eee eese eene eene enne teen naa trennt nennen 2 Selecting the Velocity Loop Feedback sisirin eee eese eterne nnne nente notet entere nte tns 2 Dual Feedback Systems Rer a is 2 Accuracy vs Stability ne Rr Rr deti polle Rot lo bed dre icon oa 4 Selecting the Master Position Source e teet E ENNE EEN 4 Selecting the Flag Register ARA 4 Selecting the Power Up Mode sese essent nh ennt tne nenne treni teste nn none Ronan etre trennt nennen 4 Types Oi POSMION SENSO un on oves ended ecu dece e cst tenente I LEM uie 5 Quadrature Encoder Feedback esses eee eee nnne tenete entren nre ennr entrent ranas 5 Ir
142. 1 The PMAC memory can be retained through a power down or reset cycle with either EEPROM or battery backed RAM the standard CPU section which comes with the default configuration Options 4 and 5 or completely with flash memory the Option CPU section which comes with Options 4A 5A and 5B With the standard CPU section the basic user card setup information I variables conversion table settings VME and DPRAM address settings are held in non volatile EEPROM after being written there with the SAVE command User programs tables buffers and definitions are simply retained in RAM by the battery No command or action is required to keep these items through a power down or reset cycle With the Option CPU section all user card information is held in non volatile flash memory after being written there with the SAVE command No information is held in RAM through a power down or reset cycle so the SAVE command must be used to keep any information in the card through a reset If jumper E51 is in its default state OFF for PMAC PC Lite VME and 1 5STD ON for PMAC STD PMAC copies the contents that were last saved into its non volatile memory into active memory For PMACS with the standard CPU section this involves just the items stored in the little EEPROM Other items are kept just as they were before the reset For PMACs with the Option CPU section this involves all user settings variables definitions programs buffers and tables All
143. 12 DAC 5 and 6 C01A DAC7 and 8 C022 DAC 9 and 10 C02A DAC 11 and 12 C032 DAC 13 and 14 and C03A DAC 15 and 16 Setting Up PMAC Commutation 8 1 PMAC User Manual TWO OUTPUTS BECOME TWO AXIS ONE AXIS NO COMMUTATION WITH COMMUTATION D C 10V SINUSOIDAL 10V CONTROL PANEL TWO AXIS THREE OR FOUR PHASE VELOCITY OR 6KHz MAX FREQ TORQUE COMM VEL amp TORQUE COMM 16 BIT RESOLUTION 16 BIT RESOLUTION DISPLAYS MW 10V y y HOST FA COMPUTER 4 OUT 1 BUS gt De pepe 2 OF 8 16 e AVAILABLE OUTPUTS 4 aov 0v 16 gt f PRU THUMBWHEELS N T2 Y OU nc M AS ONERE 3PH gt OUT3 N gt 1 gt a oe 10 V gt i Pd 8 16 POSITION AND OUT8 HANDWHEEL A A a 90 ENCODER OUT9 a E eee gt 4PH v gt 8 16 EXPANSION I O PMAC gt ANALOG INPUTS AND iSBX EXTENSION gt gt 1 AMPLITUDE TORQUE FREQUENCY VELOCITY CONTROLS ANY gt gt SETA e GENERATED BY EMER OUT 16 Habes DERIVING A CURRENT BALANCE LOOP IN THE AMP 3 D C BRUSHLESS SYNCHRONOUS A C INDUCTION COMMUTATION ASYNCHRONOUS STEPPER amp SR MOTORS Figure 15 PMAC Commutation Basic Parameter Specification Regardless of the type of motor PMAC is commutating several parameters need to be specified for the commutation Commutation parameters for motor x begin at Ix
144. 1800 RPM At this speed with no load the voltage waveforms from back EMF should be just at the saturation point for example 380V RMS Give the motor a starting magnetization current say 5 to 10 of full current Ix7721638 to 3276 Set the slip gain Ix78 according to the above equations Measure the back EMF of the motor at a known fraction of the no load speed when it is putting out zero torque use the O0 open loop command Either drive the motor from another motor at the known speed preferred or take the motor above this speed with a small open loop torque e g 05 then command 00 and take the measurements as the motor coasts through the desired speed 8 12 Setting Up PMAC Commutation PMAC User Manual If the measured voltage is too low the magnetization current is too low If the voltage is too high the mag current is too high The difference should be proportional if the voltage is only 75 of what it should be the mag current is only 75 of what it should be Adjust Ix77 according to the measurements and try again The calculations should be almost correct on the second pass Experimental Setting of Induction Motor Parameters If it is not practical to use the induction motor nameplate values to set the induction motor parameters or if it is desired to check whether the parameters derived from the nameplate values are proper the following experimental method can be used This method should be used on an unloaded motor b
145. 1825 00C004 1 T conversion of Encoder 2 722 1826 00C008 1 T conversion of Encoder 3 723 1827 00C00C 1 T conversion of Encoder 4 724 1828 10C006 Conversion of ADCI 725 1829 10C007 Conversion of ADC2 726 1830 10COOE Conversion of ADC3 727 1831 10C00F Conversion of ADCA 728 1832 30FFDO Filtered Parallel from 1st ACC 14 729 1833 00FFFF Use the low 16 bits of word 72A 1834 000100 Max change 256 counts cycle 72B 1835 30FFDI Filtered Parallel from 1st ACC 14 72C 1836 00FFFF Use the low 16 bits of word 72D 1837 000100 Max change 256 counts cycle 72E 1838 20C020 Parallel from ENC 9 timer 72F 1839 07FFFF Use low 19 bits max allowed 730 1840 20C024 Parallel from ENC 10 timer 731 1841 07FFFF Use low 19 bits max allowed 732 1842 000000 Signifies end of table To use something other than the conversion table editor screen in the PMAC Executive program view the current set up of the conversion table with a single Read Hex RH command For instance if the table were set up as in the example immediately above the command RHY 720 24 report in hex 24 Y words starting at 720 would yield the following response 00C000 00c004 00C008 00cOOC 10C006 10C007 10C00E 10COOF 30FFDO OOFFFF 000100 30FFD1 OOFFFF 000100 20C020 O7FFFF 20C024 07FFFF 000000 000000 000000 000000 000000 000000 To use something other than the conversion table editor screen in the PMAC Executive program chan
146. 2H XXX available IRQ11 73H XXX available IRQ12 74H XXX available IRQ14 76H XXX Hard Disk IRQ15 TIH XXX available BM has reserved these for as yet unimplemented functions Initializing the PC s PIC In software the PC s 8259 PIC must be set up each time the PMAC application program is run to react properly to an interrupt from PMAC This setup consists of two parts vectoring and unmasking Vectoring tells the PC where to go at what address are the instructions to execute when it receives the interrupt Unmasking enables the interrupt The TurboC 2 0 environment provides useful tools to make this process relatively easy and will be used for example here there are of course many other ways to do this Vectoring In vectoring usually the first step is to save the old vector so it can be restored on exiting the program This is essential if borrowing an interrupt line In TurboC this can be done using the getvect function as in oldvect getvect Ox0d This statement stores the existing interrupt vector for interrupt number Od hex IRQ5 in the long variable oldvect The next step is to enter an interrupt vector Do this in TurboC with the setvect function as in setvect Ox0d pmac comm The address of the interrupt service routine does not need to be specified only the name of the routine in this case pmac comm The unmasking step should wait until the PMAC has been set up properly Setti
147. 5 is set properly If it decreases change 19053 to 7 If it does not change check the connections Step 2 Interpolation Next look at the current set up of he encoder conversion table The easiest way to do this is through the Configuration menu of the PMAC Executive program If this is not available command PMAC with RHY 720 16 which causes PMAC to report the contents of addresses Y 720 to Y 72F the set up data for the table We get back something like this 00C000 00C004 00C008 00CO00C 00CO10 00C014 00C018 00CcO1C 400723 000295 000000 000000 000000 000000 000000 000000 Synchronizing PMAC to External Events 15 7 PMAC User Manual The values shown here are the default values for the table The second value returned from address Y 721 shows a 1 T conversion of Encoder 2 which occupies registers C004 to C007 49156 to 49159 This gives us our desired sub count data for smoothness We do not have to change anything here However if the entry read COC004 we could change it by commanding 50 inches 500 cycles i counts 100 000 counts sec inch cycle sec counts 100 m sec WY 721 00C004 Step 3 Time Base Calculation Now set up an entry in the table to convert the interpolated position to time base format Looking at the values reported above notice that the ninth entry from address Y 728 400723 is a time base conversion However its source is address 723 which is the interpo
148. 6 Input Output Connecting PMAC to the Machine PMAC User Manual up so that a zero command does not cause a stop Analog output offset will manifest itself as creep in a velocity mode drive on a lightly loaded torque mode drive it can show up as high speed runaway Transition When PMAC sees a fault signal from the amplifier it will kill the motor automatically taking the amplifier enable signal to the disabled state Many amplifiers when they are disabled for any reason will indicate a fault signal to the controller PMAC permits an amplifier changing the amplifier enable line from disabled to enabled to be enabled even when the amplifier shows a fault However in the PMAC next error scan which occurs in the background housekeeping task every few milliseconds if the amplifier still shows a fault PMAC will disable that axis again Refer to the Synchronizing PMAC to External Events section of this manual Sinking Drivers The default drivers for these outputs are open collector sinking circuits requiring external pull up resistors Typically they can be connected directly to the cathode negative end of an opto isolator input on an amplifier The ULN2803A ICs used are rated to 100 mA and 24V internal diode protection circuits in the IC limit the high voltage of the output to the analog positive supply voltage usually 15V To defeat this protection and allow the outputs to be pulled above 15V pin 10 of the driver IC must be remo
149. 69 e 1x08 is an internal position scaling term for motor x usually set to 96 Ix09 is an internal scaling term for the velocity loop for motor x FE n is the following error in counts in servo cycle n which is the difference between the commanded position and the actual position for the cycle CP n AP n AV n is the actual velocity in servo cycle n which is the difference between the last two actual positions AP n AP n 1 in counts per servo cycle e CV n is the commanded velocity in servo cycle n the difference between the last two commanded positions CP n CP n 1 in counts per servo cycle CA n is the commanded acceleration in servo cycle n which is the difference between the last two commanded velocities CV n CV n 1 in counts per servo cycle IE n is the integrated following error in servo cycle n which is n 1 Y FEQ j 0 For all servo cycles for which the integration is active Ix34 1 turns off the input to but not the output from the integrator when CV does not equal zero 9 6 Closing the Servo Loop PMAC User Manual Notch Filters The PMAC can be used to set up notch filters A notch filter is an anti resonance band reject filter used to counteract a physical resonance While there are many different philosophies as to how to set up a notch filter we recommend setting up a lightly damped band reject filter at about 90 of the resonant frequency and a heavily damped band
150. 70 The commutation parameters are only used if Ix01 1 Counts per Commutation Cycle First to be specified is the number of counts per commutation cycle or electrical cycle or pole pair using motor I variables Ix70 and Ix71 where Ix71 Ix70 is the number of counts per cycle Ix71 and Ix70 must both be integers These are encoder counts after the decoding so if x4 decode is used there are four counts per encoder cycle Usually Ix70 is 1 except for a few special cases like 6 pole motors where there is likely not to be an integer number of counts per single pole pair Angle Between Phases The proper angular offset between phases which is different for three and four phase motors is set by Ix72 This parameter also permits reversal of the phasing so that motor leads do not have to be flipped if the phasing was wrong in assembly The units of Ix72 are 1 256 of a commutation cycle so for a three phase motor the possible values are 85 1 3 of 256 or 171 2 3 of 256 For a four phase motor the possible values are 64 1 4 of 256 or 192 3 4 of 256 Changing Ix72 between the two values for a given number of phases has the same effect as exchanging two of the motor leads Tests for the proper setting within each pair of values are given below 8 2 Setting Up PMAC Commutation PMAC User Manual Permanent Magnet Brushless Motor Commutation When commutating a permanent magnet brushless motor often called a DC brushless motor som
151. 79 1273 Force positive bias into B ELSE Ix72 gt 128 1229 1273 Force positive bias into A I279 1273 Force negative bias into B ENDIF This should force to 60 deg M70 1274 256 Starting value for countdown timer WHILE M70 gt 0 Wait for prescribed time ENDWHILE I229 P229 Restore real bias to A for 0 deg M70 1274 256 Starting value for countdown timer WHILE M70 gt 0 Wait for prescribed time ENDWHILE M271 0 Set phase position to zero I279 P279 Restore real bias to B CMD 2J Close servo loop DISABLE PLC 1 Keep from executing again CLOSE Phasing Referenced to Absolute Sensor With a position sensor that is absolute over at least one commutation cycle of the motor it is possible to set the proper phase of the motor on power up reset without having to perform a phasing search Instead the absolute sensor is read to determine the location of the motor within its phasing cycle With this procedure the phasing reference only needs to be done once during the initial development of the system Remember that this reading of absolute position is only done at motor reset time the ongoing phase position is always read through an encoder counter I Variables Two I variables need to be set up properly to perform phasing from an absolute sensor Ix81 tells PMAC the address and format of the absolute sensor If this parameter is greater than zero PMAC will read from the specified address in the specified format on power up re
152. 9 Set these scaling factors to 32 Ix30 Set this proportional gain term to 8192 Ix31 Set this derivative gain term to 0 Ix32 Set this velocity feedforward term to 65 536 Ix33 Set this integral gain term to 0 Ix35 Set this acceleration feedforward term to 65 536 If a following error is received during a jeg likely only on a high numbered motor increase this by 65 536 phase update time servo update time usually 65 536 1 4 16 384 yielding 81 920 If still getting a following error increase again by the same increment usually yielding 98 304 Ix69 Set this DAC output limit to 524 287 219 1 Ix70 Ix71 Set Ix70 to 1 and Ix71 to 256 to provide 256 counts microsteps per electrical cycle 64 microsteps step Ix72 Set this phase angle parameter to 64 or 192 for the usual two phase microstepping motor Changing between these two values changes the direction sense of positive rotation To try microstepping a 3 phase motor use 85 or 171 Ix77 Set this magnetization current parameter to control the amount of current used in the phases This holds the maximum number of DAC bits that will be used to command a DAC output current command to the amplifier For instance a value of 16 384 provides a 5V sinusoidal output on each phase Ix78 Set this slip gain parameter equal to 4 194 304 N where N is the number of phasing cycles per servo cycle as set by E3 E6 The default setting of these jumpers provides an N of 4
153. A0OB Mailbox 0 1 2 3 4 5 Character 1 J Address 7FA001 7FA003 7FA005 7FA007 7FA009 7FAO00B Mailbox 0 1 2 3 4 5 Character 1 J Address 7FAO001 7FA003 7FA005 7FA007 7FA009 7FAO0B Mailbox 0 1 2 3 4 5 Character 1 J lt CR gt 17 18 Writing a Host Communications Program PMAC User Manual Address 7FA001 7FA003 7FA005 7FA007 7FA009 7FAO00B Mailbox 0 1 2 3 4 5 Character 1 J lt CR gt First write an ASCII 1 to location 7FA005 then a J to 7FA007 then a to 7FA009 then a carriage return ASCII code 13 to 7FA010 and finally a to 7FA001 Example The above example works just fine for a command line of 15 characters or less including the lt CR gt that was added to terminate the line but if the command line contains more than 15 characters Remember there are only 15 mailbox registers that can be written to simply send the first 15 characters do not send a lt CR gt yet followed by the remaining characters in succession until all characters have been written And after the last character send the lt CR gt which tells PMAC to act upon the command To download a motion program and if one the statements in the program happens to be the following line IF P1 1 DISPLAY DELTA TAU lt CR gt 27 characters are here to send and thus 27 VMEwrite commands must be performed The following tables a
154. A80B 7FAAOB 7FACOB 7FAEOB MB 6 7FAO00D 7FA20D 7FA40D 7FA60D 7FA80D 7FAAOD 7FACOD 7FAEOD MB 7 TFA0OF 7FA20F 7FA40F 7FA60F 7FA80F 7FAAOF 7FACOF 7FAEOF MB 8 TFAOI1 TFA211 7FA411 7FA611 TFA811 TFAA11 7FACII 7FAE11 MB 9 7FA013 7FA213 7FA413 TFA613 TFA813 TFAA13 TFAC13 TFAE13 MB 10 7FA015 TFA215 7FA415 TFA615 TFA815 TFAA15 TFACI5 7FAEI5 MB 11 7FA017 7FA217 7FA417 TFA617 TFA817 TFAA17 TFACI7 TFAE17 MB 12 7FA019 7FA219 7FA419 TFA619 TFA819 TFAA19 TFAC19 TFAE19 MB 13 7FAOIB 7FA21B 7FA41B 7FA61B 7FA81B 7FAAIB 7FACIB 7FAEIB MB 14 7FA0ID 7FA21D 7FA41D 7FA61D 7FASID 7FAAID 7FACID 7FAEID MB 15 7FAOIF 7FA21F 7FA41F TFA61F TFA81F 7FAAIF 7FACIF 7FAEIF Writing a Host Communications Program 17 23 PMAC User Manual In addition to having unique addresses each PMAC VME must also have unique interrupt vector assignments However all the PMACs may use the same interrupt level interrupt level 2 in the previous examples Table 5 2 below shows suggested interrupt vector assignments for each PMAC VME card Power up or reset PMAC Write to base 121 if using DPRAM Write 00 into maibox reg 1 Send NO alineto o PMAC lt xl Hasan NO YES l interrupt Send command line to PMAC TES iui up to 16 characte
155. AC will reject a run or step command for any of the following reasons A motor in the coordinate system has both overtravel limits tripped ERRO10 A motor in the coordinate system is currently executing a move ERRO11 A motor in the coordinate system is not in closed loop control ERRO12 A motor in the coordinate system in not activated Ix0020 ERRO13 There are no motors assigned to the coordinate system ERRO14 A fixed non rotary motion program buffer is open ERRO15 No motion program has been pointed to ERRO16 After a or stop command a motor in the coordinate system is not at the stop point ERRO17 Implementing a Machine Tool Style Program PMAC permits the execution of machine tool style RS 274 G Code programs by treating G M T and D codes as subroutine calls This permits the machine tool manufacturer to customize the codes for their own machine but it requires the manufacturer to do the actual implementation of the subroutines that will execute the desired actions Many of the codes are quite standard and Delta Tau has provided examples of these This section discusses subtler issues involved in implementing the codes G M T and D Codes When PMAC encounters the letter G with a value in a motion program it treats the command as a CALL to motion program 10n0 where n is the hundreds digit of the value The value without the hundreds digit modulo 100 in mathematical terms controls the line label within
156. AN function Function expanded arctangent function Syntax ATAN2 expression Domain all reals Domain units none Range Pi Pi radians 180 180 degrees Range units radians degrees Possible errors none Note If doing the calculation in a PLC program make sure that the proper coordinate system has been addressed in that PLC program LN Function natural logarithm function log base e Syntax LN fexpression Domain all positive reals Domain units none Range all reals Range units none Possible errors _ illegal domain EXP Note x In To implement the y function use e instead A sample PMAC expression P2 would be EXP P2 LN P1 to implement the function P1 Function exponentiation function eX Syntax EXP expression Domain all reals Domain units none Range all positive reals Range units none Possible errors none 13 16 Computational Features PMAC User Manual SQRT Function square root function Syntax SQRT expression Domain all non negative reals Domain units free Range all non negative reals Range units free Possible errors _ illegal domain ABS Function absolute value function Syntax ABS expression Domai
157. APPLICATION SAFE Responsibility for the Safety of a Control System Delta Tau Data Systems has provided many safety features on the PMAC controller and invested many resources to make PMAC a safe product However the ultimate responsibility for the safety of a control system using PMAC must lie with the system designer utilizing the safety features on PMAC and in other parts of the system Hardware Overtravel Limit Switches PMAC has positive and negative hardware overtravel limit switch inputs associated with each encoder input These inputs are optically isolated with fail safe circuit design The inputs must actively be held low with the card sourcing current i e a normally closed switch for PMAC to consider itself not into the limit The source of the current is either the external 15V input that powers the analog output stage the 12V bus power line if that is jumpered over to power the analog output stage defeating the analog optical isolation or a 24V input brought in on the JMACH2 OPTO V pin Jumpers E89 and E90 control which of these sources is used They must be set properly for the card to be able to move Each motor must be directed to look at one of these pairs of inputs this is done by setting I Variable Ix25 for motor x to the address of the register that holds the appropriate inputs On hitting a limit PMAC decelerates the offending motor at a user programmed rate see I variable Ix15 If the motor is
158. Absolute Sensor eese eese eene nennen nennen then nenne nennen nene tren rra nenas 6 Phasing Referenced to Hall Effect Sensor eee eese eene ener enne thenetne nete trennen eese Phase Advance 10 Switched Reluctance Motor COMIMULAtiOM ococcconnconnonnonnnonnconoconoco nono nonn conoce enne nennen trennen en nc enn nn nccn aran nena ninos 10 AC Induction Motor Commutation cooococcconocononononnconnconncnn nono nro non enn nan enn RR ne Dn eene RR nO enne RR RR erret nO entrent tene tenete E trennen eet 10 Semne th SUID GOIN MEE 10 Setting the Magnetization Current esee eese enne enne nn nn nn enn One Dn trennen eene nn nr tne trne tree tene tree trennen 12 Experimental Setting of Induction Motor Parameters eee eee eerte entente eene ener enne 13 Open Loop Microstepping Commutation cesses eese esee tnee trennen teste enne on acen entes enne enne enne 14 Seting ANE Variables E A vas E AE 14 Usine TNEMO A e A O e ES E 15 User Written Commutation Algorithm esses eene nennen nennen rene en ren rennen tene teet tenerse trennen 15 Memory Space Software Interface and Program Restrictions eese eene trennen rennen 16 Table of Contents 8 1 PMAC User Manual 8 2 Table of Contents PMAC User Manual SETTING UP PMAC COMMUTATION Introduction This section explains how to set up the commutation scheme if PMAC is performing the
159. EDs in the opto isolator in order to be considered in a zero state The current flow to OV just needs to be broken to put the flag in its 1 state no external pull up is required although it will not hurt For an electronic switch an open collector output is usually used For a mechanical switch an open closed contact between the flag pin and OV is usually used Overtravel Limit Inputs When assigned for the dedicated uses these signals provide important safety and accuracy functions LIMn and LIMn are direction sensitive overtravel limits that must be actively held low sourcing current from the pins to ground to permit motion in their direction The direction sense of LIMn and LIMn is the opposite of what many people would consider intuitive That is LIMn should be placed at the negative end of travel and LIMn should be placed at the positive end of travel Home Flag Input Typically the HMFLn input is used for homing or other registration functions through use of the PMAC hardware position capture feature Encoder flag I variables 2 and 3 determine which signals and which edges cause a capture Amplifier Fault Input Typically the FAULTn input is used as a signal from the amplifier that something is wrong Ix25 controls whether a high signal or a low signal means fault For more details on the actions taken on these flags refer to the Making Your Application Safe and Synchronizing PMAC to External Events sections of this manual
160. Electronic Cams ee dada cha e dx CR Ye De Lee Eaa AEROS NER Ees 3 What Is Time Base Controla eei deese iot eee eee etre retra lonis eee e eod run ese spe tesis eicere epe etna de 3 Re l Time WI DnTUI Ta 4 Constraints on Selection of RTIF resaca caian 4 Howlit Works does coran ii 5 Instructions for Using an External Time Base Signal eese eene eene none cnn non aran nenas 5 DAS DINA A iaseviacessecaaaasen sai cusadecacisuueceavesbuiases oasis aacasoi saseecadceeadscaayel E ESEE RE NEO 7 Tnesered Time Base C 8 Instructions for the Triggered Time Base esee eene nennen eene enne trennen enne trennen enne 9 Triggered Time Base Example aes pa coa dant Ne eue 10 Set up and Definitions m 10 eurer T ea ci 11 PLEC POTOM m aos 11 Synchronizing PMAC to Other PMACS sssrini draie e E aeaa ten nete trennen enne teen nnne 11 CLOCK IET IIT E 11 Sharing Clock SienalS PR aa 12 CONNEC CE 12 External TE can 12 Motion Program Tnne cuina Queue tenes ie so etate tree Deo Cdn bk Rs dut eset on E Guo aiii deentrar 12 Minimizing Imhal OFF SCL ME 13 Position Capture EUDCEUONS sacci eire stood iot ave dde dada 14 Setting the Trigger Condition eese nn reno nene enn Ran entren teen ne enne On rennen erstens enne tete tenerent nnne 14 USING JOP Homin MEMMMN www 0 n0 0n00SS4An0ST
161. Encoders 9 16 so entries for these must be added to the table Second if using an external time base frequency source the scaling factor and maybe the source should be changed Third if using 1 T interpolation on the position feedback Fourth if requiring fast control on just a few axes reduce the table to save computation time because each conversion does take a finite amount of time Example When using two axes of fast laser interferometer quadrature feedback into Encoders 1 and 3 with parallel sub count interpolation and no handwheels or external time base set up a table as follows for minimum conversion time Minimum Conversion Time Table Address Y Word Meaning 720 1824 80C000 I sub count conversion of Enc 1 721 1825 80C008 I sub count conversion of Enc 3 722 1826 000000 Signifies end of table Example To convert two 16 bit absolute encoders from the first ACC 14 filtered not to allow more than eight bits change per servo cycle four incremental encoders ENC1 4 with 1 T interpolation four A D converters ADC1 4 and two linear displacement transducers ENC9 10 timers without filtering 7 26 Setting Up a Motor PMAC User Manual The conversion table setup would be Two 16 Bit Absolute Encoders Conversion Table Address Y Word Meaning 720 1824 00C000 1 T conversion of Encoder 1 721
162. Executive Program section in the PEWIN User s Manual 3A000PEWIN 363 for details 2 4 Getting Started with PMAC PMAC User Manual Establishing Host Communications Either the Executive or Setup program can be used to establish initial communications with the card Both programs have menus that tell the PC where to expect to find the PMAC and how to communicate with it at that location If it is told to look for PMAC on the bus also tell it the PMAC base address on the bus this was set up with jumpers on PMAC If it is told to look for PMAC on a COM port tell it that the baud rate this was set up with jumpers or switches on the PMAC The Executive program ACC 9W does have an automatic baud rate search to find out how the card is set up Instructions for setting up the communications are given in detail in the PMAC Executive for Windows User s manual 3A0 0PEWIN 363 p1 Setup Manual 3A0 1SETUP 363 and P2 Setup Manual 3A0 2SETUP 363 Refer to those manuals for more explanation Once the program has been told where and how to communicate with PMAC it will attempt to find PMAC at that address by sending a query command and waiting for the response If it gets the expected type of response it will report that it has found PMAC If it does not get the expected type of response after several attempts it will report that it has not found PMAC Terminal Mode Communications Once the program reports that it has found PMAC and a key
163. FER Limited Range Many M variables have a more limited range than the PMAC full computational range If a value outside of the range of an M variable is placed to that M variable PMAC automatically rolls over the value to within that range and does not report any errors For example with a single bit M variable any odd number written to the variable ends up as 1 any even number ends up as 0 If a non integer value is placed in an integer M variable PMAC automatically rounds to the nearest integer Using M Variables Once defined an M variable may be used in programs just as any other variable through expressions When the expression is evaluated PMAC reads the defined memory location calculates a value based on the defined size and format and utilizes it in the expression Care should be exercised in using M variables in expressions If an M variable is something that can be changed by a servo routine such as instantaneous commanded position which operates at a higher priority the background expression evaluation there is no guarantee that the value will not change in the middle of the evaluation For instance if in the expression M16 M17 M16 M17 the M variables are instantaneous servo variables the user cannot be sure that M16 or M17 will have the same value both places in the expression or that the values for M16 and M17 will come from the same servo cycle The first problem can be overcome by setting P1 M16 and P2 M17 r
164. Failure to See Through Failure to See Through Inside Corner Outside Corner Tool Center Path Line emm Line Line Programmed Arc Path Line i Tool Center Line i eau Path 5 a ik Programmed i Line Path Stopping Point Overcut Exactas i Inside Corner Smaller Than Arc Radius Smaller Than Cutter Radius Cutter Radius Figure 49 Failures in Cutter Compensation Inside Corner Smaller Than Radius Second if the compensated path produces an inside corner with one of the moves shorter than the cutter radius the cutter compensation will not work properly This situation results in a compensated move that is in the opposite direction from that of the uncompensated move and there will be overcutting at the corner Inside Arc Radius Smaller Than Cutter Radius Third if the program requests an arc move with compensation to the inside and the programmed arc radius is smaller than the cutter radius then no proper path can be calculated In this case PMAC ends the program at the end of the previous move with a run time error setting the coordinate system run time bit in the status word to 1 Single Stepping While In Compensation It is possible to execute moves in single step mode while cutter compensation is active but be aware of several special considerations for this mode of operation Because of the need for the program to see ahead far enough to find the next move in the plane of compensation before the current move can b
165. Finally modify the proportional gain term to compensate for the DC gain change that the filter creates Onp Gz od 2 Onz Cp Ix30 Ix30 new For example suppose a 55 Hz resonance has been identified in the mechanical coupling To compensate for this put a lightly damped band reject filter damping ratio 0 2 at 50 Hz natural frequency and a heavily damped band pass filter damping ratio 0 8 at 80 Hz natural frequency to limit the high frequency gain of the filter The servo update time is the default of 442 microseconds T 442p sec 10 6 LC 0 000442 sec LA sec Onz 22 50Hz 314 2 rad sec Opp 22 80Hz 502 7 rad sec az 1 267z0pzTs 407 72 1 2 0 2 314 2 0 000442 314 2 0 0004427 1 0748 2 p2 ap 1 20 pOnpTs npTs 2 0 8 502 7 0 000442 502 7 0 000442 1 4049 Next compute the filter coefficients 24 0 T 2 2 02 3142 0 000442 2 Ix36 1 912 a 1 0748 9 8 Closing the Servo Loop PMAC User Manual 1 Ix37 0 930 a 1 0748 V penpTs 2 2 0 8 502 7 0 000442 2 Ix38 l A 1 677 ap 1 4049 1 Ix39 0 712 ap 1 4049 Finally compute the DC gain adjustment assuming for the example that the existing proportional gain term Ixx30 had been 500 000 2 Onp Az 502 7 1 0748 Ix30 new 1x30 y dts wm 500 000 2 979 169 Onz Cp 314 2 1 4049 DC Gain Correction Finally multiply the old proportional gain Ix30 by
166. HILE statements or GOTO statements GOSUB CALL and RETURN jumps do not count here The intent of this rule is to prevent PMAC from having to abort a program due to insufficient calculation time if it has to loop multiple time on short moves Blending Stopped PMAC will instead allow the previous move to come to a stop and will start calculating the program again at the next real time interrupt see I8 description continuing until it finds the next move statement or two more jumps back in which case the process is repeated This permits indefinite waiting loops that will not cause PMAC to abort the motion program because of insufficient calculation time Nested Loops This double jump back rule can cause programmers to inadvertently stop blending when they are calculating moves within nested while loops Consider the following example that attempts to creates continuously blended sinusoidal motion generated in the inner loop using the outer loop to index the size of the sinusoid SPLINE1 TA20 P1 0 WHILE P1 10 P2 0 WHILE P2 360 X P1 SIN P2 P2 P2 1 ENDWHILE P1 P1 1 ENDWHILE The first 360 pieces will be blended splined together on the fly as PMAC cycles through the inner loop But when PMAC increments P2 to 360 it hits the first ENDWHILE and jumps back to the inner WHILE condition which is now false so it jumps down increments P1 hits the second ENDWHILE and jumps back to the outer WHILE condition all without encountering
167. IC that will be active Write a one byte argument in which every masked interrupt to the PMAC PIC is represented by a 1 and every unmasked interrupt is represented by a zero For instance to unmask IR4 alone the argument would be ef hex to unmask IR5 alone the argument would be df hex The routines write this argument to the PMAC PIC s Operation Control Word 1 OCW1 Without the driver use a command like outportb base 9 Oxef unmask IRA only At this point unmask the interrupt being used on the PC s PIC First disable the PC interrupts TurboC command disable Next read the current mask word at I O port address 21 hex with a command like ch inportb 0x21 Then unmask the new interrupt to be use by performing a bit by bit AND between the current mask word and a mask word that would enable only the new interrupt line ef hex for IRQ4 fe hex for IRQ3 The C command for this is ch 2 ch amp Oxef The resulting new mask word is written back to I O port address 21 hex with outportb 0x21 ch Finally re enable the PC interrupts TurboC command enable This completes the setup procedure Using the Interrupts To react to an interrupt in actual use write an interrupt service routine TurboC has a special type of routine that makes this relatively easy in naming the routine specify that it is an interrupt routine The routine header line is something like static void interrupt far pmac_comm void No
168. IR5 EROR IR2 HREQ IR6 FE1 IR3 IPOS IR7 Software EROR is the coordinate system fatal following error line If the control panel is enabled 12 0 it reflects the panel selected coordinate system by FDPn lines If the control panel is disabled 12 1 it reflects the host addressed coordinate system by amp n command This signal goes high if any motor in the coordinate system exceeds the Ix11 warning following error limit FIER is the coordinate system warning following error line If the control panel is enabled 12 0 it reflects the panel selected coordinate system by FDPn lines If the control panel is disabled 12 1 it reflects the host addressed coordinate system by amp n command This signal goes high if any motor in the coordinate system exceeds the Ix12 warning following error limit Writing a Host Communications Program 17 5 PMAC User Manual HREQ is the host request line of the PMAC processor This line can be used to do character by character handshaking on communications with PMAC This line can mean read ready and or write ready depending on the value of the byte that has been written from the PC to the PMAC base address register the interrupt control register of the DSP 0 means neither 1 means host read ready generates an interrupt 2 means host write ready generates an interrupt 3 means both generate an interrupt EQUn is the compare equals bit for PMAC encoder n
169. It is important to set a reasonable fatal following error limit and to allow sufficient room past the limit switch to absorb errors up to that following error limit The polarity of the limit switches is the opposite of what many people would consider intuitive That is the LIMn input should be tied to a switch at the positive end of travel and the LIMn input should be tied to a switch at the negative end of travel Make sure you test carefully the polarity of your limit switches Software Overtravel Limits PMAC also has positive and negative software limits for each motor to complement or replace the hardware limits The user set values Ix13 and Ix14 parameters for motor x for these limits cannot be Making Your Application Safe 10 1 PMAC User Manual saved in EAROM on battery backed boards they are held in battery backed RAM The behavior on hitting these limits is the same as for hardware limits A value of zero in these parameters disables the limit The software limits are disabled automatically during homing search moves until the homing trigger is found As soon as the trigger is found the software limits are reactivated using the new home position as the reference If overtravel limits are used they should be far enough from the home position to allow for deceleration and turnaround after the trigger is found Following Error Limits PMAC has three following error limits for each motor following error is the d
170. It will also have its position following function turned on Ix06 is set automatically to 1 the motor just de selected has its position following function turned off Ix06 is set automatically to 0 Alternate Use The discrete inputs can be used for parallel data servo feedback or master position if I2 has been set to 1 The ACC 39 Handwheel Encoder Interface board provides 8 bit parallel counter data from a quadrature encoder to these inputs Refer to the ACC 39 manual and the Parallel Position Feedback Conversion sections under Setting Up A Motor in this manual for more details on processing this data Reset Input Input INIT reset affects the entire card It has the same effect as cycling power or a host command It is hard wired so it retains its function even if I2 is set to 1 Handwheel Inputs The handwheel inputs HWCA and HWCB can be connected to the second encoder counter on PMAC with jumpers E22 and E23 If these jumpers are on nothing else should be connected to the Encoder 2 inputs The signal can be interpreted either as quadrature or as pulse HWCA and direction HWCB depending on the value of I905 1905 also controls the direction sense of this input Make sure that the Encoder 2 jumper E26 is set for single ended signals connecting pins 1 and 2 Analog Input The Wiper analog input 0 to 10V on PMAC PC VME and STD 10V to 10V on PMAC Lite referenced to digital ground provides an input to a voltage to frequen
171. KKKK OPEN PROG 101 CLEAR I125 2C000 Disable LIM as limits HOME1 Home 41 into limit and offset out of it I125 COO00 Re enable LIM as limits CLOSE End of program EREEREER KERR KERER R PLC Set up Variables to be saved KKKKKKKKKKKKKKKKK CLOSE I123 10 Home speed 10 cts msec negative 1125 C000 Use Flags1 for Motor 1 limits enabled 1126 32000 Home offset of 2000 counts enough to take you out of the limit 1902 23 Capture on rising flag and rising index 1903 2 Use LIM1 as flag negative end switch M133 X 003D 13 1 Desired Velocity Zero bit M145 gt Y 0814 10 1 Home complete bit ORR RR ARID A Bel AA PLC program to execute routine KKKKKKKKKKKKKKKKKKKKK OPEN PLC 10 CLEAR 1125 2C000 Disable LIM as limits CMD 1HM Home 1 into limit and offset out of it WHILE M145 1 Waits for Home Search to start ENDWHILE WHILE M133 0 Waits for Home motion to complete ENDWHILE I125 ScC000 Re enable LIM as limits DIS PLC10 Disables PLC once Home is found CLOSE End of PLC Multi Step Homing Procedures A homing procedure may be required that cannot be executed with a single PMAC homing move In this case use two or possibly more homing search moves changing the move parameters in between Although this can be done with a sequence of on line commands it is probably easier to create a small motion program to execute the sequence Which Direction to Home The
172. M and or speeds F are implemented in modal commands Modal commands can precede the move commands they are to affect or they can be on the same line as the first of these move commands Move Commands The move commands themselves consist of a one letter axis specifier followed by one or two values constant or expression All axes specified on the same line will move simultaneously in a coordinated fashion on execution of the line consecutive lines execute sequentially with or without stops in between as determined by the mode Depending on the modes in effect the specified values can mean destination distance and or velocity see Trajectory Features section Writing Programs for PMAC 14 1 PMAC User Manual Motion Program Trajectories Among the PMAC outstanding characteristics are the power and flexibility of its trajectory generation algorithms These algorithms allow a variety of difficult maneuvers to be performed and permit the choice of tradeoffs between ease of use and degree of control It is important to remember that these trajectories are series of commanded positions only It is up to the servo loops for each axis to try to make the actual positions match the commanded positions All the times speeds distances and profiles discussed in this section are commanded ones unless otherwise noted Linear Blended Moves The easiest class of moves to make is the linear blended move category In this type of move
173. MAC communications ports each version of PMAC has two of these ports Every PMAC has a serial port that can connect to a COM port on a host computer The PMAC PC Lite and STD have a host port for bus communications to the host This port works exactly the same on all three versions The PMAC VME has mailbox registers for communications over the VME bus to the host computer Instructions for using each of these ports are discussed in the following sections This section covers the communications of text commands and text responses With the Option 2 dual ported RAM completely binary methods of communications are possible with the proper programs written on both the host computer and PMAC Note Delta Tau provides several software libraries to make the development of host communications programs easier Most notably the ACC 9P PCOMM library handles all of the low level issues described in this section Much of the discussion in this section is not required if you are using one of these communications libraries Polled vs Interrupt Based Communications Regardless of the port that is used there are two fundamental methods for doing the handshaking on the passing of characters In the first method the host can poll the PMAC interface repeatedly if necessary to see if it is ready to send or receive the next character or line In the second method the PMAC interface will interrupt the host when it is ready to send or receive the next
174. ME If connected to an RS 232 port of a host computer it is strongly recommended that an ACC 26 or similar converter be used especially in multi drop applications Note The Option 9L RS 422 interface is required on a PMAC Lite to tie it to another PMAC In this case the ACC 3D 26 pin serial cable should be used not the ACC 3L 10 pin serial cable Serial Card Addressing This software addressing is done by the n command where n is a hexadecimal digit from 0 to F 15 decimal Up to sixteen cards may be chained together under one host The command addresses all cards simultaneously but it is not legal to send a querying command for response over the serial port when the system is in this mode which card would respond Setting Up the Addresses The software address command issued by the host must match the card number of the particular PMAC as determined by jumpers E40 E43 on PMAC PC PMAC Lite PMACI 5 STD and PMAC VME or by switches SW1 1 to SW1 4 on PMAC STD See Table 4 1 for the proper jumper configurations One card on the chain must be set up as card 0 It is recommended that the other cards be numbered sequentially from zero 01 22 etc Card Address Control E Points for PMAC PC Lite 1 5 STD and VME E40 E41 E42 E43 Card Address Default ON ON ON ON 00 00 OFF ON ON ON Q1 ON OFF ON ON 02 OFF OFF ON ON 03 ON ON OFF ON 4 OFF ON OFF ON 05 ON OFF OFF ON
175. Manual Layout This manual provides a quick step by step guide for the beginner setting up a typical system as well as explaining how to use the various features available on PMAC It is organized by subject safety I O servos trajectories etc to allow quick access by the area of concern The subjects are ordered by the typical sequence of events to go through to set up a system The commands are organized in alphabetical order and the variables registers jumpers and connectors are in numerical order There is extensive cross referencing between the chapters Any variable command register jumper or connector mentioned in chapter 2 is covered in more detail in the appropriate reference chapters Reading the chapters there may be topics or depth of coverage not needed at the time Simply skip these chapters and proceed to a chapter that is of more immediate use This manual assumes the system integrator who is responsible for this installation knows the basics of working in a Microsoft Windows environment and has more than a basic understanding of electronics machine tool technology and the PMAC motion control board If any questions about a particular aspect of the installation arise do not attempt the task until a thorough understanding is gained Feel free to contact Delta Tau Data Systems Inc Technical Support at any time during installation Refer to the Technical Support section below for information on contacting our technic
176. Move e EKE EEEE E EEE 14 Setting up a Coordinate System en RERO ete pilo Herpes Dee zeit repe Debate ees tek dire eae Mba Aas 14 DEFINING an I A A A aia cs 14 CALAS GI AXIS A A Ets 15 MAUL PIE ARS A A a ini 15 Wautting a Motion PLOT ida 15 Using the Program Editor esee eet ene enn enn ne nn RR nn RR nn RR tnee then teen trenes tree test trennen eene enne en 16 Executing A Motom Propral Et 16 Table of Contents 2 1 PMAC User Manual Starting the PLO RIGID fois a ete tete tree e epe oia ad pote lays Coen ove e deste enun le doe tiques 16 hyogst audien D cd lr E EE E E ia 16 Refining the Program cccccsccscssscssssscsseseceseescsseeseesecsceseesecaseseesseescsseeseesecssesecsaecesasesesaecseesesaaesaeeseesecaaesesnaeeeeeaseneegs 16 Writing and Executing a PLC Propiciar ii dies 17 Starting the PLC PROTON a lay tvebs stars E a UN Sais iaa 17 Stopping the PLC Progr ti eiie ariete iterat tie repe lindo rmt ea pH Ek do repertis eeu nob eee iiaii 17 2 2 Table of Contents PMAC User Manual GETTING STARTED WITH PMAC Overview PMAC is a very flexible controller suitable for many different types of applications with different types of hosts amplifiers motors and sensors As such the card must be configured for a specific application using both hardware and software features in order to run that application properly PMAC is shipped from the factory with defaults set in hardware and softwar
177. O the first move starts immediately after calculations are finished Typically this is works in single card applications but not in multi card applications Time Specification of Moves In general moves in these programs should be specified by move time TM TA and TS and not by feedrate F The time for a feedrate specified move is calculated as the vector distance of all feedrate axes FRAX divided by the feedrate It is difficult to ensure that such moves on separate cards will take the same amount of time DWELL is a non synchronous move and should not be used when writing programs for multi card applications Use the DELAY command to maintain program synchronicity No Drift Conditions If motion programs are written carefully using time specified moves and the cards share common clock signals they can run indefinitely with no drift between the cards There can be an initial offset between the cards of up to a few msec as to when they start their motion programs even with simultaneous commands but this offset will not increase with properly written motion programs and shared clock signals The following section explains how to minimize and usually eliminate this offset Minimizing Initial Offset Usually PMAC cards told to simultaneously start a program will do so on the same servo cycle providing that no PLC programs are enabled Programs that do not start on the same servo cycle will start at the next real time interrupt This
178. OTCH Servo Filter oeste cies tese oer cere eire ey Bando a SES e Fk ed a 9 5 PMAC PID Servo Loop Modifiets pe Re ld 9 6 Extended Control Alogorithm Block Diagram esee nenne nennen nennen 9 10 Motor x Motion Variables ee neret tie ibis Gas Y E EE e e obrutus dis PEE ela 11 4 Homing Search Move Tr jectoty 4 e es tpe DE Rete dedos ii 11 6 PMAC Coordinate Definition epe p Get ee pe e OPE dre E e Pee HORE ie EOD EROR nga 12 5 PMAC Multitasking Example sides luto debes cededo ark Gres e reete roe sek ab Lobo alocado abia iii 13 4 PMAC Memory Mapping 5 3 pet ld oa a Re bna ra cbe EE e EUR ina 13 7 Coordinate System Variables i Ue ias eade eorpore ele EK EE aE E aea E Eaa Eae 14 4 Automatie S Curve Acceleration esie eie aL eanna anasa aero aE a ENa SEa ena E 14 5 Linear Mode Trajectories Sheet 1 of 4 ssessssssssssesseeeeeeeneenee nennen enne 14 7 Linear Mode Trajectories Sheet 2 of 4 ssssssssssssssssseseeeeeeeeenee nennen nennen nennen 14 8 Linear Mode Trajectories Sheet 3 of 4 oooconconincncnniccnonnconnnonconocononnncnnncnncono nono conc nnnn nan nn nr nan enne 14 9 Linear Mode Trajectories Sheet 4 of 4 sssssssssssssssessesseeen eene 14 10 PMAC Circular Interpolation eite tette ttt etes cree beo aae oie ed ei eere P ee E E ceret p ed 14 16 PVT Mode Contouring Hermite Spline essere ener nennen nenne 14 18 PVT Segment Shapes icem hereti
179. P1 250 P2 or T 100 which is legal but wasteful Variable Value Assignment Statement This type of statement calculates and assigns a value to a variable When a value assignment statement is sent to PMAC if a program buffer is open the statement is added to the buffer If not it is executed immediately The standard assignment syntax is variable name expression where variable name specifies which variable is to be used and expression represents the value to be assigned to the variable I Variable Default Value Assignment A statement with the syntax I data will assign to the specified I variable the manufacturer s default value for that variable not the user s EEPROM stored value Synchronous M Variable Value Assignment In a motion program when PMAC is blending or splining moves together it must be calculating in the program ahead of the actual point of movement This is necessary in order to be able to blend moves together at all and to be able to do reasonable velocity and acceleration limiting Depending on the mode of movement calculations while blending may occur one two or three moves ahead of the actual movement Why Needed When assigning values to variables is part of the calculation the variables will get their new values ahead of their place in the program when looking at actual move execution For P and Q variables this is generally not a problem because they exist only to aid further m
180. PM Rated line speed 60 Hz Number of poles 4 Amplifier Maximum RMS current 40A PMAC Peak output for max amplifier current 32 767 DAC bits 10V Phase update rate 9 04 kHz 9040 updates sec Constant of proportionality 238 From this data compute the above equations 1755 4 Sli Hz 60 1 50H ip freq Hz TE z 1 50 H _ Slip freq cycles update CH 1 659x10 4 9040 updates sec Rated Torque 32768 DAC bits 20A 40A 16384 DAC bits 214 2 cycles update E 25 1 659x10 DACbit 16384 2784 Slip gain Ix78 would be set to 2784 Setting the Magnetization Current Warning The technique described in this section can involve the measurement of high and potentially deadly voltages unless measuring voltages well isolated from the power voltages Make sure proper techniques for measuring power level AC voltages are understood thoroughly before attempting this technique Determination of the proper magnetization current is best done with a simple experimental technique The technique relies on the linear relationship between motor speed and back EMF in which the magnetization current provides the constant of proportionality Kp the velocity or back EMF constant is directly proportional to the magnetization current Consider the no load speed of the motor equivalent to the line frequency since there is zero slip at zero load For a 4 pole motor at 60 Hz the no load speed is
181. PMAC This mailbox register has a special purpose which will be covered later Knowing this the second character of the command will have to be written to mailbox register 2 the third mailbox register at location 7FA005 and so on 2 Write the first character of the message or group of 15 characters in a long message last i e write all the other characters in the command first beginning with mailbox register 2 and then write the first character into mailbox register 0 at location 7FA001 The reason for this is when writing to mailbox 0 PMAC immediately reads in all the mailbox registers and begins to act upon the received command line Note Don t forget to end all your ASCII messages commands with a carriage return CR Control character commands which do not require a CR should be written directly into mailbox register 0 Example To send the commands to select motor 1 and jog to it combine two commands to do this on one line H1J lt CR gt There are five ASCII characters here and thus write to five mailbox registers To send this command issue five VME write commands Keep the same base address of PMAC from the previous example The following tables show the contents of the mailbox registers Address 7FAO001 7FA003 7FA005 7FA007 7FA009 7FAO0B Mailbox 0 1 2 3 4 5 Character 1 Address 7FAO001 7FA003 7FA005 7FA007 7FA009 7F
182. R b f Calculate o e C No moves ahead Ix92 1 RAPID HOME DWELL S Execute P FUN Y i TUN erum ime Calculate Figure 51 PMAC Motion Program Recalculation 15 2 Synchronizing PMAC to External Events PMAC User Manual Changing Ratios on the Fly To vary the following ratio in the middle of an application change Ix07 alone Ix08 is involved in the scaling of servo feedback calculations and so should not be changed in the middle of an application There can be tradeoffs between the resolution of on the fly changes and the servo performance of the system The higher the Ix08 scale factor the finer the resolution of the changes can be However the higher Ix08 is the lower proportional gain Ix30 can be before internal saturation occurs and the lower the maximum velocity can be before there is internal saturation of those registers In general Ix08 should be kept below 1000 Superimposing Following on Programmed Moves In addition this following function can be superimposed on calculated trajectories This permits for instance shapes to be cut out of a moving web where the shape program can be written without regard to the web movement and a master signal from the web compensates for the movement Bit 16 of Ix05 determine whether the following occurs in offset mode where the reported position of the following motor does not reflect the change due to following or normal mode in which it does Usu
183. RS 422 receivers accept inputs from RS 232 well with significant noise margin Most PCs RS 232 receivers can read the PMAC RS 422 signals quite well but noise margin tends to be minimal and communications in this direction can be garbled especially in the presence of PWM amplifiers For robust communications to an RS 232 host PMAC Accessory 26 provides conversion capabilities and optical isolation Of course direct connection to a host RS 422 port can be made Baud Rate The serial port baud rate is determined at power up by jumpers E44 E47 PMAC PC Lite 1 5 STD VME or switches SW1 1 to SW1 4 PMAC STD and the PMAC master clock rate Serial baud rate can be set up to 76 800 baud on a 20 or 40 MHz board up to 115 200 baud on a 30 or 60 MHz board If E44 E47 are all ON SW1 1 to SW1 4 all OFF the serial port is disabled Signal Lines Since serial interfaces vary from system to system PMAC provides a simple but flexible interface In addition to the signal ground only four lines are required eight counting the complements data transmit data receive clear to send and ready to send These pairs of lines may be exchanged through jumpers E9 E16 if necessary to match the host configuration PMAC simply shorts together the DSR and DTR lines to provide an automatic return signal on this strobe for those systems that require it 4 2 Talking to PMAC PMAC User Manual Data Format The serial communications data format
184. Ra boni ele ER ee Eee pee tls Fatal Following Error Limit eese eene eene oen RAR RAR RRA RRA entren erster RR ren remettre tne Warning Following Error Limit esses eene eene nennen nennen eene etn tne tne narran nenes Integrated Following Error Protection eeeeee esses ennemi ona ene then nr eenene teen nac trennen bid RELIER Acceleration Lars pere ees UD et eR sas Ere Pe Eb epe A esa erre be Ebo eds Command Output Limits ai reete pee ebbe ERR e dite iet utere doble ee S eeu Integrated Current TT lunedi RR Amplifier Enable and Fault Lines sess ener enne enne tn ennt n rese nr en teen reinen enne nn MESI RPM bI CE Hardware Stop Command Inputs seeeeeeseeseeeeeseeeeeee eren nennen ren eene tnre tenete ne teet ne tenete en trennen eren Host Generated Stop Commands ssesessssseeeeeseeeeen nn enn enn RR RR enr RON nE ER EEEE sE iE Kraan EEES kairo Eesi a AAPP Firmware Checksum eee esee sees eene eene RR RR nnne nre RR n ranas User Program Checksum aee tee reta Et DAR ette Bekk ra deu tae ker e Pao esteso enira cin ege eo Ra er Erie seri Lad Communications Data Integrity Features sseeeeseeeeseeeeeeee eee nee non nn non etre nne anar cnn nan non noo none inneren eterne Table of Contents 10 i PMAC User Manual 10 ii Table of Contents PMAC User Manual MAKING YOUR
185. Triggered time base running 2 B0 Triggered time base armed 2 Cx Incremental encoder without extension 1 D0 Exponential Filter 1 Ex Reserved for future use 1 Fx High resolution sinusoidal encoder 2 x 0 for normal conversion no summing xz for conversion that sums this entry with one above it y 0 for normal conversion no summing y 1 for conversion that sums this entry with one above it y 8 for an unshifted conversion no summing y 9 for an unshifted conversion that sums this entry with one above it Incremental Encoder Entries Incremental encoders are converted with one of the conversion formats 0x 8x or Cx The low sixteen bits of the setup word specify the address of the source on the X data bus For incremental encoders the source address must be one of the DSPGATE encoder counters selected from the following list ENCI C000 ENC9 C020 ENC2 C004 ENCIO C024 ENC3 C008 ENC11 C028 ENC4 C00C ENC12 C02C ENCS C010 ENC13 C030 ENC6 C014 ENC14 C034 ENC7 C018 ENC15 C038 ENC8 C01C ENC16 C03C Use the addresses from this list even though the actual encoder counter register has an address two higher Incremental Encoder Conversion X Word Y word Converted Position Data Source and Processing of Data Bits 0 4 Fractional Bits Bits 0 15 Word address of source data Bits 5 23 Integer Bits Bits 16 23 Conversion format 00 1 T interpolation 80 parallel
186. Vectors Before you exit your application program you should remask your PC interrupt and restore the old vector and mask the interrupts on the PMAC PIC The following TurboC code does this setvect Ox0c oldvect Restore old IRQ4 vector disable Disable PC interrupts ch inportb 0x21 Get PC mask word ch ch 0x10 Make bit 4 equal 1 outportb 0x21 ch Send new PC mask word enable Re enable PC interrupts outportb base 9 Oxff Mask all PMAC interrupts VMEbus Communications Setting Up The Base Address For PMAC VME PMAC VME communicates with the VME bus as a slave device through a set of 16 8 bit mailbox registers which are essentially 16 bytes of dual ported registers not to be confused with Option 2V 8Kx16 dual ported RAM The mailbox registers occupy an address space on the VME bus starting with the base address plus 1 Before communicating with PMAC VME over the VME bus the base address of the mailbox registers must be set up Determine what memory space is available in the VME system such that PMAC VME will not conflict with other existing devices in the VME system After selecting an address location the next thing to do is to tell PMAC what VME bus address it will reside at This is done through software programming In order to do this an IBM PC compatible computer running the PMAC Executive Software is needed or some suitable terminal software talking
187. Ware Chan leS T S R 6 Software CHANGES C 6 Parallel Position Feedback ettet E Rus de nett ecu tu E N edes au p Rabe 6 Parallel Absolute Feedb k a tbe tte ette etse dur deep Ree dde dus peas 8 Linear Displacement Transducer Feedback eee eese eene teen nnen nennen ennn trennen enne 8 Analog Position Feedback ii ttr A iR At E S 9 P COUTE 10 Absolute Power Up Position sees enne aae enne nete teen trennt ie ne FEE trennt tren etane TE RE enne 10 Absolute Position Range esee esee eene eene nnne nennen nete teen trenetnsn ne tnee trennen entente ene tnst rr nan ne enne tren 10 Parallel Data Position eee en n e eaan e ase en RRA ennt en nente RR RR RR O entren tentent entree ennt a nente nein 11 Resolver POSUION FM 11 AXES O AA PR H iatedsa 12 Encoder Offs tzi 4 aL o sett ba etuer utes e miser nT lei io Ee A LULA Iud 13 Encoder Conversion Table ee terere ERI Ce ge Earle Ee E EE ER eser REE o ebbe ee RP ER e EE bese 13 Incremental Encoder Entries eee esses RR nn 16 WANT AAA HH 17 Parallel Bit Int rpolation iii s utque ii 17 NO Interp l ti h M 17 ACC 26 Analog to Digital Conversion Register Entries eese nee 17 Parallel Posi
188. Writing Programs for PMAC 14 13 PMAC User Manual Specifying the Interpolation Plane The first thing that should be done in preparing for a circular move is to specify the orientation of the plane that will contain the circle This is done by specifying the normal vector to that plane with the NORMAL command The arguments of this command are the component magnitudes of the vector I X axis direction J Y axis direction and K Z axis direction A typical command might be NORMAL 10 866 JO 5 KO 0 The length of the normal vector specified here is not important only the ratio between the component magnitudes is which determines the direction Standard Planes To specify the circles in the XY plane simply command NORMAL K 1 equivalent to G17 in machine tool code Similarly for circles in the ZX plane command NORMAL J 1 G18 equivalent for circles in the YZ plane command NORMAL I 1 G19 equivalent Clockwise Direction Sense The directional sense of the normal vector is right handed that is in a right handed coordinate system if pointing a right thumb in the direction of the specified normal vector the fingers will curl in the direction of a clockwise arc in the plane thus specified Circle Modes To put the program in circular mode use the program command CIRCLE1 for clockwise arcs G02 equivalent or CIRCLE2 for counterclockwise arcs G03 equivalent LINEAR will go back to linear blended moves Once in circular mode a c
189. Y LJIHS OAV i WIAs L 3 H3005N3 31V9 dSQ C 5 y y Ls z 43009N3 INO viva y SHSLSIDAY LAIHS DVA TVIH3S A sovV1d 4 E ME PRES 1OH1NOO M 5v14 sovid 1NdNI 4 3SVHd OAH3S JIdINVS H3aooN3 SLAdNI M9019 AON3RQ03H43 318V10313S SLNdNI yY43d09N3 v Figure 1 PMAC Motion Controller Custom Gate Array IC Input Output Connecting PMAC to the Machine 6 2 PMAC User Manual Connect pin 1 to 2 to tie differential line to 42 5V 5V Connect pin 2 to 3 to tie differential line to 5V R 2R Reversible socketed SIP on PMAC2 A E Tieto 2 5V when no connection Tie to 2 5V for single ended encoders i T ls ls pid ed for differential line driver Wv 2 2R 1 Tie to 5V for complementary open collector encoders obsolete GND e Tie to 5V to support external XOR loss of encoder circuitry Figure 2 PMAC Encoder Input Circuitry When using single ended TTL level digital encoders the differential line input should be left open not grounded or tied high this is required for the PMAC differential line receivers to work properly Differential Encoders Differential encoder signals can enhance noise immunity by providing common mode noise rejection Modern design standards virtually mandate their use for industrial systems especially in the presence of PWM power amplifiers which generate a great deal of electromagnetic interference Open Collector Differential There are two types
190. a Host Communications Program PMAC User Manual If the PMAC to Host transmission was prompted by a host command at the end of the full transmission which could be multiple lines PMAC will send the acknowledging handshake character if any followed by the checksum of the host command If the transmission was prompted by a SEND or CMD statement in a PMAC program there is no acknowledging handshake character or checksum of the command there is a checksum of the response Checksum Format In general the checksum of a line can be more than one byte long as the byte values add up the checksum rolls over into a second byte When using the serial port or the VME bus port PMAC sends only the low byte The value in this byte is that of the full checksum modulo 256 When using the PCbus or VMEbus PMAC sends the low byte to the normal communications register base address 7 but simultaneously sends the high byte to the adjacent register base address 6 There is the choice of picking up just the low byte or both bytes Example With 1323 and I4 1 and assuming P100 35 Q10 0 Q11 1 and Q12 2 Host sends J lt CR gt PMAC sends lt ACK gt lt 117dec gt 117 74 J9 43 Host sends P100 lt CR gt PMAC sends lt LF gt 35 lt CR gt lt 127dec gt 127 10 51 53 13 lt ACK gt lt 225dec gt 225 80 49 48 48 Host sends Q10 12 PMAC sends lt LF gt 0 lt CR gt lt 71dec gt 71 10 48 13 lt LF gt 1 l
191. a J 0 command can then be used to move the motor to the home position To disable the limit function of the switch you must set bit 17 of variable Ix25 for the motor to 1 For example if 1125 is normally C000 the default specifying the use of LIM1 for motor 1 setting 1125 to 2C000 disables the limit function Note The polarity of the limit switches is the opposite of what many people would expect The LIMn input should be connected to the limit switch at the positive end of travel the LIMn input should be connected to the limit switch at the negative end of travel It is a good idea to use the home offset parameter Ix26 to bring the home position out of the limit switch so the limits can be re enabled immediately after the homing search move without being in the limit Basic Motor Moves 11 9 PMAC User Manual The following examples show two quick routines to do this type of homing One uses a motion program and the other a PLC program The same function could also be done with on line commands p Motion Program Set up Variables to be saved x CLOSE I123 10 Home speed 10 cts msec negative 1125 C000 Use Flags1 for Motor 1 limits enabled 1126 32000 Home offset of 2000 counts enough to take you out of the limit 190223 Capture on rising flag and rising index 1903 2 Use LIM1 as flag negative end switch EAERREERRATIRARAR Motion program to execute routine KKKKKKKKKKKKKK
192. a request or problem to us overnight and we will deal with it the following business day Our Fax numbers and E Mail addresses are listed below Supply all pertinent equipment set up information Bulletin Board Service BBS In addition messages can be left on one of the Bulletin Board Services BBSs The BBSs are provided for customers distributors representatives and integrators et al Download and upload files and read posted bulletins and Delta Tau newsletters Messages may be left for anyone who is a member user of the Bulletin Board System s A modem and Procomm Plus or similar communications program is all that is needed to use this service Many download upload protocols such as Z Modem are supported Delta Tau Data Systems Inc Technical Support Phone 818 717 5656 Fax 818 998 7807 Email support deltatau com Website http www deltatau com Delta Tau Europa AG Rheinweg 4 CH 8200 Schaffhausen Switzerland PH 41 0 52 625 20 88 FX 41 0 52 625 44 82 Email dteuropa deltatau com Introduction 1 3 PMAC User Manual PMAC Japan 3 6 7 Nihonbashi Ningyocho Chuo Ku Tokyo 103 Japan PH 011 81 3 3665 6421 FX 011 81 3 3665 6888 Email info pmac japan co jp Website www Pmac japan co jp 1 4 Introduction PMAC User Manual 2 Getting Started with PMAC Table of Contents GETTING STARTED WITH PMATC eeeeeeeeee eese ee enne tn sens tn sins tn stes tn seta suse ta sons tn aes
193. able Continuing the example the command M0 73 writes a value of 73 to P5 13 8 Computational Features PMAC User Manual Example To create a sine table with one entry per degree in P variables PO to P359 use the following program segment this assumes the use of MO and M10 as set up above P1000 0 Starting value for array index WHILE P1000 lt 360 Loop until done M10 P1000 Point MO to the proper P variable MO SIN P1000 P1000 P1000 1 ENDWHILE Assign the sine value to this P variable Increment the array index Se Seo So e Special Use P Variable If a command consisting simply of a constant value is sent to PMAC PMAC assigns that value to variable PO unless a special table buffer such as a compensation table or stimulus table has been defined but not yet filled in that case the constant value will be entered into the table For example if the command 342 lt CR gt is sent to PMAC it will interpret it as PO 342 lt CR gt This capability is intended to facilitate simple operator terminal interfaces It does mean however that it is not a good idea to use PO for other purposes because it is easy to change this accidentally Q Variables Q variables like P variables are general purpose user variables 48 bit floating point variables at fixed locations in memory with no pre defined use However the meaning of a given Q variable and hence the value contained in it is dependent on which coordinate system
194. ach encoder has a digital delay filter consisting of three cascaded D flip flops on each line with a best two of three voting scheme on the outputs of the flip flops The flip flops are clocked by the SCLK signal This filter does not pass through a state change that only lasts for one SCLK cycle any change this narrow should be a noise spike In doing this the filter delays actual transitions by two SCLK vYYvv te DA 2d3 HUY VY yy yy yyy CHA D Q D Q D q D Q YYYYVVYYVY 2d3 Figure 3 Encoder Digital Delay Filter Frequency Tradeoffs The lower the SCLK frequency the wider the noise spike that can be rejected but the lower the maximum count frequency These aspects must be balanced in the system In general SCLK should be set to the lowest frequency that permits PMAC to keep up the maximum possible count frequency from the encoder Bypassing the Filter This delay filter may be bypassed by setting the Encoder I Variable 1 1901 1906 etc to 1 Bypassing this filter will probably be done only by those with parallel sub count interpolation for which the delay could cause transition errors Refer to the Feedback Features section of this manual Error Detection Count Error Flag If an illegal encoder tr
195. ad position minus Ix86 Motor Pos cts 0 500 1000 1500 2000 2500 3000 3500 Load Load cts 5 6 3 5 1 5 6 3 5 7 8 Load Load Ix86 cts 0 1 1 5 3 5 1 1 5 2 3 Load Load Ix86 1 16 cts 0 16 24 56 16 24 32 48 Reference point zero by definition Setting Up a Motor 7 33 PMAC User Manual The backlash table definition to create these corrections would be DEFINE BLCOMP 8 4000 16 24 56 16 24 3248 0 Notice that the first entry is for the correction at 500 counts and the added last entry is 0 for the correction at 4000 counts and O counts Torque Compensation Tables PMAC provides the capability to create a table of corrections as a function of motor position to the output of the servo loop Typically this feature will be used with the servo loop in torque mode whether or not PMAC is also performing motor commutation so this function is called torque compensation table The torque compensation tables are entered and operated much like the leadscrew compensation tables which provide a position correction However there are no cross axis or multi axis torque compensation tables The table belonging to a motor provides a torque correction to that motor as a function of that motor s position The torque compensation table for a motor is declared with the on line command DEFINE TCOMP entries count length for the addressed mo
196. addition there are GOTO statements with either constant or variable arguments the variable GOTO can perform the same function as a Case statement GOSUB statements constant or variable destination allow subroutines to be executed within a program CALL statements permit other programs to be entered as subprograms Entry to the subprogram does not have to be at the beginning the statement CALL 20 15000 causes entry into Program 20 at line N15000 GOSUBs and CALLs can be nested only 15 deep G Codes To handle machine tool G codes PMAC treats Gnn as CALL 1000 nn000 The following values on the line e g X1000 can be treated as parameters to be passed as for a canned cycle or the subprogram can execute without arguments return and execute the rest of the line as for a modal G code The machine tool designer writes Program 1000 to implement the G codes as he wishes allowing customization and enhancements Delta Tau provides a sample file implementing all of the standard G codes M S T and D codes are similarly implemented Modal Commands Many of the statements in PMAC motion programs are modal in nature These include move modes which specify what type of trajectory a move command will generate this category includes LINEAR RAPID CIRCLE PVT and SPLINE Moves can be specified either incrementally distance or absolutely location individually selectable by axis with the INC and ABS commands Move times TA TS and T
197. aintain isolation and the return on the supply must not be connected to the digital common GND or the isolation will be defeated Simulated Encoder Signals Special consideration must be given to systems that have a simulated encoder signal provided from a resolver to digital converter in a brushless motor amplifier In these systems the encoder signals are almost always referenced to the amplifier s signal return which in turn is connected to the PMAC analog common AGND The best setup in these cases is to isolate the simulated encoder signal from the PMAC digital circuitry with the ACC 8D Opt 6 isolator board or similar module This will keep full isolation between the PMAC digital circuitry and the amplifier If isolation of the simulated encoder signals is not feasible the PMAC digital circuitry and the amplifier signal circuitry including the PMAC analog circuitry must be well tied together to provide a common reference voltage Do this by putting jumpers on PMAC E Points E85 E87 and E88 tying the digital and analog circuits on PMAC together and therefore the analog signal circuits Avoid having the simulated encoder cable s providing the only connection between the circuits This can result in lost signals from bad referencing or even component damage from ground loops Wiring Techniques There are several important techniques in the wiring of the encoders that are important for noise mitigation First the encoder cable should be kep
198. ajectory calculations Acceleration Limit If the acceleration thus specified exceeds the maximum programmed acceleration set by Ix17 in counts msec for any motor involved in the move the acceleration for all motors in the move is decreased in proportion so that no motor exceeds this limit The path through space is not changed nor is the shape of the velocity profile for any motor To specify acceleration rate directly TA and TS should be set to very small to violate the limit in which case the acceleration is controlled by the motors I variables Ix17 When Too Effective When blending linear moves together the Ix17 limit is enforced even for the intermediate decelerations to a stop that are removed to blend into the next move As PMAC calculates each move in the blended sequence it has to assume that it could be the last move in the sequence and it will try to make sure that the deceleration to a stop at the programmed position obeys this limit This can result in a deceleration time longer than the programmed move time specified either directly with TM or indirectly by distance over F feedrate which will cause the move to execute at lower than the programmed speed This can be especially limiting when moves are broken into very small pieces to be blended together The Ix17 limit must be set higher than the top speed divided by the smallest segment time in order not to limit the speed This can make it too high for effective accelerat
199. al Events PMAC User Manual Position Compare Functions The position compare feature is essentially the opposite of the position capture function Instead of storing the position of the counter when an external signal changes it changes an external signal when the counter reaches a certain position In this way events can be triggered to happen on the actual position of your system Because the triggering is a pure hardware function although setup is software it is very fast and accurate Use the signal to trigger an action in the host in the plant or in PMAC itself E gt POSITION COMPARE REGISTER PEAL gt 4 CIRCUITS PER GATE ARRAY gt L A PHASE CLOCK el PHASE CAPTURE REGISTER 7 FIVE INPUTS POSITION x C CHANNEL CAPTURE CONTROL 4 FLAGS gt gt HOME CAPTURE REGISTER A A AES A A EUN 24 BIT UPIDOWN POSITION REGISTER LB pl PIETER DECODING DIRECTION TO MER MAX ENCODER INPUT 10MHz MAX i i W MODE CONTROL y X1 X2 X4 P D CLK SERVO POSITION CAPTURE REGISTER SERVO CLOCK gt y TIMER REGISTERS 2 CLOCK 10 MHz M 1 T ENCODER PERIOD MEASUREMENT BUS CONTROL REGISTER 24 BIT DATA y gt AND lt gt CONTROL D 4 BIT ADDRESS gt 2oaPTURE nl i H F amp C 3 EQL 5 INPUTS 3 STATUS 16 CONTROLS v Y s Figure 53 PMAC PC VME Custom Gate Array DSPGATE Encoder Functions Required M Variables
200. al support department Conventions Used in This Manual The following conventions are used throughout the manual ENTER Text inside arrows is used to represent keyboard keys or key combinations lt CTRL F4 gt OPEN PROGRAM Mono spaced is used for code listings Warning Information that if not observed may cause serious injury or death Caution Information that if not observed may cause damage to equipment or software Note A note concerning special functions or information of special interest Safety Summary The following are general safety precautions not related to any specific procedures and therefore may not appear elsewhere in this publication These are recommended precautions that personnel must understand and apply during many phases of operation and maintenance Keep Away from Live Circuits Do not replace components or make adjustments inside equipment with power applied Under certain conditions dangerous potentials may exist when power has been turned off due to charges retained by capacitors To avoid casualties always remove power discharge and ground a circuit before touching it Live Circuit Contact Procedures Never attempt to remove a person from a live circuit with bare hands To do so is to risk sure and sudden death If a person is connected to a live circuit the following steps should be taken Call for help immediately De energize the circuit if possible Use a wood or fiberglass hot stic
201. alculate during this time Sum Sum 1 0 0 5 Sum 0 75 Sum will increase at a rate of 0 75 per servo cycle At the default servo cycle update rate of 2 25 kHz Sum will increase at a rate of 2250 0 75 1688 per second To trip the motor after three seconds of this condition set Ix58 to 1688 3 5064 When an I T fault occurs on a motor PMAC reacts just as for an amplifier fault error The offending motor is killed and possibly other motors as set by Ix25 PMAC sets the amplifier fault motor status bit For an PT fault PMAC also sets a separate PT fault motor status bit Both bits are cleared when the motor is re enabled Note When PMAC is not commutating a motor with TT protection make sure magnetization current parameter Ix77 is still set to O In this setup Ix77 will not affect operation but it will affect IT calculations Amplifier Enable and Fault Lines The use of the amplifier enable AENA output and the amplifier fault FAULTn input lines for each motor are important for safe operation Without the use of the enable line disabling the amplifier relies on precise zero offsets in the PMAC analog output and the amplifier s analog input Without the use of the fault line PMAC may not know when an amplifier has shut down and may not take appropriate action If either the 5V supply for the PMAC computational section or the 15V analog supply is lost the amplifier will be disabled automatically because th
202. ally to superimpose following and calculated moves use offset mode in which bit 16 is 1 if the master position is taken from X register 0721 the parameter value would be for example 1105 10721 Time Base Control Electronic Cams A more sophisticated method of coordination to external axes is time base control in which the input signal frequency controls the rate of execution of moves and programs Time base control operates on an entire coordinate system together Specify which encoder register is receiving the input frequency and the relationship between the input frequency and the program rate of execution This not only varies the speed of moves in proportion to the input frequency all the way down to zero frequency but also keeps total position synchronization This permits operations such as multi pass screw threading What Is Time Base Control The PMAC motion language expresses the position trajectories as functions of time Whether the moves are specified directly by time or by speed ultimately the trajectory is defined as a position vs time function This is fine for a great number of applications However in many applications the PMAC axes is slaved to an external axis not under PMAC control or occasionally an independent axis under PMAC control in a different coordinate system In these applications define the PMAC trajectories as functions of master position not of time Synchronizing PMAC to External Event
203. alue will be wrong initially for the new firmware The easiest way of getting the proper reference checksum value is to re initialize the card with a command which automatically loads the firmware s checksum value into the reference register To make this change permanent the SAVE command should be issued before a power off reset of PMAC To update the reference checksum value without re initializing the card it is possible to utilize the fact that the running checksum register X 0794 has the last calculated value frozen in it when there is a mismatch Therefore the proper checksum value for the new version can be read with the command RHX 0794 and the returned value can be written to the reference register X 07B1 User Program Checksum PMAC continually computes the checksum of the fixed user program buffers as a background task Each time it has computed the checksum it compares this value to the checksum value that was computed the last time one of these buffers was closed If PMAC detects a mismatch between these two checksums it sets a global status bit bit 13 of X 0003 accessible with and stops performing any program checksum operations communications checksum is independent It does not shut down operation automatically It is up to the host or a PMAC PLC program to decide what action to take if there is a checksum error Communications Data Integrity Features PMAC provides a variety of techniques for ensuring
204. an geometries such as radial tables and rotary axis robots where there are odd axis profile shapes even for regular tip movements 14 18 Writing Programs for PMAC PMAC User Manual c i 2 To compute axis velocities at point P 1 Find common center of P P Pia 2 Compute velocity vector as normal to radius vector 3 Resolve velocity vector into components If segment were done at constant velocity VEL No velocity or acceleration discontinuities at segment boundaries a E Ab INCREMENTAL SPLINE TA500 X10000 X9000 X10500 X12000 l l l E ke TA TA TA TA TA TA added added TIME Figure 35 Splined Moves All Segments at Same Time Writing Programs for PMAC 14 19 PMAC User Manual v V TA added TA TA added time TA added TA TA TA added time One Programmed Segment Two Programmed Segments V V TA added TA TA TA TA added time TA added TA TA TA TA TA added time Three Programmed Segments Four Programmed Segments Figure 36 Cubic Spline Trajectories VEL E constant calculated aid P specified P V Vi specified trom A calculated before PVT200 X9000 150 TA specified MME Figure 37 PMAC Transition Point Moves PVT Mode Parabolic Velocity How They Work In SPLINE1 mode a long move is split into equal time segments each of TA time Each axis is
205. an accurate linear measurement device on the load working in both directions and the following readings of the linear device for set positions of the motor encoder expressed in units of the motor encoder Motor Pos cts 0 500 1000 1500 2000 2500 3000 3500 Load Pos cts O 510 995 1492 5 1994 2497 5 3003 5 3500 5 Load Pos cts 2 516 998 5 1494 2000 2501 3010 5 3508 5 Reference point zero by definition Only the compensation table works in the positive direction so the entries in the compensation table should be the negative of the difference between positive going load position and motor position expressed in 1 16 counts Motor Pos cts 0 500 1000 1500 2000 2500 3000 3500 Load Motor cts 0 10 5 7 5 6 2 5 3 5 0 5 Motor Load 1 16 cts 0 160 80 120 96 40 56 8 Reference point zero by definition The compensation table definition to create these corrections would be DEFINE COMP 8 4000 160 80 120 96 40 56 8 0 Notice that the first entry is for the correction at 500 counts and the added last entry is 0 for the correction at 4000 counts and O counts There is a 5 count backlash at motor position 0 so Ix86 should be set to 5 16 or 80 The backlash table should contain the differences between negative going load position and positive going lo
206. ance F TA 2 from the compensated but unblended corner The greater the portion of the blending is S curve the squarer the corner will be When coming to a full stop e g Step Quit or DWELL at the corner at an inside corner PMAC will stop at the compensated but unblended corner point Writing Programs for PMAC 14 25 PMAC User Manual Inside Corner Cutter Compensation Line Programmed Path Programmed Path Tool Center a Path _____y Line Line gt N Arc K Line Y Tool Center Path v Line to Line Line to Arc Programmed Path Arc r V 1 Tool Center 0 i Path y Arc to Line Arc to Arc 1 1 1 1 1 1 Figure 40 Inside Corner Cutter Compensation Treatment of Outside Corners For outside corners PMAC will either blend the incoming and outgoing moves directly together or it will add an arc move to cover the additional distance around the corner Which option it chooses is dependent on the relative angle of the two moves and the value of I variable I89 The relative angle between the two moves is expressed as the change in directed angle of the motion vector in the plane of compensation If the two moves are in exactly the same direction the change in directed angle is 0 if there is a right angle corner the change is 90 if there is a complete reversal the change in directed angle is 180 I89 specifies the boundary angle between directly b
207. and prevent execution of the rest of the PLC program program WHILE M11 1 P1 P1 1 ENDWHILE This structure makes it easier to hold up PLC operation in one section of the program so other branches in the same program do not have to have extra conditions and they do not execute when this condition is true Contrast this to using an IF condition see above 16 4 Writing a PLC Program PMAC User Manual Some COMMAND action statements should be followed by a WHILE condition to ensure they have taken effect before proceeding with the rest of the PLC program This is true if a second COMMAND action statement that requires the first COMMAND action statement to finish will follow Remember COMMAND action statements are processed only during the communications section of the background cycle To have an input stop any motion in a Coordinate System and start motion program 10 The following PLC could be used IF M11 1 input is ON IF P11 0 input was not ON last time P11 1 Set latch COMMAND amp 1A ABORT all motion WHILE M187 0 wait for motion to stop ENDW COMMAND amp 1B10R Start program 10 ENDIF ELSE P11 0 reset latch ENDIF Note M187 is the Coordinate System In Position bit as defined in Example program 1 Precise Timing Since PLCs 1 to 31 are the lowest computation priority on PMAC the cycle time cannot be determined precisely To hold up an action for a fairly precise amount of time
208. ansition both channels changing on the same SCLK cycle does get through or around if bypassed the delay filter and to the decoder a count error flag is set noting a loss of position information This flag is bit 18 of the encoder status control word X C000 for Encoder 1 X C004 for Encoder 2 etc Suggested M variable definitions M118 M218 etc can be used to access these bits Once per Rev Check In addition it is possible to use the third channel of the encoder to do a once around position check using the PMAC position capture feature to detect any loss of count Refer to the Position Capture description in the Synchronizing PMAC to External Events section of this manual and program example PLCMOD PMC for more details Optically Isolated Dedicated Digital Input Flags JMACH Port Each channel of PMAC has four dedicated digital inputs on the machine connector LIMn LIMn overtravel limits HMFLn home flag and FAULTn amplifier fault These inputs are typically Input Output Connecting PMAC to the Machine 6 5 PMAC User Manual assigned to a motor as a set for dedicated use as flags by addressing them with the motor I variable Ix25 Those flags not used for the dedicated purposes may be used as general purpose inputs with the assignment of an M variable Flag Wiring All of these flag inputs must be shorted to the zero volt reference voltage for the circuit usually AGND allowing current to flow through the L
209. ant speed moves these routines can issue jog commands For instance M04 Spindle On Counterclockwise NO3000 CMD 4J RET NO4000 CMD 4 3 M05 Spindle Stop RET NO5000 CMD 4 7 RET This assumes of course that motor 4 on PMAC is the spindle motor and that the counting up direction is clockwise Spindle speed will have been determined already in other routines by setting 1422 motor 4 jog speed If PMAC is controlling the spindle with an open loop voltage these routines would put a voltage on an otherwise unused analog output by writing to a DAC register For example NO3000 M402 P97 P9 RET NO4000 M402 P97 P9 RET NO5000 M402 0 This sample assumes M402 is assigned to the DACA register Y C00A 8 16 S P97 is the desired spindle speed in RPM and P9 is the scale factor relating RPM to DAC bits 3 276 7 DAC bits volt If fancier tasks such as constant surface speed are desired a separate motion program for the spindle will be required If these M codes were to interface with this example they would be N03000 M55 1 Flag for clockwise spindle CMD amp 2B1010R Start the spindle program RET N04000 M55 1 Flag for counterclockwise spindle CMD amp 2B1010R Start the spindle program RET N05000 M55 0 Flag for spindle off RET E M07 Low Level Mist Coolant On M08 High Level Flood Coolant On M09 Coolant Off The actual implementation of these M c
210. arefully the difference in syntax between the on line command and the buffered command The on line command is simply HOME or HM and it acts on the currently addressed motor so the motor number must be specified in front of the command e g 1HM In the buffered command the motor number is part of the command following immediately after HOME or HM letters e g HM1 Homing from a PLC Program PMAC PLC programs can command homing search moves by giving on line commands with the COMMAND statement e g COMMAND 1HM These commands simply start the homing search move code must be written to monitor for finishing if that is desired The motor number must be specified in the specific command string or with the ADDRESS n statement without this statement motor addressing is not modal within PLC programs 11 8 Basic Motor Moves PMAC User Manual Motion vs PLC Program Homing Table 11 1 summarizes the differences between homing using Motion programs and PMAC PLC programs Motion vs PLC Program Homing Motion Programs PLC Programs Program execution point stays on the line containing the The PLC does not monitor for the start and end of the Home command until the homing move is finished homing move automatically Home command can be combined with programmed Axis motion can only be performed through Jog axis moves commands The C S must be ready to run a motion program The C S does
211. assing Arguments to Subroutines eese eese eee nn Rao nn anna ethernet te innen ete tnet ne tnetn sente te innen enne 4 Example ini 4I What Has Been Passed ono 41 PRELUDE Subprogram Calls p pte ada 42 R nn ine ionis uc M M HP 42 Pointing to the Progra ao EORR ac 42 Running the Propano 43 Stepping th Pro agri m cano 43 What PMAC Checks Lor naa 43 Implementing a Machine Tool Style Program sees rennen ener trennen trennen 43 GM T GN D gt e da 43 Standard G CODES TP 44 Spindle Programs ci deese gutta fecto ctied eee tacks itat t deese i tree duo dup deu 48 Standard M C d s P 49 JA HTC eT KM ie dieta 51 Rotary Motion Program Buffers sessi eene ne enne nenne enne treten tesn etes trennen teen te tnne trennen enne 51 Defining a Rotary Buffer eise eeeeee eese netten enne nene ennt entente ns ee tenetis entente nt interesset tentent intent nnns ene 51 PHEPATING 10 RUM i acces 52 Opening JOP ENILY e 52 Staying Ahead of Executing Line eene nenne Dane one on ne enn enn ne tne trne tenete entren trennen 52 Closing and Deleting Buffersi tite RE ede Rte Ui eee eee dde pedido e tue qe Reeve vod a 53 How PMAC Executes a Motion Program essesseeeeseeeeeeeeeneene nennen nennen trennen trennen trennen nenne nre 53 Calculati
212. ater If using the complements as well connect DACI pin 45 and DAC2 pin 46 the minus command inputs otherwise leave the complementary signal outputs floating To limit the range of each signal to 5V do so with parameter 1169 as discussed below Auxiliary Connections There are several other lines for each motor that are important These are Limit Signals LIMn and LIMn PMAC has two inputs for each motor intended for the hardware overtravel limit switches These lines must actively be held low to draw current through the LED in the optoisolator in order for the motor to able to move This requires the use of normally closed or normally conducting if solid state limit switches These inputs are direction sensitive they only stop movement in one direction To implement limit switches wire the LIMI input pin 53 to one side positive voltage end if there is a polarity of the limit switch expected to be on the positive end of travel wire the LIM1 input pin 51 to the equivalent side of the limit switch expected to be on the negative end of travel Wire the other side of the limit switches negative voltage end if there is a polarity to PMAC AGND pin 58 unless keeping the flags on the digital circuit side isolated from the analog circuitry in which case wire the other side to PMAC GND line pins 3 and 4 If not using limit switches e g for a rotary axis or for a preliminary test set up either tie the limits pins
213. ation limits are enabled here In all other cases PMAC is calculating one move ahead Note No velocity or acceleration limiting done on the fly can be entirely foolproof The more moves that an on the fly algorithm looks ahead the more likely it is to be successful in catching all cases but to be certain the entire move sequence must be evaluated ahead of time Starting Calculations Upon the command to start the program PMAC will calculate program statements down to and including the first or second move statement depending on the mode of the move and the setting of I13 This can include multiple modal statements calculation statements and logical control statements Actually the programmed moves will not start executing until I11 milliseconds have passed even if the calculations were finished earlier This permits proper synchronization between cards so one will not start before the other If I11 is set to zero the first move will start as soon as the calculations have finished Statements down to and including the next move statement putting the data thus computed into a queue for the trajectory generator Program calculation is then held up until the trajectory generator starts the next move and PMAC performs other tasks PLC programs communications etc Calculation of Subsequent Moves As soon as the actual execution of a move by the trajectory generating routines starts a flag is set for PMAC to calculate the ent
214. ation table for a motor is not required to have a backlash table for that motor 7 32 Setting Up a Motor PMAC User Manual The backlash table for a motor is only active if the most recent commanded direction of movement is negative it is still active if the motor is currently commanded to stand still but reached this position by traveling in the negative direction In operation the table reads the present nominal motor position and computes a weighted average of the two closest table entries creating a first order interpolation between table points The backlash compensation is defined directly for a range of motor position starting a zero counts and going in the position direction to the count length declared by the last argument in the DEFINE BLCOMP command The spacing between entries is this length divided by the number of entries which is the first argument in the command The first entry in the table defines the correction at on spacing from the zero position of the motor the second entry at two spacings and so on Outside this range the uncorrected position is rolled over to within this range before the compensation is done This rollover occurs exactly as for leadscrew compensation tables The constant backlash parameter Ix86 is always potentially active Backlash tables are potentially active if I51 is set to 1 they are inactive if I51 is set to 0 Example Imagine the calibration of an axis was performed against
215. atus bit is the trigger torque limited triggering O flags 1 error status If input flags are to create the trigger Ix25 specifies the flag register e If input flags are to create the trigger Encoder Flag I variables 2 and 3 for this set of flags specify which edges of which signals will cause the trigger 1x03 bit 16 specifies whether the hardware captured counter value is used as the trigger position suitable for incremental encoder signals real or simulated or the software read position is used instead suitable for other types of feedback O hardware 1 software The software read position must be used if the following error status is used for the trigger Notice that each motor has an independent triggering function and move relative to the trigger even if the motors are assigned to the same axis If a common trigger signal is desired for multiple motors the same trigger signal must be wired into the flag inputs for all of those motors PMAC will blend each motor smoothly from the pre trigger move to the post trigger move according to the jog home acceleration parameters Ix19 Ix20 and Ix21 All motors must come to a stop either at the originally specified position or at the post trigger position before PMAC will calculate any further in the motion program This means that there is no blending of the post trigger move into any subsequent moves The captured value of the sensor position at the trigger is stored in a dedicate
216. aveforms with zero offset defined such that the V signal transition when the U signal is low defined as the zero point in the hall effect cycle represents the zero point in the PMAC commutation cycle If the hall effect sensors do not have this orientation bits 16 to 21 of Ix81 can be used to specify the offset between The PMAC zero point and the hall effect zero point These bits can take a value of 0 to 63 with units of 1 64 of a commutation cycle 5 625 e The offset can be computed by doing a phasing search move to establish a phase reference without the hall sensors then reading the 24 bit phase position register suggested M variable Mx71 for the high 24 bits at the V signal transition with U low the hall effect zero point This is best done by killing the motor and rotating it by hand while watching the U and V signals on an oscilloscope or matching M variables in the PMAC Executive program Watch Window and Mx71 in the Watch Window The offset value can then be calculated as Mx71 1x71 Ix71 Offset 64 The offset computed here should be rounded to the nearest integer The description of Ix81 in the Software Reference manual shows the common values of offsets used for all the cases where the zero point in the hall effect cycle is at a 0 60 120 180 120 or 60 point where manufacturers generally align the sensors Setting Up PMAC Commutation 8 9 PMAC User Manual To find the precise phase po
217. be used for a coordinate system without overlap provided no higher number coordinate systems are used Computational Features 13 9 PMAC User Manual PMAC Q Variable Memory Map Memory Coord Coord Coord Coord Coord Coord Coord Coord Location Sys 1 Sys 2 Sys 3 Sys 4 Sys 5 Sys 6 Sys 7 Sys 8 1400 0 512 768 256 896 384 640 128 147F 127 639 895 383 1023 511 767 255 1480 128 640 896 384 0 512 768 255 14FF 255 767 1023 511 127 639 895 383 1500 256 768 0 512 128 640 896 384 157F 383 895 127 639 255 767 1023 511 1580 384 896 128 640 256 768 0 512 15FF 511 1023 255 767 383 895 127 639 1600 512 0 256 768 384 896 128 640 167F 639 127 383 895 511 1023 255 767 1680 640 128 384 896 512 0 256 768 16FF 767 255 511 1023 639 127 383 895 1700 768 256 512 0 640 128 384 896 177F 895 383 639 127 767 255 511 1023 1780 896 384 640 128 768 256 512 0 17FF 1023 511 767 255 895 383 639 127 Addressing a Q Variable Set How to know which set of Q variables are working within a command It depends on the type of command When you are accessing a Q variable from an on line immediate command from the host working with the Q variable for the currently host addressed coordinate system with the amp n command is selected When accessing a Q variable from a motion program statement the Q variable belonging to the coordi
218. bit interpolation C0 no interpolation 7 16 Setting Up a Motor PMAC User Manual The source counter already reflects the method of decoding the incoming quadrature or pulse and direction waveform whether there are one two or four counts per cycle The decode method is determined by Encoder I variable 0 1900 1905 etc for that encoder One bit in the counter is a count whether it represents a full half or quarter wave cycle 1 T Interpolation Most people will use the 1 T extension conversion method 0x which uses timers associated with each counter to estimate fractional resolution see previous illustration A typical setup word for this would be 00C008 which provides 1 T extension conversion of the encoder 3 counter Parallel Bit Interpolation If the set up uses the parallel sub count interpolation for incremental feedback use the 8x conversion format In this case the source address must be one of the odd numbered encoders A typical setup word in this case would be 80C010 which provides parallel extension of the encoder 5 counter using encoder 6 s flags No Interpolation For conversion without any sub count interpolation the Cx conversion format should be used A typical setup word in this case would be COCOOC which provides a non interpolated conversion of the encoder 4 counter ACC 28 Analog to Digital Conversion Register Entries The 1x conversion format picks up data from th
219. board itself Starting Address Before choosing the DPRAM starting address determine what memory space is available in the VME system so that the PMAC DPRAM does not interfere with existing RAM or other devices on the VME bus Just like setting up the base address of PMAC VME the starting address of DPRAM is done through software but in a somewhat different manner The best way to describe how to setup DPRAM is to give an example Most will simply use the ConfigurelVME Communications window in the PMAC Executive program to set the address for DPRAM The following section explains how to perform this setup without the Executive program Example Suppose a starting address of 1FC000 has been selected for the DPRAM Just like what was done for the base address of PMAC it is best to rewrite this address in binary and label the address bits starting with AO as the rightmost bit Address Bit A31 A24 A23 A16 A15 AS A7 A0 Binary 0000 0000 0001 1111 1100 0000 0000 0000 Hex 00 1F CO 00 There is a value of 00 for address bits A31 A24 1F for address bits A23 A16 CO for bits A15 A8 and 00 for bits A7 AO To tell PMAC where DPRAM should begin break up this starting address into two parts 1 The first part will represent the value address bits A23 through A20 2 The second part will represent the value address bits A19 through A14 If using 32 bit addressing address bits A31 t
220. calculated to take the longest time at its specified speed will actually be commanded to move at that speed The commanded speeds for other motors are lessened so that they have the same ratio of distance to speed This makes the move path approximately linear However if the acceleration times are not the same for all motors the commanded move path will not be perfectly linear A rapid mode move is never blended with another move all motors will be commanded to at least a momentary stop before the next move is commanded to start A motion program is put into this mode using the RAPID statement It is taken out of this mode by another move mode command e g LINEAR CIRCLE1 CIRCLE2 PVT SPLINE1 RAPID is equivalent to the RS 274 G Code G00 Motion Program Move Until Trigger The move until trigger function permits a programmed move to be interrupted by a trigger and terminated by a move relative to the position at the time of the trigger It is very similar to a homing search move except that the motor zero position is not altered and there is a specific destination in the absence of a trigger The move until trigger is a variant of the RAPID move mode on PMAC Speeds and accelerations are governed by the same variables as for regular rapid moves The move until trigger function for an axis and therefore for any motor s defined to that axis is specified by adding a data specifier to the move command for the axis where data is th
221. can be performed among the X Y and Z axes which should be physically perpendicular to each other The compensation offsets the described path of motion perpendicular to the path automatically by a programmed amount compensating for the size of the tool This permits programming the path along the edge of the tool letting PMAC calculate the tool center path based on a radius magnitude that can be specified independently of the program Cutter radius compensation is valid only in LINEAR and CIRCLE move modes The moves must be specified by F feedrate not TM move time PMAC must be in move segmentation mode 113 gt 0 to do this compensation 113 gt 0 is required for CIRCLE mode anyway Note In CIRCLE mode a move specification without any center specification results in alinear move This move is executed correctly without cutter radius compensation active but if the compensation is active it will not be applied properly in this case A linear move must be executed in LINEAR mode for proper cutter radius compensation Defining the Plane of Compensation Several parameters must be specified for the compensation First the plane in which the compensation is to be performed must be set using the buffered motion program NORMAL command Any plane in XYZ space may be specified This is done by specifying a vector normal to that plane with I J and K components parallel to the X Y and Z axes respectively For example NORMAL
222. ce eie teo ferret oed Er PU e onm sstaseceiMegusduaesducesagesureseteaneets 14 19 Splined Moves All segments at same time ooooccnccconcconononocononononnnonn nono nonn canon nono nennen een eene entere 14 19 Cubic Spline Trajectories Em 14 20 PMAC Transition Point Moves PVT Mode Parabolic Velocity oooonooccnnccnoncnnncccnonccnoncconenonnncnnnos 14 20 Compensation Inside Comer sein ettet beetles ette rb ep trt rd epe s e Eee e kde eae edes bep SE Ferr Edere eU peus 14 24 Compensation Outside COME 5 onini b estet eese ete ctt pees tee depot Und ees ee ee do eae eis paese aer E eaii 14 25 Inside Cutter ComperfisatiOn edente Per bo pneri ni ele Pl rbaa te ER ERRARE aa ainn Rahi 14 26 Outside Corner Cutter Compensation Sharp Angle esee eene 14 27 Outside Corner Cutter Compensation Shallow Angle esee 14 27 Reversal in Cutter Compensation eene eene een remettre nre tren trennen 14 28 Failure When Compensation Extends Full Circle esee eene 14 29 Cutter Compensation in Change of Direction sees nre nennen 14 30 Cutter Compensation Change of Direction No Intersection eee 14 30 Removing Compensation Inside Corner esee nennen eene nennen 14 31 Removing Compensation Outside Corner esee eene nee nennen nennen 14 32 Failures in Cutter Compensation nene enne enne nre nre nennen en
223. ch function before the first programmed move after power up reset Usually this is done automatically by having I14 equal to 1 If this is not done PMAC will calculate the first move for the motor assuming a starting point of Zero instead of the true position leading to unexpected performance on the first move Setting Up a Motor 7 9 PMAC User Manual Resolver Feedback PMAC can accept resolver feedback through its ACC 8D Option 7 resolver to digital converter board This board which can be purchased in two channel and four channel configurations processes the resolver data two ways first into an absolute word within one revolution of the resolver and second into a quadrature signal Both have 4096 counts per electrical cycle of the resolver An electrical cycle is a pole pair so a 4 pole resolver has two electrical cycles per mechanical revolution or 8192 counts The reading of the absolute word is too slow to perform every servo cycle so in typical use this is only done at power up reset if at all The ongoing position is received from the quadrature encoder counter to which the converted quadrature signal has been connected To the PMAC software this then looks exactly like a real quadrature encoder For this type of device PMAC can use the Ix10 I9x and I8x parameters to read the absolute power on reset position of a single resolver or of a system of 2 or 3 geared resolvers If Ix10 is set to O the absolute power on r
224. ch can be given from a PLC program using the COMMAND syntax or a motion program statement On Line Command A homing search move can be initiated with the on line motor specific command HOME short form HM This is simply a command to start the homing search PMAC provides no automatic indication that the move is completed unless the system is set up to recognize the in position IPOS interrupt Basic Motor Moves 11 7 PMAC User Manual Monitoring for Finish If monitoring the motor from the host or from a PLC program to see if it has finished the homing move it is best to look at the home complete and desired velocity zero motor status word accessed either with the command or with M variables The home complete bit is set to zero on power up reset it is also set to zero at the beginning of a homing search move even if a previous homing search move was completed successfully It is set to one as soon as the trigger is found in a homing search move before the motor has come to a stop The home search in progress bit simply is the inverse of the home complete bit during the move itis 1 until the trigger is found then 0 immediately after Therefore the monitoring should also look for the desired velocity zero status bit to become 1 which will indicate the end of the move Monitoring for Errors A robust monitoring algorithm will look also for the possibility that the homing search move could end in an error condition Oft
225. channel are wired in just as for a digital differential encoder It is better but not required to jumper the input for differential In this case the 12V input limit is a peak to peak measurement Input Output Connecting PMAC to the Machine 6 3 PMAC User Manual Power Supply and Isolation In the basic configuration of PMAC the encoder circuitry is not isolated from the PMAC digital circuitry and the signals are referenced to the PMAC digital common level GND Typically the encoders in this case are powered from the PMAC 5V lines with a return on GND The total encoder current draw must be considered in sizing the PMAC power supply It is also possible to use a separate supply for the encoders with non isolated signals connected to PMAC In this case the return of the supply should be connected to the digital common GND on PMAC to give the signals a common reference The 5V lines of separate supplies should never be tied together as they will fight each other to control the exact voltage level Isolated Encoder Signals In many systems the encoder circuitry is optically isolated from the PMAC digital circuitry This is common in systems with long distances from the encoder to the controller gt 10m or 30 ft and or systems with very high levels of electrical noise Isolation can be achieved using the ACC 8D Opt 6 4 channel encoder isolator board With an isolated encoder a separate power supply is required for the encoders to m
226. character or line Polled communications handshaking is easier to write but it is less efficient because of the time the program can spend waiting for PMAC to be ready Interrupt based communications is more efficient because the host computer can be performing other tasks while PMAC is not ready but it is much more difficult to write Initialize vector and unmask the interrupts write the interrupt service routines decide which routines disable which other interrupts and you must restore the interrupts when completed Serial Port Communications When communicating to the PMAC through the PMAC serial port typically one of the COM ports in the host computer is used In an IBM PC or compatible usually these are the built in COMI and COM2 RS 232 ports but they can be on expansion cards as well Most COM ports even on non IBM compatible computers use the same ICs so usually they have the same registers on the host side Setting Up the Interface Every time the system is started up the serial port of the host computer must be initialized to interface properly with the settings of PMAC This is done with some simple byte write commands to the I O space of the computer Writing a Host Communications Program 17 1 PMAC User Manual Base Address The first thing to know is the base address of the COM port in the computer s I O space In an IBM PC the COMI port base address is at 3F8 hex 1016 decimal and the COM2 port is at 2F8 hex
227. chine PMAC User Manual Isolation The analog command output circuitry is optically isolated from the digital logic circuitry on PMAC Usually the analog circuitry will get its power from the amplifier most amplifiers provide 15V for this purpose It is possible to jumper the power supply for the analog circuitry from the digital side of the board by using Jumpers E85 E87 E88 and E90 but this defeats the optical isolation it is not recommended for any high power or high noise environment especially when PMAC is electrically connected to a host computer either by backplane bus or by non isolated serial cable Drive Capability The analog outputs are intended to drive high impedance inputs with no significant current draw The 2200 output resistors will keep the current draw lower than 50mA in all cases and prevent damage to the output circuitry but any current draw above 10mA can result in noticeable signal distortion General Purpose Use Any analog output not used for dedicated servo purposes may be utilized as a general purpose analog output Usually this is done by defining an M variable to the digital to analog converter register suggested M variable definitions M102 M202 etc then writing values to the M variable General Purpose Digital Inputs and Outputs JOPTO Port The PMAC JOPTO connector J5 on PMAC PC Lite and VME provides eight general purpose digital inputs and eight general purpose digital outputs Eac
228. choing PMAC accepts the character writes it to its input queue in memory and then copies it from memory to its transmission port Therefore this is a complete check of the command cycle If the host receives an echoed character different from the one it sent it should send a CTRL X character to clear out the command line then re send the command line Communications Checksum PMAC is capable of performing checksum calculations on communications lines sent between it and the host computer This mode is enabled when I4 1 and disabled when 14 0 It will operate for serial PC bus STD bus or VME bus communications PMAC computes the checksum of the individual bytes characters in a communications line sent in either direction between it and the host It simply adds together the ASCII value of each character into an accumulating sum At the appropriate time it sends the checksum at least the low byte to the host It is the host s responsibility to make the comparison between the checksum that PMAC has computed and the one that it has computed itself PMAC does not do this comparison The host should never send a checksum byte to PMAC The way the checksum works is subtly different between host to PMAC communications and PMAC to host communications Each case is explained in detail below Host to PMAC Checksum After a full command line including the terminating Carriage Return CR byte has been sent to PMAC PMAC will
229. cifier to the end of a regular definite jog command for the motor where this constant is the distance to be traveled relative to the trigger position before stopping in encoder counts It cannot be used with the indefinite jog commands J and J This makes the jog command for a jog until trigger something like J210000 100 J 50 or J 50000 0 The value before the is the destination position or distance depending on the type of jog command to be traveled in the absence of a trigger If this first value is represented by a symbol PMAC looks in a pre defined register for the position or distance The second value is the distance to be traveled relative to the position at the time of the trigger This value is always expressed as a distance regardless of the type of jog command Both values are expressed in encoder counts The trigger condition for the motor is set up just as for homing search moves 1x03 bit 17 specifies whether input flags are used to create the trigger or the warning following error limit status bit is the trigger torque limited triggering O flags 1 error status If input flags are to create the trigger Ix25 specifies the flag register e If input flags are to create the trigger Encoder Flag I variables 2 and 3 for this set of flags specify which edges of which signals will cause the trigger 11 2 Basic Motor Moves PMAC User Manual 1x03 bit 16 specifies whether the hardware captured counter
230. cise TUNING aseo titi T iaa b Compiled PLC Programs iti bre ebbe eco t e UI e eate tete Pte e de eee utere ep e Eg 6 Execution Of Compiled PEGCS iet tite p ostio eint p le tra Poe rtp a enda pip De tre Get ioter a 6 Preparing Compiled PLCS iae ette a HS ce nie tercie diis itii abe teo iot tet iii 7 Variable Value Assignment Statements eese esee eene enne nnne tnee trente entren eren ener enne et rennen 9 Intestatins PBEC Piles M ad de aati ees 12 Link Address e iaa 12 Executing the Compiler ue rte iia 12 Compiler TTI ONS 5 A Hber poet depo aeu i 13 Compiler Processing REM 13 Downloading the Compiled Code to PMAC sss eene nennen nenne ne entren eterne rre 14 Running th Compiled PLOs eet ete pute c 14 Table of Contents 16 1 PMAC User Manual 16 2 Table of Contents PMAC User Manual WRITING A PLC PROGRAM PLC Programs In addition to the motion programs which operate sequentially and synchronously in time any move command takes a specified amount to execute before succeeding program lines are executed PMAC has 64 PLC programs that operate asynchronously and with rapid repetition 32 compiled PLC programs as well as 32 uncompiled PLC programs They are called PLC programs because they perform many of the same functions as hardware programmable logic controllers PLC programs have most of the same logical constructs as the motion programs but no move type statem
231. commutation for a motor If not using PMAC to perform the commutation on any of the motors skip this section Simply make sure that Ix01 is set to zero for all of the activated motors so PMAC will not try to commutate them If using PMAC to commutate a motor tell PMAC how to perform the commutation This is done by proper setup of I variables to Ix83 for the motor This section explains how to set these variables Once this setup is done the commutation operation proceeds automatically and invisibly PMAC has sophisticated on board commutation features for DC brushless variable switched reluctance AC induction and stepper motors These algorithms allow PMAC to drive the phases of the motor directly requiring only simple current loop bridges for the amplifier As its commutation feedback device PMAC can utilize the same feedback device that is used for servo position feedback an encoder or resolver Incremental Encoder Feedback Requirement The ongoing commutation position information for a motor must come through an incremental encoder counter If the commutation feedback device is an absolute encoder or resolver the power up information can be received straight from the device but an incremental signal must be derived from the absolute position information for the ongoing commutation The PMAC ACC 8D Option 7 resolver to digital converter board does this automatically for resolvers and Option 6 on an ACC 14 does this for absolute enc
232. condition after one single line condition has been found false An example is IF M11 1 OR M12 1 AND M13 1 OR M14 1 Timers There are four timer registers at addresses X 0700 Y 0700 X 0701 and Y 0701 These four 24 bit registers are general purpose timers for user program use PMAC decrements them once per servo cycle It is permitted to write to them as desired Typically read and write access is through M variables Usually a value is written equal to the time to wait scaled in servo cycles Then the program waits for the register to become less than 0 The registers will continue to count down until they reach 2 8 388 608 They will not roll over back to positive values Since these timers have units of servo cycles and it is preferred to work in milliseconds a conversion must be done To convert from milliseconds to servo cycles multiply by oi 8 388 608 and divide by the value of I10 13 22 Computational Features PMAC User Manual When looking for a zero crossing on these registers it is important to treat them as signed two s complement variables Any M variable definitions should be in S signed format For example M90 gt 0700 0 24 S Example In a PLC program to turn on an output for a fixed number of milliseconds M1 1 Turn on Machine Output 1 M90 125 8388608 110 Set timer M90 to 125 msec in servo Cycles WHILE M90 gt 0 Wait for counter to count down to zero ENDWHILE
233. connector and allow this to pull up the outputs by connecting pins 1 and 2 of Jumper El Jumper E2 must also connect pins 1 and 2 for a ULN2803A sinking output Input Output Connecting PMAC to the Machine 6 9 PMAC User Manual Option for Sourcing Outputs Caution Having Jumpers E1 and E2 set wrong can damage the IC It is possible for these outputs to be sourcing drivers by substituting a UDN2981A IC for the ULN2803A This IC U3 on the PMAC PC U26 on the PMAC Lite U33 on the PMAC VME is socketed and so may be replaced easily For this driver use pull down resistors With a UDN2981A driver IC Jumper El must connect pins 2 and 3 and Jumper E2 must connect pins 2 and 3 Input Source Sink Control Jumper E7 controls the configuration of the eight inputs If it connects pins 1 and 2 the default setting the inputs are biased to 5V for the OFF state and they must be pulled low for the ON state If E7 connects pins 2 and 3 the inputs are biased to ground for the OFF state and must be pulled high for the ON state In either case a high voltage is interpreted as a 0 by the PMAC software and a low voltage is interpreted as a 1 Thumbwheel Multiplexer Port I O JTHW Port Multiplexed Uses The Thumbwheel Multiplexer Port or Multiplexer Port on the JTHW J3 connector has eight input lines and eight output lines The output lines can be used to multiplex large numbers of inputs and outputs on the port and Delta Tau
234. coordinate system by amp n command For a coordinate system to be in position three conditions must be met the desired velocity must be zero on all axes no move timers can be active in any move DWELL or DELAY and all motors must have a following error smaller than the in position band 1x28 BREQ is the buffer request signal It is high when a regular buffer still has room for more lines to be entered you can define how much memory left means enough room with I18 When a rotary buffer is open it is high when less than a prescribed number of lines ahead of the executing line set by I16 and I17 have been loaded It is low when buffers are closed When a program line is sent to an open buffer it is always set low then set high again if the conditions as explained above warrant This rising edge can generate an interrupt to tell the host to send the next program line PMAC PC PMAC Lite Input Signal Matching PIC Input PMAC Signal IRO IPOS IRI BREQ IR2 EROR IR3 FIER IRA HREQ IR5 EQUI thru E65 EQUS thru E64 AXEXPI thru E63 MII thru E62 IR6 EQU2 thru E61 EQU6 thru E60 AXEXPO thru E59 MD thru E58 IR7 EQU3 thru E57 EQU7 thru E56 EQUA thru E55 EQUS thru E54 The following table shows which signals match to each input on the PMAC STD PMAC STD Input Signal Matching Input Signal Input Signal IRO RESET IR4 BREQ IR1 RESET
235. cutive program V3 x and newer when it establishes communications with a PMAC in this re initialization mode will notice automatically that PMAC is in this mode In this mode the menu selection Download binary firmware file in the File menu can be selected to take a binary file from disk and copy over the serial port to PMAC The program then forces an exit to the operating system At this point turn off power to PMAC and remove the E51 jumper With older versions of the PMAC Executive program or with a terminal emulator program running on a PC the procedure for downloading new firmware is as follows remember to back up the PMAC software and delete any compiled PLC programs first Establish communications to PMAC over the serial port at 38400 baud Confirm that PMAC is in this re initialization mode by seeing that it responds to the command with BOOTSTRAP PROM If using the Executive program make sure that all windows other than the Terminal window such as the position window are closed so no other commands are being sent to PMAC e Type a CONTROL O character in the terminal window and immediately exit to DOS Do not send any other characters to PMAC here e Use the binary version B of the DOS COPY command to download the file containing the new firmware to PMAC The command typed at the DOS prompt will look something like COPY B B V115A BIN COM1 e Where B V115A BIN is the directory and name of the file containing the
236. cutive program could be used to force a motor to the zero position in its phasing cycle set the phase position register as zero and enable the motor 100 Enable the motor with open loop zero magnitude 1129 0 No offset on Phase A I179 3000 Positive offset on Phase B to force to 0 deg Ix72 85 M171 0 Write zero into phase position register 1179 0 No offset on Phase B J Close servo loop The time between typing the commands would provide sufficient delay for settling into position The following PLC program is a good starting point for variants on the stepper motor phasing search method Extensions to this program could be to phase two gantry motors simultaneously or to step out of a position limit This example uses Ix73 and Ix74 as they would be used in the automatic stepper motor phasing search method Setting Up PMAC Commutation 8 5 PMAC User Manual PRK eR KORR A e RR CE Set up and Definitions Ck ckckckckckckckck ckck ck ckckckckok kc CLOSE Make sure all buffers are closed M70 X 0700 0 24 S 24 bit automatic timer register M271 gt X 007D 0 24 S Motor 2 phase position register PRARRRER ERA EK NAAA Program to do phasing Search Ck ckckck kckckckck kck kk OPEN PLC 1 CLEAR CMD 200 Force zero magnitude open loop P229 1229 Save real Phase A bias P279 1279 Save real Phase B bias IF 1272 lt 128 I229 1273 Force negative bias into A 12
237. cy converter V F with a gain of 25 kHz Volt providing a range of 0 250 kHz The output of the V F can be connected to the Encoder 4 counter using jumpers E72 and E73 If these jumpers are on nothing else should be connected to the Encoder 4 inputs Make sure that the Encoder 4 jumper E24 is set for single ended signals connecting pins 1 and 2 Frequency Decode When used in this fashion Encoder 4 must be set up for pulse and direction decode by setting 1915 to O or 4 Usually a value of 4 is used because with CHB4 direction unconnected a positive voltage causes the counter to count up Input Output Connecting PMAC to the Machine 6 11 PMAC User Manual Power Supply For the V F converter to work PMAC must have 12V supply referenced to digital ground If PMAC is in a bus configuration this usually comes through the bus connector from the bus power supply In a standalone configuration still this supply must be brought through the bus connector or the supply terminal block on the PMAC Lite or it must be jumpered over from the analog side with E85 E87 and E88 defeating the optical isolation on the board PMAC Lite Special Considerations Since the PMAC Lite s Wiper input has bipolar capability it has a few special considerations If used in bipolar fashion the offset potentiometer R18 should be adjusted for minimum deadband in the zero crossing monitor on CHA4 on the JMACHI connector If used in unipolar fashion R18
238. cy would be entirely arbitrary Any frequency can be selected as the RTIF and a motion program can be written for that RTIF However PMAC does its time base calculations in integer arithmetic which limits the resolution and in 24 bit registers which limits the dynamic range These limitations lead to three restraints on the selection of the RTIF e The time base scale factor TBSF derived from the RTIF must be an integer The value that PMAC needs for its calculations is not the frequency in cts msec but the inverse of the frequency in msec ct In order for this number to be in the range of integer values the rule is to multiply the frequency inverse by 2 131 072 Ifa value of 100 cts msec were chosen for RTIF then the TBSF would be 131 072 100 131 072 which is not an integer PMAC could only accept the integer part of 131 and drift would occur 15 4 Synchronizing PMAC to External Events PMAC User Manual e A choice of real time input frequency that is a power of 2 in cts msec e g 32 64 128 will always produce an integer TBSF Also RTIF values that are equal to a power of 2 divided by an integer will work typically For example 204 8 cts msec 2048 10 27 10 will yield a TBSF of 2 2 10 640 The time base calculations will saturate at an input frequency IF where IF RTIF equals the servo update frrequency in kHz At the default servo update frequency of 2 25 kHz and an RTIF of 32 cts msec the maximum
239. d by the first Y word that is all zeros The encoder table as shipped from the factory converts the eight incremental encoder registers on the base PMAC board in locations 720 through 727 1824 to 1831 Locations 728 and 729 create time base information from the converted Encoder 4 register 723 Y 72A is zero ending the active part of the table Setting Up a Motor 7 25 PMAC User Manual Default Encoder Conversion Table Address Y Word Meaning 720 1824 00C000 1 T conversion of Encoder 1 721 1825 00C004 1 T conversion of Encoder 2 722 1826 00C008 1 T conversion of Encoder 3 723 1827 00C00C 1 T conversion of Encoder 4 724 1828 00C010 1 T conversion of Encoder 5 725 1829 00C014 1 T conversion of Encoder 6 726 1830 00C018 1 T conversion of Encoder 7 727 1831 00C01C 1 T conversion of Encoder 8 728 1832 400723 Time base from converted Enc 4 729 1833 000295 Time base scale factor for above 72A 1834 000000 Signifies end of table This table can be used unchanged by the great majority of PMAC users Note that the default motor feedback position address and master position address I variables 1103 1105 1203 205 etc point to locations in this table and assume the default setup of the table However there are several reasons to change the table First if the application uses an ACC 24 axis expansion board it will need to convert
240. d is not shipped from the factory in this configuration Incremental Encoder Connection Each JMACH connector provides two 5V outputs and two logic grounds for powering encoders and other devices The 5V outputs are on pins 1 and 2 the grounds are on pins 3 and 4 The encoder signal pins are grouped by number all those numbered 1 CHA1 CHA1 CHB1 CHC1 etc belong to encoder 1 The encoder number does not have to match the motor number but usually does If the PMAC is not plugged into a bus and drawing its 5V and GND from the bus use these pins to bring in 5V and GND from the power supply Connect the A and B quadrature encoder channels to the appropriate terminal block pins For encoder 1 the CHA 1 is pin 25 CHB1 is pin 21 If using a single ended signal leave the complementary signal pins floating Do not ground them For a differential encoder connect the complementary signal lines CHA 1 is pin 27 and CHB1 is pin 23 The third channel index pulse is optional for encoder 1 CHC1 is pin 17 and CHC1 is pin 19 2 6 Getting Started with PMAC PMAC User Manual Amplifier Connection If PMAC is not performing the commutation for the motor only one analog output channel is required to command the motor This output channel can be either single ended or differential depending on what the amplifier is expecting Single Ended Command Signal For a single ended command using PMAC channel 1 connect DACI pin 43 to the
241. d move it has the minimum time of the acceleration time which can cause a slowdown on a very shallow angle While the default value for I89 of 0 9998 cos1 causes an arc to be Writing Programs for PMAC 14 27 PMAC User Manual added on any change in angle greater than 1 many users will set 189 to 0 707 cos45 or 0 0 cos90 so arcs are only added on sharp corners When coming to a full stop e g Step Quit or DWELL at an outside corner with an added arc PMAC will include the added arc move before stopping When coming to a full stop at an outside corner without an added arc PMAC will stop at the compensated but unblended corner point Treatment of Full Reversal If the change in directed angle at the boundary between two successive compensated moves is 180 1 the included angle is less than 1 this is considered a full reversal and special rules apply If both the incoming and outgoing moves are lines the corner is always considered an outside corner and an arc move of approximately 180 is added If one or both of the moves is an arc PMAC will check for possible inside intersection of the compensated moves If such an intersection is found the corner will be treated as an inside corner Otherwise it will be treated as an outside corner with an added 180 arc move Reversal In Cutter Compensation Programmed Path Line S Line lt 1 Arc A 3 E a Tom Line we Tool Cen
242. d of the buffer Downloading the Program Typically in program development the editing will be done in a host based text editor and the old buffer is cleared every time the new version is downloaded to the card When finished close the buffer with the CLOSE command Opening a PLC program buffer disables that program automatically After it is closed it remains disabled but it can be re enabled again with the ENABLE PLC n command where n is the buffer number 0 31 I5 must also be set properly for a PLC program to operate The general form for this technique is CLOSE DELETE GATHER DELETE TRACE OPEN PLC n CLEAR PLC statements CLOSE ENABLE PLC n Note Because all PLC programs in the PMAC memory are enabled at power on reset it is good practice to have I5 saved as 0 in the PMAC memory when developing PLC programs This will allow you to reset PMAC and have no PLCs running an enabled PLC only runs if I5 is set properly and more easily recover from a PLC programming error Closing the Buffer At the closing PMAC checks to make sure all IF branches and While loops have been terminated properly If not it reports an error and the buffer is inoperable Correct the PLC program in the host and re enter it clearing the erroneous block in the process of course This process is repeated for all of the PLC buffers in use Erasing the Program To erase an uncompiled PLC program open the buffer clear the contents then cl
243. d rate of 38 400 regardless of the setting of the baud rate jumpers Only a very basic bootstrap firmware is executing in this mode In this bootstrap mode there are very few command options PMAC will respond to any of the status bit query commands or with the response BOOTSTRAP PROM This permits the host to know whether PMAC is in this mode or not PMAC will respond to the VERSION query command with the number of the bootstrap firmware e g 1 01 which will probably be different than the operational firmware version Normal Re initialization To bypass the download operation in this mode send a CONTROL R character to PMAC This puts PMAC in the normal operational mode with the existing firmware Factory default values for I variables conversion table settings and bus addresses for DPRAM and VME are copied from the firmware section of flash memory into active memory The saved values of these values are not used but they are still kept in the user section of flash memory For any change in the operational firmware the compiled PLCs will have to be re compiled with the LIST LINK file for the new firmware version It is important to delete all compiled PLCs DELETE PLCC n before attempting to change the operational firmware version Compiled PLC programs running under a firmware version other than that which they were compiled for can have unpredictable consequences To download new operational firmware to the PMAC send a
244. d register if later access is needed The units are in counts for incremental encoders they are relative to the power up reset position PMAC sets the motor home search in progress status bit bit 10 of the first motor status word returned on a command true 1 at the beginning of a programmed move until trigger move The bit is set false 0 either when the trigger is found or at the end of the move PMAC also sets the motor trigger move status bit bit 7 of the second motor status word returned on a command true at the beginning of a programmed move until trigger move and keeps it true at least until the end of the move If a trigger is found during the move this bit is set false at the end of the post trigger move however if the pre trigger move finishes without finding a trigger the bit is left true at the end of the move Therefore this bit can be used at the end of the move to tell whether the trigger was found successfully or not Circular Blended Moves PMAC allows circular interpolation on the X Y and Z axes in a coordinate system As with linear blended moves TA and TS control acceleration to and from a stop and between moves Circular blended moves can be feedrate specified F or time specified TM just as with linear moves It is possible to change back and forth between linear and circular moves without stopping Note In order for PMAC to do circular moves parameter 113 must be greater than zero
245. dback signal would be Using the 1 T conversion method here is recommended because this method gives a very good sub count interpolation of the signal using timers associated with the counter that significantly enhances the smoothness of the time base information Make sure that the conversion table is set up to process the counter from the input signal this way The encoder conversion table is set up at the factory to do 1 T conversion on encoder counters 1 through 8 See the description of the encoder conversion table for more details Step 3 Time Base Calculation A separate entry in the encoder conversion table takes the interpolated position information from the above step subtracts out the interpolated position information from the previous servo cycle and multiplies this difference by a scale factor to produce the time base value for the servo cycle This time base value is then a multiplying factor in the position update calculations so the amount of update is proportional to the number of counts received from the time base signal in the last servo cycle The two set up items in this step are the source of information the interpolated position register and the scale factor Both of these are entries in the encoder conversion table See the description of the table for more details on how to enter these The equation for the time base conversion is _ 100 0 SCALE _ FACTOR INPUT _ FREQ 217 value where the value also k
246. de and should therefore always be a positive number A negative Feedrate will cause the motion to be opposite of what is defined as positive in the Coordinate System definition Short Moves If a feedrate specified move segment is so short in distance that it cannot reach its target velocity it will spend its entire time in acceleration yielding a triangular rather than trapezoidal profile The minimum time for such a move is thus the specified acceleration time TA or 2TS For a single move remember to add on the extra acceleration time to decelerate to a stop In a time specified move segment if TM is less than the acceleration time the segment will be done in acceleration time not TM time In other words the acceleration time 1s the minimum time for an individual blended move or blended move segment This is in part a protection against move times getting so short that PMAC cannot calculate them in real time If working with very short move segments and the move sequence is going more slowly than desired this acceleration time limit may well be causing the problem Long Moves The maximum time for one programmed move is 2 4 8 388 607 msec approximately two hours and 20 minutes This is the maximum value that PMAC will accept with a TM command It is also the maximum value PMAC will compute for a feedrate specified move when it divides the vector distance for the move by the feedrate If the vector distance for the move divided by th
247. defines only two counts per encoder cycle The difference between 3 and 7 or 2 and 6 is for which sense of the signal does the decoder count up Synchronizing PMAC to External Events 15 5 PMAC User Manual Make sure that to count up in the direction that the master signal is going Counting down would imply a negative time base which PMAC cannot handle Analog Source for Frequency PMAC has a single on board voltage to frequency V to F converter that allows a voltage level input to the Wiper line of the JPAN connector Pin 20 of J2 to control the time base The input is 0 to 10V analog signal that is converted to a nominal 0 to 250 KHz frequency 25KHZ V Jumpers E72 and E73 ON connect this signal to the Encoder 4 decoder counter there is no choice about which encoder Make sure jumper E24 connects pins 1 and 2 the default I variable I915 which controls decoding this signal should be set to 4 pulse and direction counting up on this signal From this point on the time base control can be treated just as if it came from an external frequency source Note that the default conversion table is set up to handle time base information from this encoder counter Refer to the diagram under Control Panel I O in the Connecting PMAC to the Machine section of this manual Step 2 Interpolation Once decoded and counted the value from the signal is brought into the encoder conversion table once per servo cycle exactly as a position fee
248. der see above For this type of device PMAC can use the Ix10 parameter to read the absolute power on reset position up to a width of 16 bits If Ix10 is set to 0 the absolute power on reset position read function is disabled and the power on reset position is set to zero regardless of the setting of the sensor and subsequent position readings are incrementally referenced to this zero position For more information refer to the Absolute Power Up Position section in this manual the Ix10 description in the Software Reference manual and the ACC 28 or ACC 36 A D Converter manual With the V1 15 firmware it is also possible to use the A D converters on a single ACC 36 for servo loop feedback 160 and 161 are used to specify the address and number of ACC 36 ADC registers to be copied into RAM automatically during phasing interrupts The servo loop feedback functions read the data from these RAM registers and should treat the data as 12 bit parallel position feedback see above section For this type of device PMAC can use the Ix10 parameter to read the absolute power on reset position up to a width of 12 bits If Ix10 is set to 0 the absolute power on reset position read function is disabled and the power on reset position is set to zero regardless of the setting of the sensor and subsequent position readings are incrementally referenced to this zero position It is important with this type of feedback device to perform a PMATCH position mat
249. development of the system There are several ways to do this phasing search PMAC has two automatic Setting Up PMAC Commutation 8 3 PMAC User Manual methods executed by firmware other methods or enhancements of these methods can be executed with PLC programs A power on phasing search permits commutation of permanent magnet brushless motors without the need for a more expensive and possibly less accurate absolute sensor However a phasing search may not be dependable in some applications in these cases an absolute sensor will be required Two Guess Phasing Search The PMAC first automatic phasing search method is called the two guess phasing search because it makes two arbitrary guesses as to the phase position briefly applies a torque command using each guess and observes the response of the motor to each command Based on the magnitude and direction of the two responses PMAC calculates the two responses and the proper phasing reference point It then starts the commutation based on this reference and closes the servo loop to hold position The two guess phasing search is very quick and requires little movement It works well provided that external loads such as gravity and friction are low However if there are significant external loads it may not prove to be a reliable phasing search method and unreliable phasing search methods can be dangerous if this is the case another method such as the stepper motor method described b
250. ding this correction would have motor 1 as the source motor and motor 2 as the target motor A second use for cross axis compensation is what is often known as the electronic cam In this case the entire movement of the target motor is caused by the entries in the compensation table not just the corrections This method of implementing electronic cam operation has two significant advantages over The PMAC time base following the other method of creating electronic cams the compensation table is bidirectional the master can turn in either direction and it is absolute so the phasing in is simply a matter of homing the axes The time base method in which the motion program of the slave motor s defines the motion retains the advantage of being able to change on the fly through math and logic in the program and of second or third order interpolation between points rather than the compensation table s first order interpolation Two Dimensional Leadscrew Compensation It is possible to set up two dimensional compensation tables on PMAC where the compensation is a function of the position of two motors This makes it possible to set up planar compensation functions by specifying a grid of compensation points A 2D compensation table has two source motors and one target motor The target motor can be one of the source motors If the size parameter in the DEFINE COMP command that establishes the compensation table has a decimal point it is
251. drature or pulse and direction signal must be decoded so that the counter counts up This is set with Encoder I variable 0 1900 1905 etc Step 2 Interpolation and Time Base Setup The triggered time base conversion in the encoder conversion table handles both the 1 T count interpolation and the time base calculation from the interpolated value In the initial setup a triggered time base entry is created in the conversion table usually in the running not frozen or waiting for trigger state The time base scale factor is also entered here it is calculated in exactly the same way as for the standard time base Step 3 Writing the Motion Program In writing the motion program that is to use triggered time base all of the axes must be brought to a stop at the point where they will wait for the trigger If this is not at the beginning of the motion the section should be preceded immediately by a DWELL command At the start of the calculations for the moves that are to be started on the trigger the time base should be frozen to prevent the move from starting Use an M variable that has been assigned to the process bits for the triggered time base entry in the conversion table If the previous moves were done working from a different time base source the time base address for the coordinate system 1x93 should be changed to the triggered time base entry These commands in the motion program are followed immediately by the calculations and com
252. drift apart since each card references time from its own crystal oscillator However the tolerances on the oscillators are so tight that no drift would be noticed until after 10 or 15 minutes of continuous motion Data Integrity Checks Serial Parity Check PMAC has the capability to do parity checks on serial communications If jumper E49 is removed PMAC will expect an odd parity bit on each character it receives from the host over the serial port and it will send an odd parity bit with each character it sends to the host over the serial port If PMAC detects a parity error in any character in the command it sets a flag so that the entire command line will be rejected with a syntax error after PMAC receives the CR character If 14 0 or 1 PMAC also immediately sends a lt BELL gt character to the host to notify it of the error on the character With 14 2 or 3 the host should just check for a BELL character at the end of the line However there is no direct way to tell whether this was due to a parity error or a real syntax error Also if the parity error occurred on the lt CR gt character itself PMAC would not respond at all since it never saw the end of the line In this case the host must be prepared to time out gracefully and either resend the lt CR gt or send a lt CTRL X gt to clear out the line With 14 0 or 1 the host can either check for the BELL character after every character it sends or wait until the end
253. e For example M171 gt TWR 0 2 Resolver at multiplexer address 0 location 2 at that address on an ACC 8D Opt 7 board M171 gt Y FFDO 0 16 U 16 bit parallel absolute sensor at first ACC 14 Port A Next manually run the stepper motor phasing search using on line commands The point of this sequence is to force the motor into the zero point of the phasing cycle At this point read the absolute sensor using the M variable we have defined Use Motor 1 for the example The exact sequence depends on the phase angle value in Ix72 For 1172 64 4 phase or 85 3 phase 100 Open loop command of zero magnitude 1129 2000 1179 2000 Force motor to preliminary position 1129 0 Now force motor to zero point of phase cycle Ix29 can be set to non zero value here if the current loop bias has been evaluated in which case Ix29 is set to the value that forces zero current through the phase For 1172 192 4 phase or 171 3 phase e 100 Open loop command of zero magnitude I129 2000 1179 2000 Force motor to preliminary position 1129 0 Now force motor to zero point of phase cycle See note above on phase current bias At this point read the absolute position sensor by querying the M variable value For example M171 Ask for value of M171 475 PMAC responds Take the value PMAC returns negate it multiply it by Ix70 and put the resulting value in Ix75 Continuing our example if
254. e PMAC VME and PMAC STD there is a JEQU connector to bring out the Compare Equals outputs These output are open collector sinking outputs rated to 24V and 100 mA The existing socketed driver IC may be replaced with a sourcing driver IC UDN29814A Example The program COMPPULS PMC in the examples section shows how to use this feature to generate a very rapid series of equals pulses on position intervals As soon as PMAC detects that the previous compare position has been reached it clears the flag loads the next compare position and calculates the position after that Offset from Motor Position Encoder position is referenced to the position at the most recent power on or reset regardless of any homing moves or offset commands done since then To relate this encoder position to motor position one must know the offset between encoder zero and the homing zero positions Fortunately this is simply the position captured during the homing move which PMAC stores for future use in registers Y 0815 1 Y 08D5 2 etc Note The position compare feature uses encoder position rather than motor or axis position 15 16 Synchronizing PMAC to External Events PMAC User Manual Synchronous M Variable Assignment Synchronous M variable assignment statements allow outputs to be set and cleared synchronously with the start of the next commanded move in the motion program The output is synchronous with the commanded pos
255. e executed the execution of an S single step command may not produce the intuitively expected results The single step command on a move in compensation causes the preliminary calculations for that move to be done not for the move to be actually executed This has the following ramifications e A single step command on the lead in move for compensation will produce no motion because the next move has not yet been found Single step commands on compensated moves in the plane of compensation will cause the previous move to execute e A single step command on the lead out move will cause both the last fully compensated move and the lead out move to execute Writing Programs for PMAC 14 33 PMAC User Manual Unlike many controllers PMAC can execute non motion program blocks with single step commands with cutter compensation active However be aware that the execution of these blocks may appear out of sequence because the motion from the previous programmed move block will not yet have been executed Synchronous M variable assignments in this mode are still buffered and not executed until the actual start of motion execution of the next programmed move Lookahead A move exactly perpendicular to the plane of compensation will temporarily turn off compensation because PMAC does not know on which side of the point to compensate A tiny component of the move in the plane of compensation is enough to keep compensation turned on Two
256. e a ARANDA Rana rare 4 Hydraulic Servo Amplifiers 4 5 rd Eee ue Et ade e peo ME ete ee Guedes ata eMe Eee eae 4 PID Servo FINEP 2 3 0 c 4 How the PID Filter AAA 4 TUNING the PID Filter 5e aan aaen a Ea a Eae a aanas ae e eaan Ran E oana e bx Actual PID Algorithm eite ee aai i eot eee b eI SHE C Een ee a eee ERE Qe des gres d due E E ea tee ere pide dd 6 Notch Ellters e 7 Automatic Notch Specification eee eese sees eee enne enne tee etr enn Dann enne enn enn non neon arena near nan entrent 7 Manual Notch Specification eese esee eese eene enne then tnen tr enee te enne teens tee testen enne nan trennen 7 Other Uses of the Notch Filter eee eese eene enne ene teen nn ana nn RR a RR Ran Ran aran enn ete trsn e tnee trennen enne 9 Extended Pole Placement Servo Filter oooooonoccccnonoccnononononononnnoonnncnnnonnncnnonnnnnnnonnc nono nnnnnnnn nn nro nenne nennen nennen nennen nnne 9 User Written Servo Eternidad id 10 What is Needed to Write the Filter eese eee enne ener enne terere trennen enne 10 Dowrload and Enable Procedure iiit eee e eR e Ree e RRA cesa 10 Memory Space Software Interface and Program Restrictions eene enne ener 12 Usable Data Spaces RE EEEE 12 Interface to Othe
257. e again Movement But Sluggish Check the following e Is proportional gain Ix30 too low Try increasing it as long as stability is kept Is the big step limit Ix67 too low Try increasing it to 8 000 000 near the maximum to eliminate any effect Is the output limit 1x69 too low Try increasing it to 32 767 the maximum to make sure PMAC can output adequate voltage e Can an integrator help Try increasing integral gain Ix33 to 10 000 or more and the integration limit Ix63 to 8 000 000 Runaway Condition Check the following e Is there feedback Check that position changes can be read in both directions e Does the feedback polarity match output polarity Recheck the polarity match as explained above Brief Movement Then Stop Check the following e Is this following error limit being tripped Disable fatal following error limit 1x11 by setting it to Zero then try to move again 5 2 Troubleshooting PMAC User Manual Motion Program Troubleshooting If the program does not run at all there are several possibilities e Can the program be listed In terminal mode type LIST PROG 1 or whichever program and see if itis there If not try to download it to the card again e Is the program buffer closed Type A just in case the program is running type CLOSE to close any open buffer type B1 or the program to point to the top of the program and type R to try to run it again Can each
258. e derivative gain of the PMAC position loop provided that the velocity loop is well tuned In these systems the PMAC analog output represents a velocity command These amplifiers also close current loop s internally and if the motor is brushless they perform the phase commutation The key virtue of velocity mode amplifiers is that in closing an analog velocity loop they are not subject to the quantization errors and sample rate limitations of a digital velocity loop Therefore they can often achieve higher velocity loop gains resulting in higher stiffness and better disturbance rejection For this reason they are used widely in machine tool cutting applications maintaining accuracy against high cutting forces Because of these high gains the position loop proportional gain in PMAC tends to be much lower for these amplifiers than for other types However much of the velocity loop stiffness comes from velocity integral gain Integral gain in a loop creates a lag and this makes response to external commands sluggish Therefore these amplifiers are not well suited to applications with quick starting and stopping as many indexing applications use As processor speeds increase with DSPs and higher clock rates helping to overcome sample rate limitations and digital velocity estimation techniques improve with methods such as 1 T reducing quantization errors velocity mode amplifiers are being used less and less Before tuning the PMAC positi
259. e distance to be traveled relative to the trigger before stopping This makes the axis command for a move until trigger axis data data something like X50 5 The first value is the destination position or distance depending on whether the axis is in absolute or incremental mode to be traveled in the absence of a trigger The second value is the distance to be traveled relative to the position at the time of the trigger This value is always expressed as a relative distance regardless of whether the axis is in absolute or incremental mode Both values are expressed in the axis user units Other axes can be specified on the same line without a colon and second value These axes will do a simultaneous normal rapid move However if an axis matrix transformation is active for the X Y and Z axes in this coordinate system TSELECT has been used to select a matrix or if there is a move until trigger on any of the X Y and Z axes the other axes in the XYZ triplet will also execute a move until trigger If no post trigger move is specified for the axis the post trigger distance is assumed to be zero If no move at all is specified for the axis a zero distance pre trigger move is assumed The trigger condition for each motor is set up just as for homing search moves 14 12 Writing Programs for PMAC PMAC User Manual e 1x03 bit 17 specifies whether input flags are used to create the trigger or the warning following error limit st
260. e feedrate yields a time greater than 8 388 607 msec PMAC will use 8 388 607 msec as the move time and the speed will be higher than what was programmed 14 6 Writing Programs for PMAC PMAC User Manual Small acceleration time I t M or A PECES ane M TA gt V era or TM or A a IM or rs ch time MK TM or A P F eia M or A BP Ti time TA V TA M TM or A TM or P F TM or AP F time ETA gt Figure 28 Linear Mode Trajectories Sheet 1 of 4 Writing Programs for PMAC 14 7 PMAC User Manual Acceleration time matches move time vA M TM or AP F gt time gt TM or AP F TM or AP F time E TA gt TA gt lt TA gt gt M TM or AP F TM or AP F time lt TA pid TA gt lt TA gt i MK TM or AP F gt 4 TM or AP F gt time TA Pi TA gt TA gt lt TA gt Figure 29 Linear Mode Trajectories Sheet 2 of 4 14 8 Writing Programs for PMAC PMAC User Manual Large velocity limiting acceleration time V A TM or AP F gt time 4 TA Pa TA gt V A gt TM or AP F gt TM or AP F gt time 4 TA ba TA bi TA gt V A TM or AP F gt TM or
261. e output transistor will go into its non conducting state To get this failsafe protection without connecting a signal of this polarity directly to the amplifier use intermediate circuitry to change the signal format With the alternate sourcing drivers the high true enable polarity provides better failsafe protection For more details refer to the Error Reference source not found and Error Reference source not found sections of this manual Making Your Application Safe 10 5 PMAC User Manual Note With the default sinking drivers for the amplifier enable signals using the low true enable polarity low voltage conducting is enable high voltage non conducting is disabled provides better failsafe protection against loss of power supply Watchdog Timer PMAC has an on board dead man or watchdog timer This subsystem provides a fail safe shutdown to guard against software malfunction To keep it from tripping the hardware circuit for the watchdog timer requires that two basic conditions be met First it must see a DC voltage greater than 4 75V If the supply voltage is below this value the circuit s relay will trip and the card will shut down This prevents corruption of registers due to insufficient voltage The second necessary condition is that the timer must see a square wave input provided by the PMAC software of a frequency greater than 25 Hz In the foreground the Real Time Interrupt routine s
262. e same precedence as and and have the same precedence as and Use of parentheses can override this default precedence Note Bit by bit logical operators differ from the simple Boolean operators AND and OR used in compound conditions q v Functions These perform mathematical operations on constants or expressions to yield new values The general format is function name expression The available functions are SIN COS TAN ASIN ACOS ATAN ATAN2 SQRT LN EXP ABS and INT Note The global I variable I15 controls whether the units for the trigonometric functions are degrees or radians SIN Function standard trigonometric sine function Syntax SIN fexpression Domain All real numbers Domain units none Range 1 0 1 0 Range units none Possible errors none 13 14 Computational Features PMAC User Manual COS TAN ASIN ACOS ATAN Function standard trigonometric cosine function Syntax COS expression Domain All real numbers Domain units radians degrees Range 1 0 1 0 Range units none Possible errors none Function standard trigonometric tangent function Syntax TAN fexpression Domain all real numbers except Pi 2 3P1 2 5Pi 2 Domain units radians degrees Range all real Range units none Possible errors Divide by zero o
263. e sensor position is zero It is independent of the axis scale factor counts per engineering unit in the same axis definition statement 7 12 Setting Up a Motor PMAC User Manual For instance to assign Motor 1 to the X axis with 10 000 counts per unit if the axis zero position should be at the point where the absolute sensor reads 50 247 counts then the axis position would be 50 247 counts when the sensor reads zero so the axis definition statement would be 1 gt 10000X 50247 Encoder Offset If using resolvers for absolute power on position information subsequent position information comes through the encoder counters which are set to zero on power on For most purposes this is transparent to the user but to use encoder registers directly usually for position capture and compare functions then know the difference between the encoder counter zero position and the motor resolver zero position This value is kept in the Motor Encoder Position Offset Register Y 0815 Motor 1 Y 08D5 Motor 2 etc For an example of the use of this register see the Storing the Home Position under Basic Motor Moves section of this manual Encoder Conversion Table The PMAC Executive Program for PC compatible computers has a special editing screen for the conversion table that makes viewing it and changing it very easy The detailed instructions here show how to view and change the table even without the help of the executive progra
264. e setup to be satisfactory for the most common application types This section explains this configuration process for the inexperienced user Note The PMAC Setup PS program that is provided on the Executive program diskette walks you through each of these steps in an interactive fashion Use of that program may enable you to skip this part of the manual By following this procedure those unfamiliar with PMAC should be able to get the card going quickly and reliably Once more acquainted with the card these tasks may be performed in a different order and some of the checking steps may be skipped to perform the installation more quickly The Getting Started section is a quick introduction to exercise the basic functionality of the card Each of the areas dealt with in this section is also covered in later chapters in more detail Preparing the Card First inspect the card for any signs of damage PMAC was thoroughly tested burned in and tested again including actually running motors before it left the factory but there always exists the remote possibility of shipping damage If any visible damage is seen report this to Delta Tau immediately E Point Jumpers On the PMAC there are many jumpers pairs of metal prongs called E points on the bottom board of the PMAC STD they are called W points Some have been shorted together others have been left open These jumpers customize the hardware features of the board for a given
265. e shipped from the factory set to communicate over the PC bus at I O address 528 decimal 210 hex This setting is controlled by jumpers E91 E92 and E66 E71 located on the rightmost of the lower edge bank of jumpers for this default address E91 E92 are ON E66 is OFF E67 E70 are ON and E71 is off Unless there is a conflict at this address start using the first card at this address If the address must be changed change the jumpers as shown in the detailed E point descriptions in the Hardware Reference manual STDbus Address Jumpers PMAC STD is shipped from the factory set to communicate over the STD bus at I O address 61 584 decimal F090 hex This setting is controlled by jumpers W11 to W22 on the bottom circuit board for this default address W11 W14 are OFF W15 W18 are ON W19 is OFF W20 W21 are ON and W22 is OFF Unless there is a conflict at this address start using the first card at this address If the address must be changed change the jumpers as shown in the detailed E and W point descriptions in the Hardware Reference manual PMAC VME Interface Setup The VMEbus interface is set up by writing to PMAC registers through the serial port If using the PMAC VME the initial development is done by communicating to the PMAC over the serial port from an IBM PC or compatible host Follow the directions for using the serial port Information for setting up the VME bus interface is provided in the Writing a Host Communications Program
266. e slave axes dwelling at the start up position freeze the time base with the motion program command M199 90 If Ix93 is not already pointing to X register 072B do this at this time The motion program commands immediately following this calculate the move but with a zero time base value the move execution is stuck at the starting point Meanwhile a PLC program is looking for M199 to be equal to 90 at which time it changes it to BO arming for the trigger Since a PLC program cannot interrupt motion program calculations for a move this will not be done until after the calculations are completed This change can be done with three program lines in a PLC program IF M199 90 M199 B0 ENDIF Once the trigger is armed by the PLC program when the capture trigger occurs PMAC starts the time base and changes the process bits to A0 automatically Exponential Filter Entries It is possible to use the conversion table to create an exponential filter on a word of input data This is particularly useful for position following electronic gearing especially when the slave is geared up from the master i e the slave moves more than one count for each count of the master where it can significantly smooth the motion of the following axis The equation of the exponential filter executed every servo cycle n is Out n Out n 1 K 2 In n Out n 1 If Out n Out n 1 gt Max_change Out n Out n 1 Max_change If Out n Out n 1
267. e the X displacement equal to Q25 the Y displacement equal to Q26 and the Z displacement equal to Q27 Incremental Displacement The IDIS constant incremental displacement command changes the displacement portion of the selected matrix by adding the values of the three Q variables to the existing displacement Absolute Rotation Scaling The AROT constant absolute rotation command sets up the rotation scaling portion of the selected matrix by making the nine rotation scaling values equal to the nine Q variables starting with the one specified by constant Forinstance AROT 71 would make R11 in the matrix equal to Q71 R12 equal to Q72 and so on to R33 equal to Q79 Incremental Rotation Scaling The IROT constant incremental rotation command changes the rotation scaling portion of the selected matrix by multiplying it by a matrix consisting of the nine Q variables starting with the one specified by constant This has the effect of adding angles of rotation and multiplying scale factors For instance IROT 100 would multiply the existing matrix by multiplying it by a matrix consisting of the values of Q100 to Q108 After using any of these commands any changes to the Q variables used do not change the selected matrix Another command using the Q variables must be executed to change the selected matrix When using axis matrix transformation for scaling do not use the R radius specification for circular interpolation because the
268. e to X10 but the action is not actually performed until the start of blending into the next move X20 Note With synchronous assignment the actual assignment is performed where the blending to the new move begins which is generally ahead of the programmed point In LINEAR and CIRCLE mode moves this blending occurs V TA 2 distance ahead of the specified intermediate point where V is the commanded velocity of the axis and TA is the acceleration blending time Also notice that the assignment is synchronous with the commanded position not necessarily the actual position It is the responsibility of the servo loop to make the commanded and actual positions match closely In applications where PMAC is executing segmented moves 11320 the synchronous M variables are executed at the start of the first I13 spline segment after the start of blending into the programmed move Note Synchronous M variables after the last move or DWELL in the program do not execute when the program ends or temporarily stops Use a DWELL as the last statement of the program to execute these statements Syntax There are four forms of synchronous M variable assignment statements M constant expression Straight equals assignment M constant amp expression AND equals assignment M constant expression OR equals assignment M constant expression XOR equals assignment In all of these forms the expression on the ri
269. e top 16 bits of a 24 bit word It is intended for use with the A D converter registers in the DSPGATEs which are fed by Accessory 23 obsolete or Accessory 28 When using the ACC 36 A D converter board treat the data as 12 bit parallel format data The source address specifies a word in the Y memory space and should be one of the following ADCI C006 ADC9 C026 ADC2 C007 ADCIO C027 ADC3 C00E ADCII C02E ADC4 COOF ADC12 C02F ADCS C016 ADCI3 C036 ADC6 C017 ADC14 C037 ADC7 COIE ADCIS5 CO3E ADCS COIF ADCI6 CO3F A typical setup word for an A D register would be 10C006 which provides the conversion of the ADCI register With A D conversion there is no software extension performed so rollover should not be permitted The result is placed in the X register of the entry scaled so that there are 19 bits of integer the highest three bits are simply sign extended and five bits of fraction the fraction is always zero Integrated Analog It is possible to use the conversion table to integrate an analog input or equivalent This is done with conversion format 50 instead of the 10 used for normal unintegrated analog conversion The address of the A D source register is specified just as for the 10 format An entry to integrate the input of ADCI would be 50C006 Bias Term The integrated analog format requires a second entry to specify the bias of the A D This is a signed quantity with units of 1 256 of
270. each frequency version of the board Hydraulic Servo Amplifiers Hydraulic servo valves create a pressure or force proportional to their command voltage by controlling the orifice opening Therefore to the controller s servo loop it looks like a torque mode amplifier requiring derivative gain for stability Some machine builders use the less expensive hydraulic proportional valves These valves have substantial crossover deadband compared to the servo valves This deadband can be compensated for to some extent with the PMAC Ix64 and Ix65 deadband compensation but the physical limitations of such an amplifier must still be realized Hydraulic motor amplifiers can be either torque mode or velocity mode depending on whether they use a velocity sensor and close a velocity loop themselves To the PMAC servo loop these amplifiers look just like the amplifiers of the same type for electromagnetic motors PID Servo Filter The standard PMAC controller provides a PID position loop servo filter Usually this filter is sufficient to control the system and easily understandable as well even for non control specialists The filter is tuned by setting the appropriate I variables for each motor How the PID Filter Works The proportional gain P Ix30 provides the stiffness of the system the differential gain D Ix31 provides the damping for stability the integral gain I Ix33 eliminates steady state errors Ix34 determines whether the i
271. ecause it utilizes open loop commands that create a large number of revolutions that are not well controlled The settings derived from the tests on an unloaded motor are valid even with the load because the induction motor parameters are load independent functions only of the electrical properties of the motor Select an arbitrary value for Ix77 magnetization current If there is a calculated number from the nameplate values use it If starting without any previously calculated value 3000 about 1 10 of maximum is a good starting value Select an arbitrary value for Ix78 slip gain If there is a calculated number from the nameplate values use it If starting without any previously calculated value 4000 is a good starting value Gather actual position data from the motor while accelerating the motor with an open loop command Use the PMAC Executive program to select gathering of the actual motor position To perform the actual gathering use the following sequence of on line commands Note The values obtained in this test are dependent on the motor s rotor temperature because the resistance of the rotor and hence its L R time constant change with temperature It is best to optimize the settings with the rotor hot In this case the motor will run less efficiently with the rotor cold which will require more current heating up the motor towards the proper settings Run the motor for several minutes at a significant current level e g O3
272. ed This will tie the flag circuitry to the digital circuitry In this case usually it is desirable to supply the remaining true flags from the digital 12V circuitry by moving the E90 jumper and to tie the low ends to digital ground GND this will retain the isolation between digital and analog circuitry Software Changes In software it is important to disable the digital delay filters on the encoder inputs of both the main encoder and the encoder matching the flag bits even though that encoder is not actually used for this function This is done by setting Encoder I Variable 1 I901 I906 I911 etc to 1 for both of these encoders Parallel Position Feedback PMAC can take parallel position feedback e g from an absolute encoder laser interferometer or an already converted analog signal through its I O expansion board Accessory 14D V Each ACC 14D V board has 48 bits of input so it may be connected to two parallel feedback devices of up to 24 bits each or one of over 24 bits Up to six ACC 14D boards may be connected to a single PMAC The parallel feedback devices must provide straight binary data not gray code The PMAC internal registers will extend the count automatically if the parallel device rolls over unless the PMAC register is set up to roll over as well Parallel position feedback requires one of the conversion formats 20 30 60 or 70 see below 7 6 Setting Up a Motor PMAC User Manual qauisaa sv
273. ed in PMAC through use of the INC command The INC command without a list of axes puts all axes in the coordinate system in incremental move mode The typical implementation would be G91000 INC RET If the G Code dialect has G90 and G91 also affecting the mode of circle move center vectors non standard an INC R command should be added to this routine G92 Position Set Preload Command If this code is used just to set axis positions the implementation is very simple G92000 PSET RET With the return statement on the same line the program would jump back to the calling line and use the values there e g X10 Y20 as arguments for the PSET command However if the code is used for other things as well such as setting maximum spindle speed the subroutine will need to be longer and do the setting inside the routine For example if G92 is used to preload positions on the X Y and Z axes set the maximum spindle speed S argument and define the distance from tool tip to spindle center R argument the subroutine could be N92000 READ X Y Z S R IF Q100 amp 8388608 gt 0 PSET X Q124 X axis preload IF Q100 amp 16777216 0 PSET Y Q125 Y axis preload IF Q100 amp 33554432 gt 0 PSET Z Q126 Z axis preload IF Q100 amp 262144 gt 0 P92 Q119 Store S value IF Q100 amp 131072 gt 0 P98 M165 Q118 Store R value RET The purpose of the condition in each line is to see if that argument has been sent to
274. ed in two types of statements in compiled PLCs variable value assignment statements and conditional statements IF WHILE AND OR Writing a PLC Program 16 7 PMAC User Manual Creating L Variables To implement integer arithmetic in a compiled PLC define any L variables to be used and substitute them in the programs for the variables that were used in the interpreted form usually M variables The compiler will interpret statements containing only L variables properly defined and integer constants as operations to be executed using integer arithmetic in compiled PLCs L variables are defined like X or Y format M variables but they exist only for the compiler PMAC does not recognize L variables or L variable definitions and PMAC will reject any uncompiled command containing an L variable that is sent to it All L variable definitions must precede the first PLC program to be compiled in the file Legal L variable names for the compiler contain the letter L followed by an integer in the range 0 to 1023 for a total of 1024 possible L variables LO to L1023 Put all of the L variable definition statements in a separate file that will be combined with the main PLC file using the include statement e g include lvardef pmc This single line can be commented out with a semicolon while debugging the programs in interpreted mode Remember that if using a standalone compiler this definition file must be combined with the main file in
275. ed with the sequence of motions For these types of tasks PMAC provides the capability for users to write PLC programs These are named after Programmable Logic Controllers because they operate in a similar manner continually scanning through their operations as fast as processor time allows These programs are very useful for any task that is asynchronous to the motion sequences Refer to the Writing Programs for PMAC section of this manual for more details Servo Loop Update In an automatic task that is essentially invisible to the PMAC user PMAC performs a servo update for each motor at a fixed frequency usually around 2 kHz The servo update for a motor consists of incrementing the commanded position if necessary according the equations generated by the motion program or other motion command comparing this to the actual position as read from the feedback sensor and computing a command output based on the difference This task occurs automatically without the need for any explicit commands Refer to the Closing the Servo Loop section of this manual for more details Commutation Update If PMAC is requested to perform the commutation for a multiphase motor it will perform commutation updates automatically at a fixed frequency usually around 9 KHz The commutation or phasing update for a motor consists of measuring and or estimating the rotor magnetic field orientation then apportioning the command that was calculated by the servo
276. ediate data Adding Entries For many conversion table entries those with a second digit of x or y in the above table setting bit 16 of the setup word to 1 means that the result of the conversion is not just from the specified source Instead it is the sum of this entry and the entry above in the table This permits the servo feedback to use the sum of two sensors If the polarity of the sensors or their counters is opposite this provides the difference of the sensors This can be useful for doppler type sensors where the reference wave and the shifted frequency wave are fed into different counters one counting up the other counting down summing the two counters provides position 7 14 Setting Up a Motor PMAC User Manual Example Setup Words WX 720 00C000 T entry for encoder channel 1 WX 721 01C004 T entry for encoder channel 2 summed with channel WX 722 680721 FFFFFF Intermediary entry for sum of encoder channel 1 and 2 WX 724 00C008 T entry for encoder channel 3 summed with Intermediary entry Each type of conversion is now discussed below Note If the conversion table has two or more summing entries in a row only the first entry will perform summing The other entries will only process their source data with no summing This means that it is not possible to directly sum three or more sources To sum three or more sources an intermediary non summing entry mus
277. eedrate axes The default feedrate axes for a coordinate system are the X Y and Z axes Note If a feedrate specified move is requested only of non feedrate axes PMAC calculates the vector distance to be zero because none of the feedrate axes move yielding a zero move time Therefore the move time will be controlled by the acceleration time and or the motor velocity limits Example Vector Feedrate Calculations INC Dist SQRT 32 42 5 FRAX X Y Move Time 5 10 0 5 X3 YA F10 Vx 3 0 5 6 Vy 4 0 5 8 INC Dist SQRT 3 42 5 FRAX X Y Move Time 5 10 0 5 X3 Y4 Z12 F10 Vx 3 0 5 6 Vy 4 0 5 8 Vz 12 0 5 24 INC Dist SQRT 32 42 122 13 FRAX X Y Z Move Time 13 10 1 3 X3 Y4 Z12 F10 Vx 3 1 3 2 31 Vy 4 1 3 3 08 Vz 12 1 3 9 23 INC Dist 0 FRAX X Y Z Move Time 0 10 0 TA C10 F10 Acceleration limited move Velocity Limit The velocity thus requested of each motor is constrained by the velocity limit for that motor 1x16 If a request exceeds this limit all motors involved in the move are slowed in proportion so that the motor does not exceed its limit but the path in space is preserved Note If PMAC is operating in move segmentation mode 113 gt 0 which is required for circular interpolation this Ix16 velocity limit is not observed The Blending Function If more than one move is specified in success
278. eee eese eee nn none nennen then enne tr Ron nana trente tee tenerent enne tee nnne 18 Synchronous M Variable Value Assignment eese eene nennen eren ren ren ettet netten trennen ne 18 Ug 19 Inca m Ma 19 Ny TeT Mov NUT CR 20 Table of Contents 13 1 PMAC User Manual IPOD MEME 20 COMPparators PM MMOr 21 Sui P 21 Simple CONAULONS p A ita edi 21 Compound Conditions eee eese esee teen ettet ether RR Dann enne teet RRE RR trente teeth tee tiennent ennt enn enne nnne 22 Single Line Condition Actions eee eese eese eene nennen ener then enee then tne te tnen trennt ne enne tren netenn ne 22 MULTIPLE Conditi nS E P 22 Mu M 22 Vind 23 Computational Considerations eseeeseseeeeeeeeeeee eene enne enne nenne nenne ener innere nete enr non enne tr E aE nre 23 13 2 Table of Contents PMAC User Manual COMPUTATIONAL FEATURES Advanced Computational Features PMAC has advanced computational features that permit off loading of many operations from a host or even stand alone operation in ways that were not
279. een sent PMAC now inserts this line into the program buffer previously opened remember in this example a motion program was being downloaded to PMAC Writing a Host Communications Program 17 19 PMAC User Manual Reading Data from PMAC VME Through Mailbox Registers Now that data has been sent to PMAC VME using the mailbox registers determine how to read data from PMAC Reading data will involve using the interrupts and interrupt vectors generated by PMAC VME over the VME bus In the following examples the PMAC base address is at 7FA000 and the I variable I3 is set to 2 the best setting of I3 for writing host communications routines The key to reading data from PMAC through the mailbox registers is that writing to mailbox register 1 permits PMAC to place its data in the mailbox registers when it has something to say This can be done ahead of time effectively pre enabling the PMAC response This is the strategy used in all of the following examples If not pre enabling write to mailbox register 1 only when immediately expecting a response which is usually after acknowledging the A0 interrupt see examples If this is not done PMAC will not interrupt with the A1 vector The only real advantage in not pre enabling is that the middle of a long PMAC response can be broken to issue a command Note that if using the pre enable strategy pre enable once after power up or reset Refer to the flowchart in figure 3 1 after readin
280. efine the motor for PMAC That is they tell it where to get its inputs and where to put its outputs which is as much as PMAC can really know By making all of these locations set up by variable values PMAC provides incredible flexibility in setting up a system Motor I Variables Each motor has an identical set of I variables The hundreds digit of the I variable number corresponds to the number of the motor To refer to a motor I variable generically we replace the hundreds digit with the letter x where x represents the number of whichever motor we are dealing with at the time for example Ix03 could represent 1103 1203 1303 and so on to 1803 The default values of the variables provide the settings that most will want to use so they will not need to change these settings But if a different setup from the default is desired it is a simple matter of changing a variable or two Activating the Motor Variable Ix00 for Motor x controls whether PMAC does calculations for this motor or not If using Motor x at all set Ix00 to 1 activated If not using the motor at all set Ix00 to 0 de activated so PMAC does not waste processor time doing calculations for the non existent motor An activated motor can be either enabled or disabled activation simply means that PMAC is paying attention to what happens on the motor Does PMAC Commutate This Motor Virtually all motors need to be commutated somehow the only significant exception
281. eger variable value assignment statements e g L1 SIN L2 Intermediate Values All intermediate values of these integer calculations are signed 24 bit values Make sure that no intermediate value in the calculations goes outside of this range For example the statement L500 1000000 20000000 4000000 would not execute properly because the product of the first two values is more than 24 bits in length The resulting value of the calculation in a variable value assignment statement must be written to an L variable This variable may be less than 24 bits wide For an L variable N bits in length only the low N bits of the calculated value are written to the register the rest of the bits are lost These N bits do not have to be lowest bits in the register For example with the definition L102 gt Y C003 8 16 S DACI register in the high 16 bits of a 24 bit word the statement L102 1000 shifts the value automatically to start at bit 8 in Y C003 Examples Examples of legal integer statements L100 1 LO L1 L2 L3 14 1024 L5 L5 1000 L6 L1 FF Examples of illegal integer statements L10 P10 P10 L10 L11 L11 P11 L13 16777216 L12 L253 L14 ATAN L16 Conditional Statements In a conditional statement any simple condition expression comparator 23 23 expression that contains only L variables and integer constants in the range 2 to 2 1 will be evaluated using the faster integer arithmetic Any simple condition in a compi
282. egisters to be used in user written commutation are Servo filter result X 0045 X 0081 etc e Encoder phase position register X C001 X C005 etc The following restrictions must be observed in the user written commutation algorithm The code must start with ORG P BB00 No assumptions can be made as to the state of any internal DSP registers on entry No stack use is allowed If any R M or N registers are used they must be restored before exiting The B accumulator register must be cleared on exit required for PMACI only The code must finish with an RTS instruction 8 16 Setting Up PMAC Commutation PMAC User Manual 9 Closing the Servo Loop Table of Contents CLOSING THE SERVO LOOP 1 The Purpose of the Servo Loop rani atada 1 Servo Update Rate icon nose dle caen 1 Reasons to Increase TE drid de head Rd A A ed 1 Reasons EDITRICE 1 Ramifications of Changing The Rate esee nono nn nono nono nano nnne trennen trennen nenne entren nest eneenneene 1 ADPIC Ty Pes Rc CCS 2 Velociiy Mode Amplifiers a e Re Se aa i dae ii 2 Torque Mode Amplifiers e Ee REC E ias 2 Voltage Mode Amplifiers Stine Serb HERI eno ege depen cue e Er Ro toe Re cL eMe ber eR ec 3 Sinusoidal Input Amplifiers ia Ege See a a ie PER Boe ce ee docs 3 Pulse and Direction Amplifiers eee e ee e eee essen ei ei a a
283. eived something like P5 0 which means that the coordinate system is pointing to motion program 5 at the top address offset of 0 14 42 Writing Programs for PMAC PMAC User Manual Running the Program Once pointing to the motion program to run issue the command to start execution of the program For continuous execution of the program use the R command CTRL R for all coordinate systems simultaneously or take the START line on the JPAN connector low with the coordinate system selected on the FPDn lines of the same connector The program will execute all the way through unless stopped by command or error condition Stepping the Program To execute just one move or a small section of the program use the S command CTRL S for all coordinate systems simultaneously or take the STEP line on the JPAN connector low with the coordinate system selected on the FPDn lines of the same connector The program will execute to the first move DWELL or DELAY or if it first encounters a BLOCKSTART command it will execute to the BLOCKSTOP command What PMAC Checks For When a run or step command is issued PMAC checks the coordinate system to make sure it is in proper working order If it finds anything in the coordinate system is not set up properly it will reject the command sending a BELL command back to the host If I6 is set to 1 or 3 it will report an error number as well telling the reason the command was rejected PM
284. elocity loop tachometer amplifier would be required for this mode of operation See the example OPENCLOS PMC for more details Constant Surface Speed Spindle To perform in constant surface speed CSS mode write a motion program because the speed must vary as a function of another axis position The suggested method shown in the example SPINDLE PMC is to break the move into small time slices with the commanded distance for each slice dependent on the system conditions at the time including commanded speed mode and tool radial position If the spindle is to be controlled in open loop fashion in CSS mode it would be best to have a PLC program modifying the output command Mx25 or Ix29 as a function of tool radial position The structure of the PLC program would be like that of the closed loop motion program example SPINDLE PMC except no actual move command would be needed once the math was processed the value would simply be assigned to the appropriate variable Standard M Codes The sections below detail what is involved in implementing the standard M codes It is important to realize the difference between an M code in a program and an M variable They may look the same but to be interpreted as an M variable it must be used in an equation or expression For instance MO1 1 refers to M variable number 1 usually this sets Machine Output 1 whereas MO1 by itself is the M code number 1 M codes are treated as subprogram calls to the a
285. elow should be used The two guess method is selected by setting Ix80 to O or 1 With Ix80 at 0 the phasing search is not executed automatically during the power on reset cycle a command must be used to execute the phasing search With Ix80 at 1 the phasing search will automatically be executed during the power on reset cycle it can also be subsequently executed with a command Two parameters must be specified to tell PMAC how to do this phasing search Ix73 specifies the magnitude of the torque command during each guess with units of 16 bit DAC bits Typical values are 2000 to 6000 4000 about 1 8 of full range is a usual starting point Ix74 sets the duration of each torque command and the evaluation of its response with units of servo cycles Typical values are 3 to 10 5 about 2 msec at the default servo update is a usual starting point Stepper Motor Phasing Search The other automatic method of phasing search for a synchronous motor is the stepper motor method This method forces current through particular phases of the motor as a stepper motor controller would and waits for it to settle With proper operation this will be at a known position in the commutation cycle The stepper motor phasing search requires more movement and more time than the two guess method but it is more reliable in finding the phase accurately in the presence of large external loads The stepper motor method is selected by setting Ix80 to 2 or 3 Wit
286. em that is running a motion program an Abort command should be issued before the K command Any of these commands may be issued from within a PMAC program using the COMMAND command or the COMMAND letter syntax However a motor kill K command for a motor in the coordinate system will be rejected automatically when issued from within a motion program running in that coordinate system Program Checksums PMAC continually computes the checksum of its internal program firmware as a background task Each time it has computed the checksum it compares this value to a reference register in memory X 07B1 that has been manually entered with the correct value PMACS shipped from the factory are preloaded with the correct reference value for that firmware version at the factory Firmware Checksum If PMAC detects a mismatch between its calculated checksum and the reference checksum it sets global status bits bits 12 and 13 of X 0003 accessible with the command and stops performing any checksum operations This leaves the calculated value frozen in the running checksum register X 0794 PMAC does take any other action in the event of a firmware checksum error it is up to the host or a PMAC PLC program to decide what action to take When a PMAC is upgraded to new firmware by replacement of the PROM IC in standard CPU sections or downloading of new firmware into the flash EEPROM IC in Option CPU sections the reference checksum v
287. en this is just part of the general error monitoring that is done at all times looking for overtravel limits fatal following errors and amplifier faults If an error does occur during the homing move it is important to distinguish between one that occurs before the trigger has been found and one that occurs after If the error occurs after PMAC knows where the home position is and the homing search does not need to be repeated Once the error cause has been fixed the motor can simply be moved to the home position with a command such as J 0 Buffered Program Command The homing search move can also be commanded from within a motion program with the HOMEn command where n is the motor number This command specifies a motor unlike other motion program commands that specify an axis move In a motion program the PMAC automatic program sequencing routines monitor for the end of the move When the move is successfully completed program execution continues with the next command Multiple homing moves can be started together by specifying a list or range of motor numbers with the command e g HOME1 3 or HOME2 6 Further program execution will wait for all of these motors to finish their homing moves Separate homing commands even on the same line e g HOME1 HOME2 will be executed in sequence with the first finishing before the second starts It is not possible to execute partially overlapping homing moves from a single motion program Note c
288. ents Most compiled PLC programs are very similar if not identical to uncompiled PLC programs In fact before compiling a PLC program it should be tested and debugged as an uncompiled PLC The differences between the two types of PLC programs are in the area of buffer control L variables some command syntax and the use of the compiler Because of these similarities much of the section about uncompiled PLC programs also applies to compiled PLC programs The information specifically concerning compiled PLC programs is contained in the section entitled Compiled PLC Programs When To Use PLC programs are designed for actions that are asynchronous to the motion If the action you want is synchronous to the programmed motion e g once per move use a motion program instead to create the action Common Uses PLC programs are particularly useful for monitoring analog and digital inputs setting outputs sending messages and monitoring motion parameters issuing commands as if from a host changing gains and starting and stopping moves By their complete access to PMAC variables and I O and their asynchronous nature they become powerful adjuncts to the motion control programs 32 PLC Programs PLC programs are numbered 0 through 31 for both the compiled and uncompiled PLCs This means that both a compiled PLC n and an uncompiled PLC n can be stored in PMAC PLC program 0 is a special fast program that operates at the end of the servo interrup
289. er Execution of Compiled PLCs Of the 32 compiled PLC programs PLCC 0 to PLCC 31 only PLCC 0 operates in the foreground triggered by the real time interrupt RTI PLCCs 1 to 31 operate as background tasks At each real time interrupt PMAC checks to see whether several user tasks need to be done The real time interrupt occurs every 18 1 servo cycles PMAC checks the tasks in the following order Motion program move planning PMAC checks to see in each coordinate system whether it is time to calculate the next move in the program e Interpreted PLC 0 PMAC checks to see if I5 1 or 3 and if PLC 0 is enabled If so it executes one scan of PLC 0 e Compiled PLC 0 PMAC checks to see if I5 1 or 3 and if PLCC 0 is enabled If so it executes one scan of PLCC 0 It is very important that the scan execution time of PLCC 0 and PLC 0 be kept less than one real time interrupt period Otherwise their repeated execution will starve the background for time and probably trip the watchdog timer In background PMAC executes one scan of a single background interpreted PLC program uninterrupted by any other background task although higher priority tasks will interrupt In between each scan of each individual background interpreted PLC program PMAC will execute one scan of all active background compiled PLCs This means that the background compiled PLCs execute at a higher scan rate than the background interpreted PLCs For example if there are
290. er Path Compensated Circle Skipped Programmed 2 Full Circle Figure 44 Failure When Compensation Extends Full Circle Speed of Compensated Moves Tool center speed for the compensated path remains the same as that programmed by the F parameter On an arc move this means that the tool edge speed the part of the tool in contact with the part will be different from that programmed by the fraction R po Rare tool Changes in Compensation PMAC permits changes both to the radius of compensation and the direction of compensation while the compensation is active It is important to understand exactly how PMAC changes the compensated path in these cases Radius Magnitude Changes Changes in the magnitude of compensation new CCR values made while compensation is active are introduced linearly over the next move When this change is introduced over the course of a LINEAR mode move the compensated tool path will be at a diagonal to the programmed move path When this change is introduced over the course of a CIRCLE mode move the compensated tool path will be a spiral Compensation Direction Changes Changes in the direction of compensation between CC1 and CC2 made while compensation are generally introduced at the boundary between the two moves Writing Programs for PMAC 14 29 PMAC User Manual Cutter Compensation Change of Direction gt CC1 A S ho Programmed Line Path cc2 CC1
291. er by freezing the time base until the trigger is received then starting the time base referenced to the position that was captured by that trigger The triggered time base entry in the conversion table is similar to the standard time base entry Itisa two line entry with the first line specifying the process and the source address for the master encoder data and the second line specifying the time base scale factor There are two important differences between the triggered time base entry and the standard time base entry First the value specifying the process is different and it is changed during the process of triggering 90 A0 and BO versus the 40 for standard time base Second the source address is that of the actual master encoder counter registers not the processed encoder data in the conversion table The scale factor is the same as for the standard time base The rules for this entry are discussed in detail in the instructions for the conversion table Instructions for the Triggered Time Base Using the triggered time base feature involves proper setup of I variable values M variable definitions and conversion table entries these can be done ahead of time writing motion programs and writing PLC programs Each of these is covered in this section first with a general explanation then with a specific example Step 1 Signal Decode Setup The signal decoding of the master signal is the same as for standard time base the qua
292. er position as the starting point for the time base Triggered Time Base Example Motor 1 is the A axis in Coordinate System 1 It is a rotary axis with a 2500 line per revolution encoder on the motor and its load is geared down from the motor at a 3 to 1 ratio It is to be slaved to a master encoder connected to PMAC on Encoder 4 The master encoder has 4096 lines per revolution and typically rotates at about 600 rpm After being given the command to run the X axis must wait for the index pulse of the master and for 45 degrees past it For the next 36 degrees of the master it must accelerate up to speed then run at speed for 144 degrees of the master and finally decelerate over 36 degrees of the master This move must cover one full revolution of the A axis For this example use the triggered time base triggering from the master encoder s index pulse Choosing 600 rpm as the real time speed for the master compute the real time input frequency RTIF in counts msec 00 rev min 4096 lines la counts Y sec 2163 84 counts min 60 sec rev line 1000m sec m sec The time base scale factor SF is p 131072 _ 131072 800 decimal RTIF 163 84 At the real time speed of 600 rpm 10 rps one revolution of the master takes 100 msec so 45 degrees of the master takes 12 5 msec and so on Set up and Definitions 1915 3 x4 decode of ENC 4 set to count up in direction of motion I917 1 ENC 4 capture trigger
293. er position loop The position loop can take a correction as position information from its master position register This conversion table entry makes it possible to convert the velocity output of the outer loop to the position input of the inner loop The outer loop would direct its command output to an unused internal memory register e g Y 07FO by setting Ix02 to that register Ix02 07F0 The integrated analog entry in the conversion table uses this register as its source 5007F0 Probably no bias is needed Ix05 for the inner loop points to the second line of the entry where the integrated value is giving the position loop its correction Unsigned Analog If bit 19 of the analog conversion setup word is set to 1 18xxxx for normal analog 58xxxx for integrated analog then PMAC treats the A D number in the high 16 bits of the source word as an unsigned number with a range of 0 to 65 535 instead of a signed number with a range of 32 768 to 32 767 The unsigned conversion is required for use of the newer ACC 28B The usual signed conversion bit 19 0 is required for use of the older ACC 28 and ACC 28A 7 18 Setting Up a Motor PMAC User Manual Parallel Position Feedback Conversion If providing position information to PMAC as a parallel data word as from an absolute encoder or processed from a laser interferometer use one of the conversion formats 2x 3x 6x or 7x Formats 2x and 3x get data from the specified so
294. erent the concept of the table belonging to a motor is useful only for PMAC s bookkeeping purposes 7 28 Setting Up a Motor PMAC User Manual The compensation is performed inside the servo loop every servo cycle to obtain the maximum speed and accuracy PMAC takes the position of the source motor and finds the matching position in the table Typically this is between two entries in the table so PMAC linearly interpolates between these two entries to obtain the correction for the current servo cycle It then adds this correction to the position of the target motor The entries of corrections in the table must be integer values with units of 1 16 count so an entry of 48 represents three counts of the target motor Multiple Tables Per Motor A motor may provide the source data for up to eight compensation tables it may also be the target of up to eight motors Table Range The compensation is defined directly for a range of source motor positions starting at zero counts the most recent home or power up reset position and going in the positive direction The size of this range is declared as the last argument of the DEFINE COMP command This argument has units of counts of the source motor The spacing between entries is the total range divided by the number of entries which is the first argument of the DEFINE COMP command The first entry in the table defines the correction at one spacing from the zero position of the source motor t
295. errupt must be serviced or acknowledged by the host computer before PMAC withdraws its interrupt assertion Interrupt Vector Number When an interrupt is generated by PMAC VME the host computer will also read an interrupt vector which is sent with the interrupt PMAC will send one of two interrupt vectors with each interrupt generated indicating a particular condition The factory default is a value of A1 which means PMAC will send either an A0 or A1 interrupt vector every time it generates an interrupt But when does PMAC send an A0 vector and when does PMAC send an A1 vector We know that PMAC generates an interrupt on the VME bus every time it has data to send whether it is only one character like a linefeed lt LF gt character or several characters like the current position of a motor In this example using the factory default an A0 vector will be sent every time PMAC receives a set of characters from the mailbox registers whether it is a partial or full command line This is the PMAC way of acknowledging the receipt of a command line such as I100 1 lt CR gt or 1J lt CR gt An AI vector will be sent if there is data waiting to be read by the host For example if asking PMAC for the value of a P variable or ask to list a program in the PMAC memory PMAC will generate an interrupt accompanied by an A1 vector indicating that there is data to be read in its mailbox registers a detailed example of how to read and write to the ma
296. es PMAC waits until that operation is finished before it starts calculations on the next move or two moves During any of these breaks PMAC will use the I11 calculation time to delay the start of the next move DWELL Commands A DWELL command in a motion program breaks the blending of moves so PMAC will not calculate through a DWELL PMAC does not start the calculation of subsequent moves until after the DWELL time is complete A DELAY command by contrast is really a zero distance move command of the specified time PMAC does calculate through a DELAY HOME RAPID Moves If a homing search move HOMEn or a RAPID mode move is commanded from within a program it is not blended with any other move PMAC does not start the calculation of subsequent moves until after all motors have completed their commanded moves of these types Writing Programs for PMAC 14 55 PMAC User Manual PSET Command If a PSET command is used within a motion program to redefine axis position s PMAC will not blend the move before the PSET to the move after It will not start the calculation of the subsequent move until after the previous commanded move has finished and the PSET command has been executed Double Jump Back Rule If in the course of trying to calculate the next move PMAC detects two backward jumps in the logic of the program PMAC will not try to blend the last calculated move to an upcoming move These backward jumps can be caused either by ENDW
297. ese enne NE teen tenete enne nn eren enne nenne trennen 4 Establishing Host Communications eee ese esee eee eene testen eene ne enne trennen eterne nennen inneren ennt 5 Terminal Mode Communications iei treten iaa dese ete ede ee dde BE Inedec ee tee ck Eaa Ss 5 Connecting PMAC to the Systetni 4 nette usc etie ie e E HEC TIRE eee in I tede Eee eU E deseen 5 Machine Connectors EET 6 Connecting the Analog Power Supply eese eene nente neon nena conan tne teee tene teen neen trennen nennen 6 Incremental Encoder Connection eid teet EH dale Raa 6 Amplifier CONNECTION m mt 7 Auxihary CONNECH ONS MEE t 7 Software Setup for a Motors sins dine 8 Encoder T Variables ii diia gae HERB 9 Motor Ie vanables 9 Motor ACHVGHON EET 9 For PMAC Commutated Motors Only eese eee eese esent nn none enne the nennen eene eterne trennt tente tn enne ennn teen nne 9 For Motors Not Commutated By PMA Co rrienak e nnee tree teen teen tenete nennen ener enne enne 10 I PLUME UE H M 10 Testing the Output and Polarity sssrinin tetto ce 12 Non PMAC Commutated Motors oe EE a Rio 12 Overtravel Limit Pol rity is 12 Setting up the Servo EoOp id 13 Closing the LOOP E A id 13 J OB BIN GM OVES om ERR 13 Power Up Modes ieceri 14 Tloming Search
298. eset the contents of the flash memory are copied into active memory Running the Compiled PLCs I variable I5 is the master control for both uncompiled and compiled PLCs The PLC programs can be individually enabled and disabled with the ENABLE PLC ENABLE PLCC DISABLE PLC and DISABLE PLCC commands These can be given as on line commands or as buffered commands within motion programs uncompiled PLC programs or compiled PLC programs A PLC program can even disable itself Do not use the DISABLE PLCC command from within either PLC 0 or PLCC 0 they cannot be guaranteed to work here It can be useful to think of the two bits of I5 as being like the master breakers for a house and the individual program enable disable controls as being like light switches within the house Both the master breaker and the light switch must be in the ON setting for the light to work The breakers and the light switches are separately controllable When the compiled PLC programs are downloaded to PMAC they are all individually enabled They will start running immediately if permitted by I5 On power up reset all existing PLC programs compiled and uncompiled are individually enabled If I5 was saved to a value that permits a given PLC program to run it will be ready to run on power up PLC 1 will be the first PLC to execute after power up reset before even PLCC 1 Many people use this as their reset PLC executing once and disabling itself to prevent repeated e
299. eset position read function is disabled and the power on reset position is set to zero regardless of the setting of the sensor and subsequent position readings are incrementally referenced to this zero position If the absolute position of a single turn resolver will be used only to prevent the need for a power on phasing search Ix81 is used to specify the absolute power on phase position read For more information refer to the Absolute Power Up Position section in this manual the Ix10 description in the Software Reference manual and the ACC 8D Opt 7 R D Converter manual Absolute Power Up Position In some applications it is not permissible or desirable to do a homing search move after power up or reset In these applications an absolute position sensor can be used so that the true position is known immediately on power up reset and there is no need to move to a known home position The typical sensors used for this purpose are absolute encoders and resolvers PMAC can support absolute power on position reading from both of these sensors Absolute Position Range To get absolute power on position sufficient that no homing search move is required the position sensor must be absolute over the entire range of travel of the axis If the travel covers multiple revolutions of the motor and the sensor is absolute over only a single turn of the motor a homing search will still be required Although such a sensor can be used for power on phasing of a
300. esolver or primary resolver will be used for the fine resolver connected directly to the motor shaft The resolver geared down from the first resolver coarse in a two resolver system medium in a three resolver system will be called the second ary resolver The next resolver will be called the third resolver If a set of geared resolvers is to be used to determine power on position with PMAC variables I9x and possibly I8x must be changed from their default values of zero as well The second resolver must be connected to the R D converter at the next higher location at the same multiplexer address than the primary resolver 19x represents the gear ratio between the primary and secondary resolvers It must be an integer number If the second resolver is geared down from the primary resolver by a 16 1 ratio I9x would be set to 16 A value of 0 for I9x tells PMAC that there is no secondary resolver If there is a third resolver geared down from the second resolver I8x is used to specify the gear ratio between the second and third resolvers The third resolver must be connected to the R D converter at the next higher location at the same multiplexer address than the second resolver It must be an integer number If the ratio between the two is 36 1 I8x would be set to 36 A value of O for I8x tells PMAC that there is no third resolver Even in a geared resolver system the most significant bit of Ix10 determines whether the combined quantity wil
301. etimes called an AC synchronous motor very little beyond the basic commutation cycle parameters noted above must be specified Getting the Polarity Right For proper commutation it is required that the feedback polarity as determined by the encoder wiring and the Encoder Decode I variable I900 I905 etc match the output polarity as determined by the amplifier and motor wiring and by Ix72 That is when PMAC issues a positive command through its commutated outputs it must cause the encoder counter to count up If the polarity is mismatched on a permanent magnet brushless motor the motor will lock in quickly and refuse to move Testing the Polarity A quick test early in the setup of the motor can verify whether the polarity is correct The test uses the output offset variable Ix29 and Ix79 to force current directly into the particular phases and drive the motor like a stepper motor Observing the direction the motor position counts as different phases are driven we can tell whether the polarity is correct given the present encoder wiring and decode variable and the present motor wiring and output phasing variable This test which can be done easily from the terminal window of the Executive program by typing in a few simple commands is best illustrated by an example which will use Motor 1 100 Command zero output 1129 2000 Positive offset of 2000 bits on 1st phase P Request
302. ets the signal and then the background routine resets it If the card for whatever reason due either to hardware or software problems cannot set and clear this bit repeatedly at this frequency or higher the circuit s relay will trip and the card will shut down When the timer trips line F2LD on the JPAN connector and if E28 is connected 2 3 line FEFCO on the JMACH connector s are taken low the DAC outputs are forced to zero and the AENA lines are forced to the disable state In addition a level 3 IR3 interrupt is triggered on the PMAC PC s Programmable Interrupt controller PIC and a level 5 IR5 interrupt is triggered on the PMAC STD s PIC The red LED on the CPU section of the board is turned on It is important to shut down your power circuitry if the PMAC watchdog timer trips The FEFCO output on the JMACH1 connector is useful for this purpose It is an open collector output referenced to AGND that goes low 100 mA sinking capability when the watchdog trips It may also trip on the loss of 5V power if the loss is slow enough that the watchdog trips from under voltage before complete shutdown This use must be evaluated on an individual system to see if it is reliable Once the watchdog timer has tripped power to the PMAC must be cycled off and on or the INIT line on JPAN must be taken low then high to restore normal functioning Hardware Stop Command Inputs PMAC has hardware inputs that can stop a move or a program w
303. ever needs access to this information e g host computer operator motion program can be assured of having current data Conditional Statements Most action in a PLC program is conditional dependent on the state of PMAC variables such as inputs outputs positions counters etc The action can be level triggered or edge triggered both can be done but the techniques are different Level Triggered Conditions A branch controlled by a level triggered condition is easier to implement Taking the incrementing variable example and making the counting dependent on an input assigned to variable M11 IF M11 1 P1 P1 1 ENDIF As long as the input is true P1 will increment several hundred times per second When the input goes false P1 will stop incrementing Writing a PLC Program 16 3 PMAC User Manual Edge Triggered Conditions To increment P1 once for each time M11 goes true triggering on the rising edge of M11 sometimes called a one shot or latched To do this there must be need a compound condition to trigger the action then as part of the action set one of the conditions false so the action will not occur on the next PLC scan The easiest way to do this is using a shadow variable which will follow the input variable value Action is only taken when the shadow variable does not match the input variable The code could become IF M11 1 IF P11 0 P1 P1 1 P11 1 ENDIF ELSE P11 0 ENDIF Make sure that P11 can foll
304. expected performance on the first move Parallel Incremental Feedback A device such as a laser interferometer often provides parallel feedback data but the device is fundamentally incremental so it does not know where it is on power on reset The PMAC setup to accept this type of feedback is the same as for an absolute parallel device but recognize that a homing procedure is necessary For this type of device leave Ix10 equal to zero so that PMAC does not perform an absolute power on reset position read However since the position information is not absolute and since PMAC has the ability to extend position range in software it is not necessary to bring all the lines of a device to PMAC This can save money on interfacing costs All that is needed is enough lines starting from the LSB so that half the range of those lines will not be covered in a single servo cycle For instance a typical interferometer interface has 32 bits of parallel data Even with a servo cycle of 1 msec which is slow for PMAC wiring only the low 16 lines to PMAC is sufficient as long as the maximum speed is less than 32 768 215 counts msec or 32 768 000 counts sec Software Capture on Homing The motor using this device for position feedback must be programmed to do a software position capture on a homing search move instead of the hardware position capture performed with incremental encoders This is done by setting bit 16 of variable Ix03 for the motor to 1
305. f argc gt 1 infile fopen strcat strcpy buf argv 1 lod r if infile NULL outfile fopen strcat strcpy buf argv 1 pmc wb setvbuf outfile bufr IOFBF 32767 while fgets buf 80 infile NULL amp amp strncmp buf _ DATA P 7 0 sscanf buf 8 4x amp y while fgets buf 80 infile NULL amp amp strncmp buf END 4 0 n 0 9 14 Closing the Servo Loop PMAC User Manual 1 strlen buf while 1 gt n 5 switch m case 0 fprintf outfile WP 04X y y 5 default fprintf outfile c c c c c c buf n buf n 1 buf n 2 buf n 3 buf n 4 buf n 5 n 7 m 1 fprintf outfile r n if m gt 0 fprintf outfile r n Closing the Servo Loop 9 15 PMAC User Manual I0 Making Your Application Safe Table of Contents MAKING YOUR APPLICATION SAFE escis eene essen en sets tns tn suns ta sins tn sts tuse sa suse ta sens tn sesso sees suse ta sensn sossa Responsibility for the Safety of a Control System eese nennen eene nre nennen teneret Hardware Overtravel Limit Switches eeeeseeseseeeeseeeeeeene nete nnne enne nren etre nennen reinen trennen ene nnnn nete nnne Software Overtravel Limits eese eeeeeee nennen tnnt enne nenne nnen nennen nenne RR nn ainean enne enne teen Tea enne nete nne Following Error A ipee Toa eSa ara UHR e ERE ai ene s Ere Pes
306. fer to the host selected coordinate system amp n If 12 0 but no coordinate system is selected all FPDn inputs are floating or pulled high these lines can be used as general purpose outputs addressed as bits 20 23 of Y FFC2 Y FFFD bits 0 3 on PMAC STD Display Port Outputs JDISP Port The JDISP connector J1 allows connection of the ACC 12 or ACC 12A liquid crystal displays or of the ACC 12C vacuum fluorescent display Both text and variable values may be shown on these displays using the DISPLAY command executing in either motion or PLC programs 6 12 Input Output Connecting PMAC to the Machine PMAC User Manual 193443 AHL SNILON ANV ASVLIOA LNdNI JHL 9NIAHVA A8 ATJALLOVHAAINI GANIINYS LAG 38 NVO AN TVA SIHL Gr18VL NOISH3ANOO INVITA SHL HOW 622 A NI INTIVA JHL A8 L3S SI DNITVIS n vz o 624 x o9w B 9 Y31SID3Y SIHL OL 318VIH VA W NV NDISSV ATdINIS ISOdYNd H3HLO ANOS HOS INTIVA SIHL ASN OL 624 81 OL X S HOS 6XI 318 VIHV I SS3HQQV 39YNOS 3SV8 INIL AHL 13S AldWIS WALSAS 31VNIQHOOO V HOW 3GIHH3AO 3 1VH0333 HO INTIVA SIHL ISN OL H31H3ANOO NOLLVILN3H34HIG NOILV1OdH3INI Y INNOI 3HVMGHVH A9NANO384 0 1 39VLTOA 3HVMLJOS 3HvMLJOS a3sunb9I4NO9 3HVMLJOS 3HVMQHVH SNI1VOS 62 A aba EZLO0V 8ZL A 200200 7 24 A p SL6l NZHA SZ 622 X ZL X 9009 X c3 wyoyg NOISH3ANOO NOISH3ANOO uainnoo VHO d sva Z yaqoona 4 83a0
307. files are desired on a single axis the easiest way to do this is to have a second phantom axis and program circularly interpolated moves Axis Definition Statements A coordinate system is established by using axis definition statements An axis is defined by matching a motor which is numbered to one or more axes which are specified by letter Matching Motor to Axis The simplest axis definition statement is something like 4 1 X This simply assigns motor 1 to the X axis of the currently addressed coordinate system When an X axis move is executed in this coordinate system motor 1 will make the move Scaling and Offset The axis definition statement also defines the scaling of the axis user units For instance 1 gt 10000X also matches motor 1 to the X axis but this statement sets 10 000 encoder counts to one X axis user unit e g inches or centimeters This scaling feature is almost universally used Once the scaling has been defined in this statement the axis can be programmed in engineering units without ever needing to deal with the scaling again The statement 1 gt 10000X 20000 also sets the axis zero at 20 000 count 2 user unit distance from the motor zero home position This offset is rarely used Further an axis definition statement can match a motor to a linear combination of cartesian axes see section below which allows for rotation of a coordinate system or orthogonality correction 12 2 Set
308. g Up a Coordinate System 12 1 PMAC User Manual commanded trajectory for the slave whose actual trajectory will have even more errors The roughness in the slave motor s commanded trajectory makes it difficult or impossible to use feedforward properly which introduces a lag True if the master gets a disturbance the slave will see it and attempt to match it but if the slave gets a disturbance the master will not see it Care must be taken in the startup and homing of gantry motors that have a tight mechanical linkage In general the motors will power up not quite in ideal alignment with each other The usual procedure is to do a homing search move on one motor with the second motor slaved to it followed by an offset back out far enough that the second motor knows which way it has to go to its home trigger Next the second motor is made the master and is told to do a homing search move with the first motor slaved to it This will leave the first motor slightly off from its home position it can now be told to go there with just a J 0 command The slaving is then turned off and the motors are then commanded identically through joint axis commands Phantom Axes An axis in a coordinate system can have no motors attached to it a phantom axis in which case programmed moves for that axis cause no movement although the fact that a move was programmed for that axis can affect the moves of other axes and motors For instance if sinusoidal pro
309. g Up a Motor 7 1 PMAC User Manual To the beginner the need to specify addresses for input and output may seem cumbersome However for basic applications most can use the sensible default values Motor n uses DACn Encoder n and Flags n and the ability to assign inputs and outputs at will provides unprecedented flexibility in more sophisticated applications Hex vs Decimal Reporting If I9 is 0 or 1 PMAC will report address I variable values as decimal numbers If I9 is 2 default or 3 it will report these values as hexadecimal numbers Usually it is much easier to interpret these values as hexadecimal numbers especially when alternate modes are used because the address digits themselves can be seen For example setting 1102 to C003 49155 specifies the use of DACI for Motor 1 command output in the normal bipolar mode Setting bit 16 to 1 tells PMAC to use the register in unipolar magnitude and direction mode In hexadecimal form PMAC would report this value back as 1C003 so the address is still obvious but in decimal form PMAC would report 114691 completely obscuring the address Selecting the Output s Variable Ix02 determines in which register or pair of registers if PMAC commutated motor x places its command output every cycle The value of Ix02 is the address of the register This is almost always a digital to analog converter DAC register The default value of Ix02 is the register address of DACx e g Motor
310. g of the specified distance from the commanded position at the time of the command Jog Moves Specified By A Variable Jogging moves to a position or of a distance specified by a variable are possible Each motor has a specific register L 082B for motor 1 L 08EB for motor 2 etc that holds the position or distance to move on the next variable jog command This register contains a floating point value scaled in encoder counts It should be accessed with an L format M variable The J command causes PMAC to use this value as a destination position The J command causes PMAC to use the value as a distance from the actual position at the time of the command The J command causes PMAC to use the value as a distance from the commanded position at the time of the command Each time one of these commands is given the acceleration and velocity parameters at that time control the response to the command To change speed or acceleration parameters of an active jog move change the appropriate parameter s then issue another jog command Jog Until Trigger The jog until trigger function permits a jog move to be interrupted by a trigger and terminated by a move relative to the position at the time of the trigger It is similar to a homing search move except that the motor zero position is not altered and there is a specific destination in the absence of a trigger The jog until trigger function for a motor is specified by adding a constant spe
311. g the following examples Example This command line has been sent to PMAC 1J lt CR gt This command line is not a request for any data so PMAC will not respond with any data except an acknowledge lt ACK gt signifying an acknowledgment of receipt of a valid command line if an invalid command was sent a BELL character would be sent instead of lt ACK gt In this case PMAC will generate an interrupt sending with it an interrupt vector A0 as defined in PMAC register X 0789 After seeing this interrupt and accompanying interrupt vector the VME master or host computer must properly service or acknowledge this interrupt so that PMAC will withdraw its interrupt assertion Generally when servicing any VME interrupt the interrupt vector will be available PMAC will then interrupt again this time with interrupt vector A 1 signifying there is new data in the mailbox registers to be read Now read mailbox register 0 at 7FA001 to pick up the lt ACK gt character put there by PMAC if desired but this is only necessary to verify that the command line just sent was received as a valid command by PMAC Finally write 00 into mailbox register 1 location 7FA003 allowing PMAC to write new data into the mailbox registers if necessary also read the next example to better understand this The next example shows how to read data written in the mailbox registers by PMAC Example Assume the command to ask for the position of motor
312. gain show the contents of the mailbox registers After writing the first group of 14 characters the characters F through Y in the above command line the mailbox registers look something like this Address 7FAO001 7FA003 7FA005 7FA007 7FAO0ID 7FAOIF Mailbox 0 1 2 3 14 15 Character F A Y Now write the first character I Address 7FAO001 7FA003 7FA005 7FA007 7FAO0ID 7FAOIF Mailbox 0 1 2 3 14 15 Character I F A Y At this point PMAC has taken these characters into its command queue but has not done anything with them yet since no CR has been encountered yet It asserts the selected interrupt level default is 2 and provides the command a receipt interrupt vector default is A0 which must be acknowledged Now we send the next 11 characters D through followed by a CR Address 7FA001 7FA003 7FA005 7FA007 7FA01D 7FAO1F Mailbox 0 1 2 3 11 12 Character D E t lt CR gt Finally send the first character of this second and last group of characters which is a Address 7FA001 7FA003 7FA005 7FA007 7FA01D 7FA01F Mailbox 0 1 2 3 11 12 Character D E i CR PMAC again asserts interrupt level 2 and provides the command receipt interrupt vector Since a CR has been included PMAC knows that the command line has b
313. ge the entries in the table with one or more Write W commands For example to change the third and fourth entries above to straight conversion of the same registers command WY 722 C0C008 COCOOC While the set up values may be specified in decimal it is easier to specify them in hexadecimal except possibly for scale factors The set up of the Encoder Conversion Table can be stored in EAROM with the SAVE command The most recently saved set up is copied from EAROM into RAM active memory on power up or reset so SAVE changes to the table to keep them Further Position Processing Once the position feedback signals have been processed by the Encoder Conversion Table which happens at the beginning of each servo cycle the data is ready for use by the servo loop Software Position Extension For each activated motor PMAC takes the position information in the 24 bit register pointed to by Ix03 and extends it in software to a 48 bit register that holds the actual motor position In the process of extension it multiplies the value by the Ix08 position scale factor Since the register in the conversion table is in units of 1 32 of a count the actual motor position register is in units of 1 Ix08 32 of a count Setting Up a Motor 7 27 PMAC User Manual These extended motor position registers are set to zero on power up reset unless there is an absolute position sensor and again at the end of a homing search move The encode
314. ght side of the statement is evaluated when the line is encountered in the program ahead of the execution of the move The value of the expression the variable number and the operator are placed on a stack for execution at the proper time Execution When actual execution of the appropriate move starts these items are pulled off the stack and the actual action is performed In the case of the syntax the value is simply assigned to the variable at this time In the case of the other forms amp and the variable is read at this time the bit by bit Boolean operation AND OR XOR respectively is performed between the variable value and the expression value and the result is written back to the variable Computational Features 13 19 PMAC User Manual Special Boolean Feature These Boolean assignment operators are subtly different from what would seem to be equivalent statements Consider the two statements acting on an 8 bit M variable which attempt to make all of the odd bits 1 while leaving the even bits where they are M50 M50 amp SAA M50 amp SAA The difference between the two statements is in when M50 is read for the operation In the first case it is read when the statement is first evaluated in the program In the second case it is read when the operation is pulled off the stack immediately before the variable is written to In this second technique there is no chance that the value of the M variab
315. gisters Remember that because the L variable definitions are used only at the time of compilation it is not possible to use the array indexing techniques with L variables that can be performed using M variables by changing the definitions at run time Variable Value Assignment Statements Variable value assignment statements are used by PMAC to write to any register whether an output a general purpose variable in memory a memory register used for a specific purpose such as a gain or a hardware register such as a flag control register Many of these statements can be executed using integer arithmetic Valid Values In a given variable value assignment statement variable expression L variables cannot be combined with any other type of variable that is if there is any L variable in the statement all variables in the statement on both sides of the equals sign must be L variables Any constants in the statement must be integers in the range 8 388 608 to 8 388 607 27 to 2 1 Any variable value assignment statement in a compiled PLC containing an L variable that also contains 2 23 another type of variable a non integer constant or an integer constant outside the range 2 to2 1 will be rejected by the compiler The compiler will report the error and line number Valid Operators All of the mathematical operators and bit by bit boolean operators that can be used in floating point operations in
316. given a destination position in the motion program for each segment with a normal move command line like X1000Y2000 Looking at the move command before this and the move command after this PMAC creates a cubic position vs time curve for each axis so that there is no sudden change of either velocity or acceleration at the segment boundaries The commanded position at the segment boundary may be relaxed slightly to meet the velocity and acceleration PMAC can only work with integer millisecond values for the TA segment times If a non integer value is specified for the TA time PMAC will round it to the nearest integer automatically It will not report an error This rounding will change the speeds and times for the trajectory PMAC computes intermediate way points for each axis for each point along the spline by taking a weighted average of the specified point X n and the specified points on either side according to the equation 14 20 Writing Programs for PMAC PMAC User Manual X n 1 4X n X n 1 6 WP n PMAC also computes the velocity for each axis at each way point along the spline by taking the velocity halfway between the average velocities of the segments on either side of the way point _ X n 1 X n X n X n 1 _ X n 1 X n 1 J 2 TA 2 TA V n Having computed exact positions and velocities at segment boundaries PMAC calculates the unique cubic position equation parabolic velocity profile that
317. h Ix80 at 2 the phasing search is not executed automatically during the power on reset cycle a command must be used to execute the phasing search With Ix80 at 3 the phasing search automatically executes during the power on reset cycle this is not recommended it can also be subsequently executed with a command In this method Ix73 controls the magnitude of the current through the phases with 32 767 representing full range Typically a value near 3000 about 1 10 of full range will be used although the actual value will depend on the loads Ix74 controls the settling time for each of the two steps used in the search In this mode the units of Ix74 are servo cycles 256 about 1 10 sec with the default servo cycle time Typically a settling time of 1 2 seconds is used In the stepper motor phasing search PMAC first forces current to put the motor at the 60 point in the phasing cycle and waits for the settling time Then it forces current to put the motor at the 0 point in the phasing cycle and again waits for the settling time It checks to see that there has been at least 1 16 cycle 8 4 Setting Up PMAC Commutation PMAC User Manual 22 5 movement between the two steps If there has been it forces the phase position register to 0 clears the phasing search error motor status bit and closes the servo loop If it has detected less movement than this it sets the phasing search error bit and disables kills the servo
318. h input and each output has its own corresponding ground pin in the opposite row The 34 pin connector was designed for easy interface to OPTO 22 or equivalent optically isolated I O modules Delta Tau s Accessory 21F is a six foot cable for this purpose The PMAC STD has a different form of this connector from the other versions of PMAC Its JOPT connector J4 on the base board has 24 I O individually selectable in software as inputs or outputs The rest of this discussion does not pertain to the PMAC STD port unless specifically mentioned Refer to the PMAC STD Hardware Reference Manual for details on its JOPT port Software Access These inputs and outputs are typically accessed in software through the use of M variables In the suggested set of M variable definitions variables M1 through M8 are used to access outputs 1 through 8 respectively and M11 through M18 to access inputs 1 through 8 respectively This port maps into the PMAC memory space at Y address FFC2 Standard Sinking Outputs Caution Having Jumpers E1 and E2 set wrong can damage the IC PMAC is shipped standard with a ULN2803A sinking open collector output IC for the eight outputs These outputs can sink up to 100mA but must have a pull up resistor to go high Caution Do not connect these outputs directly to the supply voltage or damage to the PMAC will result from excessive current draw Provide a high side voltage 5 to 24V into Pin 33 of the JOPTO
319. have been passed the letters listed in the READ statement are those that can be passed The bits of Q100 for the coordinate system are used to note whether arguments have been passed successfully bit O is 1 if an A argument has been passed bit 1 is 1 if a B argument has been passed and so on with bit 25 set to 1 if a Z argument has been passed The corresponding bit for any argument not passed in the latest subroutine or subprogram call is set to 0 If the logic of the subroutine needs to know whether a certain argument has been passed to it or not it should use the bit by bit AND operator amp between Q100 and the value of the bit in question The value of bit 0 is 1 of bit 1 is 2 of bit 2 is 4 and so on bit value is 2N for the Nth letter of the alphabet For instance to see if a D argument has been passed the condition would be IF 0100 amp 8 O D is the fourth letter so the bit value is 2 8 To see if an S argument has been passed S is the 19th 18 letter so the bit value is 2 262 144 the condition would be IF Q100 262144 gt 0 Writing Programs for PMAC 14 41 PMAC User Manual PRELUDE Subprogram Calls PMAC permits creation of an automatic subprogram call before each move command or other letter number command in a motion program or section of a motion program If the subprogram starts with a READ command then the move command or letter number command itself is turned arguments fo
320. have been set up properly the homing function will use the position capture feature automatically Using in User Program If using the position capture function in the own program these two I variables still control the capture event Access the captured position through a full word M variable M103 is the suggested M variable for the Encoder 1 capture register M103 X C003 0 24 S Use the position captured flag bit bit 17 of the control status register For example M117 X C000 17 1 This bit goes true when the trigger condition has gone true it goes false when the capture register is read when M103 is used in an expression As long as the bit is true the capture function is disabled read the capture register to re enable the capture function The example program MOVTRIG PMC shows how this function can be used for precision registration Offset from Motor Position Encoder position is referenced to the position at the most recent power on or reset regardless of any homing moves or offset commands done since then To relate this encoder position to motor position one must know the offset between encoder zero and the homing zero positions Fortunately this is simply the position captured during the homing move which PMAC stores for future use in registers Y 0815 1 Y 08D5 2 etc Note The position capture feature gets encoder position rather than motor or axis position 15 14 Synchronizing PMAC to Extern
321. he program When writing the program that is to be under external time base control simply write it as if the input signal were always at the real time frequency When run the program will execute at a rate proportional to the input frequency There is full floating point resolution on the move times and feedrates specified Remember that DWELL commands always execute in real time regardless of the input frequency If you want pauses in your program that are proportional to an input frequency use the DELAY command not DWELL Time Base Example There is a web of material moving at a nominal speed of 50 inches per second There is an encoder on the web that gives 500 lines per inch There is a crosscutting axis under PMAC control When the web is moving at nominal speed you want to make a cutting move in 0 75 seconds and be ready to start another move 2 50 seconds later The web encoder is attached to Encoder 2 input lines Step 1 Signal Decoding Since the web encoder is Encoder 2 I905 controls the decode For maximum resolution set I905 to 3 or 7 for 4x decode Try 3 first Looking in the list of suggested M variables in the manual notice that the encoder position M variable for this encoder is M201 Make the definition for M201 and query its value repeatedly probably using the Executive program Watch window while turning the web encoder in the direction it will be going in the application If the value increases as the encoder is turned I90
322. he second entry at two spacings and so on Rollover Outside of this range the uncorrected position is rolled over to within this range essentially a modulo remainder operation before the compensation is done This permits compensation of rotary axes over several revolutions and simple compensation for encoder eccentricity Of course if the table is made big enough to cover the entire source motor travel the rollover feature will never be used If the motor has a travel range to the negative side of zero and compensation is desired here these entries should be made as if they were past the positive end of the motor range For instance if the motor travel were 50 000 counts and a table entry was to be made every 500 counts so 200 entries total the table would be set up with a DEFINE COMP 200 100000 command The first 100 entries would cover the 500 to 250 000 count range and the last 100 entries would cover the 50 000 to 0 count range Usually the table is referenced so there is a zero correction at the source motor Zero position so the last entry in the table should be 0 Essentially the 50 000 to 0 range would be mapped into the 50 000 to 100 000 range Example If the following simple table were entered 1 DEFINE COMP 8 4000 Table of 8 entries over 4000 cts belonging to motor 1 Uses motor 1 for source amp target because no other motors specified 160 Correction at 4000 8 500 cts
323. heir position data in parallel form but they are incremental sensors and a motor using one for position feedback still must be homed Ix10 should be left at O no absolute power on read for any incremental sensors Resolver Position The other type of power on position data that can be specified with Ix10 is serial data from an ACC 8D Option 7 resolver to digital R D converter board brought in through the thumbwheel multiplexer port In this format the low 16 bits of Ix10 specify the multiplexed address on this port a value from 0 to 256 decimal matching the address set on the board with DIP switches Multiplexer addresses are even numbers ranging from 0 to 254 a value of 256 0100 should be used to specify multiplexer address 0 because PMAC interprets a value of 0 to mean no absolute power on position read The high eight bits of Ix10 contain a value from 0 to 7 specifying the location of the particular R D converter at that multiplexer address there are potentially eight at each multiplexer address Also the most significant bit value 80 specifies whether the position is to be treated as a signed or unsigned quantity If the MSBit is set to O the value read from the resolver is treated as an unsigned quantity with a range of O to 4095 if the MSBit is set to 1 the value is treated as a signed quantity with a range of 2048 to 2047 For example to use an R D at location 3 of multiplexer address 2 treating the value as an u
324. her 8G 8 589 934 592 Using this unshifted format be aware that PMAC will treat on LSBit of the feedback device as 1 32 of a count not as a full count For example if there is a sensor on motor 1 X axis with 2 5 nanometer resolution to program the axis in millimeters treat one count as 80 nm 2 5 32 and make the axis definition 1 gt 12500X 1 000 000 80 The conversion table entry for this would consist of a source and process word 38FFC2 unshifted parallel conversion of Y FFC2 a mask word 00FF00 to use only the middle eight bits of the 24 bit word and a filter word value of something like 000020 maximum speed 32 counts per servo cycle Ix05 for any motor x to be slaved to this hand wheel would be set to the address of the third line of this entry in the table For a 1 1 following ratio and a default Ix08 value of 96 Ix07 would be set to 12 instead of the usual 96 to reflect that fact that each count from this accessory appears eight times bigger than normal Shift Right Parallel Conversion If both bit 19 and bit 18 of the source and process word for a parallel data conversion are set to 1 the raw data at the source address is shifted right three bits before being placed in the result word Entries of this form would have the conversion formats bits 16 23 of this word 2C 3C 6C or 7C This conversion format is intended for data that is found in the high 16 bits of the 24 bit word LSB is bit 8 as for feedback fr
325. his same data may be obtained much faster via the DPRAM without the time required to send the command through the communications port and wait for the response 17 22 Writing a Host Communications Program PMAC User Manual PMAC provides many facilities for using the dual ported RAM DPRAM to pass information back and forth between the host computer and PMAC These facilities are comprised of the following functions DPRAM Control Panel Function Host to PMAC DPRAM Servo Data Reporting Function PMAC to Host DPRAM Background Fixed Data Reporting Function PMAC to Host DPRAM Background Variable Data Reporting Function PMAC to Host DPRAM ASCII Communications Buffer Bidirectional DPRAM Binary Rotary Program Buffer Host to PMAC DPRAM Data Gathering Buffer PMAC to Host already existing DPRAM CONTROL W ASCII Command Function Host to PMAC already existing In addition to these automatic functions otherwise unused registers can be accessed in the DPRAM through the use of M variables on the PMAC side and through pointer variables on the host side for sending data either way between the host and PMAC The M variable formats likely to be used are X Y for 1 to 16 bits DP for 32 bit fixed point and F 32 bit floating point For sending data back to the host the PMAC data gathering function can also be used directed to the dual ported RAM rather than the regular RAM 145 controls See the PMAC DPRAM User
326. hrough A24 for the dual ported RAM are determined by the PMAC memory location X 0785 which is also used for the same address bits of the base address of the mailbox registers First write the value of address bits A23 through A20 into bits 7 through 4 high order nibble of the PMAC memory location X 078A i e the left hex digit most significant bits will be the value of address bits A23 A20 and the other digit right digit amp least significant bits will always be 0 In this example the value for address bits A23 A20 would be 1 therefore write a value of 10 into location X 078A Now we have to write the value of address bits A19 through A14 into the PMAC base address 121 remember from the previous examples the PMAC base address is 7FA000 This needs to be done every time PMAC is powered up or reset either with the hardware reset line or use of the command In this example constructing a 6 bit hex number from bits A19 A14 gives a value of 3F Address Bits A19 A18 A17 A16 A15 A14 Binary 1 1 1 1 1 1 Hex 3 F 17 16 Writing a Host Communications Program PMAC User Manual So we write 3F from the VME host computer master into VMEbus location 7FA121 after PMAC is powered up or reset At this point the starting address of DPRAM is fully specified However check two more register locations in the PMAC memory to make sure they have appropriate values Location X
327. huge file may get 1000 lines ahead then start again when the program has caught up to within 500 lines PR Command The PR program remaining command returns the number of lines ahead This provides a simple polling scheme but one that is probably not good for tight real time applications BREQ Interrupt For tightly coupled applications there are hardware lines to handle the handshaking for the rotary buffer and variables to control the transition points of the lines The BREQ Buffer Request line goes high when the rotary buffer for the addressed coordinate system wants more program lines and it goes low when it does not This line is wired into PMAC PC s programmable interrupt controller so it can be used 14 52 Writing Programs for PMAC PMAC User Manual to generate an interrupt to the host PC The complement BREQ is provided on the JPAN connector In addition there is a Buffer Full BREQ status bit for each coordinate system 117 Stops Interrupts Variable I17 controls how many lines ahead the host can load and still get BREQ true If a program line is sent to a rotary buffer BREQ is taken low at least temporarily If still less than I17 lines ahead of the executing line BREQ is taken high again which can generate an interrupt If I17 or more lines ahead BREQ is left low When a rotary program buffer is entered with OPEN ROT or change the addressed coordinate system BREQ is taken low and then set high if the buffer
328. ial signal with up to 10V between the lines each line is 5V set 1169 to 16 384 or less Getting Started with PMAC 2 11 PMAC User Manual Testing the Output and Polarity Next check the outputs and whether the output polarity matches the feedback polarity To do this provide power to the amplifier First have PMAC disable its own outputs for the motor by typing K CR kill Make sure that the motor has no load at this point so that uncontrolled motion cannot damage anything Now provide power to the amplifier PMAC Commutated Motors If PMAC is commutating this motor get the polarity of the commutation feedback and the phased commutation outputs to match If the feedback polarity direction has been set to get it to count up when moving in the proper direction test whether the phasing polarity of the outputs as set by I172 is correct There is a 5046 chance of having this correct Permanent Magnet Brushless Motors If using a permanent magnet brushless motor check the polarity match by a technique that drives the motor like a stepper motor First type OO lt CR gt open loop output of zero magnitude Then type 1129 2000 lt CR gt which puts an offset on one of the phases forcing current through it Note the position of the motor in this state Next type 1179 2000 lt CR gt which puts the same offset in the next phase Note the position again and determine whether it counted up or counted down since the first check
329. if Ix03 were 0720 it would become 10720 The delay in software capture can be a few milliseconds the speed of the homing search move may need to be limited for high homing accuracy Linear Displacement Transducer Feedback PMAC can accept feedback from a linear displacement transducer LDT through its ACC 29 interface board The best known brand name for this type of device is Temposonics from MTS Corp This type of device operates much like sonar and what is being measured is the time before the echo is returned ACC 29 uses the timer registers of its on board DSP GATE ICs to record this information the larger the time the longer the distance 7 8 Setting Up a Motor PMAC User Manual To PMAC itself this type of feedback looks like an absolute encoder The source of the data is the appropriate timer register not the ACC 14D I O register The 20 or 30 conversion format would be used and the data would be found in the Encoder 9 through Encoder 16 timers that measure the time between the last two pulses Y C020 Y C024 Y C03C See below under Parallel Position Feedback Entries for instructions on the software setup for this type of feedback For this type of device PMAC can use the Ix10 parameter to read the absolute power on reset position up to a width of 24 bits If Ix10 is set to O the absolute power on reset position read function is disabled and the power on reset position is set to zero regardless of the set
330. ifference between the commanded position and the actual position at any time The following error limit is an important protection against serious system faults such as loss of feedback that can cause dangerous conditions like full speed runaway Fatal Following Error Limit One of these limits Ix11 is a fatal limit which causes a shutdown of the system zero output commanded amplifier disabled i e the motor is killed moves for the motor and programs for the motor s coordinate system aborted Which amplifiers get disabled only the offending motor all in the coordinate system or all in PMAC is determined by Ix25 This limit is intended for conditions where something has gone seriously wrong e g loss of feedback or power stage and all operation should cease After the motor or motors have been killed due to the fatal following error limit closed loop control can be re established with the J command single motor the A command coordinate system or the lt CTRL A gt command entire card Warning Following Error Limit The second limit Ix12 is a warning limit when exceeded PMAC sets status bits for the motor and the motor s coordinate system and can set output lines on the control panel connector the machine connectors and through the programmable interrupt controller for PMAC PC and PMAC STD This permits special action to be taken either by PMAC itself through a PLC program by the host which can fi
331. ifficult to read as far as the proper sequence of operations Synchronous M Variable Assignment The synchronous M variable assignment statement is designed to get around this problem This type of statement uses a double equals sign instead of a single equals sign This is a flag to PMAC to hold off the actual execution of the statement until the beginning of the move immediately following it so the actual action coincides with the actual motion Synchronous M variable assignment statements are discussed in detail in the Computational Features section of the User s Guide with syntax instructions under M constant expression Writing Programs for PMAC 14 57 PMAC User Manual 14 58 Writing Programs for PMAC PMAC User Manual I5 Synchronizing PMAC to External Events Table of Contents SYNCHRONIZING PMAC TO EXTERNAL EVENTS eese cesses eese testen atentos eta so se tasto suse ta sens enses sns ena 1 Features To Help Synchronize Motion esses eee nennen nennen nennen netten nenne tree ten tnen teen teen eene 1 Position Following Electronic Gearing essent anno nn non nc nono nono tenet teet tr enne cn nena nenne ene 1 Position Following Variables iii et eei Erin criada bebo on iet Ie eterno o DDS 1 Changing Ratios on the Ely iuge nda eee 3 Superimposing Following on Programmed Moves eese eene ener ettet tree tren trente enne 3 Time Bas Control
332. ight above this but there is no general solution to the second problem Computational Features 13 13 PMAC User Manual Operators PMAC operators work like those in any computer language they combine values to produce new values Arithmetic Operators PMAC uses the four standard arithmetic operators and The standard algebraic precedence rules are used multiply and divide are executed before add and subtract operations of equal precedence are executed left to right and operations inside parentheses are executed first Modulo Operator PMAC also has the modulo operator which produces the resulting remainder when the value in front of the operator is divided by the value after the operator Values may be integer or floating point This operator is particularly useful for dealing with counters and timers that roll over When the modulo operation is done by a positive value X the results can range from 0 to X not including X itself When the modulo operation is done by a negative value X the results can range from X to X not including X itself This negative modulo operation is very useful when a register can roll over in either direction Logical Operators PMAC has three logical operators that do bit by bit operations amp bit by bit AND bit by bit OR and bit by bit EXCLUSIVE OR If floating point numbers are used the operation works on the fractional as well as the integer bits amp has th
333. ilbox registers is given in subsequent sections Dual Ported RAM Base Address The dual ported RAM if used has a different base address from that of the mailbox This register X 078A is where specify address bits A23 through A20 of the dual ported RAM DPRAM starting address The first four bits of this register specify A23 A20 of the base address The low four bits of this register should be set to 0 For example if the base address of the DPRAM is 780000 this register would be set to 70 where the 7 in the high four bits of the byte represents the 7 in bits 23 20 of the base address If using A32 32 bit addressing address bits A24 A31 of the DPRAM are the same as for the mailbox base address as specified in X 0785 Bits A19 A14 of DPRAM base address must be specified by the host computer every time the system is powered up or reset The host computer does this by writing a byte to the mailbox IC at the mailbox base address 121 The low 6 bits of this byte represent bits A19 A14 of the DPRAM base address For example with the mailbox base address at 7FA000 and the DPRAM base address at 780000 bits 19 to 14 of the DPRAM base address can be represented as 100000 binary or 20hex so the host computer would write a byte value of 20 to bus address 7FA121 The VME controller IC on PMAC uses this IC to permit dynamic switching between multiple pages of DPRAM The DPRAM IC on PMAC VME has only one page but this page must sti
334. in a coordinate system that is running a motion program at the time all motors in the coordinate system are decelerated to a stop at their own Ix15 rate The effect is equivalent to issuing an A abort command The limit input pins are direction sensitive the LIM pin only stops positive direction moves those coming at it from the negative side and the LIM pin only stops negative direction moves those coming at it from the positive side This makes it possible to command a move out of the limit that you have run into However this also makes it essential to have your limit switches wired into the proper inputs or they will be useless The hardware limit function can be disabled for a motor by setting bit 17 of Ix25 to 1 This can be useful for homing into a limit switch which will not work if the limits are enabled the default condition or for a system where hardware overtravel limit switches are not practical such as rotary tables If the address of the flags in Ix25 were C004 the value of Ix25 with limits disabled would be 2C004 Note PMAC brings the commanded trajectory for the motor to a stop at the Ix15 rate as soon as it detects a limit condition If there is significant following error at the time the actual position can try to catch up to the commanded position for a long period of time With a large enough following error it is possible that the commanded position would be well past the limit and into the hard stop
335. in quotes amp lt 255 char 49 L Variable address not defined 50 Two L Variables with same address definition or has already been defined Compiler Processing The compiler observes the following rules in interpreting the input file e Comments all characters from a semicolon character to the end of a line are ignored and they are not passed on to the output file e The compiler recognizes and uses L variable definitions but does not pass them on to the output file e All statements between OPEN PLCC n and CLOSE except comments are compiled into DSP machine code The CLEAR command is not required after OPEN PLCC n because the act of downloading new compiled PLCCs erases the existing version automatically However there is no need to remove the CLEAR command for the compiler e For each compiled PLC n that is created the compiler will add the commands OPEN PLC n CLEAR CLOSE to the output automatically When sent to PMAC this erases the uncompiled PLC of this number automatically The reason this is done is to prevent uncompiled and compiled versions of the same PLC from trying to execute simultaneously Writing a PLC Program 16 13 PMAC User Manual To use a different uncompiled PLC of the same number as a compiled PLC include it in the input file to the compiler after the text for the compiled PLC The compiler will pass it through to the output and it will be reloaded each time Otherwise do a
336. indicating to PMAC that it has faulted Servo Loop and Jogging Troubleshooting If holding position well but cannot move the motor make sure that the hardware limits are held low Check which limits 1125 is addressed to usually LIM1 then make sure those points are held low to AGND and sourcing current unscrew the wire from the terminal block and put the ammeter in series with this circuit to confirm this If this is not right refer to the Connecting PMAC to the System section previously and the PMAC Opto Isolation drawing to re check the connections Troubleshooting 5 1 PMAC User Manual If the motor dies after it is given a jog command the fatal following error limit has been exceeded If this has happened it is either because a move that is more than the system can physically do has been requested if so reduce 1122 or because it is badly tuned if this is the case increase proportional gain I130 To restore closed loop control issue the J command Homing Search Troubleshooting No Movement At All Check the following e Are both limits held low to AGND and sourcing current out of the pins Isthere a proper supply to A 15V A 15V and AGND e Is the proportional gain Ix30 greater than zero Can any output be measured at the DAC pin when an O command has been given e Is the following error limit being tripped Disable the fatal following error limit Ix11 by setting it to Zero and try to mov
337. ing a signal of this polarity directly to the amplifier use intermediate circuitry to change the signal format With the alternate sourcing drivers the high true enable polarity provides better failsafe protection Direction Bit Use An alternate use for these outputs is as the direction sign bits for drive systems expecting sign and magnitude commands Some servo amplifiers expect this command format and if the signal needs to be run through a voltage to frequency converter such as the ACC 8D Opt 2 to create a pulse train for a stepper drive this format should be used To use the output in this manner bit 16 of Ix25 for the motor using this line must be set to 1 This disables its use as an amplifier enable line Also bit 16 of Ix02 for the motor must be set to 1 This makes the analog output an absolute value and places the sign bit on this output Input Output Connecting PMAC to the Machine 6 7 PMAC User Manual General Purpose Use If no dedicated use is made of this output it may be used as a general purpose output by assigning an M variable to the bit M114 M214 etc in the suggested M variable definitions Compare Equals Outputs The compare equals EQU outputs have a dedicated use of providing a signal edge when an encoder position reaches a pre loaded value This is very useful for scanning and measurement applications Instructions for use of these outputs are covered in detail in the Synchronizing PMAC to External E
338. ing from This is what the PMATCH function does Second if there is an absolute position sensor the PMATCH function should be used before the first programmed move because the motor will not in general power up at zero position as it does for an incremental sensor and the axis must be given this starting point Setting Up a Coordinate System 12 3 PMAC User Manual The PMATCH function effectively inverts the equations contained in the Axis Definition statements for the coordinate system using motor commanded positions and solves for axis commanded positions If more than one motor is assigned to the same axis e g 1 gt 10000X 2 gt 10000X the commanded position of the lower numbered motor is used in the PMATCH calculations If variable 114 is equal to 1 the PMATCH function is executed automatically every time motion program execution is started on all R run and S step commands It does not hurt to do a PMATCH function if the positions already match so use the card with 114 1 12 4 Setting Up a Coordinate System PMAC User Manual 1 Scaling and Translation Y un 1 gt 10000X 40000 Motor 2 1 0 000 AS 2 gt 10000Y 20000 Motor 1 10 000 2 Scaling and Rotation d 1 gt 7071 07X 7071 07Y Motor 2 10 000 2 gt 7071 07X 7071 07Y Motor 1 10 000 3 Orthogonality Correction cts Y in Motor 2 10 000 95 1 gt 10000 00X 2 91Y 2 gt
339. ing to simple provided rules to optimize the tuning Detailed instructions and examples are provided in the Executive Program manual The Executive program also has an auto tuning function that stimulates the motor evaluates the response and calculates the gains required for the desired response level This function allows the computer to make all of the decisions as to what the proper gains should be Closing the Servo Loop 9 5 PMAC User Manual NQ Friction E Phase 1 Bias Feedforward SC y Command 4 F Velocity 1 Z A B 1x29 Signum Ix68 SIN Phase 2 Bias Function A Input Big Step Output x79 Deadband Limit iit oe a Command l K Position 7 pa E X i e 1x02 1x64 65 Ix67 S i D En Actual E Position ron ode D x E mt qo Limit Ix34 1x29 Motor Position Ix63 Figure 19 PMAC PID Servo Loop Modifiers Actual PID Algorithm The actual equation used in the PID algorithm to compute the commanded output for motor x is as follows DACont nea 1x30 1x08 FE n 4 1x32 CV n Ix35 CA n aii Ix31 Ix09 AV n 128 223 128 where e DACout n is the 16 bit output command 32768 to 32767 in servo cycle n It is converted to a 10V to 10V output DACout n is limited by Ix
340. inneren nnne ennt ranas 11 10 Storing the Home Position esses eene eee teen teen nest nr etre rentrer tnnt tene tret trennen tenete entrent 11 13 Open Loop MOVES eter dit 11 14 Table of Contents 11 1 PMAC User Manual Table of Contents PMAC User Manual BASIC MOTOR MOVES Commanding Some Basic Moves for the Motor Once the motor is defined and basically working command some basic moves for the motor Jogging commands allows the motor to make simple moves independent of other motors without writing a motion program Use these moves for development diagnostics and debugging but also use them in the actual application Another type of simple motor move is the homing search move This is basically a jog until trigger type of move where PMAC commands the motor to move until it sees a pre defined trigger It then brings the motor to a stop and returns to the trigger position possibly with an offset and sets the motor position to zero A homing search move should be performed when it is not known where home position is If there is an incremental position sensor the location is not known on power up Therefore the homing search move is typically the first move done in this type of system If the home position is known to return to that position there is no need to do a homing search move simply command a move to the zero position e g J 0 or X0 The trajectories for jogging and homing moves are
341. ion i eei rani neseserai innin ni eei ireak e Enar Enion 32 Single Stepping While In Compensation eese eene nennen nnne nennen ren nena nena nena errar teneret ne 33 AAN M 34 Axis Transformation Matrices sucesoria iro ren i ee e E RR oo Ee Ea o eg ER eu ERU ERA ea ecc 34 Setting Up the T 34 USING Te MAUHICOS EC 34 Calculation Implications 52 rp kae ey Ete no erae Er c saa Ee RR HERES ERE RE ER eub ote nente Pene epe eb acia 35 PAD NM Ed 35 Entering A Motion Prostatic o einer e POE Ern E ean eenen RE HE ERER o et Ehe eL REL Le ebbe ee s Ee TR Roue Raae eenas 37 Learning a Motion Program concibe oe 38 Motion Program Structure cintia 38 Basic Move Specifications EE n 38 A A 39 Controlling Parametros ironia FE sodes iesuavelogusoacveenoguuas 39 Simultaneous Moves on Multiple Axes esee entente nennen trennen eren enne enter teee trennen 39 Seguential MOVES ET 39 Adding mp dT I eee e ao EEG cw eed 39 Line Label m 40 GOTO Conmmand EE 40 Adding Variables and Calculations eese eene nennen nennen eene en rennen nenne eret tene tret easan 40 Subroutines and Subprogram Siisera reir streets io E a EE ae aa ARa EE oen b Sou ep eet PE ee dina 4l P
342. ion usually an encoder only on the load where the derivative gain cannot be raised enough to give adequate damping without causing an unstable buzz due to amplified quantization errors In this case slowing down the update rate increasing the update time can help to give adequate damping without excessive quantization noise Ramifications of Changing The Rate If changing the servo update time many of the existing servo gains Ix30 to Ix39 will behave differently To retain equivalent servo performance change these values Refer to the Notch Filter section in this manual to see how to re compute the notch filter parameters Ix36 Ix39 Closing the Servo Loop 9 1 PMAC User Manual If changing the servo update time with the jumpers change parameter I10 to match the change in order that trajectories are executed at the right speed 110 does not have to be changed to match changes in Ix60 Amplifier Types PMAC can interface to a variety of different types of amplifiers The type of amplifier used for a particular motor has important ramifications for the tuning of the servo loop Each of the common types is explained below Velocity Mode Amplifiers Many amplifiers accept a velocity command from the controller and a velocity feedback signal from a motor sensor usually from a tachometer or synthesized from a resolver Motors using these amplifiers have their velocity loops closed in the amplifier and should not require use of th
343. ion control 14 2 Writing Programs for PMAC PMAC User Manual Note If PMAC is operating in move segmentation mode 113 gt 0 which is required for circular interpolation this Ix17 acceleration limit is not observed Do not set both the TA and TS Ix87 and Ix88 times to zero even if planning to rely on the acceleration limit This would cause a divide by zero error yielding possible erratic performance When Not Effective Enough PMAC looks two moves ahead of actual move execution to perform its acceleration limit and can recalculate these two moves to keep the accelerations under the Ix17 limit However there are cases where more than two moves some much more than two would have to be recalculated in order to keep the accelerations under the limit In these cases PMAC will limit the accelerations as much as it can but because the earlier moves have already been executed they cannot be undone and therefore the acceleration limit will be exceeded Writing Programs for PMAC 14 3 PMAC User Manual Ix87 DEFAULT ACCELERATION TIME PROGRAM Units msec integer Overridden by TA in program Ix88 DEFAULT S CURVE TIME PROGRAM Units msec integer Overridden by TS in program Ix87 gt 2 Ix88 Ix87 2 Ix88 1x88 1x88 gt T 4 2 1x88 Ix88 0 N 4 Ix88 1x88 x T Figure 26 Coordinate Sys
344. ion without any intervening dwell commands each motor blends smoothly from its velocity for the first move to the velocity for the second move according to the acceleration and S curve values in force at the time This change in speed which can be a zero change starts at the point where the first move would start to decelerate to a stop at its specified end position not at the first move s endpoint itself However if Ix92 is set to one blended moves in that coordinate system always come to a stop before the next move Writing Programs for PMAC 14 11 PMAC User Manual The acceleration parameters TA and TS can change between each move If the final deceleration to a stop should use a different TA or TS from the previous blending acceleration time in a sequence declare the new TA or TS after the final move command in the sequence but before the DWELL or other feature that stops the continuous sequence Rapid Mode Moves Rapid mode moves are essentially jog moves for each motor assigned to an axis specified in the move The acceleration for each motor is controlled by the values of Ix19 to Ix21 jog acceleration limit and time in force at the time of the move The speed of the move is controlled either by the jog speed parameter Ix22 or the maximum speed parameter Ix16 Global variable I50 controls which of these is used for all motors I5020 means Ix22 is used I5021 means Ix16 is used On a multi axis rapid mode move only the motor
345. ircular move is specified with a move command specifying the move endpoint and either the vector to the arc center or the distance radius to the center The endpoint may be specified either as a position or as a distance from the starting point depending on whether the axes are in absolute ABS or incremental INC mode individually specifiable Center Vector If the vector method of locating the arc center is used the vector is specified by its I J and K components 1 specifies the component parallel to the X axis J to the Y axis and K to the Z axis This vector can be specified as a distance from the starting point i e incrementally or from the XYZ origin i e absolutely The choice is made by specifying R in an ABS or INC statement e g ABS R or INC R This affects I J and K specifiers together ABS and INC without arguments affect all axes but leave the vectors unchanged The default is for incremental vector specification Note The standard machine tool usage is for incremental vector specification even when move endpoint specification is absolute A typical circular move command with a vector specification is X1000 Y2000 1500 J 500 14 14 Writing Programs for PMAC PMAC User Manual Example Starting from the point X0 YO make a quarter circle clockwise in the XY plane to X20 Y20 then a linear move to X40 Y20 then a three quarters circle clockwise to X20 YO With the default modes of absolute
346. ire succeeding program insufficient calculation time If PMAC ever cannot finish calculating the trajectory for a move by the time execution of that move is supposed to begin PMAC will abort the program showing a run time error in its status word Usually this happens when move times are made short a few milliseconds and or there is a large amount of calculation in between move commands The limit on this move block calculation rate is application dependent but generally is several hundred blocks per second If concerned about this move calculation limit during development make the move times continually shorter until PMAC fails Then for the final application make sure that the minimum move time is kept greater than this usually with a safety margin of at least 2596 14 54 Writing Programs for PMAC PMAC User Manual A Two moves ahead LINEAR with 113 0 SPLINE1 e a Execute R Y NM Y p gt do o time X Calculate B One move ahead LINEAR with 113 gt 0 CIRCLE PVT e Execute R f gt Hi O 5 time Calculate C No moves ahead 1x92 1 RAPID HOME DWELL S Beel ORE D Es E FA Y y y i y E ttt ttal DWELL le 111 ol dno e me Kg Calculate Figure 50 PMAC Motion Program Recalculation When No Calculation Ahead There are several conditions in a motion program that break the blending and stop the calculation ahead In these cas
347. is 160 16 10 cts 80 Correction at 1000 counts is 5 counts 120 Correction at 1500 counts is 7 5 counts 96 Correction at 2000 counts is 6 counts 20 Correction at 2500 counts is 1 25 counts 56 Correction at 3000 counts is 4 5 counts 12 Correction at 3500 counts is 0 75 cts 0 Correction at 4000 and 0 cts is zero Setting Up a Motor 7 29 PMAC User Manual and the axis definition were 1 gt 1000X a commanded move to X1 3 would give an uncorrected motor position of 1300 counts The applied correction would be linearly interpolated from the table 7300 1000 500 Correction 7 5 5 5 6 5counts At X8 4 PMAC would calculate an uncorrected motor position of 8400 counts roll this over to within the table range 8400 mod 4000 400 counts and the correction from the table would be 400 0 500 Correction 10 0 0 8counts Enabling and Disabling All leadscrew compensation tables are enabled when I51 is set to 1 When I51 is set to O all are disabled Uses of Cross Axis Compensation The ability to have separate source and target motors for a table has several uses The first is the traditional compensation for imperfect geometry as in a bowed leadscrew For instance on an XY table 1f the X axis leadscrew is bowed the Y axis position should receive a correction as a function of X axis position If motor 1 is the X axis and motor 2 is the Y axis the table hol
348. is a motor by motor function not a coordinate system function as time base following is An encoder signal from the master axis which is not under the PMAC control is fed into one of the PMAC encoder inputs Typically this master signal is either from an open loop drive or a handwheel knob Position Following I Variables One or more of the PMAC motors is told that this encoder register is the master with Ix05 Ix05 is an address I variable that is its value contains the address of the register holding the master position information Typically this register is that of some processed position data in the Encoder Conversion Table It is helpful to have done the 1 T interpolation or similar to reduce the quantization noise in the sampling of the master encoder this is done automatically in the default setup The following ratio for each motor is set by Ix07 and Ix08 which can be analogized to the number of gear teeth on master and slave in a mechanical following application The following function is turned on and off with Ix06 When it is on the input stream from the master acts just like a trajectory generator creating a series of commanded positions to which the following axis controls Synchronizing PMAC to External Events 15 1 PMAC User Manual A Two moves ahead LINEAR with 11320 SPLINE1 e 0 a Execute D UEM e time alculate B One move ahead LINEAR with 113 gt 0 CIRCLE PVT e O 4 Execute
349. is a separate input interrupt level The PC must then be programmed to recognize this particular interrupt level the interrupt level must be unmasked and vectored and react appropriately through an interrupt service routine These will be explained below Selecting a Host Interrupt Line PMAC STD The user should use one and only one of the PMAC STD CPU board jumpers W1 W2 and W3 to select between STDbus interrupt lines INTRQ INTRQI and INTRQ2 respectively Interrupt Functions The first and most common use of these interrupts is for basic communications By using the HREQ line into the PIC PMAC can interrupt the host PC whenever it has something to say to the host and or whenever it is ready to accept a character This can eliminate the need for the host to poll PMAC regularly to see if it is ready for communications Refer to the Appendix or the Executive Program diskette for demonstration PC programs 17 6 Writing a Host Communications Program PMAC User Manual r e E62 e Mil m e E63 AXEXP1 e E64 EQU5 E65 EQUI Ra HREQ Read Ready Write Ready Ml2 E58 IR5 IR3 Warning ASEAED E59 Y Y FIER Fouowing Error EQU6 E60 7 IR6 IR2 Fatal EQU2 Epe1 PMAC EROR Following Error IR1 lt a a 8 2 59 BREQ Buffer Request IR7 IRO EQU8 E54 PIC pos In Position EQUA E55
350. is eight bits one start bit one stop bit with no parity if jumper E49 is ON or odd parity if jumper E49 is OFF opposite for PMAC STD PMAC can echo back to the host each character it receives from the host the CTRL T command toggles this function on and off No XON XOFF handshaking is supported Line by line checksums can be computed Variable I4 controls this function PC bus Interface The PC bus interface for the PMAC PC and the PMAC Lite can work with just the PC XT bus eight bits wide The additional AT bus connecter is provided but it can only be used to access the additional AT interrupt lines One PMAC occupies 16 addresses in the PC s port I O space The base address of this space is determined by jumpers E91 E92 and E66 E71 Of course the address should be chosen so as not to conflict with anything else in the PC The factory default setting is for address 528 210 hex The Jumper Description section contains a thorough mapping of a typical PC s I O mapping and likely empty addresses Characters are passed one at a time through one of these addresses The software to support this interface is very similar to that for the serial port Of course characters can be sent much faster over the bus port The Option 2 dual ported RAM board provides 8k x 16 bits of shared memory for passing data back and forth between PMAC and the host computer The data path for this memory is 16 bits wide and so supports the AT bus directly STD bus I
351. is independent of tool radial position With the spindle axis in a separate coordinate system the subroutine executing this code simply sets a variable and a flag for that program to see Usually a G97 code will carry with it a spindle speed S code in RPM If it does the routine picks it up and puts it into a variable If it does not the routine allows the spindle program to keep its last RPM computed under G96 from surface speed and radial distance A typical G97 routine using this approach would be N97000 READ S Read spindle RPM into Q119 IF M100 262144 gt 0 P97 Q119 Store for spindle prog M96z0 Cancel CSS mode Spindle Programs Controlling the spindle axis in PMAC may be done in different ways depending on what the spindle needs to do The simplest type of spindle operation of course is the one in which the spindle is simply asked to move at constant speeds for substantial periods of time in one direction or another In this case there is no need to write a spindle motion program either PMAC just puts out a voltage proportional to speed so the spindle is open loop as far as PMAC is concerned or the spindle motor is jogged under PMAC closed loop control Jogged Spindle The jogged spindle motor does not need to be in any coordinate system it must not be in the same coordinate system as the other axes or it cannot be jogged while a parts program is running but it is a good idea to put it in a different coordinate sys
352. is less than I17 lines ahead of the executing point 116 Restarts Interrupts Variable 116 controls where BREQ gets set again as the executing program in the rotary buffer catches up to the last loaded lines If after execution of a line there are less than I16 lines ahead in the rotary buffer BREQ is set high This can be used to signal the host that more program lines need to be sent By using these two variables and the BREQ line for interrupts an extremely fast and efficient system for downloading programs in real time from the PC is created If the Buffer Runs Out If the program calculation catches up with the load point of the rotary buffer there is no error program operation will suspend until more lines are entered into the rotary buffer Technically the program is still running a Q or A command must be given to truly stop the program If PMAC is in segmentation mode 11320 and is executing the last line in the rotary buffer as long as a new line is entered before the start of deceleration to stop PMAC will blend into the new move without stopping Closing and Deleting Buffers The CLOSE command closes the rotary buffers just as it does for other types of buffers Closing the rotary buffers does not affect the execution of the buffer programs it just prevents new buffered commands from being entered into the buffers until they are reopened DELETE ROT erases the rotary buffer for the addressed coordinate system and de alloca
353. is set up include it in this same coordinate system For instance 2 gt 10000Y matches the second motor to the Y axis in this coordinate system at 10 000 counts per user unit This is about all there is to defining a coordinate system If a motor is assigned to a coordinate system make sure that both its limits are held low either through switches or directly to AGND nothing else for that motor needs to be connected Define the time units to work in 1190 for coordinate system 1 This parameter holds the number of milliseconds in the time units being used For instance to specify the velocity in user position units per second e g inches sec set 1190 to 1000 this should be the default To work in minutes e g rpm set I190 to 60 000 Writing a Motion Program With the coordinate system s defined begin to write a program Open a program buffer for entry by typing OPEN PROG 1 lt CR gt and CLEAR lt CR gt to erase anything that might exist in the buffer Now the program lines entered will be held in program buffer 1 A program to do a simple back and forth trapezoidal move will look like this with comments LINEAR Linear interpolation mode ABS Absolute move mode F2 00 2 inches sec X10 0 move to X 10 inches x0 0 move back to X 0 inches If the X axis is defined with a 1 to 1 scaling 1 gt X this program would only cause a 10 count move over 5 seconds and back which might not be noticeable The accele
354. it will report an error to the host General Housekeeping Between each scan through each background PLC program PMAC performs its housekeeping duties to keep itself properly updated The most important of these are the safety limit checks following error overtravel limit fault watchdog etc Although this happens at a low priority a minimum frequency is ensured because the watchdog timer will trip shutting down the card if this frequency gets too low e Priority Level Optimization PMAC will usually have enough speed and calculation power to perform all of the tasks asked of it without having to worry Some applications will put a large demand on a certain priority level and to make PMAC run more efficiently some priority level optimization should be done When PMAC begins to run out of time problems such as sluggish communications slow PLC PLCC scan rates run time errors and even tripping the Watchdog timer can occur The specific solutions to the above symptoms are discussed in the sections of this manual dedicated to those subjects The general solution to such problems is two fold First high priority jobs could be slowed down or moved to a lower priority position Jobs such as the Encoder Conversion Table PLC PLCCO and the Real Time Interrupt RTI should be evaluated Check to see if everything in these jobs is necessary or if some of it could be moved to a lower priority or slowed down For example A 5 axis application migh
355. ith user set decelerations The Abort input stops motion of all axes in the selected coordinate system s as determined by the motor system select inputs starting immediately and with each motor decelerating at a rate set by Ix15 The Hold input performs the same function except that the axes are decelerated at rates such that the desired multi axis path is maintained during deceleration These dedicated inputs are on the PMAC control panel connector JPAN J2 Which coordinate system they act on is determined by the binary number produced by the four low true input lines FPDO LSBit FPD1 FPD2 and FPD3 MSBit A value of zero all high disables the functions values of 1 through 8 select the numbered coordinate system Host Generated Stop Commands These functions and several others also can be performed from the host with one or two character commands For instance CTRL A performs the same function as the Abort input with all coordinate systems selected and A aborts the software addressed coordinate system CTRL O holds all coordinate systems and H holds the software addressed coordinate system In addition CTRL Q stops all programs at the end of the upcoming move and Q stops the program of the software addressed coordinate system CTRL K disables all motors immediately and K disables the software addressed 10 6 Making Your Application Safe PMAC User Manual motor if the motor is in a coordinate syst
356. ition not necessarily the actual position which can be different due to following error These statements are discussed in detail in the Computational Features section of this manual Synchronizing PMAC to External Events 15 17 PMAC User Manual 15 18 Synchronizing PMAC to External Events PMAC User Manual 16 Writing a PLC Program Table of Contents WRITING A PLC PROGRAM m none noas 1 A 1 A bunseadebedss eneee os a ri A EE E ERE beaten dudeageay ears ENE ENE E E AE ENESES 1 COMMON MISES Li oe iea aE ra aAa E RES ENA E E a ERE EE a O E EENES 1 32 PLC Program d e E ene E Eune E EPEE EERE EE ERE a TESEU EEE R E ceba REEERE TETEE EEEE Sa 1 Entering a PEG Pr ogta mM ussen mosni aris ee ae EER EN EE ehe E EEEE A EE Bp he RR LER ROEN ESE ES 2 Opening the Buffet sesupe sneep aaneen a a EEEa AE SE aa E ES EE e EE N aE AE E e Ee NS 2 Downloading the Program eese esee esee estet enne th enne tee nennen tnen trennen teen en trennen enne trennen 2 Closing the Buffer ceci aa E E RSE EA Ea AE EE E Ea E Rene e E E E RENES ERS 2 Erasing the Programs Em 2 Example iia ta E sshd sh a R A E E E E 3 PEC Program Structure 4 o ate terre ie 3 Calculation Statements aestatis celos titi 3 Conditional Statements 3i eet ti ratita 3 Leyel Iriggered Conditions ettet a e ie b Cete a alate sient adit 3 Edge Triggered Conditions citet i ot 4 WHIEE EO0DS artos 4 Pre
357. ity permits establishing contact with the cutting surface very gently important for fine finishing cuts Inside Corner Introduction If the lead in move and the first fully compensated move form an inside corner the lead in move goes directly to this point When the lead in move is a LINEAR mode move the compensated tool path will be at a diagonal to the programmed move path When the lead in move is a CIRCLE mode move the compensated tool path will be a spiral Writing Programs for PMAC 14 23 PMAC User Manual Introducing Compensation Inside Corner Line Programmed Path Tool Center C2 Line to Line Line Programmed Path Tool Center Arc to Line E CC2 v Programmed Path Line A Ne Arc Line Tool Center d Path 1 A CCo y Line to Arc Programmed Path Arc Pa Spiral Tool Center Path Arc to Arc Figure 38 Compensation Inside Corner Outside Corner Introduction If the lead in move and the first fully compensated move form an outside corner the lead in move first moves to a point one cutter radius away from the intersection of the lead in move and the first fully compensated move with the line from the programmed point to this compensated endpoint being perpendicular to the path of the lead in move at the intersection When the lead in move is a LINEAR mode move this compensated tool path will be at a diagonal to the programmed move path When
358. k of any kind is used in the amplifier itself However they are usually unsuitable for industrial position control applications for several reasons First a voltage command to the motor must overcome the motor s L R electrical time constant to cause current in the motor This can create delays in motor response Second the voltage command to the motor that can produce current even after the delay is only that voltage above the back EMF of the motor therefore the torque produced is dependent on the motor speed For both of these problems it is up to the slower digital position and velocity loops to try to correct Finally controlling current directly is the best way of preventing damaging overcurrent conditions Most industrial servomotors work with a supply voltage that could burn them up if they were exposed fully to it for just several milliseconds without substantial back EMF If current sensors are required anyway for protective overcurrent shutdown they can also be used to close current loops at very little additional cost The behavior of voltage mode amplifiers is somewhere between velocity mode amplifiers and torque mode amplifiers At low loads the speed is limited by the back EMF of the motor at low speeds the current is limited by the resistance of the armature From the controller s point of view the motor gets some damping from its own back EMF but not enough for most positioning applications so it must be supplemented with the
359. k to pull the person free of the circuit Apply cardiopulmonary resuscitation CPR if the person has stopped breathing or is in cardiac arrest Obtain immediate medical assistance 1 2 Introduction PMAC User Manual Electrostatic Sensitive Devices Various circuit card assemblies and electronic components may be classified as Electrostatic Discharge ESD sensitive devices Equipment manufacturers recommend handling all such components in accordance with the procedures described in Appendix A Failure to do so may void your warranty Magnetic Media Do not place or store magnetic media tapes discs etc within ten feet of any magnetic field Related Technical Documentation Manual Number Manual Title 3A0 602204 363 PMAC amp PMAC2 Software Reference 3A0 602191 363 PMAC PC Hardware Reference Manual 3A0 602274 363 PMAC Lite Hardware Reference Manual 3A0 602244 363 PMAC STD Hardware Reference Manual 3A0 602199 363 PMAC VME Hardware Reference Manual 3A0 602812 363 Mini PMAC Hardware Reference Manual Technical Support Delta Tau is happy to respond to any questions or concerns regarding PMAC Contact the Delta Tau Technical Support Staff by the following methods By Telephone For immediate service contact the Delta Tau Technical Support Staff by telephone Monday through Friday Our support line hours and telephone numbers are listed below By Fax and E Mail Fax or E Mail
360. l Register Base 1 Command Vector Register Base 2 Interrupt Status Register Base 3 Interrupt Vector Register Base 4 Unused Base 5 High Byte Data Transmit and Receive Base 6 Middle Byte Data Transmit and Receive Base 7 Low Byte Data Transmit and Receive Base 8 Interrupt Controller Command Word 0 Base 9 Interrupt Controller Command Word 1 Base 10 Interrupt Acknowledge Word Registers for Simple Polled Communications Basic polled communications can be accomplished with just two of these addresses Base 7 holds each byte character as it is passed to or from the PMAC The read and write registers are separate so do not worry about overwriting a character sent in the other direction Writing a Host Communications Program 17 3 PMAC User Manual Base 2 holds the handshaking status bits even though this is called the Interrupt Status Register it can be used for polled communications with the host The Write Ready Bit bit 1 is true when PMAC is ready to have the PC write it a character and the Read Ready Bit bit 0 is true when PMAC is ready to have the PC read a character Setting Up the Port No real setup is required for the host port although it is advisable to write zero values to the high byte and middle byte registers to clear them The following sample C code segment does this outportb combase 5 0 Clear high byte register outportb combase 6 0 Clear mid btye regi
361. l address is a constant that in the range of 0 65535 0 FFFF if specified in hex Do not confuse the memory and I O addresses of PMAC itself with those of the host computer Examples of legal address specifications are Y FFC2 word containing machine I O X 1824 interpolated encoder 1 position X C003 captured encoder 1 position Y49155 DACI output value This form of address specification is used particularly in M variable definitions and direct read R and write W commands There are I variables that specify addresses but these are usually pre defined to the X or Y space so all that is needed is the numerical value The data gathering address I variables I21 I44 use an extra hex digit in front of the numerical value to specify the memory half see I21 description Variables PMAC has several types of variables In PMAC a variable is specified by a single letter I P Q or M followed by a number from 0 to 1023 Each letter denotes a different type of variable each type with its own properties The different types share the characteristics that when their name is cited in an expression the current value of the variable is used reading from them and values can be assigned to them in an equation writing to them Variable names may not be specified on PMAC however the Editor in the PMAC Executive Program has a substitution macro scheme that allows programs to be written using user defined variable names but
362. l be rejected by PMAC reporting an ERROOS if I6 is set to 1 or 3 if there is no buffer open Still other commands such as J are on line commands only and cannot be entered into a program buffer unless in the form of CMD J for instance Types of On Line Commands There are three basic classes of on line commands Motor specific commands which affect only the motor that is currently addressed by the host Coordinate system specific commands which affect only the coordinate system that is currently addressed by the host e Global commands which affect the card regardless of any addressing modes In the reference chapter each command is classified into one of these types under the Scope descriptor Motor Specific Commands Motor Addressing A motor is addressed by a n command where n is the number of the motor with a range of 1 to 8 inclusive This motor stays the one addressed until another n is received by the card For instance the command line 13 2J tells Motor 1 to jog in the positive direction and Motor 2 to jog in the negative direction like most commands the jog command does not take effect until the carriage return character is received so both axes start acting on the command at roughly the same time in this case Note Each program that can use the COMMAND statement to issue on line commands from within the card has its own motor and coordinate system addressing independent of which motor and coordinate sys
363. l be treated as a signed or unsigned value If it is to be treated as unsigned the zero position should be set up past the negative end of travel so power up position cannot be to the negative side of zero If itis to be treated as signed the zero position should be in the normal range of travel setting it in the middle of travel maximizes the usable range of the axis On any motor using a resolver or resolvers for position feedback all position information used in the servo loop after the initial power on read comes through the quadrature signals generated by the R D converter for the primary resolver counted in one of the PMAC encoder counters The software setup to support this Ix03 Ix04 conversion table is the same as for a real quadrature encoder There is no need to used the quadrature signals generated from the second or third resolvers for the motor Axis Offset What if the absolute sensor s zero position is not where the axis zero position for programming purposes should be This is a very common occurrence both because it is difficult to line up the sensor exactly and because the zero position of the sensor typically must be outside the range of travel if the position information is treated as an unsigned value The difference between sensor motor zero and axis zero can be set by the axis offset parameter of the axis definition statement for the axis This parameter with units of counts should contain the axis position when th
364. lated position from Encoder 4 not Encoder 2 as it should be To change it command WY 728 400721 Now compute the scaling factor Look at the nominal speed of 50 inches sec the resolution of 500 cycles inch and the 4x decode and calculate Since the math works out more easily if this number is a power of two declare the real timecount rate to be 128 counts msec Then calculate the scale factor as 131 072 128 1024 Enter the scale factor by commanding WY 729 1024 note that the value can be entered as a decimal number by omitting the dollar sign Step 4 Using the Time Base Calculation Since working in Coordinate System 1 assign 1193 to 729 1833 decimal to point to this time base value Set I194 to the maximum value of 8 388 607 so we do not lose synchronicity on rapid changes Step 5 Writing the Program In writing the program work at the real timeinput frequency which differs from the nominal speed that was started with in this case it is exactly 2846 faster Therefore any programmed speeds would be 2896 higher any programmed times would be 28 less Take the nominal cut time of 750 msec 0 75 sec and multiply it by 100 128 to get exactly 585 9375 msec The 2500 msec return is similarly scaled to 1953 125 msec If these numbers do not come out exactly in the program put the math directly in the program PMAC calculates with 48 bit floating point precision There will be a main program loop something like this
365. le provides a more accurate measure of position than a sensor on the motor because its accuracy is not affected by imperfections in the motor load coupling However it can also make the axis less stable because these coupling imperfections typically compliance and backlash are now inside the loop A sensor on the motor while less accurate provides better stability because these imperfections are not inside the loop In many cases it is possible to get both accuracy and stability by using sensors on both the motor and the load In a PMAC system simply use the load encoder to close the position loop for accuracy using Ix03 to point to this encoder and use the motor encoder to close the velocity loop for stability using Ix04 to point to this encoder Note When using dual feedback the motor flags specified by Ix25 see below should have the same number as the position loop encoder Otherwise the hardware position capture function for homing will not work and the less accurate software position capture function must be used For example if the velocity loop encoder is ENCI 1x04 0720 and the position loop encoder is ENC2 Ix03 0721 the motor flags must be Flags 2 Ix252 C004 in order to use the hardware position capture If the flags are of a different number the software position capture function must be specified for homing by setting bit 16 of Ix03 to 1 e g Ix03 10721 Selecting the Master Position Source Va
366. le can be changed by some other task in the mean time Limitations There are a few limitations to these functions to be aware of Valid Forms These statements may not be used with any of the thumbwheel multiplexer port M variable forms TWB TWD TWR or TWS The Boolean assignments amp z cannot be used with any double width M variable forms D L or F Stack Limits Second the stack space that holds these actions is limited to 32 words of memory per coordinate system Each assignment occupies two or three words of memory while it is pending and there is one extra word per move to mark the end of actions for that move When PMAC is working n moves ahead it is always safe to allot 32 n 1 words per move This rule of thumb will give PMAC adequate stack space for its stack manipulations and will give enough synchronous M variables When PMAC is working one move ahead this rule of thumb gives 16 words per move of stack space which is at least five assignments plus one end word when PMAC is working two moves ahead this rule of thumb gives 10 words per move of stack space which is at least three assignments plus one end word More assignments than this can be made with a single move if for instance it is known that the next move will have no synchronous assignments or that some of the assignments will occupy less than three words on the stack In no case may the assignments for a single move occupy more than 32 words of me
367. lectrical shorts When our products are used in an industrial environment install them into an industrial electrical cabinet or industrial PC to protect them from excessive or corrosive moisture abnormal ambient temperatures and conductive materials If Delta Tau Data Systems Inc products are exposed to hazardous or conductive materials and or environments we cannot guarantee their operation PMAC User Manual Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Table of Contents Introduction Getting Started with PMAC PMAC Features Talking to PMAC Troubleshooting Input Output Connecting PMAC to the Machine Setting up a Motor Setting up PMAC Commutation Closing the Servo Loop Making Your Application Safe Basic Motor Moves Setting up a Coordinate System Computational Features Writing Programs for PMAC Synchronizing PMAC to External Events Writing a PLC Program Writing a Host Communications Program Table of Contents PMAC User Manual Table of Contents PMAC User Manual Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 Figure 23 Figure 24 Figure 25 Figure 26 Figure 27 Fig
368. led PLC containing an L variable that also contains another type of variable a non integer constant or an integer constant outside the range End to 2 4 will be rejected by the compiler The compiler will report the error and line number The integer simple condition always compares two 24 bit signed quantities against each other and all intermediate values in evaluating the conditions are held as 24 bit signed quantities as well so all values 2 2 must be kept in the range 2 to2 1 for proper evaluation 16 10 Writing a PLC Program PMAC User Manual All of the mathematical operations permitted in integer variable value assignment statements are also permitted in integer condition statements All of the same rules and speed memory benchmarks see below apply Compound conditions which are comprised of simple conditions separated by AND or OR logical operators may contain both simple conditions evaluated with integer arithmetic and simple conditions evaluated with floating point arithmetic All of the comparators that are permitted in PMAC floating point programs except the approximately equal to and not approximately equal to comparators are also permitted in integer only conditions in compiled PLCs These valid comparators are gt gt lt and Examples Examples of legal condition statements IF L50 1 WHILE L75 L76 IF L1 amp L2 L4 L5 gt O AND P1 Q2 OR L6 0 OR L3 amp
369. lended outside corners and added arc outside corners It is expressed as the cosine of the change in the directed angle of motion cos0 1 0 cos90 0 0 cos180 1 0 at the boundary of the programmed moves The change in directed angle is equal to 180 minus the included angle at the corner Sharp Outside Corner If the cosine of the change in directed angle is less than I89 which means the corner is sharper than the specified angle then an arc move will be added around the outside of the corner 14 26 Writing Programs for PMAC PMAC User Manual Outside Corner Cutter Compensation Sharp Angle cos AO lt Isx99 he Tool le a aati ine Line to Line 55s Arc Tool Center Path a Arc to Line Pro Id Line Line to Arc Arc Programmed Path SS Arc Tool Center Path Arc to Arc Figure 41 Outside Corner Cutter Compensation Sharp Angle Shallow Outside Corner However if the cosine of the change in directed angle is greater than I89 which means that the corner is flatter than the specified angle the moves will be directly blended together without an added arc Outside Comer Cutter Compensation Shallow Angle cos AO gt Isx99 Arc to Line D Ac Tool Center A Path Arc to Arc Figure 42 Outside Corner Cutter Compensation Shallow Angle The added arc prevents the compensated corner from extending too far out on the outside of a sharp corner However as an adde
370. les are provided for those interested in this technique There are other common uses of interrupts Use of the BREQ line allows for an interrupt driven line by line handshaking in the downloading of program lines that is useful for fast real time communications to rotary program buffers The IPOS line can signal the host that the system has gotten to the proper position and stabilized so that the desired action is ready to be taken The FIER line can tell the host that an axis is not following well and that remedial action needs to be taken The EQUn lines can be used to signal the host that the actual position of an axis has reached a certain point so that the appropriate action can be taken Alternately these are the best way to have a PMAC motion or PLC program interrupt the host during the program flow Setting Up Proper setup of the interrupt structure both in hardware and software is essential to a properly working interrupt scheme Some tasks need be done only once in development others must be done every time the system is powered on Finding an Open Interrupt Line The first thing that must be done is to select an interrupt line on the PC that can be used The important thing is to find one that will not be used for other purposes during the time when the PC is working with PMAC using this interrupt PMAC can interrupt on lines IRQ2 IRQ3 IRQ4 IRQ5 and IRQ7 on all PCs and also on lines IRQ10 IRQ11 IRQ12 IRQ14 and IRQ15 on PC
371. ll be a one to one correspondence between motors and axes That is a single motor is assigned to a single axis in a coordinate system Even when this is the case however the matching motor and axis are not completely synonymous The axis is scaled into engineering units and deals only with commanded positions Except for the PMATCH function calculations go only from axis commanded positions to motor commanded positions not the other way around Multiple Motor Axes More than one motor may be assigned to the same axis in a coordinate system This is common in gantry systems where motors on opposite ends of the crosspiece are always trying to do the same movement By assigning multiple motors to the same axis a single programmed axis move in a program causes identical commanded moves in multiple motors Typically this is done with two motors but up to eight motors have been used in this manner with PMAC Remember that the motors still have independent servo loops and that the actual motor positions will not necessarily be the same Coordinating parallel gantry motors in this fashion is in general superior to using a master slave technique which can be done on PMAC with the position following feature described in the Synchronizing PMAC to External Events section of this manual In the master slave technique the actual trajectory of the master as measured at the encoder with all of the disturbances and quantization errors becomes the Settin
372. ll be dynamically selected by this operation 17 14 Writing a Host Communications Program PMAC User Manual DPRAM Enable This register X 078B enables or disables the DPRAM Write a 60 to this register if not using DPRAM write an EO to this register if using DPRAM Address Bus Width This register X 078C states what size address bus being using and whether DPRAM is installed or not Select the proper value from the following table Address Bus Width Register Setup Values Bus Width No DPRAM DPRAM 16 bit 30 BO 24 bit 10 90 32 bit 00 80 Saving These Setup Values Once these settings have been made save them to non volatile memory Then reset the card command because PMAC only copies these values into the working registers on power up reset Example If the VME address 7FAO000 has been selected for the base address of the PMAC VME the address width is 24 bits and no DPRAM is installed An AM of 39 is being used with a don t care bit value of 04 and interrupt level 2 using interrupt vectors A0 and A1 which happen to be the factory defaults The only real work to do is to break up the base address into four pieces It is sometimes best to rewrite the address in binary and label the address bits starting with AO as the rightmost bit Address Bit A31 A24 A23 A16 A15 AS A7 A0 Binary 0000 0000 0111 1111 1010 0000 0000 0000 Hex 00 TF AO 00
373. loop If the stepper motor phasing search is done outside the power on reset cycle the phasing search algorithm will also fail if an amplifier fault or overtravel limit condition is detected PMAC will set the phasing search error bit and disable the servo loop If done inside the power on reset cycle PMAC cannot automatically detect these errors the search will likely fail due to lack of movement Custom Phasing Search Methods It may be necessary or desirable to write a custom phasing search algorithm Usually these are executed as PMAC PLC programs but often they can be tried and debugged using on line commands The on line commands are useful particularly if the phasing search is done only in development to establish a reference for an absolute sensor Most custom algorithms are variations on the stepper motor phasing search method They use the phase current offset values Ix29 and Ix79 with an O0 command to force current into particular phases so the motor will lock at a certain physical position in its phasing cycle The following table shows the positions in the phasing cycle created by different combinations of Ix29 and Ix79 for 3 phase motors Usually the magnitude of the non zero values are 2000 to 3000 Ix29 0 PH Ix79 gt 0 0 Pos 1x72 85 0 9 60 e Pos Ix72 171 41809e 1209e 36098 09e 609e 1209e For example the following set of on line commands typed into the terminal window of the PMAC Exe
374. losing the Servo Loop 9 3 PMAC User Manual Finally it provides a safer failure mode on loss of feedback When a servo algorithm loses feedback it puts out a large torque command which can cause runaway However when a commutation algorithm loses its feedback it will either lock in like a stepper motor for a synchronous motor or at least fail to generate significant torque for an asynchronous induction motor When both the servo and commutation algorithms use the same feedback sensor connected over the same cable both will lose feedback if one does creating a much more benign failure condition Pulse and Direction Amplifiers Most stepper motor amplifiers and some stepper replacement servo amplifiers accept pulse and direction inputs where each pulse is a position increment PMAC can generate this command format by passing its analog command voltage through a voltage to frequency V F converter such as the ACC 8D Option 2 board In these systems the true position loop is closed in the amplifier as well as any velocity loops current loops and motor commutation PMAC must close a false position loop for these motors using the electronically generated pulse train as feedback Since the output command is a frequency or rate of position change it is effectively a velocity command and the loop can be tuned like that for a velocity loop amplifier The manual for ACC 8D Opt 2 V F board has a list of optimal gain settings for
375. ly and the second data is a value representing the ending velocity The units for position or distance are the user length or angle units for the axis as set in the Axis Definition statement The units for velocity are defined as length units divided by time units where the length units are the same as those for position or distance and the time units are defined by variable Ix90 for the coordinate system feedrate time units The velocity specified for an axis is a signed quantity PMAC Calculations From the specified parameters for the move piece and the beginning position and velocity from the end of the previous piece PMAC computes the only third order position trajectory path to meet the constraints This results in linearly changing acceleration a parabolic velocity profile and a cubic position profile for the piece Problems in Stepping Since a non zero end velocity for the move can be specified directly or indirectly it is not a good idea to step through a program of transition point moves and care must be exercised in downloading these moves in real time With the use of the BLOCKSTART and BLOCKSTOP statements surrounding a series of PVT moves the last of which has a zero end velocity it is possible to use a Step command to execute only part of a program Use to Create Arbitrary Profiles The PVT mode is useful for creating arbitrary trajectory profiles It provides a building block approach to putting together parabolic
376. m screens PMAC uses a multiple step process to work with its feedback and master position information and with external time base sources to provide maximum power and flexibility For most PMACS with quadrature encoders this process can be virtually transparent with no need to worry about the details However some basic understanding is needed of this conversion process to make the changes necessary to use other types of feedback to optimize the system or to perform special functions The first step in the position and time base conversion process is the hardware encoder counters with associated timers A D registers or accessory cards for parallel input These work continually without direct software intervention although they can be configured through software Beyond this point the process is software controlled At the start of each servo cycle a servo interrupt signal is sent out to latch all of the registers At this point PMAC uses a software structure called the Encoder Conversion Table to process the information in the latched registers This table tells PMAC what registers to process and how to process them it also holds the intermediate processed data Ix03 Position Loop Feedback Address Servo Address x04 Velocity Loop Feedback Address l Variables Ix05 Master Position Address Ix93 Time Base Source Address To Servo Address Algorithms Encoder Conversion PMAC Hardware Table Registers
377. m the variables is easy Simply replace the constant specifying the variable number with an expression in parentheses use the expression syntax instead of the P constant syntax PMAC simply treats this syntax as a type of function call like SIN expression Example To move in sequence to the positions specified by P101 to P200 you could use a program segment like the following F10 P1 101 Array index variable WHILE P1 201 Start loop X P P1 As P1 changes the destination position changes DWELL100 P1 P1 1 Increment the index ENDWHILE Array Writing Writing to a set of P variables as an array must be done with indirect addressing techniques To set this up first define an M variable to point to PO e g MO gt L 1000 Next define a second M variable to point to the lowest twelve bits of the first M variable s definition word which is in Y register BC00 e g M10 gt Y BCO0OO 0 12 defines M10 to the low 12 bits of the definition word for MO To point to the definition word for M1 use Y register BCO1 for M2 Y BC02 for M100 Y BC64 64 hex is 100 decimal for M1023 Y BFFF Now by giving a value to the second M variable it changes which P variable the first M variable points to In the example the command M10 5 makes MO point to variable P5 Once the first M variable has been pointed to a particular P variable giving a value to this M variable writes that value into the addressed P vari
378. mands for the first move s that are to be started on the trigger With the time base frozen PMAC will perform all of the calculations but not start actual execution of these moves Variable I11 calculation delay should be set to 0 so PMAC will be ready to start the move as soon as the time base starts Synchronizing PMAC to External Events 15 9 PMAC User Manual Step 4 Arming the Trigger The motion program that calculates the moves cannot arm the trigger itself without having a chance that the trigger could occur before the calculations are done If this were to happen the program would be behind the desired synchronization Therefore for reliable operation the trigger should be armed by a task that cannot execute until all of the move calculations are done usually a PLC program Arming the trigger requires just one simple conditional branch in a PLC program it just looks to see if the time base is frozen and if it is the PLC program arms the trigger Since the PLC program cannot interrupt the motion program this is guaranteed to happen after the motion program has finished the calculations for the move Step 5 Starting on the Trigger Once the trigger has been armed PMAC waits for the position capture trigger to occur on the master encoder Encoder Flag I variables 2 and 3 determine which edge s of which signal s cause the trigger When PMAC sees that the trigger has occurred it starts the time base using the captured mast
379. manual Option 2 manual for details Using Multiple PMAC VME Cards On the VME bus Install multiple PMAC VME cards on the VME bus Up to 16 PMAC VME cards may be controlled by a single host computer Each card or course must have a unique base address and DPRAM starting address if installed such that none of the cards overlap each other or any other device on the VME bus in memory Also set up each card to have unique interrupt levels with unique interrupt vector numbers Each PMAC VME card occupies 512 VME bus memory locations not including the 8K of memory space taken up by DPRAM That is if the first PMAC VME is base addressed at 7FA000 the second PMAC card must be base addressed at 7FA200 If there are PMAC VME cards installed on the VME bus with the first card starting at 7FA000 the addresses of the mailbox registers MB of each card could be set according to the following table Suggested Base Addresses For Multiple PMAC VMEs Card 0 Card 1 Card 2 Card 3 Card 4 Card 5 Card 6 Card 7 Base TFA000 7FA200 7FA400 TFA600 7FA800 7FAA00 TFACOO TFAE0O MB 0 7FA001 7FA201 7FA401 7FA601 7FA801 7FAA01 7FACOI TFAEOL MB 1 TFA003 7FA203 7FA403 TFA603 TFA803 TFAA03 7FACO3 7FAE03 MB 2 7FA005 7FA205 TFA405 TFA605 TFA805 TFAAOS TFACOS TFAEOS MB 3 7FA007 7FA207 7FA407 7FA607 7FA807 TFAAO7 TFACO7 TFAEO7 MB 4 TFA009 7FA209 TFA409 TFA609 TFA809 TFAA09 TFACO9 TFAE09 MB 5 7FAO00B 7FA20B 7FA40B FA60B 7F
380. me base feedrate override control which makes the speed of PMAC execution proportional to an external frequency usually the speed of a master device Refer to the Synchronizing PMAC to External Events section of this manual for details on how this is used Time Base Conversion X Words Y words 1 Lastcycle s source data 1 Source and process Bits 0 4 Fractional Bits Bits 0 15 X Address of source data usually Bits 5 23 Integer Bits a converted position register Bits 16 23 40 for time base conversion 2 Actual time base value product of scale 2 Time base scale factor supplied by user factor and difference between last two source values For example the default conversion table creates a time base value from the data in the Encoder 4 counter It is desirable in this time base conversion to have the source data with sub count interpolation this significantly smoothes out the process by reducing the quantization error created by digital differentiation To do this the source register should be from the conversion table itself not from the encoder counter In the default conversion table the converted data from Encoder 4 is found in X 0723 1827 decimal Therefore the first setup Y word for the time base conversion entry is 400723 the 40 specifies time base conversion and the 0723 specifies the source address Scale Factor The second setup Y word is the scaling factor
381. mentation of these codes would be N17000 NORMAL K 1 RET N18000 NORMAL J 1 RET N19000 NORMAL I 1 RET It is important that the RET command be on a separate line here otherwise when PMAC returns to the line that called the subroutine the NORMAL command would try to pick up more arguments from that line To use this information for other routines such as G68 rotation set some variable s in these routines to note what plane has been specified The PMAC circular interpolation and radius compensation routines do not need such a variable G40 G41 G42 Cutter Radius Compensation Cutter radius compensation can be turned on and off easily with the CCO CC1 and CC2 PMAC commands corresponding to G40 G41 and G42 respectively The subroutines to implement this would be NA40000 CCO RET Turn off cutter compensation N41000 CCl RET Turn on cutter compensation left N42000 CC2 RET Turn on cutter compensation right G90 Absolute Move Mode Typically this code is implemented in PMAC through use of the ABS command The ABS command without a list of axes puts all axes in the coordinate system in absolute move mode The typical implementation would be G90000 ABS RET Also if the G Code dialect has G90 making the circle move center vectors absolute an ABS R command should be added to this routine Writing Programs for PMAC 14 45 PMAC User Manual G91 Incremental Move Mode Typically this code is implement
382. mits PMAC has a programmable velocity limit for each motor Ix16 that is in effect for linear blended program moves Circular PVT rapid and splined moves do not observe this limit If the commanded velocity requested of a motor exceeds the limit for the motor the move is slowed so that the velocity limit is not exceeded In a multi axis programmed move all axes in the coordinate system are slowed proportionally so that no change in path occurs Velocities are compared to these limits assuming no feedrate override value of 100 if feedrate override a k a time base control is used the velocity limits scale with the override When PMAC is automatically segmenting moves 113 0 the Ix16 velocity limits are not observed Acceleration Limits PMAC has two programmable acceleration limits for each motor one for jogging and homing moves Ix19 and one for linear blended program moves Ix17 Circular rapid PVT and splined moves do not observe this limit If the commanded acceleration requested of a motor exceeds the limit for the motor the acceleration is stretched out so that the acceleration limit is not exceeded In a multi axis blended programmed move all axes in the coordinate system are slowed proportionally so that no change in path occurs Accelerations are compared to these limits assuming no feedrate override value of 100 if feedrate override a k a time base control is used the acceleration limits scale with the o
383. mmutation of each motor takes approximately 3 of the PMAC computational power Servo Update The servo update computing the new commanded position reading the new actual position and computing a command output based on the difference between the two is the third highest priority on PMAC For each activated motor on PMAC this task takes 30 usec per update cycle 20 usec for the 30 MHz card plus about 30 usec for general servo tasks such as the encoder conversion table The frequency of this task is determined by the master clock frequency and jumpers E98 E29 E33 E3 E6 The default update frequency is 2 26 kHz 442 usec cycle At the default the servo update of each motor takes approximately 7 of the PMAC computational power See Closing the Servo Loop section in this manual for details on optimizing this update rate e Real Time Interrupt Tasks The real time interrupt RTI tasks are the fifth highest priority on PMAC They occur immediate after the servo update tasks at a rate controlled by parameter I8 every 18 1 servo update cycles There are two significant tasks occurring at this priority level PLC 0 and motion program move planning e PLC Program 0 PLC 0 is a special PLC program that operates at a higher priority than the other PLC programs It is meant to be used for only a few tasks usually a single task that must be done at a higher frequency than the other PLC tasks The PLC 0 will execute every real time interrupt as
384. mory The following table shows the number of words of stack space required for each type of assignment 13 20 Computational Features PMAC User Manual Function Expression 1 to 20 bit M or 24 bit M 32 or 48 bit M Value Variable Variable Variable All 1 s 2 2 3 All 0 s 2 2 3 Others 3 2 3 amp All I s 0 no op 0 no op illegal amp All 0 s 2 2 illegal amp Others 2 2 illegal All 1 s 2 2 illegal All 0 s 0 no op 0 no op illegal l Others 2 2 illegal All 1 s 2 2 illegal All 0 s 0 no op 0 no op illegal N Others 2 2 illegal Comparators A comparator evaluates the relationship between two values constants or expressions It is used to determine the truth of a condition in a motion or PLC program The valid comparators for PMAC are equal to not equal to gt greater than gt not greater than less than or equal to lt less than notless than greater than or equal to approximately equal to within one notapproximately equal to at least one apart Notice that lt and gt are not valid PMAC comparators The comparators and respectively should be used in their place Conditions A condition can be used to control program flow in motion or PLC programs It is evaluated as either true or false It can be used in an IF branching statement or WHILE looping
385. move for the motor automatically This value is kept in the Motor Encoder Position Offset Register Y 0815 Motor 1 Y 08D5 Motor 2 etc which is set to zero on power up reset for motors without absolute power on position If Ix10 gt 0 to specify an absolute power on position read from a resolver so no homing is necessary this register holds the negative of the power on resolver position In either case it contains the difference between the encoder counter zero position power on position and the motor zero home position scaled in counts Note Prior to V1 14 firmware this value could be obtained by using the PLC program HOMOFFST PMC Starting in V1 14 PMAC stores this value automatically Uses There are two main uses for this register First it provides a reference for using the encoder position capture and position compare registers These registers are referenced to the encoder zero position which is the power up position not the home motor zero position This register holds the difference between the two positions This value should be subtracted from encoder position usually from position capture to get motor position or added to motor position to get encoder position usually for position compare Example To move an axis until a trigger is found then convert the captured encoder position to a motor position use the following M variable definitions M103 X C003 24 S Encoder 1 position capture registe
386. move to tell whether the trigger was found successfully or not The motor desired velocity zero status bit can be used to determine the end of the move Basic Motor Moves 11 3 PMAC User Manual IxX20 ACCELERATION TIME JOG HOME Units msec integer Ix21 S CURVE TIME JOG HOME Units msec integer Ix20 gt 2 Ix21 1x20 V Ix20 lt 2 Ix21 ke x21 Ix21 poo Iix21 oie H T 2 Ix21 gt 2 Ix21 V Ix21z0 a aj Figure 21 Motor x Motion Variables 11 4 Basic Motor Moves PMAC User Manual Homing Search Move Control Homing Acceleration The acceleration for homing search moves is controlled by the same parameters Ix19 Ix20 and Ix21 as for jogging moves These are described in the previous section Homing Speed Homing speed and direction are specified by Ix23 If Ix23 is greater than zero the homing search move will be positive If it is less than zero the move will be negative The magnitude of Ix23 controls the speed of the move in counts msec Home Trigger Condition The PMAC homing search moves utilize the hardware position capture feature built in to the DSPGATE IC Because no software action is required to do the actual capture it is incredibly fast and accurate delay less than 100 nsec This means that the capture is fully accurate regardless of motor speed so there is n
387. mple PMAC will have six characters waiting to be read 19 2 CR ACK Assume that I variable I3 is set to 2 The data will be in the registers as follows Address 7FAO001 7FA003 7FA005 7FA007 7FA009 Mailbox 0 1 2 3 4 Character 1 9 2 CR Start reading the characters at 7FA001 mailbox register 0 There is a CR in mailbox register 4 so stop reading and write a 00 into mailbox register 1 to tell PMAC it is fine to send more Since PMAC must still send the final lt ACK gt it interrupts again and it is in the mail box registers Address 7FAO001 7FA003 7FA005 7FA007 7FA009 Mailbox 0 1 2 3 4 Character lt ACK gt 9 2 lt CR gt Now start and stop at mailbox register 0 because it contains an lt ACK gt Now simply read in these characters beginning with mailbox register 0 at 7FA001 Never write into mailbox register 1 when sending data to PMAC VME This is because PMAC will be allowed to write new data into the mailbox registers as soon as we write to mailbox 1 Incidentally it actually does not matter what value is written into mailbox register 1 it s the fact that this register is written to that counts However it is recommended to write a value of 00 into mailbox register 1 for reasons given later After writing a 00 into mailbox register 1 PMAC may or may not interrupt again depending on whether or not PMAC
388. n OPEN PLCC n command This is the signal to the compiler that what follows until the CLOSE command is to be compiled Any ENABLE PLC andDISABLE PLC commands that refer to PLC programs to be compiled must be changed to ENABLE PLCC and DISABLE PLCC commands whether or not these commands themselves are in PLC programs to be compiled Executing Integer Arithmetic The compiled PLCSs have the capability to perform arithmetic and logical operations in 24 bit signed integer form By contrast all arithmetic and logical operations in uncompiled PLC programs are performed in 48 bit floating point form even if acting on integer variables The short integer math operations execute at least 10 times faster than the floating point operations Combined with the two to three times improvement from compilation this provides execution 20 to 30 times faster than uncompiled floating point operations A compiled PLC program can have some statements that are executed using integer arithmetic and other statements that are executed using floating point arithmetic However a given statement within the compiled PLC is executed either entirely with integer arithmetic or entirely with floating point arithmetic even if it is working with integer registers Using L Variables The use of L variables in a PLC program statement is the sign to the compiler that the statement is to be executed using integer operations instead of floating point operations L variables can be us
389. n Program Timing Whether or not cards share a common clock signal the synchronization of moves between multiple cards is only as good as the time specification in the motion programs in each card If one card is told to do a 3 second long move and another to do a 4 second long move and they are started at the same time they will obviously not finish together Therefore it is imperative that motion programs on several cards that are intended to run together must be written very carefully so that they take the same amount of time for moves 15 12 Synchronizing PMAC to External Events PMAC User Manual Initial Calculation Delay After receipt of a Run or Step command a PMAC requires some initial calculation time before it can start the first move typically a few milliseconds If several PMACS are told to start a program simultaneously the cards will in general not take the same amount of time to calculate their first move If each card started its first move immediately on finishing the calculations there would be a loss of synchronicity between cards PMAC parameter I11 Motion Program Calculation Delay exists to prevent this problem It determines the number of milliseconds between the receipt of the Run or Step command and the start of the first move I11 should be set to the same value on all cards for which synchronicity is desired the default value of 10 210 msec delay can be used in virtually all applications If 111 is set to
390. n a positive and negative magnitude is different from changing the direction of compensation See the Changes in Compensation section in this manual Also the behavior in changing between a non zero magnitude and a zero magnitude is different from turning the compensation on and off See the appropriate sections Turning On Compensation The compensation is turned on by buffered motion program command CC1 offset left or CC2 offset right These are equivalent to the RS 274 G Codes G41 and G42 respectively If implementing G Code subroutines in PMAC motion program 1000 simply incorporate in PROG 1000 N41000 CC1 RETURN N42000 CC2 RETURN Turning Off Compensation The compensation is turned off by buffered motion program command CCO which is equivalent to the RS 274 G Code G40 If implementing G Code subroutines in PMAC motion program 1000 simply incorporate in PROG 1000 N40000 CCO RETURN How PMAC Introduces Compensation PMAC gradually introduces compensation over the next LINEAR or CIRCLE mode move following the CC1 or CC2 command that turns on compensation This lead in move ends at a point one cutter radius away from the intersection of the lead in move and the first fully compensated move with the line from the programmed point to this compensated endpoint being perpendicular to the path of the first fully compensated move at the intersection Note that few controllers can make their lead in move a CIRCLE mode move This capabil
391. n all reals Domain units free Range all non negative reals Range units free Possible errors none INT Note This function returns the greatest integer less than or equal to the argument INT 2 5 22 INT 2 5 3 Function truncation function Syntax INT expression Domain all reals Domain units free Range integers Range units free Possible errors none Expressions A PMAC expression is a mathematical construct consisting of constants variables and functions connected by operators Expressions can be used to assign a value to a variable to determine a motion program parameter or as part of a condition A constant can be an expression so if the syntax calls for expression a constant may be used as well as a more complicated expression no extra parentheses are required for non constant expressions unlike when data is specified Examples of expressions are 512 P1 P1 018 1000 COS Q25 3 14159 180 I100 ABS M347 ATAN P 03 1 6 28 5 Computational Features 13 17 PMAC User Manual Data For PMAC purposes if command syntax requires data either a constant that is not surrounded by parentheses or an expression that is surrounded by parentheses can be utilized Since a constant can be an expression it is legal to put a constant in parentheses but this takes more storage and more calculation time For example if the listed command syntax is T data it is legal to use T100 T
392. n for Sourcing OUlpulS E 10 OD TINTO EDT M N 10 Thumbwheel Multiplexer Port I O JTHW Port eeeeeeeeeeeeeeeeeeeee nennen nennen nennen enne nro nc en tenr enne intent tnter tentent enne 10 Multiplexed Use in didas 10 Non M ltiplexed Use id bio een duoi Pot e ERE NER ERU 10 Control Panel Port VO JPAN Port cionado bid a SUELE RASEN E Rod da Pa To ib decada 10 DES CYCLE ign pe EET 11 Alternate U Se ET HE 11 Reset A O A AN 11 Handwheel Inputs EIER 11 Analog A a i 11 Table of Contents 6 1 PMAC User Manual Display Port Outputs JDISP Port 6 2 Table of Contents PMAC User Manual Table of Contents PMAC User Manual INPUT OUTPUT CONNECTING PMAC TO THE MACHINE Capabilities and Features PMAC has extensive input and output capabilities analog and digital special purpose and general purpose The I O has many features to ensure the integrity of the signals as the different types of I O are introduced the steps taken to improve the integrity of each type of I O is explained Quadrature Encoder Inputs JMACH Port PMAC is equipped to take digital quadrature encoder signals at O to 5V levels as a standard feature For each DSPGATE IC in a PMAC configuration four encoders can be attached Single Ended vs Differential PMAC has differential line receivers for each encoder channel but can accept either single ended one signal line
393. n from a register that is set by commands from the host computer A 100 command puts a value equal to I10 in this register a 50 command puts a value equal to 110 2 in this register Regardless of the source of the time base information a query command causes PMAC to report back the value of the present time base expressed as a percentage of I10 Time base information can come from other sources The most common alternative to command sourced time base is external frequency sourced time base where the time base value is proportional to the frequency of a master encoder This provides a powerful position synchronized slaving mechanism that is commonly called electronic cam 12 6 Setting Up a Coordinate System PMAC User Manual 13 Computational Features Table of Contents COMPUTATIONAL FEATURES eere eee eene seen enean thats enses tuse ta sone ta sonata sts en senses ease sa sds tn sense satus tasas toan 1 Advanced Computational Eeatures 1 ate ee ee m Ero e Ere RUE RR E b Pe Ebo Ra E cie Eo bep eb ERR E he EE ER eo EAEE 1 Computational AAA pe eee PORE ee Ee Eaa r in eee SEHR Eze Pe ER airetan enire iiine ER en lea 1 NS coecpnebe doco sos leven vabeblebugec dois salted acts leaepanhesd Eea EEE EEE ETE siR a an e TEn 3 Internal Qoi gu Tor REPRE 3 RECEIVING VALUES E Es 3 VETAT l A urea E bie EM c bI Moe s 5 Reporting E o aae 5 VAS OIEA E E
394. n illegal domain may just return maximum real value instead Function Syntax Domain Domain units Range Range units Possible errors inverse sine arc sine function with its range reduced to 90 degrees ASIN expression 1 0 1 0 none Pi 2 Pi 2 radians 90 90 degrees radians degrees Illegal Domain Function inverse cosine arc cosine function with its range reduced to 0 180 degrees Syntax ACOS expression Domain 1 0 1 0 Domain units none Range 0 Pi radians 0 180 degrees Range units radians degrees Possible errors Illegal Domain Function standard inverse tangent arc tangent function Syntax ATAN fexpression Domain all reals Domain units none Range Pi 2 Pi 2 radians 90 90 degrees Range units radians degrees Possible errors none Computational Features PMAC User Manual ATAN2 This function returns the angle whose sine is the expression in parentheses and whose cosine is the value of QO for that coordinate system Actually it is only the ratio of the magnitudes of the two values and their signs that matter in this function It is distinguished from the standard ATAN function by the use of two arguments The advantage of this function is it has a full 360 degree range rather than the 180 degree range of the single argument AT
395. n iuc m 1 IJ Een x lp reia ide ei 1 A RN 1 Modal Cs is 1 Move Commands e IR 1 Motion Progr m Trajectories citan io Re As edie ea aa 2 Linear Blended Moves iii ali a detainee oie at 2 Acceleration Parametros 2 Acceleration DUAE 2 Feedrate or Move Time Specification sess eee nennen nennen trennt keie nena eika e iaee 6 SOME MOVES om 6 PONE MOVES mp RR ND 6 Feedrat e os NC OC DIE 11 Velocity Limit rm 11 The Blending Function AA 11 Rapid Mode DT PREX P 12 Motion Program Move Until Trigger eese teen nennen eren ret rennen nette sinees iskisi nest 12 Circular Blended Moves isis titi iia EEEO tup ewe sees 13 Specifying the Interpolation Pl fie isi A dee ee Ree eden dedo 14 Circle Modes E 14 Center Vecina E N E E E AREA A 14 EXA E OE E A E E EA E OEE T 15 Radius Size SDecifiGatlOn ut As 15 Example eeen e E A A 15 N Center Specification sisser aiai n aene O 16 Feedrate AXes RR 16 Circle Radius AA 16 Move Segmentati ti DM O ESEE E A ENa eE 16 LA MISCUIT E e O E EER 17 Mode Statement RR 17 MOVE Statements sssusa decencia 17 PMAC Calla a S E A Sie aasta 17 Problems in Stepping esee eese eese seen enne airosa rise eonenna r SERE E E EEEa E Ee terne trennen 17 Use to Create Arbitrary Profiles ii o o dc datan ficha 17 EA NA 18 SJ
396. n nennen 6 Global Commands tiia stetit AN 6 Buffered Program Commands tr dete e eren ee Eee o abeat ederet eee Aid 6 Rotary Motion Program Buffer eese esee eene ettet etre nenne nn nene nen ne nn Reno Reno enn naar anne non eren enne entrent nnne Z Multiple Card Applications ir nne re tbe a ai E a e a a e Eds 7 Urgent 7 SUMULLANCOUS C OMIMNANAS ERN 7 Serial Communications see deseen EVER EE E een Ouen ue aaa 7 Serial Card Addyessing aci iod de A Fee Eg Debet HR Ete Eo Pudet E ena tutis 8 Setting Up tlie Addresses da 8 Multi Card Mode Variable ed ce EEE a E E E staan EEE Cote bet see OY CERE EEEE R E ER 9 Addressed Card ACHONS D M 9 Simultaneous Addressing curieri aeger etre e Seg eee AA aee ee piget tuta ox 9 Handling Data RESPONSE M Hm 9 POWer UD State m L 10 Control Character Commands eese eeeeeeeee eene eene enne nnne en nnet RR REO nest tenet net nn Ren n nn tents entrent nnns en tenter nen 10 De uDpAd io 11 PMAC Reset UD Ie 11 PMAC Re initialization Actions Standard CPU sees netten trennen 11 PMAC Re initialization Actions Flash CPU eee esee eene enne nene enne nene tnnt cane n ron nc intentis enne 12 Re initialize Command sessen e e ee er Ai diciendo andino eed eene ue eee 13 Table of Contents 4 i PMAC User Manual 4 ii Table of Contents
397. n of the parallel data word fed into Port A of the first ACC 14 connected to PMAC Bit Enable Mask Word Parallel feedback conversion requires a double for non filtered or triple for filtered entry in the conversion table The second entry filtered or non filtered specifies the size of the feedback word used The entry is a 24 bit word in which each bit actually used for the parallel feedback is a one the unused bits above are zeros parallel feedback is typically connected starting at bit O of the data word For a 12 bit absolute encoder this entry would be 000FFF for 14 bits it would be 003FFF For the standard shifted conversion the maximum effective mask word is 0 7FFFF unmasking the low 19 bits any data in the high five bits is shifted out of the word For the unshifted conversion up to 24 bits of real data can be used with a mask word of SFFFFFF The mask word allows PMAC to detect rollover in the source data so it can extend the count properly in software Filter Word If the conversion format is 3x or 7x the parallel data word is filtered The filter simply sets a maximum amount the data word is permitted to change in a single servo cycle If PMAC sees a change larger than this in the source data word the converted data only changes by the maximum amount There is no permanent loss of position information if the filter kicks in Setting Up a Motor 7 19 PMAC User Manual Purpose of Filtering This filte
398. nate system running the program is selected If a different coordinate system runs the same motion program it will use different Q variables When accessing a Q variable from a PLC program statement the Q variable for the coordinate system that has been addressed by that PLC program with the ADDRESS command is the one working Each PLC program can address a particular coordinate system independent of other PLC programs and independent of the host addressing If no ADDRESS command is used in the PLC program the program uses the Q variables for C S 1 Array Capabilities Array Reading It is possible to use a set of Q variables as an array To do this when reading from the variables simply replace the constant specifying the variable number with an expression in parentheses use the expression syntax instead of the Q constant syntax PMAC simply treats this syntax as a type of function call like SIN expression 13 10 Computational Features PMAC User Manual Example To move in sequence to the positions specified by Q51 to Q100 use a program segment like the following F10 P1 51 Array index variable WHILE P1 101 Start loop X Q P1 As P1 changes the destination position changes DWELL100 P1 P1 1 Increment the index ENDWHILE Array Writing Writing to a set of Q variables as an array must be done with indirect addressing techniques To set this up first define an M variable to point to QO of C
399. ncy of these background tasks is controlled by the computational load on PMAC the more high priority tasks are executed the slower the background tasks will cycle through and the more background tasks there are the slower they will cycle through e PLC Programs 1 31 PLC programs 1 31 are executed in background Each PLC program executes one scan to the end or to an ENDWHILE statement uninterrupted by any other background task although it can be interrupted by higher priority tasks In between each PLC program PMAC will do its general housekeeping and respond to a host command if any Compiled PLC Programs 1 31 Compiled PLC programs PLCC programs 1 31 are executed in background All enabled PLCC programs execute one scan to the end or to an ENDWHILE statement starting from lowest numbered to highest uninterrupted by any other background task although it can be interrupted by higher priority tasks At power on reset PLCC programs run after the first PLC program runs Host Command Response The receipt of a control character from any port is a signal to PMAC that it must respond to a command The most common control character is the carriage return CR which tells PMAC to treat all the preceding alphanumeric characters as a command line Other control characters have their own meanings independent of any alphanumeric characters received Here PMAC will take the appropriate action to the command or if it is an illegal command
400. nd out through an interrupt or by polling the card or by an operator notified with one of the external signals These limits may be disabled by setting the parameter to zero but this is strongly discouraged in any application that has the potential to kill or injure people or even to cause property damage Disabling the fatal limit removes an important protection against serious fault conditions that can cause runaway situations bringing the system to full power output faster than anybody could react Integrated Following Error Protection In addition to the normal following error protection provided by the Ix11 variable for each motor PMAC can shut down the motor if the time integrated value of the following error exceeds a preset value This integrated error feature can protect against those cases where the magnitude of the measured following error never gets very large for example a loss of feedback followed by a very short commanded move PMAC only performs the integrated following error check if the Ix63 integration limit parameter is less than zero When this is the case the magnitude of Ix11 is used for the normal unintegrated following error check but in addition the value of the PID integrator is compared against the Ix63 integration limit magnitude If the integrator value has saturated at Ix63 the limiting function in the PID loop will not let it exceed this value then PMAC will trip kill this motor on an integrated followi
401. ne DEFINE GATHER constant command If no value is specified the whole of the PMAC open memory is reserved for this buffer This means that no new motion or PLC programs can be added to PMAC as long as this space is reserved The actual data gathering function is started with the GATHER command When this has been done PMAC will store the specified data at the specified rate into the gather buffer until told to stop with the ENDG or until space runs out The stored data can be uploaded to the host with the LIST GATHER command The data is sent to the host in ASCII hexadecimal form with six characters per item for the single X or Y words and 12 characters per item for the double L or D words The data is provided in twelve character groupings If the data gathered for a sample leaves the last grouping with only six characters this last grouping is filled out with the contents of the servo cycle counter register It is the host program s responsibility to decode and process this data for plotting storage analysis or other use The space reserved for the data gathering buffer can be freed with the DELETE GATHER command On line Data Gathering The lt CONTROL E gt command is a sort of single shot data gathering On receipt of this command PMAC reports the contents of the registers specified by 120 144 to the host Here the contents are sent in binary not ASCII form and without any handshaking characters There are three bytes pe
402. ne non nene enne 14 33 PMAC Motion Program Recalculation eese een eem ee eene trennen 14 55 PMAC Motion Program Recalculation sessi enne ener ennt cnn cnn nn teen neennes 15 2 Position Following Parameters ocoomoornonoconconnocnnno nene nonn cnn onda sitera te rennen tete nite e teet teen enne 15 4 PMAC PC VME Customer Gate Array DSPGATE Encoder Functions 15 15 Table of Figures i PMAC User Manual Figure 54 PMAC PC PMAC Lite Interrupt Structure essere en rennen ene 17 7 Figure 55 PMAC STD Interrupt Structure eese teen nne nein en rennen tenerent tenerent 17 8 Figure 56 PMAC VME Communications Flow DiagraMW conccnonnnnocnncnonnnnnnncnnnnnononononnnononn conocia nc non enne nrenneneene 17 24 Figure 57 Dual Ported RAM Data Gathering Formats sees 17 30 ii Table of Figures PMAC User Manual 1 Introduction Table of Contents INTRODUCTION Pero O 1 1 PNEACUOOVOEVIOW sees ien dae tec tcececonses suceentun E ceaneesd iceausteteencie te EUER cU ae ess UIN EAE OE EE ERE PAS ENSE 1 1 PUCK EI Rm 1 1 Configuration For Task RR 1 1 PMAC IS a COMPUIO E lt td dd qa e dao oa side ias 1 1 Manual Layont Um 1 2 Conventions Used in This Manual eee eese eene nennen ettnen nnn nn nr nn nc nn test nennen test nnne ens senes enne 1 2 Say UM E 1 2 Keep Away from Live Circuits esee eene entente enne RR RR nn RR tene nn R
403. ng Make sure the motor can run free preferably no plant attached at this point and that things can be stopped quickly so that no damage can be caused Type K lt CR gt to disable the output s then restore the proportional gain by setting 1130 try 2000 initially for very fine resolution systems 50 000 for very coarse systems or somewhere in between for medium resolution Closing the Loop Now close the motor s servo loop by typing J CR the jog stop command which brings the motor into zero velocity position control It should hold position at this point resisting attempts to move it away at least gently If it runs away there is a mismatched polarity re run the above polarity tests If there is loss of control or the motor starts behaving wildly type K CR to disable the motor Weak Loop If it does not resist being turned or does so very weakly try increasing proportional gain 1130 Try doubling it until there is some reasonable stiffness but do not try yet to get the maximum possible stiffness The tests described below will help do that Oscillations If the motor has a tendency to oscillate at low to moderate frequency there is inadequate derivative gain Try doubling 1131 and see if the oscillation goes away Buzzing If the motor has a tendency to oscillate at high frequency a buzz there is too much proportional gain or maybe too much derivative gain Try lowering 1130 or I131 until the buzz disappears Exten
404. ng Ahead iste AA PERO aN NS Reate diia 53 Starting Calculations E TO 54 Calculation of Subsequent Moves eese eene nennen RR RR RR eer et rene eene tenen neee trennen eren ens 54 Implications of Calculating Ahead eee esee eene teen ne enne nren enne eene trennen inneren 57 14 ii Table of Contents PMAC User Manual WRITING PROGRAMS FOR PMAC Writing A Motion Program PMAC can hold up to 256 motion programs at one time Any coordinate system can run any of these programs at any time even if another coordinate system is already executing the same program PMAC can run as many motion programs simultaneously as there are coordinate systems defined on the card up to eight A motion program can call any other motion program as a subprogram with or without arguments The PMAC motion program language is perhaps best described as a cross between a high level computer language like BASIC or Pascal and G Code RS 274 machine tool language In fact it can accept straight G Code programs directly provided it has been set up properly It has the calculational and logical constructs of a computer language and move specification constructs very much like machine tool languages Numerical values in the program can be specified as constants or expressions Flow Control In a motion program PMAC has WHILE loops and IF ELSE branches that control program flow These constructs can be nested indefinitely In
405. ng error fault just as it would for a normal following error fault 10 2 Making Your Application Safe PMAC User Manual For the integrated following error limit to be effective the Ix33 integral gain must be greater than zero and preferably set as high as can be tolerated Also the Ix34 integration mode parameter must be set to 0 so that the integrator is on during programmed moves Remember that the integrator stops increasing in magnitude if the command output has saturated at Ix69 The magnitude of Ix63 must be small enough that it will trip before the output saturates The magnitude of Ix63 that would cause output saturation at Ix69 from the integrator alone is 1x08 Ix30 The magnitude of Ix63 must be less than this value for the shutdown function to be effective Remember that there will be other components to the output for instance from the proportional gain With a bare motor test to see that this limit can trip the motor reliably When a motor is killed due to integrated following error fault the standard following error fault motor status bitis set In addition a separate integrated following error fault motor status bit is set Both bits are cleared when the motor is re enabled Note The integrated following error protection feature is not available on PMACS with the Option 6 Extended Servo Algorithm firmware That algorithm has no integrator register in the servo to compare against a limit Velocity Li
406. ng up the Host Request Function To set up PMAC first write a value to the DSP s interrupt control register which is at the PMAC base address in the PC s port space this address is set by jumpers E66 E71 and E91 E92 This value will determine what if any character by character handshake interrupts will be used Refer to the HREQ description above for the proper value The TurboC command would be outportb base value The equivalent Microsoft C command is outp base value This command or its equivalent in other languages can also be used to perform the steps below 17 10 Writing a Host Communications Program PMAC User Manual Initializing the PMAC PIC Next write to the PMAC PIC s Initialization Command Words IC Ws to set up the PIC properly Although this IC is on PMAC it is mapped into the PC s port space as two registers at the PMAC base address plus 8 and 9 To do this perform the following steps e Write a byte of 17 hex to PMAC base address 8 This sets up ICW1 for edge triggered interrupts Write a byte of 08 hex to PMAC base address 9 This sets up ICW2 Write a byte of 03 hex to PMAC base address 9 This sets up ICW4 for 8086 mode operation e Write a byte of FF hex to PMAC base address 9 This writes to Operation Control Word 1 to mask all eight interrupts into the PMAC PIC Unmasking Interrupts When ready to accept interrupts from PMAC unmask the interrupt s into the PMAC P
407. nment and query commands are also coordinate system commands because the Q variables themselves belong to a coordinate system Note A command to a coordinate system can affect several motors if more than one motor is assigned to that coordinate system For instance if motor 4 is assigned to coordinate system 1 a command to coordinate system 1 to run a motion program can start motor 4 moving Global Commands Some on line commands do not depend on which motor or coordinate system is addressed For instance the command P 1 1 sets the value of P1 to 1 regardless of what is addressed Among these global on line commands are the buffer management commands PMAC has multiple buffers one of which can be open atatime When a buffer is open commands can be entered into the buffer for later execution Control character commands those with ASCII values 0 31D are always global commands Those that do not require a data response act on all cards on a serial daisy chain These characters include carriage return CR backspace BS and several special purpose characters This allows for instance commandis to be given to several locations on the card in a single line and have them take effect simultaneously at the CR at the end of the line amp 2R amp 2R CR causes both Coordinate Systems 1 and 2 to run Buffered Program Commands As their name implies buffered commands are not acted on immediately but held for later execu
408. nn RR nn ne tree tree trente Donne nan non nette tenete 1 2 Live Circuit Contact Procedures eee esses eee eene enne non nr nn nn enter ente senes r erre sn nine e eres enne seien serene nnn 1 2 Electrostatic Sensitive Devices eese seen en nennen teer se nnns innen sr en tens sete nn esee nnns ee nensi nn nns 1 3 WT Medid iiini eee o tevanegsatelvasades E E dncceenstbudgedacns T EEE e E A E tie 1 3 Related Technical Documentation seesesseseeseeeeeeeeeee eene nennen enr entente entere enne aanre ar En raS en nennen enne 1 3 Technical SUPPOrt 5 esses 1 3 MITT T 1 3 By Fax and E Mail eee eese sees E nn nn Ron inse tease annie tese sais s EOE AAE Senar nn anar rca ARENAN ASEE 1 3 Bulletin Board Service BBS esses eese ener enn en there en nennen enne nr er nnne nens ee rese near er rn sene nsns enn 1 3 Table of Contents l i PMAC User Manual Table of Contents PMAC User Manual INTRODUCTION PMAC Overview The Delta Tau Data Systems Inc Programmable Multi Axis Controller PMAC is a family of high performance servo motion controllers capable of commanding up to eight axes of motion simultaneously with a high level of sophistication Through the power of a Digital Signal Processor DSP PMAC offers a price performance ratio for multi axis control that was not previousl
409. nnen 10 Initializing the PMAG PIC ie teet etm e ee UH de I ote vb Gite o iria 11 Unmasking Interrupts sts insti 11 Using the Interrupts conca iii iii 11 Restonnge Preyious VECOS sirain iaa ie 12 VMEbus Communications erect ioi rette PR eet br ene d ved idea deere ie 12 Setting Up The Base Address For PMAC VME esee eene nennen ener nne eene tnen trennen innere nennen 12 Address Modifier AA at t ie te etis sag hed puce rp el tee egre oaae eip sighs esa Sage 13 Address Modifier Don t Carbo 13 PMAC Base Address Bilsi ee etna Soul ette eet see rige qe ey da 14 Interrupt PAUJN LC 14 Interrupt Vector Number deduced use teen tte aia 14 Dual Ported RAM Base Address eei erede ib 14 DPRAM D TII 15 Address Bus A 15 SAVING These Setup VALUES it A a steve cuesistepenend carta E E 15 Jeune doo E E ooo 15 Setting Up VME Dual Ported RAM Option LV coocccoononnocnnncononnnoncnononnonnonnnnnonnonnonnrnnnn nenne trennen ener an rennen enne 16 SUTURA 16 EXAMEN on Aa E E N 16 Talking to PMAC VME Through The Mailbox Registers eese esee eene aran nn re enne rn cnica arios 17 Sending Commands to PMAC VME Through Mailbox Registers eese eene 18 EXAMPLE E 18 Pv de 19 Reading Data from PMAC VME Through Mailbox Registers eese eee enne 20 EXAMEN MU MED E D MMC Ic PEE URL 20 TEN ON DLC ar ie abone A
410. nown as feedrate override value is what controls the rate of position update when it equals 100 0 programs and moves operate in real time i e at the times and speeds specified in the program SCALE FACTOR is the integer value that must be determined to set up time base following properly INPUT FREQ is the count rate as determined by the signal and Encoder I variable 0 in counts millisecond 2 is 131 072 To set the scale factor decide on a real timeinput count frequency which is the rate of input counts at which the program and moves should execute at the specified rate Since this is the rate at which the value will be 100 0 solve it simply for the scale factor 131 072 REAL TIME _ INPUT FREQ SCALE _ FACTOR Since the scale factor must be an integer and 131 072 is a power of two make the real time input frequency a power of two in units of counts msec For instance if using a system where the typical full speed input count frequency is 60 000 counts second define the real time input frequency to be 64 counts msec This would then make the scale factor 131 072 64 2 048 15 6 Synchronizing PMAC to External Events PMAC User Manual So far all there is only a value in a register proportional to the master frequency Now make use of this value to control the motion program Step 4 Using the time base calculation Time base values work on a coordinate system Each coordinate system has an I variable that
411. ns over the VME bus using the mailbox registers When PMAC is asked to list out a motion program or PLC with a command like LIST PROG 10 or LIST PLC O0 PMAC will have multiple lines of data to be read Simply wait for the interrupt to occur read the mailbox registers write 00 to mailbox register 1 and wait to be interrupted again repeating this procedure until all data from PMAC has been sent and read Dual Ported RAM Communications The PMAC Option 2 provides an 8K x 16 bit dual ported RAM that allows PMAC and its host to share an area of fast memory For the PMAC PC and the PMAC Lite Option 2 is a separate board that sits on the PC bus and cables to PMAC For the PMAC VME Option 2 V consists of ICs added to the main board itself Option 2 is not available for the PMAC STD The dual ported RAM can be used for extremely fast communication of data and commands to and from PMAC Uses of DPRAM The typical use in writing to PMAC is for a very fast repetitive downloading of position data and or rotary program information in real time The typical use in reading from PMAC is getting very fast status information repetitively Data such as motor status position velocity following error etc can be continuously updated and written to DPRAM by PLC programs or automatically by PMAC Without using DPRAM this data must be accessed by sending PMAC on line commands such as P V and F through the VME mailbox registers or over the PCbus T
412. nsated move and the lead out move form an inside corner the lead out move starts directly from this point to the programmed endpoint When the lead out move is a LINEAR mode move the compensated tool path will be at a diagonal to the programmed move path When the lead in move is a CIRCLE mode move the compensated tool path will be a spiral Removing Compensation Inside Corner Line Programmed cco Path Programmed Path Tool Center EEA Path ____ Line Line Arc d EN Tool Center Line Path 2s i Line to Line Line to Arc Line Programmed Path CCo cco Programmed Path Tool Center Arc Tool Center Path Spiral Spiral s Arc to Line Arc to Arc Figure 47 Removing Compensation Inside Corner Outside Corner If the last fully compensated move and the lead out move form an outside corner the last fully compensated move ends at a point one cutter radius away from the intersection of the last fully compensated move and the lead out move with the line from the programmed point to this compensated point being perpendicular to the path of the fully compensated move at the intersection PMAC then adds a circular arc move with radius equal to the cutter radius ending at a point one cutter radius away from the same with the line from the programmed point to this compensated endpoint being perpendicular to the path of the lead out move at the intersection Finally PMAC g
413. nsigned quantity Ix10 would be set to 030002 treating the value as a signed quantity Ix10 would be set to 830002 To use an R D at location 0 of multiplexer address 0 treating the value as an unsigned quantity Ix10 would be set to 000100 treating the value as a signed quantity Ix10 would be set to 800100 Setting Up a Motor 7 11 PMAC User Manual Geared Resolvers Typically a single resolver on the back of the motor is not sufficient to determine power on position If true power on position information is required a set of geared resolvers is used each one geared down to a slower speed and therefore a coarser resolution than the resolver before it in the chain The first resolver usually on the back of the motor and rotating with the motor turns the fastest and has the highest resolution It is called the fine resolver or the first resolver The last resolver in the gear chain turns the slowest and has the lowest resolution It should never turn more than one revolution one electrical cycle really and it is called the coarse resolver Theoretically any number of geared resolvers can be used to establish power on position In practice most systems use two or three resolvers In a two resolver system these are called the fine and coarse resolvers In a three resolver system they are called the fine medium and coarse resolvers Since PMAC can interface to both two and three resolver systems the terminology first r
414. nt down If it counts up there is a polarity mismatch If the counter does not count in opposite directions for the two tests there is an encoder and or amplifier problem If there is a polarity mismatch there will be a potentially dangerous runaway condition when trying to close the loop To fix this change 1900 e g from 7 to 3 or 3 to 7 to reverse the counting sense This will change the positive direction of the axis Alternatively exchange the motor leads instead If there is no movement check the voltage on the output pin It should be approximately 1V relative to AGND If it has not changed recheck I102 the analog power supply and the limit input configuration If the voltage has changed but there is still no movement recheck the amplifier and motor connections Overtravel Limit Polarity Make sure as the direction sense of the motor is verified the hardware position limit switches are wired into the proper inputs That is the limit switch on the positive counting up end of travel must be wired into the LIMn input and the switch on the negative end must be wired into the LIMn input If these are reversed the hardware limit functions will not work 2 12 Getting Started with PMAC PMAC User Manual Setting up the Servo Loop Warning Make sure the motor is in open loop mode before restoring the proportional gain Otherwise it may lurch to an old commanded position This is enough to see if the motor is worki
415. ntegral gain is active all the time or just during periods when the commanded velocity is zero 9 4 Closing the Servo Loop PMAC User Manual K 1 271 vff Y Ss F 1 2 Kat 1 22 z R Notch Filter eference v m Big Step 1 2 Position gt Penabad 5 E NE gt K Ten z n az gt 5 Filter S A ted z 5d 2 Notch Coefficients n 1x36 M 4 K No Ix37 D I iz Ka d4 1x38 d3 1x39 Secondary Position r Velocity K_ Proportional Gain Ix30 m Feedback K Derivative Gain Ix31 iz A K Velocity Feedforward Gain 1x32 usually K Integral Gain Ix33 rca IM Integration Mode Ix34 gt A rimar Ki Acceleration Feedforward Gain 1x35 iin Ed Feedback Figure 18 PMAC PID and NOTCH Servo Filter In addition velocity feedforward gain 1x32 reduces following errors introduced by damping which are proportional to velocity and acceleration feedforward gain 1x35 reduces or eliminates following errors due to system inertia which are proportional to acceleration Tuning the PID Filter The PMAC Executive Program for PC compatible computers provides an easy means of tuning the PID filter It allows simple commands that automatically perform standard moves gather the response data plot this data to the screen and compute important statistics for the response This permits even inexperienced users to make some judgments accord
416. nterface The bus interface for the PMAC STD works virtually identically to the PC bus interface on the PMAC PC or Lite The interface can work with either the original 8 bit STD bus or the new 32 bit STD32 bus It occupies 16 words in the I O space of the host computer The base address of these 16 words is determined using jumpers W11 W22 on the baseboard of the PMAC STD The factory default setting is for address 61 584 F090 hex The Jumper Description section contains a thorough mapping of a typical STD bus computer s I O mapping and likely empty addresses The new PMACI 5 STD does not support the 32 bit features of STD32 although it will work in either STD80 or STD32 buses with 16 bit addressing On the PMACI 5 STD the DIP switch bank S1 1 to S1 12 controls the address of the board on the STD bus VME bus Interface The PMAC VME interfaces to the VME bus as a slave device Commands and responses are sent through a set of 16 8 bit mailbox registers Binary data can be passed through the on board Option 2V dual ported RAM 8k x 16 bits The data bus is eight bits wide for the mailbox and 16 bits wide for the DPRAM The address bus can be configured for 16 24 or 32 bits The address and nature of this interface must be set up through the serial port by writing to registers in PMAC saving the values to non volatile memory and resetting the card Typically for this model of board the initial setup and development is done through the serial
417. ntire file successfully it will create an output file containing the PMAC machine code in form that can be directly downloaded to PMAC This file has the same name as the input file but with a 56K extension The following message displays on the screen PMAC PLC Compiler V1 2 04 28 94 PLC compile complete no errors Downloadable PLCC code in file MYPLCC 56K PLCC program memory use 7343 of 15360 words 16 12 Writing a PLC Program PMAC User Manual If the compiler finds an error no output file is created The compiler stops on the first error that it finds The following message displays on the screen PMAC PLC Compiler V1 2 04 28 94 Compilation aborted due to error Compile error 4 35 xXx PLC source file line 27 Compiler Errors The compiler can report the following errors Number Type of Error 33 Unable to pack floating point number 34 Unable to convert string to float number 35 Illegal Command or Format in string 36 Integer number out of range 37 Unmatching parenthesis 38 Illegal Else Cmd 39 Illegal EndIf Cmd 40 Illegal EndWhile Cmd 41 PLCC Output File Error 42 PLCC Input File Error 43 Unclosed If or While Cmd 44 PLCC 56k maximum memory exceeded 45 PLC 56k conversion stack exceeded 46 First pass of Tokens exceeded maximum 47 Far heap allocate error 48 String must be
418. o DAS 13 12 Computational Features PMAC User Manual Typical M variable definition statements are M1 gt Y FFC2 8 1 M102 gt Y 49155 8 16 S M103 gt X C003 0 24 S M161 gt D 002B M191 gt L 0822 M50 gt DP D201 M51 gt F D7FF M100 gt TWD 4 0 8 3 U See the instructions for each type of M variable definition in the On Line Commands section of this manual Many suggested M variable definitions are given in SETUP PMC in the Examples section of the manual Itis a good idea to prepare a single file with all of the M variable definitions and to put at the top of this file the command MO 1023 gt This will remove all existing definitions and help to prevent mysterious problems caused by stray M variable definitions The M variable definitions are stored as 24 bit codes at PMAC addresses Y BCO00 for MO to Y BFFF for M1023 For all but the thumbwheel multiplexer port M variables the low 16 bits of this code contains the address of the register pointed to by the M variable the high eight bits tell what part of the address is used and how it is interpreted If another M variable points to this part of the definition it can be used to change the subject register The main use of this technique is to create arrays of P and Q variables as is explained above with examples in the descriptions of those variables It can also be used to create arrays in dual ported RAM or in user buffers see on line command DEFINE UBUF
419. o need to slow down the homing move to get an accurate capture Specify Flag Set In the basic setup of the motor Ix25 specifies which set of flags associated with one of the encoder counters is used for that motor It is important that the flag number match the position encoder number for the motor e g if using ENCI as the position loop feedback use Flags HMFL1 LIM1 FAULT1 for the flags and CHC1 as the encoder index channel in order to make use of the PMAC accurate hardware position capture feature Software Capture Option If not using quadrature encoder feedback for the position loop but a homing search move still needs to be done set bit 16 of the position loop feedback address parameter Ix03 to 1 to tell PMAC that it cannot use the hardware capture feature so it must use a software capture technique For example if the address for Ix03 is 0724 Ix03 should be set to 10724 for the software capture of home position When software capture is used there is a potential delay between the actual trigger and the PMAC position capture of several milliseconds This can lead to inaccuracies in the captured position the speed of the motor at the time of the trigger must be kept low enough to achieve an accurate enough capture A two step procedure with a fast inaccurate capture followed by a slow accurate capture is commonly used in these types of systems Basic Motor Moves 11 5 PMAC User Manual Trigger Home Comple
420. o the detailed E point description Getting Started with PMAC 2 1 PMAC User Manual Communications Baud Rate Jumpers The PMAC was shipped configured to be able to communicate either over the bus interface or over the serial interface at 9600 baud The communications setting is controlled by jumpers E44 E47 on the PMAC PC Lite and VME and by DIP switches SW1 5 to SW1 8 on the PMAC STD If communicating over the bus port for the initial setup of the board the settings of these jumpers is not important However if the initial communications is over the serial port make sure these jumpers enable the serial port and provide the baud rate you desire The Setup program and Executive program do have automatic baud rate search algorithms As sent from the factory E44 and E47 should be OFF while E45 and E46 should be ON on PMAC STD SW1 5 and SW1 8 should be ON SW1 6 and SW1 8 should be OFF PMAC can receive commands from both the bus and serial ports Keep commands on the two ports from overlapping PMAC powers up or resets in a mode to respond over the serial interface but any character received over the bus interface changes the mode so it will respond over the bus interface instead A lt CTRL Z gt character received over the serial port changes PMAC back to responding over the serial port If the default jumper setting must be changed refer to the detailed E point description PCbus Address Jumpers PMAC PC and PMAC Lite ar
421. oders Specify the address of the register holding the ongoing commutation position feedback information with Ix83 Usually except for PMAC microstepping this is the phase position register for an encoder in the DSPGATE addresses X C001 X C005 X C0009 etc Phase Referencing When commutating a synchronous motor permanent magnet brushless or switched reluctance it is necessary to reference the phasing cycle to physical features of the motor Contrary to much that is written this does not require an absolute sensor An incremental sensor can be used if a reliable phasing search can be performed on power up PMAC is capable of performing such a phasing search If an absolute sensor is used the phase referencing is performed only once on assembly of the system Both methods of phase referencing are covered in this section Two Analog Output Requirement If PMAC is commutating a motor two analog output channels are required per motor the third and fourth if necessary phases are generated by balance loops in the amplifier Remember that if a multiphase motor is commutated inside the amplifier only one PMAC analog output is required As mentioned previously in the Selecting the Output s for a PMAC commutated motor specify the lower address of the pair of adjacent DAC registers that will be used to output the phase commands with Ix02 The legitimate values of Ix02 are C002 DAC 1 and 2 C00A DAC 3 and 4 C0
422. odes will be machine dependent but typically it will be simple For instance if the coolant on off control were wired into the PMAC Machine Output 7 and the coolant high low control were wired into the PMAC Machine Output 8 the routines could simply be NO7000 M7 1 Set Mach Out 7 Coolant On M8 0 Clear Mach Out 8 Low Level RET NO8000 M7 1 Set Mach Out 7 Coolant On M8 1 Set Mach Out 8 High Level 14 50 Writing Programs for PMAC PMAC User Manual RET NO9000 M7 0 Clear Mach Out 7 Coolant Off RET DWELL statements could be added before and or after the setting of the outputs if it is desired to provide some time for the change to occur M12 Chip Conveyor On M13 Chip Conveyor Off The implementation of these codes will be machine dependent but typically very simple For instance if the conveyor on off line were wired into Machine Output 2 these routines could simply be N12000 M2 1 Set Mach Out 2 Conveyor On RET N13000 M2 0 Clear Mach Out 2 Conveyor Off RET M30 End of Program with Rewind See M02 description M30 will be essentially equivalent to M02 in most systems but will return to the beginning of the program Default Conditions Typically a machine running G code style programs requires many default values and modes beyond what PMAC sets automatically during its power up reset cycle To set these defaults it is best to use the PLC 1 program which will be the first
423. of 04 tells PMAC to ignore bit 2 value of 4 of the AM so for example it will recognize both 39 and 3D as valid 24 bit AMs There should be no reason to change this from the default Address Modifiers Commonly Used With PMAC VME Address Modifier Function 29 A16 16 bit addressing 39 A24 24 bit addressing 09 A32 32 bit addressing Writing a Host Communications Program 17 13 PMAC User Manual PMAC Base Address Bits The base address for PMAC VME is split into three values since there are three registers X 0785 0787 here to contain the base address The first register holds address bits A31 through A24 the second holds bits A23 through A16 and the last holds bits A15 through AS the AS bit must be 0 Address bits A7 through AO of the base address are not specified and therefore are taken to be all 0 If the base address in hex is written it is easy to figure out which address bits are A31 A24 etc Interrupt Level When PMAC VME acknowledges the receipt of a command valid or invalid and or has data to be read by the host computer or master typically it generates asserts an interrupt on the VME bus This register X 0788 tells what interrupt level from 1 to 7 will be used by PMAC The factory default is a value of 02 for interrupt level 2 Therefore when the host detects an interrupt on interrupt level 2 it is PMAC who generated this interrupt Be aware that the int
424. of the line In either case upon receiving the lt BELL gt character the host should send a lt CTRL X gt command to clear out the PMAC communications buffers in both directions The host should then check for incoming characters for a period of time equivalent to the transmission time for three characters discarding any characters it receives to ensure any characters already in transmission have been eliminated Then it can re send the line If jumper E49 is ON parity is disabled in both directions PMAC will not be expecting a parity bit and if one is sent it will create a framing error see below PMAC will not send parity bits with the characters it transmits Writing a Host Communications Program 17 25 PMAC User Manual Serial Framing Error Check PMAC has the capability to check for framing errors on the serial port commands sent to it This check is always active If PMAC detects a framing error in any character in the command it reacts just as it would for a parity error including the I4 control of the response Serial Duplex Control PMAC has the capability to confirm serial transmissions to it by immediately echoing back every character it receives over the serial port This mode known as full duplex can be turned on and off by sending PMAC the CTRL T command PMAC powers up in half duplex mode not echoing received characters so the host must send PMAC a CTRL T command to enable full duplex To perform the e
425. of two more terms one is the magnitude of the magnetization inducing current Ix77 which is kept parallel to the estimated rotor field and a slip gain term Ix78 which determines how much the estimated rotor field angle is advanced in response to each unit of stator torque current which is kept perpendicular to the estimated rotor field Setting the Slip Gain There is a simple technique for setting the slip gain for an induction motor Slip gain is the constant of proportionality between applied torque and slip frequency If the matching values of slip frequency and torque are known divide the former by the latter and convert units to get the slip gain Get all of the information needed from nameplate information for the motor amplifier and controller 8 10 Setting Up PMAC Commutation PMAC User Manual Motor Information From the motor obtain the following information Rated full load speed in RPM Rated line field frequency in Hertz Number of poles Rated full load current RMS From this information compute the rated full load slip frequency of the motor as the difference between the field frequency and the rotor frequency Rated speed RPM poles Slip freq Hz Field freq Hz pared Heg freue 60sec min 2 Use the current information later Amplifier Information From the amplifier obtain the maximum overload RMS current as a percentage of the motor s rated full load RMS current Contr
426. oint M60 to the proper Q variable Assign square root value to this O variable 0100209010041 Increment array index ENDWHILE T Computational Features 13 11 PMAC User Manual Special Use Q Variables Several Q variables have special uses that need to be watched The ATAN2 two argument arctangent function uses QO as its second argument the cosine argument automatically The READ command places the values it reads following letters A through Z in Q101 to Q126 respectively and a mask word denoting which variables have been read in Q100 The S spindle statement in a motion program places the value following it into Q127 M Variables To permit easy access to the PMAC memory and I O space M variables are provided Generally a definition only needs to be made once with an on line command On PMACS with battery backup the definition is held automatically On PMACs with flash backup the SAVE command must be used to retain the definition through a power down or reset Define an M variable by assigning it to a location and define the size and format of the value in this location An M variable can be a bit a nibble four bits a byte eight bits 1 1 2 bytes 12 bits a double byte 16 bits 2 1 2 bytes 20 bits a 24 bit word a 48 bit fixed point double word a 48 bit floating point double word or special formats for dual ported RAM and for the thumbwheel multiplexer port There are 1024 M variables
427. oint X n with the following formula before sending to PMAC X n 1 8X n X n 1 X n 6 Non Uniform Spline The PMAC SPLINE2 mode is very similar to the SPLINE1 mode except that the requirement that the TA spline segment time remain constant is removed The removal of this constraint makes the SPLINE2 mode a non uniform non rational cubic B spline whereas the SPLINE1 mode is a uniform non rational cubic B spline The non rational specification indicates that there are no independent weightings ratios of the different points in the spline The extra freedom of non uniform segment times makes the SPLINE2 mode more flexible than the SPLINE1 mode but at the cost of about 20 extra calculation time SPLINE2 mode is still more efficient than any of the non spline calculation modes Ifthe TA segment time is held constant SPLINE2 mode produces trajectories that are identical to SPLINE1 mode The added segment at the beginning of a spline has the same time as the first programmed segment the added segment at the end of a spline has the same time as the last programmed segment Writing Programs for PMAC 14 21 PMAC User Manual The combined time of any three consecutive segments in a SPLINE2 continuous spline must be less than 8 388 608 msec or about 2 hours and 20 minutes Cutter Radius Compensation PMAC provides the capability for performing cutter tool radius compensation on the moves it performs This compensation
428. ol commands as explained previously The F feedrate statement specifies a speed the X statements command actual moves for the X axis and the DWELL statement commands a halt for the specified time This program simply specifies a basic move and return 14 38 Writing Programs for PMAC PMAC User Manual Defaults A program this simple relies on quite a few default settings and modes This one uses the following defaults LINEAR move mode ABS absolute axis specification with Ix87 and Ix88 specifying the TA and TS acceleration times respectively Controlling Parameters What the values in the program mean can depend on external parameters as well The X positions are in user units as defined in the axis definition statement for the X axis The F speed specification is in terms of user position units divided by feedrate time units as set by variable Ix90 for the coordinate system Simultaneous Moves on Multiple Axes To perform simultaneous coordinate moves of several axes in a coordinate system simply put their move specifications on the same line For instance if we changed the above program to F5000 X10000 Y10000 210000 DWELL1000 XO YO 20 the X Y and Z axes will command a simultaneous move to 10000 stay there for one second then command a simultaneous move to 0 If an axis in the coordinate system is not commanded in a given move line a zero distance move for that axis is assumed note that it is technically pe
429. oller Information From PMAC obtain e The frequency at which the phasing calculations are done e Number of peak output DAC bits required to command the amplifier to its maximum RMS current e The constant of proportionality in the equation relating slip frequency applied torque and slip gain The first piece of information will allow conversion of the rated slip frequency to units of electrical cycles per phase update the slip units PMAC uses Slip Freq Hz PhaseUpdateRate updates sec Slip Freq cycles update The phase update rate for PMAC is determined by the master clock frequency and by jumpers E29 E33 and E98 The default rate is 9 04 KHz or 9040 updates sec The second piece of information will allow conversion of the rated applied torque to units of DAC bits the torque units PMAC uses RatedMotorRMSCurrent A MaxAmplifierRMSCurrent A RatedTorque MotorTorque DAC bits DAC bits The third piece of information allows division of the slip frequency by the torque to get slip gain in the proper units The equation for slip gain is 2s cycles update _ 238x Slip freq cycles update DACbit Torque DACbits Slip gain This value then gets put into Ix78 Setting Up PMAC Commutation 8 11 PMAC User Manual Example The technique is best illustrated by an example Take a system with the following parameters Motor Rated RMS current 20A Rated full load speed 1755 R
430. om a MACRO input register Another use of this format is with the ACC 39 Handwheel Decoder This board contains an HCTL 2000 quadrature decoder IC that converts the quadrature signal from a handwheel to an 8 bit parallel word that is brought in on the JPAN control panel port On the PMAC PC Lite and VME this byte appears on bits 8 15 of register Y SFFCO A normal parallel conversion would put the 1 s bit of the handwheel counter at bit 13 effectively making it 256 times greater than if it were at the normal bit 5 location This shift right conversion puts the 1 s bit at bit 5 as for normal encoders Setting Up a Motor 7 21 PMAC User Manual When using this shift right format the bits enabled mask word should reflect the locations of the bits used after the shift For example if all 16 high bits are used bits 8 to 23 then the bits enabled mask word should be 1FFFCO to mark the use of bits 5 to 20 after the shift With the ACC 39 which uses bits 8 15 the mask word should be 001FCO to mark the use of bits 5 to 12 after the shift Time Base Conversion Entries A time base conversion is basically a scaled digital differentiation When the source data is a counter the result is a frequency value Every servo cycle the table calculates the difference between the values of the source register for this cycle for the last cycle and multiplies the difference by the scale factor The most common use for the resulting value is for ti
431. ometimes called torque mode triggering because it effectively triggers on a torque level except for velocity mode amplifiers because output torque command is proportional to following error It is also called a torque limited mode because it provides an easy way to create moves that are limited in torque and that stop when the torque limit is reached To enable this torque mode triggering set bit 17 of the position loop feedback address I variable Ix03 to 1 Also Bit 16 of Ix03 should be set to 1 to tell PMAC to use the software read position on a capture instead of the hardware latched position because there is no input signal to latch the position in this mode Bits 0 15 contain the actual address of the feedback For example the default value of 1103 is 0720 specifying the address of the first entry in the encoder conversion table and specifying signal based triggering If 1103 is changed to 30720 the same register is used for feedback but torque mode triggering is specified In this mode the trigger for a homing search move or a move until trigger is a true state of the warning following error status bit for the motor The warning following error magnitude for the motor is set by Ix12 with units of 1 16 of a count When PMAC detects this transition it will read the present feedback position as the trigger position then move relative to this position In a homing search move the relative distance is specified by Ix26 in units of 1
432. on loop it is important that the velocity loop of a velocity mode drive be well tuned with the load that it will drive Because the velocity loop tuning is load dependent the amplifier manufacturer cannot do the final tuning the machine builder must tune the loop The velocity step response must not have any significant overshoot or ringing if it does it will not be possible to close a good position loop around it with PMAC The PMAC Executive Program s tuning section has a function called Open Loop Tuning that can be used to give velocity command steps to the amplifier and to observe the response plotted on the screen This makes it easy to tune the amplifier or simply to confirm that it has been well tuned Torque Mode Amplifiers Another popular type of amplifier is the torque mode amplifier in which the analog voltage from the controller represents a torque command for the motor a force command for a linear motor Since the basic motor equation shows that torque is proportional to motor current these are often called current mode or current loop amplifiers a current loop must be closed to ensure that the torque out is proportional to the voltage in Another name occasionally used for these types of amplifiers is the transconductance amplifier signifying that a voltage input results in a proportional current output If the motor is brushless these amplifiers also perform the motor phase commutation Newton s second law states that torque
433. on stays locked and a SPLINE or PVT sequence can be written that corresponds to an exact number of spindle revolutions How It Works Time base control works by lying to the commanded position update equations that occur every servo cycle about the amount of elapsed time since the last servo cycle Variable I10 contains the actual amount of time Note The actual time between servo cycles does not change nor do the dynamics of the servo loops It is only the rate of the commanded trajectories that change with the external frequency and since all of the trajectories in the coordinate system change together the path through space does not Instructions for Using an External Time Base Signal Using an external time base signal requires several steps to set up However once the setup is complete the time base control is automatic The steps in the set up are detailed below Step 1 Signal Decoding The signal is input to the PMAC at one of the incremental encoder inputs Channels A and B The signal must be either a quadrature signal as out of an encoder or a pulse and direction signal pulse into A direction into B For the encoder inputs used one of the Encoders 1 to 16 Encoder I variable 0 1900 for Encoder 1 I905 for Encoder 2 etc controls the decode method and defines what a count 1s For instance with a quadrature signal into Encoder 4 lines 1915 3 or 7 defines four counts per encoder cycle whereas 1915 2 or 6
434. on the number and length of the data sources and the worst case number of gathering cycles that the host could fall behind in reading data from the DPRAM This size must not be greater than 3500 for the SKx16 DPRAM Typical sizes are 20 to 100 words The DPRAM gathering function is started and stopped the same as for the standard gathering either with the GATHER and ENDGATHER ENDG commands or by setting and clearing the data gather control bits directly through M variables 17 28 Writing a Host Communications Program PMAC User Manual Getting the Data Once the gathering function has begun the host must monitor registers in the DPRAM that contain pointers to the data that has been loaded into the DPRAM There are two key registers and only one of these needs to be read repeatedly At the DPRAM base address plus 07FE 2046 is the pointer to the end of the buffer This value is determined by the DEFINE GATHER command and will be fixed for a given application At the DPRAM base address plus 07FC 2044 is the pointer to the next address where gathered data will be placed in DPRAM It is this register that the host should monitor repeatedly to see if it has changed meaning that new data has been placed in the DPRAM and if it has changed how many times data has been placed Both of these registers contain a PMAC memory word address actually the offset from the start of the gather buffer D200 To translate into a host memor
435. ons are 4 10 Talking to PMAC PMAC User Manual lt CTRL H gt lt CTRL H gt backspace to erase last character sent actually acts on the entire data stream as it is sent to the cards It erases the last alphanumeric character sent in the stream Repeated CTRL H characters can erase all the alphanumeric characters sent since the latest carriage return character If this includes addressing characters these are erased as well lt CTRL T gt Full duplex communication echoing of characters is not permitted in daisy chained serial mode Therefore the CTRL T command full half duplex toggle will be rejected in this mode Resetting PMAC There are several ways that PMAC can be reset The first way is by cycling the 5V power off then on The second way is by taking the INIT line on the JPAN connector low then high The third way is to use the backplane bus reset line This method depends on the setting of jumper E39 and in PC bus versions E93 and E94 The fourth method is to send the command to PMAC over either port PMAC Reset Actions When PMAC receives the reset signal or command from any of these sources it immediately stops all active computations and starts its reset cycle At the beginning of the reset cycle it disables all outputs and loads the firmware into active memory It then proceeds to load active memory in a manner dependent on the hardware configuration and the setting of re initialization jumper E5
436. operational firmware in binary machine code format and COM1 is the serial port being used for communications Shut off power to PMAC and remove the E51 jumper Restore power to PMAC and resume normal operation with the new firmware To update the firmware checksum reference value so PMAC does not report a firmware checksum error the easiest method is to send the command which causes PMAC to compute the new reference value automatically but it also clears all of your programs and buffers from active memory As an alternative method send the command RHX 0794 several times If the same value is received each time PMAC has stopped its checksum calculations on an error and the reported value is the value it calculated for the firmware checksum Write this value into reference register X 07B1 For example if RHX 0794 returns 943B12 several times send the command WX 07B1 9A3B12 to PMAC Remember that for either method store this reference value to flash memory with the SAVE command e To re compile PLC programs either use the LISTLINK TXT file that corresponds to the new firmware version or create this file by sending the LIST LINK command to the PMAC with the new firmware and storing the response in a text file of this name Re initialize Command The command causes a reset and full re initialization of PMAC In addition to loading default parameter values it also clears out all of the buffers in battery backed RAM m
437. or force is proportional to rotary or linear acceleration respectively so the commands into these amplifiers are effectively acceleration commands No velocity loop is closed in the amplifier so it is up to PMAC to close the velocity loop itself to get enough damping 9 2 Closing the Servo Loop PMAC User Manual for a stable system With the standard PID filter this is done with the derivative gain so it is important to have enough derivative gain in these systems for stable response Torque mode amplifiers are popular for several reasons Since they do not need a tachometer or analog velocity loop electronics they can be simpler and less expensive Because the current loop gains are dependent only on motor properties and not on the load they can be tuned by the manufacturer for the particular motor that is being used No retuning is required by the machine builder when the motor is connected to the load In addition torque mode amplifiers generally work better in applications with rapid accelerations and decelerations They do not depend heavily for their performance on error integrators which introduce time lags and slow response to velocity changes As such they are often preferred over velocity mode amplifiers even without the cost advantage Voltage Mode Amplifiers Voltage mode amplifiers are the simplest and least costly amplifiers A voltage command input causes a larger proportional voltage output to the motor No feedbac
438. or the coordinate system The R command will start execution of the program Stopping the Program There are several ways to stop a running program Q CR Quit stops the program at the end of the presently executing move A CR Abort causes the motors in the coordinate system to start decelerating immediately Both of these commands leave the program ready to execute run or step the next line in the program To re start the program at the beginning type B CR the B command without a number operates on the current working program This resets the program counter to the top completion of a program automatically resets the counter to the top Remember that the motor velocity and acceleration limits Ix16 and Ix17 are in effect for all motors in the coordinate system If a motor is asked to exceed one of these limits all motors in the coordinate system are slowed to honor the limit If the programmed moves seem slower than what as expected this could be the cause Refining the Program Few times will the program work exactly right the first time Go through an iterative process of editing downloading executing and evaluating This is one of the key reasons for using the program editor The required changes can be made in the editor without re typing the entire program Then the entire revised program can be downloaded to PMAC This process is why it is a good idea to have the CLEAR command immediately after the OPEN command it erase
439. ort being used on the PC If the Executive program is addressing the COMI port make sure that it is cabled out of the COMI connector Does the baud rate specified in the Executive program match the baud rate setting of the E44 E47 jumpers on PMAC With a breakout box or oscilloscope make sure there is action on the transmit lines from the PC as you type into the Executive program If there is not there is a problem on the PC end Probe the return communication line while giving PMAC a command that requires a response e g CONTROL F If there is no action change jumpers E9 E16 on PMAC to exchange the send and receive lines If there is action but the host program does not receive characters RS 232 may be receiving circuitry that does not respond at all to PMAC RS 422 levels If using another model of PC try using it as a test most models accept RS 422 levels quite well If the computer will not accept the signals a level conversion device such as Delta Tau s Accessory 26 may be needed Commutation Troubleshooting If there was no movement check to make sure that output voltages were received on DAC and DAC2 A value of 2000 should put 0 6V on the DAC lines If voltage outputs were received from PMAC but no movement check the amplifier and motor setups If voltage outputs were not received check the analog supply to PMAC make sure that the limits are held low or disabled and make sure that the amplifier fault signal is not
440. ose the buffer again This can be done with three commands on one line as in OPEN PLC 5 CLEAR CLOSE 16 2 Writing a PLC Program PMAC User Manual Example A quick example of a PLC block entry is shown below OPEN PLC 2 CLEAR IF M11 1 1130 10000 ELSE I130 8000 ENDIF CLOSE ENABLE PLC 2 PLC Program Structure The important thing to remember in writing a PLC program is that each PLC program is effectively in an infinite loop it will execute over and over again until told to stop These are called PLC because of the similarity in how they operate to hardware Programmable Logic Controllers the repeated scanning through a sequence of operations and potential operations Calculation Statements Much of the action taken by a PLC is done through variable value assignment statements variable expression The variables can be I P Q or M types and the action thus taken can affect many things inside and outside the card As shown in the Getting Started section of the manual perhaps the simplest PLC program consists of one line P1 P1 1 Every time the PLC executes usually hundreds of times per second P1 will increment by one Of course these statements can get a lot more involved The statement P2 M162 1108 32 10000 COS M262 I208 32 100 could be converting radial M162 and angular M262 positions into horizontal position data scaling at the same time Because it updates this very frequently who
441. otion calculations However for M variables particularly outputs this can be a problem because with a normal variable value assignment statement the action will take place sooner than is expected looking at the statement s place in the program For example in the program segment X10 Move X axis to 10 M1 1 Turn on Output 1 x20 Move X axis to 20 expect that Output 1 would be turned on at the time the X axis reached position 10 But since PMAC is calculating ahead at the beginning of the move to X10 it will have already calculated through the program to the next move working through all program statements in between including M1 1 which turns on the output Therefore using this technique the output will be turned on sooner than desired 13 18 Computational Features PMAC User Manual How They Work Synchronous M variable assignment statements were implemented as a solution to this problem When one of these statements is encountered in the program it is not executed immediately rather the action is put on a stack for execution at the start of the actual execution of the next move in the program This makes the output action properly synchronous with the motion action In the modified program segment X10 Move X axis to 10 M1 Turn on Output 1 synchronously X20 Move X axis to 20 the statement M1 1 the double equals indicates synchronous assignment is encountered at the beginning of the mov
442. otion program PLC program tables etc Some users will always have the card set up to re initialize during the reset cycle they then download all parameter settings and programs immediately after each cycle The logic behind this strategy is that the same startup sequence of operations is used even if a new replacement board has just been put in It is also useful for those applications that do not wish to rely in any way on the PMAC own non volatile storage EEPROM and battery backed RAM or flash Talking to PMAC 4 13 PMAC User Manual For a complete re initialization of PMAC to known state the following commands can be added PO 1023 0 Q0 1023 0 MO 1023 gt UNDEFINE ALL Remember that these commands directly affect only active memory RAM To copy new settings into non volatile memory EEPROM or Flash use the SAVE command 4 14 Talking to PMAC PMAC User Manual 5 Troubleshooting Table of Contents TROUBLESHOOTING 1 PMAC Card Troubleshooting retener etre tertie etia ede ebrei UE cree ge tee dese te exe E ed hides 1 GENET GL A RN 1 BUS COMMUMNICALIONS EE 1 Serial Commuhicatiofis A EVE RR EREE uu Ee e Be RENE SENA RS Eua 1 Cormmutation Troubleshooting muii rete eU e toca di 1 Servo Loop and Jogging Troubleshooting eese nennen ener nennen nennen sten tee nennen nennen 1 Homing Search Troubleshooting sieisen a ce sein ria ae 2 No M
443. otor by setting Ix00 to 1 For Motor 1 set 1100 to 1 For PMAC Commutated Motors Only If using PMAC to commutate this motor set up the commutation algorithm I variables at this point First set 1101 to 1 to tell PMAC that motor 1 is to be commutated by PMAC Analog Outputs Tell PMAC which pair of analog outputs are being used to command the amplifier Do this by setting Ix02 to the lower address of the pair of outputs that have been wired to the amplifier To tell motor 1 to use DACI and DAC2 in the example set 1102 to C002 49154 Getting Started with PMAC 2 9 PMAC User Manual Commutation Encoder The encoder register used for commutation feedback must be specified with Ix83 The default value of Ix83 specifies Encoder 2x 1 e g ENCI for Motor 1 ENC3 for Motor 2 and ENC15 for Motor 8 The actual value of Ix83 is the address of the phase position register for that encoder For ENCI Motor 1 this value is 49153 C001 If setting up a PMAC commutated Motor 1 using ENC1 make sure 1183 is set equal to 49153 C001 Counts per Commutation Cycle Next determine the number of encoder counts per commutation cycle per pole pair 1900 defines an encoder count here 1 2 or 4 counts per line For instance if using a 2500 line per revolution encoder with x4 decode and a 4 pole motor the calculation would be 2500 lines rev 4 counts line 2 pole pairs rev 5000 counts pole pair If this value is an integer
444. ove is calculated then it will not be able to compute the intersection point between the two moves This can happen for several reasons e There is a move with no component in the plane of compensation 1 e perpendicular to the plane of compensation as in a Z axis only move during XY compensation before the next move in the plane of compensation e There is more than one DWELL before the next move in the plane of compensation e Program logic causes a break in blending moves e g looping twice through a WHILE loop If PMAC cannot find the next move in time it will end the current move as if the intersection with the next move would form an outside corner If the next move when found does create an outside corner or continues straight on compensation will be correct On an outside corner an arc move is always added at the corner regardless of the setting of I89 However if the next move creates an inside corner the path will have overcut into the corner In this case PMAC will then move to the correct intersection position and continue with the next move leaving the overcutting localized to the corner 14 32 Writing Programs for PMAC PMAC User Manual Failures in Cutter Compensation Programmed Tool Center Path Tool d Center Point at Failure y NorOvoreut Programmed PAY Tod i wut Path Center Point t Line zat Failure Line Line Tool Center trees Path Line Pi
445. ovement At All E E 2 Movement But SiG UY ENTENDER 2 R naway CONGO ores E ERE eie eM gen Dot ate id 2 Brief Movement Then Stop eret ertet dt 2 Motion Program Troubleshooting sssrini pi Ee none ro nono enn nn nennen reine trennen Nae E reiner nne nn enne 3 Table of Contents 5 1 PMAC User Manual 5 2 Table of Contents PMAC User Manual TROUBLESHOOTING PMAC Card Troubleshooting General Is the green LED power indicator on PMAC CPU board ON as it should be If it is not find out why PMAC is not getting a 5V voltage supply Is the red LED watchdog timer indicator on PMAC CPU board OFF as it should be If it is ON make sure PMAC is getting close to 5V supply at less than 4 75 V the watchdog timer will trip shutting down the card The voltage can be probed at pins 1 and 3 of the J8 connector A1 and A2 on the PMAC VME If the voltage is satisfactory inspect PMAC to see that all inter board connections and all socketed ICs are well seated If the card will not run with the red LED off contact the factory Bus Communications Do the bus address jumpers E91 E92 E66 E71 set an address that matches the bus address that the Executive program is trying to communicate with Is there something else on the bus at the same address Try changing the bus address to see if communications can be established at a new address Address 768 300 hex is usually open Serial Communications Is the proper p
446. ow M11 both up and down Set P11 to 0 in a level triggered mode This could have been done this edge triggered as well but it does not matter as far as the final outcome of the routine is concerned It is about even in calculation time and it saves program lines Any SEND COMMAND or DISPLAY action statement should be done only on an edge triggered condition because the PLC can cycle faster than these operations can process their information and the communications channels can get overwhelmed if these statements get executed on consecutive scans through the PLC More examples of how to program using these statements can be found in chapter 9 IF M11 1 input is ON IF P11 0 input was not ON last time COMMAND 1J JOG motor P11 1 Set latch ENDIF ELSE P1120 reset latch ENDIF WHILE Loops Normally a PLC program executes all the way from beginning to end within a single scan The exception to this rule occurs if the program encounters a true WHILE condition In this case the program will execute down to the ENDWHILE statement and exit this PLC After cycling through all of the other PLCs it will re enter this PLC at the WHILE condition statement not at the beginning This process will repeat as long as the condition is true When the WHILE condition goes false the PLC program will skip past the ENDWHILE statement and proceed to execute the rest of the PLC program To increment the counter as long as the input is true
447. p from the spindle center Usually this distance is the X axis position implying that the X axis zero position is at the spindle center Some G code dialects allow the parts program to create an X axis offset with G92 R q v which defines what the radial distance is at the current X axis commanded position The method suggested here for CSS mode has the spindle in a separate PMAC coordinate system from the other axes This allows a spindle program to be executing and reacting at a different rate from the main parts program yet to be ultimately controlled by the parts program through variables and flags This type of spindle program is explained in detail below A G96 code will carry with it a spindle surface speed S code in either feet minute or meters minute This value should be placed in a variable for the spindle program to pick up A flag should also be set noting Writing Programs for PMAC 14 47 PMAC User Manual which mode the spindle is in Note that spindle mode and speed can be set independently of spindle on off state and direction for which see M03 M04 MO5 A typical G96 routine using this approach would be N96000 READ S Read spindle surface speed into Q119 P96 0119 Store spindle speed M96 1 Flag to mark CSS mode RETURN G97 Constant Surface Speed Disable This code cancels spindle constant surface speed mode and puts the spindle into a constant angular velocity mode In this mode the spindle speed
448. parse the line to figure out what action it has to take As it parses the line it computes an accumulating checksum of all the character bytes in the command line The checksum does not include any control characters either those that may have been interjected into the middle of the line or the trailing CR character PMAC will return the checksum to the host immediately after it sends the acknowledging handshake character if any For I3 0 there is no acknowledging character for I321 PMAC uses lt LF gt for I322 or 3 PMAC uses ACK If the command required a data response from PMAC the acknowledging character and the checksum are returned to the host after the data response to the command and after the checksum for the data response If PMAC detects an error in the command line through its normal syntax checking it will respond with the BELL character for all values of I3 but it will not follow this with a checksum byte the line has been thrown away PMAC to Host Checksum PMAC will compute the checksum of any communications line it sends to the host This checksum includes control characters sent with the line including leading line feed lt LF gt characters if any and the final CR character The checksum is sent immediately following the CR character For a multiple line transmission one checksum is sent for each line of the transmission immediately following the CR for that line 17 26 Writing
449. peed To double the speed decrease Ix77 to 50 of its present value If able to tolerate a lower maximum speed and a higher torque at low speed increase the Ix77 value If changing the Ix77 value change the Ix78 value in inverse proportion so the Ix77 Ix78 product stays constant newIx78 IdealProduct newIx77 Open Loop Microstepping Commutation PMAC has the ability to do open loop microstepping direct microstepping of standard stepper motors working off internally generated pseudo feedback for both commutation and servo algorithms This technique is different from using PMAC with a voltage to frequency converter to command an external microstepping drive that technique does not utilize the PMAC commutation algorithms at all When microstepping PMAC provides two analog outputs that are used as current commands for phases of the motor Typically for a microstepping motor the two phases are electrically independent and 909 out of phase with each other In this case the two outputs are simply bidirectional current commands for the H bridge amplifiers driving each phase These amplifiers can be simple torque mode current mode DC brush motor amplifiers The PMAC microstepping algorithm provides 256 microsteps per electrical cycle which is 64 microsteps step On a typical 200 step revolution motor this amounts to 12 800 microsteps per revolution With the default phase update frequency of 9 kHz PMAC can slew at over 576 000 microstep
450. position after motor settles 382 PMAC responds with position I179 2000 Positive offset of 2000 bits on 2nd phase P Request position after motor settles 215 PMAC responds with position Polarity Rule With 1172 equal to 64 or 85 the motor should have moved in the negative direction when the second phase positive offset was added on top of the first phase positive offset as it did in this example With I172 equal to 171 or 192 the motor should have moved in the positive direction Alternatively stated if the motor counted down in the test 1172 should be set at 64 or 85 if it counted up in the test 1172 should be set at 171 or 192 For the motor in this example we conclude that we want a value of 64 if it is a 4 phase motor or 85 if it is a 3 phase motor If the encoder direction is changed for system reasons 1172 should be changed as well to match Power on Phasing Search Warning An unreliable phasing search method can lead to a runaway condition Test the phasing search method carefully to make sure it works properly under all conceivable conditions Make sure the Ix11 fatal following error limit is active and as tight as possible so the motor will be killed quickly in the event of a serious phasing search error If a non absolute sensor is used for commutation PMAC must perform a search move for the proper phasing reference every time it powers up with an absolute sensor this only needs to be done once in the
451. ppropriate line label of motion program 1001 M00 Programmed Stop The routine to execute this code simply needs to contain the STOP command This code is looking for the line label NO of PROG 1001 and the beginning of any program is always implicitly NO so this must be at the very top of PROG 1001 The part of the file to implement this could be CLOSE OPEN PROG 1001 Buffer control command CLEAR To erase old when sending new STOP First line of actual program RET Will jump back when restarted M01 Optional Stop Typically this code is used to do a stop if the Optional Stop switch on the operator s panel is set Assuming this switch is wired into the PMAC Machine Input 1 and variable M11 has been assigned to this input this is the default then the routine to execute this code could be NO1000 IF M11 1 STOP RET M02 End of Program Since PMAC recognizes the end of a program automatically and resets the program pointer back to the top of the program the routine for this code could be empty RET statement only However in many systems a lot of variables and modes get set to default values here A typical end of program routine might be N02000 M55 0 Turn off spindle M7 0 Turn off coolant M2 0 Turn off conveyor LINEAR Make sure not in circular mode RET Writing Programs for PMAC 14 49 PMAC User Manual M03 Spindle On Clockwise If the spindle is simply doing const
452. previously possible Many arithmetic logical and transcendental operations can be performed on variables and constants in user programs on board the card Computational Priorities As a multi tasking real time computer PMAC has an elaborate prioritization scheme to ensure that vital tasks get accomplished when needed and that all tasks get executed reasonably quickly The scheme was designed to hide its complexity as much as possible but also to give some flexibility in optimizing the controller for his particular needs The tasks at the different priority levels are e Single Character I O Bringing in a single character from or sending out a single character to the serial port or host port PC or STD is the highest priority in PMAC This task takes only 200 nsec per character but having it at this high priority ensures that PMAC cannot be outrun by the host on a character by character basis This task is never a significant portion of the PMAC total calculation time This task does not include processing a full command that happens at a lower priority see below e Commutation Update The commutation phasing update is the second highest priority on PMAC For each motor commutated by PMAC this task takes 3 usec per update cycle 2 usec for the 30 MHz card The frequency of this task is determined by the master clock frequency and jumpers E98 E29 E33 The default update frequency is 9 kHz 110 usec cycle At the default the co
453. provides accessory boards and software structures special M variable definitions to capitalize on this feature Up to 32 of the multiplexed I O boards may be daisy chained on the port in any combination Port Accessories The ACC 18 Thumbwheel Multiplexer board provides up to 16 BCD thumbwheel digits or 64 discrete TTL inputs per board The TWD and TWB forms of M variables are used for this board The ACC 34 34A and 34B Serial I O Multiplexer boards provides 64 I O point per board optically isolated from PMAC The TWS form of M variables is used for these boards The ACC 8D Option 7 Resolver to Digital Converter board provides up to four resolver channels whose absolute positions can be read through the thumbwheel port The TWR form of M variables is used for this board The ACC 8D Option 9 Yaskawa Absolute Encoder Interface board can connect to up to four of these encoders The absolute position is read serially through the multiplexer port on power up Non Multiplexed Uses If none of these accessory boards is used the inputs and outputs on this port may be used as discrete non multiplexed I O They map into the PMAC processor space at Y address FFC1 The suggested M variable definitions for this use are M40 to M47 for the eight outputs and M50 to M57 for the eight inputs The ACC 27 Optically Isolated I O board buffers the I O in this non multiplexed form with each point rated to 24V and 100mA Control Panel Port I O JPAN Po
454. pture on rising edge of a flag Use LIM2 as flag positive end limit Home into limit Waits for Home Search to start Waits for Home motion to complete Home speed 10 cts msec negative direction Re enable LIM2 as limits Capture on flag low and index channel high Use HMFL2 home flag as trigger flag Do actual homing move Waits for Home Search to start zai aits for Home motion to complete Disables PLC once Home is found End of PLC Basic Motor Moves 11 11 PMAC User Manual Already Into Home A similar situation occurs when it is not known on power up whether or not it is positioned already into the home trigger Here the easiest solution is to write a program that evaluates this condition if it is in the trigger it moves out before doing the real homing p EXRORXEXXWE Motion Program Set up variables to be saved CLOSE M320 gt X C008 20 1 Variable for HMFL3 input 1325 C008 Use Flags3 for Motor 3 P A A Motion program to execute routine Ck cock ck ck cock ockockckockckockckockckckckck OPEN PROG 103 CLEAR IF M320 1 Already in trigger 1323 10 Home speed 10 cts msec positive direction I326 1600 Home offset 100 counts to make sure clear 1912 11 Capture on falling flag and rising index I913 0 Use HMFL3 as flag HOME3 Home out of switch ENDIF 1323 10 Home speed 10 cts msec negative direction I326 0 No home offset 1912 3 Capt
455. r M117 gt X C000 17 Encoder 1 position capture flag M125 gt Y 0815 24 S Motor 1 encoder position offset register Now use a motion program segment like the following INC Incremental moves TM10 TA10 Move segment time 10 msec WHILE M117 0 While no trigger to capture position x20 Command next move segment ENDWHILE P103 M103 M125 Read captured position subtract offset to get motor position at trigger The second use for this register is to determine whether the encoder counter has lost any counts This can be done by performing a second homing search move after an operation and comparing the contents of the register after the second homing search move to the contents after the first homing search move Basic Motor Moves 11 13 PMAC User Manual Open Loop Moves Open loop moves as their name implies do not do closed loop position control They open up the servo loop and just put commands of the specified magnitude on the outputs Typically these are used for diagnostic purposes but they can also be used in the actual applications These moves are executed using the motor specific O constant on line command where constant represents the magnitude of the output as a percentage of Ix69 the maximum output parameter This command may not be part of a motion program and it may not be given to a motor when that motor s coordinate system is executing a motion program even if it is not moving that motor
456. r Firmware eee esee eese eee testen eene RR RR RR RR RR RR a RARE enne nee nenne tette trennen enne teen enn 12 Hype KE 13 Alternative Uses for User Written Servo sssrinin aesae nene tenete a nest reno reete rennen 13 Simple User Written Servo Example sssrinin osrin aeon aeran nennen rem rennen nennen nennen trennen 13 C Program to Convert LOD File to PMAC Format eese enne nennen nen nenne trennen 14 Table of Contents 9 1 PMAC User Manual 9 2 Table of Contents PMAC User Manual CLOSING THE SERVO LOOP The Purpose of the Servo Loop PMAC automatically closes a digital servo loop for all activated motors The purpose of the servo loop is to command an output in such a way to try to make the actual position for the motor match the commanded position How well it does this depends on the tuning of the servo loop filter the setting of its parameters and the dynamics of the physical system under control Servo Update Rate The servo loop is closed updated at a frequency determined by the master clock rate jumper E98 jumpers E29 E33 which divide down the master clock to generate the phase clock jumpers E3 E6 which divide down the phase clock to generate the servo clock parameter Ix60 which can extend the servo clock in software Ix60 is useful to slow down the servo update rate for a particular motor while leaving the faster rate
457. r address form the exponent Bits 12 23 of this word form the low 12 bits of the 36 bit mantissa Bits 0 23 of the 32 bit word form the high 24 bits of the mantissa bits 24 31 are sign extension The following code shows one way of creating these pieces not the most efficient exp first word amp Ox00000FFFL Select low 12 bits for exponent low mantissa first word gt gt 12 OxOOFFFL Select next 12 bits for mantissa shift right and mask high mantissa second word The floating point value can then be reconstructed with mantissa high mantissa 4096 0 low mantissa value mantissa pow 2 0 exp 2047 35 2047 is subtracted from the exponent to convert it from an unsigned to a signed value 35 is subtracted to put the mantissa in the range of 0 5 to 1 0 Writing a Host Communications Program 17 29 PMAC User Manual The following procedure in C performs the conversion efficiently and robustly double DPRFLoat long first word long second word return mantissa 2 35 2 exp 2047 double mantissa long int exp m double second word 4096 0 double first_word gt gt 12 amp OxOOFFFL if m 0 0 return 0 0 exp first word amp Ox00000FFFL 2082 208222047435 return mantissa pow 2 0 double exp To reassemble a long floating point word in the host treat the less significant word the same as for the fixed point case above Take the bottom 12 bits of
458. r minus an offset amount determined by 1126 Setting up a Coordinate System In order to run a program on PMAC first define a coordinate system These motors execute a program For this example set up coordinate system 1 Defining an Axis Type amp 1 CR This will address coordinate system 1 Confirm which coordinate system is addressed by typing amp CR and PMAC will return the number of the currently addressed coordinate system Next type 1 gt X lt CR gt the arrow between and X is comprised of the minus sign and the greater than symbol 2 14 Getting Started with PMAC PMAC User Manual there should be no space before the arrow This matches the X axis of coordinate system 1 amp 1 to motor 1 As it is here one unit in X is one encoder count Scaling an Axis To scale the X units place a scale factor before the X in the definition statement 1 e this axis definition statement is what defines the scale of the user position units For instance if using a 500 line encoder on the motor with 4X decoding refer to I900 and a 5 pitch five turns per inch screw converting to linear motion yielding 10 000 counts inch use the command 41 10000X to define the X axis in inches Multiple Axes Caution Every motor in the coordinate system must have its limit inputs held low in order for any program to run in that coordinate system even if the program does not use that motor If another motor
459. r position registers are only set to zero on power up reset Therefore after a motor is homed there is an offset between motor zero position and encoder zero position Only worry about this offset if using the encoder registers directly e g position capture and compare or to relate these values to motor position Find and store the offset which is the value in the position capture register when the home trigger is found Program HOMOFFST PMC in the Examples section shows how to do this They may also have to handle rollover of the encoder registers if they will be traveling more than 8 million counts The modulo 46 operator is useful for this For more details refer to the Synchronizing PMAC to External Events section of this manual Input Encoder Encoder Motor Axis Signal Position Position Position Position Quadrature Capture Position Mx03 Act Pos Cmd Target Pos Move End Pos Parallel Compare Position Mx03 P Mx62 Mx61 Mx63 Mx65 Analog Phase Position Mx01 Extended ele Interpolated Count User Integer Count 1x08 32 ct Units Count 1 32 ct fixed point floating point PMATCH gt Y v v 24 bits Encoder 24 bits 48 bits a 48 bits Decoder jos Position died Axis Conversion i i Counter Extension Scaling e g 1 T 32 1x08 Axis Coefficients Done Always Done Always Done for Done for Activated Motor Defined Axis Set to Zero on Set to Zero on Set to Zero on Can be Offset Powe
460. r short word and six bytes per long word This command is useful for quick status and position querying Real Time Data Gathering Through Dual Ported RAM Using the dual ported RAM it is possible to perform the PMAC data gathering function and upload the gathered data to the host computer in real time The standard data gathering function used by the PMAC Executive Program to produce plots performs the data gathering in real time storing to open regular RAM in PMAC then uploads to the host afterwards This real time uploading requires tight handshaking between the host and PMAC to ensure that the data is passed reliably and efficiently Setting Up The DPRAM data gathering function is set up the same way as for the standard data gathering function with PMAC I Variables 119 to 144 controlling what data is to be gathered and how often To specify data gathering into the DPRAM I45 should be set to 3 it is set to O for the standard gathering The buffer for temporary storage of the gathered data is established by the DEFINE GATHER constant command where constant is the size of the buffer in PMAC words each PMAC word is 32 bits in the DPRAM The buffer always starts at PMAC word address D200 which from the host side is DPRAM base address plus 0800 2048 bytes Each short data source occupies one word in the buffer each long data source fixed point or floating point occupies two words Set the size of the buffer based
461. r the subprogram call This functionality is very useful for executing canned cycles in machine tool style programs or for turning ordinary move commands into arguments for a subprogram that executes inverse kinematic or similar calculations This capability is accomplished through the motion program PRELUDE command To turn on the function declare PRELUDE1 in the motion program followed by the subprogram call you wish to be executed before each subsequent move command or letter number command This subprogram call can be declared with a CALL command or a G M T or D code any of which is a special subprogram call In a PRELUDE1 declaration the value in the subprogram call specifying which subprogram and which line must be a constant it cannot be a variable or expression Once PMAC has encountered a PRELUDE1 command in the program it will execute the specified subprogram call each time it encounters a move command or other letter number command in the motion program including G M T and D codes but excluding N and O line labels The move command or letter number command must be at the beginning of a program line or immediately following an N or O line label at the beginning of a program line Once PMAC has jumped to the subprogram specified by PRELUDE1 it will treat any move command or letter number command in the subprogram as it normally would these will not cause another subprogram call automatically Automatic PRELUDE subprogram call
462. r up Reset Power up Reset Power up Reset Axis offset PSET and Home axis COMMAND ACTUAL POSITION POSITION Figure 12 PMAC Position Processing Axis Position Scaling Motor position is always kept in terms of counts When a motor is assigned to an axis through an Axis Definition statement the scale factor in the statement determines what the units of the axis are usually inches millimeters degrees etc Programmed moves are given for an axis and PMAC converts this to motor moves using the scale factors from the Axis Definition statements It is important to realize that this conversion is for commanded positions only and that the conversion normally goes only one way from axis to motor PMAC never computes actual axis positions Leadscrew Compensation PMAC is capable of performing what is commonly called leadscrew compensation This technique which also goes by other names allows for a table of corrections to be entered into PMAC as a function of motor position PMAC can store up to eight of these compensation tables Each motor can have one table that belongs to it Unless otherwise specified the table uses position information from this motor source data to determine the location in the table and also adds its correction to this motor target data However either the source motor or both the source and the target motors may be specified to be motors other than the motor to which the table belongs If both motors are diff
463. radually removes compensation over the lead out move itself ending at the programmed endpoint of the lead out move When the lead out move is a LINEAR mode move this compensated tool path will be at a diagonal to the programmed move path When the lead in move is a CIRCLE mode move this compensated tool path will be a spiral Writing Programs for PMAC 14 31 PMAC User Manual Removing Compensation Outside Corner Line Programmed UAE Path Tool Center N Path i Tool Center A UI Line Line to Line i i i i i M i x Line n Spiral S Programmed D V Arc Path Tool Center s f Path X Tool Center Arc to Line Arc to Arc Figure 48 Removing Compensation Outside Corner Note that this behavior is different from changing the magnitude of the compensation radius to zero while leaving compensation active An arc move is always added at the corner regardless of the setting of I89 This ensures that the lead out move will never cut into the last fully compensated move Failures in Cutter Compensation It is possible to give PMAC a program sequence in which the cutter compensation algorithm will fail not producing desired results There are three types of reasons the compensation can fail Inability to Calculate Through Corner First if PMAC cannot see ahead far enough in the program to find the next move with a component in the plane of compensation before the present m
464. rage On PMACS with battery backed RAM most of the I variable values can be stored in a 2K x 8 EEPROM IC with the SAVE command These values are safe here even in the event of a battery backed RAM failure so the basic setup of the board is not lost After a new value is given to one of these I variables the SAVE command must be issued in order for this value to survive a power down or reset The I variables that are not saved to EEPROM are held in battery backed RAM These variables do not require a SAVE command to be held through a power down or reset and the previous value is not retained anywhere These variables are 119 144 Ix13 Ix14 On PMACS with flash memory backup those with Option 4A 5A or 5B all of the I variable values can be stored in the flash memory with the SAVE command If there is an EEPROM IC on the board it is not used After a new value is given to any I variable the SAVE command must be issued in order for this value to survive a power down or reset Default values Default values for all I variables are contained in the manufacturer supplied firmware They can be used individually with the I constant command or in a range with the I constant constant command Upon board re initialization by the command or by a reset with E51 in the non default setting all default settings are copied from the firmware into active memory The last saved values are not lost they are just not used See the I variable
465. raight across 26 strand flat cable connector For a DB 9 host connector a standard 9 to 25 pin adapter should be used on the other end of the cable PMAC Lite PMAC Lite has an RS 232 interface on a 10 pin IDC connector J4 This port can connect directly with a standard DB 9 connector on a host computer with a straight 10 strand flat cable connector For a DB 25 host connector a standard 25 to 9 pin adapter should be used on the other end of the cable For an RS 422 interface the Option 9L piggyback board can be added This provides a DB 25 connector for the RS 422 port The RS 232 port is disabled PMAC STD PMAC STD has both an RS 232 interface on a 5 pin SIP connector bottom board J1 and an RS 422 interface on a 20 pin mini IDC connector bottom board J3 Only one of these interfaces should be connected at any one time PMAC1 5 STD PMACI 5 STD has an RS 232 interface on a 5 pin SIP and a 10 pin IDC connector the 10 pin connector can connect directly with a standard DB 9 connector on a host computer with a straight across 10 strand flat cable It also has an RS 422 interface on a 26 pin IDC connector which can connect directly with a standard DB 25 connector on a host computer with a straight across 26 strand flat cable RS 422 vs RS 232 The PMAC RS 422 serial interface is very similar to the RS 232 interface that most PCs have RS 422 has differential 0 to 5V signals whereas RS 232 has single ended 10 to 10V signals The PMAC
466. ransformation matrices Use the on line command DEFINE TBUF constant where constant represents the number of matrices to be defined Each matrix is set automatically to the identity matrix at this command This needs to be done only once as the space and the values for the matrices will be kept in battery backed RAM until a DELETE TBUF or command is given Using the Matrices Inside the motion program the TSEL constant transform select command picks one of the matrices that has been defined for use as the active transformation matrix for the coordinate system This matrix will be in force for the next calculated moves in the program Once selected the matrix may be processed with several program commands The processing serves to put new values in the selected matrix The matrix is used with whatever values it contains at the time during the calculation of any move involving the X Y or Z axes Initializing the Matrix 14 34 Writing Programs for PMAC PMAC User Manual The TINIT transform initialize command makes the selected matrix the identity matrix so that transformed positions would equal untransformed positions Absolute Displacement The ADIS constant absolute displacement command sets up the displacement portion of the selected matrix by making the three displacement values D1 D2 amp D3 equal to the three Q variables starting with the one specified with constant Forinstance ADIS 25 would mak
467. ration time for the moves is controlled by Ix87 and the S curve portion of that acceleration time is controlled by Ix88 for the coordinate system x that is running the program Getting Started with PMAC 2 15 PMAC User Manual When finished entering the program type CLOSE CR to exit the program buffer To enter a new program in the place of the one in the buffer open the buffer type CLEAR and enter the new program An example follows OPEN PROG 1 CLEAR erase old program F2 36 2 36 in sec X5 346 YO first side of square X5 346 Y5 346 Second side XO Y5 346 third side X0 YO fourth side CLOSE Using the Program Editor It is easiest to type programs using the program editor in the PC Executive terminal Program Here the program can be changed at will and then it can be downloaded to the card by selecting the Download Editor to PMAC menu option or by hitting lt ALT D gt when the editor screen is displayed Include in each program space the lines to open the buffer to clear out the old program and to close the buffer at the end Executing A Motion Program Starting the Program With a program held in PMAC buffer it is easy to run To run program 1 make sure the coordinate system to run the program is addressed amp 1 in this case type B1 CR point to beginning of program 1 then type R CR The B command with a number makes the specified program the working operative program f
468. rds For more detailed information refer to the Writing a Host Communications and Synchronizing PMACs to Other PMACS sections of this manual Bus Communications When the interface is a bus type interface e g PC bus STD bus or VME bus the distinction between cards is taken care of by hardware addressing This means that the different cards respond to different bus address locations as selected by the bus address lines The setup of the hardware addressing of multiple cards is done just as it is for single cards above one simply cannot put two different cards at the same hardware address on the bus Simultaneous Commands A little trickier task is to initiate simultaneous action on all boards because commands must be issued sequentially to the different boards However characters can be sent to all of the boards in sequence so quickly that this delay will not be the major limitation in keeping action simultaneous between the boards The commands should be sent so that everything except the carriage return character is sent to all of the boards then the CR command is sent to each board in rapid succession If checking for the write ready bits make sure they are true on all boards before sending the character to any board On a typical bus system send these characters one microsecond apart This is much faster than the approximately one millisecond software scan time of the command interpreters on PMAC so the commands are effectively
469. register is 39 specifying standard 24 bit addressing While there is many address modifiers possible only three are commonly used with PMAC VME PMAC VME Default Setup Register Values PMAC Default Description Memory Values Address X 0783 39 Address modifier AM X 0784 04 Address modifier Don t care bits In this example address modifier bit 2 is a don t care bit thus allowing AM 29 or AM 2D X 0785 FF PMAC base address bits A31 A24 not used when using A16 or A24 address bus X 0786 7F PMAC base address bits A23 A16 not used when using A16 address bus X 0787 A0 PMAC base address bits A15 A08 Selects base address with any address bus width which must be an even number i e address bit A08 must be 0 X 0788 02 Interrupt level X 0789 AI Interrupt vector number which is the upper number of a vector pair in this example we have the vector pair AO A 1 X 078A 00 Dual ported RAM starting address bits A23 A20 X 078B 60 Use E0 with DPRAM Use 60 without DPRAM X 078C 10 Address bus width select 30 selects A16 address bus 10 selects A24 address bus 00 selects A32 address bus Add 80 to these values when using DPRAM Address Modifier Don t Care Bits This register X 0784 simply states which bits of the address modifier are don t care bits In other words this tells which bits of the AM are ignored The factory default
470. rforming a move so it cannot be in position Sequential Moves If the program is in LINEAR CIRCLE PVT or SPLINE mode and there is more than one move command line in a program without a DWELL or DELAY in between there can be other statements in between the moves will blend together without stopping The exact form of the blending will depend on the move mode in force see the Program Trajectory section of this manual However if Ix92 for the coordinate system Move Blend Disable this blending capability is disabled Adding Logic A little logic can be added to make the language more powerful Suppose we wanted to repeat the above sequence 100 times Rather than repeating the above statements 100 times we can create a loop F5000 P120 WHILE P1 100 X10000 DWELL1000 x0 DWELL1000 P1 P1 1 ENDWHILE Notice that the F5000 statement is not inside the loop By putting it before the loop we save PMAC from having to interpret and execute the statement every time through the loop Since it is a modal statement its effect stays in force This is not essential but if loop time is very short it can make a difference Writing Programs for PMAC 14 39 PMAC User Manual Line Labels It is possible to put line labels in the motion program to mark particular sections of the program The syntax for a line label is N constant or O constant where constant is an integer from 1 to 262 143 Notice that these are line labels
471. riable Ix05 determines from which register Motor x gets its master position information The value of Ix05 is the address of the register This is almost always a register in the Encoder Conversion Table that contains processed information from a position sensor With the default setup of the Encoder Conversion Table the default value of Ix05 is the register address of processed data from Encoder 2 i e all motors use Encoder 2 as a master This setting permits a single master encoder to be brought in on the control panel port J2 and have any motor follow it if that motor s following function is enabled The master position is the source of data for the PMAC position following function often called electronic gearing This topic is covered in detail in the Synchronizing PMAC to External Events section of this manual Selecting the Flag Register Variable Ix25 determines which register Motor x uses for its flag inputs limits home flag amplifier fault and index channel and output amplifier enable direction The value of Ix25 is the address of the register Usually this is a control status register in the DSPGATE IC The default value of Ix25 is the register address of the control status register for Encoder x e g Motor 4 uses LIM4 LIM4 HMFLA FAULT4 CHC4 and AENA4 DIR4 In order to use the accurate hardware position capture function for homing the number of the flag set must match the number of the position loop encoder specified b
472. riggered time base entry will take on three values during the normal course of use This is done with an 8 bit M variable First with the slave axes dwelling at their starting position these process bits should be set to 90 in the sequence of motion program calculations for the first move This forces the time base value to Zero putting the coordinate system in feed hold mode Setting Up a Motor 7 23 PMAC User Manual Next another program usually a PLC program changes the bits from 90 to BO This arms the time base so that it is waiting for the position capture trigger on the source encoder as defined by Encoder Flag I variable 2 for that encoder When the capture occurs the time base starts up with the captured position register used as the initial value for the time base difference equations When this happens PMAC automatically changes the process bits from B0 to A0 For untriggered use of this format set the process bits to A0 Example For example if adding a triggered time base entry working from Encoder 8 to the end of the standard conversion table with a real time input frequency of 64 cts msec These entries would reside in registers 072A 1834 and 072B 1835 Initially we would write to Y 072A a value of A0CO1C running time base from Encoder 8 registers and to Y 072B a value of 800 131 072 64 2048 800 We define an M variable to the process bits with the command M199 gt Y 072A 16 8 With th
473. ring permits protection against spurious changes on high order data lines while not delaying legitimate changes at all This maximum amount is the third setup entry for the encoder in the Y column of the conversion table It should be set slightly greater than the maximum actual velocity expected on the sensor expressed in counts bits per servo cycle Converted Data The converted data from the parallel word is put in the X data word matching the last second or third setup word for the entry This is the address that should be used by the motor I variable that picks up position Ix03 Ix04 or Ix05 For instance if the first setup entry address Y 0720 in the conversion table were 30FFDO filtered parallel data the size entry would be in Y 0721 and the maximum change entry would be in Y 0722 The converted data would be placed in X 0722 If this were the position feedback for motor 1 1x03 would be set to 0722 1826 decimal For incremental parallel feedback bit 16 of Ix03 should be set to 1 for proper homing search moves Unshifted Conversion If bit 19 of the source and process word for a parallel data conversion is set to 1 the converted data contains no fractional bits Entries of this form would have the conversion formats bits 16 23 of this word 28 38 68 or 78 as opposed to the standard entries 20 30 60 and 70 which provide five fractional bits in the converted data Unfiltered Parallel Feedback
474. rn the motor shaft by hand and type P CR again The reported position should have changed Alternately use the F7 position reporting window of the PMAC Executive program which automatically polls position repeatedly Repeat this as often as needed to verify that the position counting is working properly in both directions If it is not check the following Is the encoder receiving power 4 5 V and GND Are both quadrature channels connected properly If single ended are the complementary lines floating If single ended is E27 or equiv in default setting If differential has E27 been changed Is the motor activated 110021 Is 1103 set to the proper encoder input Is I900 set for proper decode of the signal Can a signal be detected with a scope or voltmeter Changing Position Direction If getting position feedback but want to change the positive and negative directions use I900 for ENC 1 to change the direction sense or exchange the Channel A and Channel B inputs For example if I900 is 7 changing it to 3 will change the direction sense Setting DAC Output Range Check the output range by looking at 1169 This is the maximum value that can be written to the DAC whose full range is 32 768 to 432 767 16 bits for 10V The default value of 1169 is 20 480 which is about 6 25V If the amplifier is expecting 10V and the full range is being used set 1169 to 32 767 If the amplifier is expecting a different
475. rogram memory locations The amp l operators take one or two DSP instruction cycles The divide operator takes nominally 82 DSP instruction cycles e The modulo 46 operator takes nominally 76 DSP instruction cycles Writing a PLC Program 16 11 PMAC User Manual Integrating PLC Files Before using the standalone compiler PLCC EXE all of the PLC programs that are to be compiled must be combined into one file The CNC Executive program and the new general PMAC Executive program V3 x can use multiple files if the main file references all of the other files to be used with include commands The standalone compiler will only operate on one file assuming that it contains all of the PLC programs to be compiled It is acceptable to leave PLC programs that will not be compiled and other commands in the file The compiler will simply pass these through unchanged The standalone compiler cannot work with the define macros and include files that the PMAC Executive program editor and download routines use The substitutions into true PMAC code must be performed before the compiler starts The program PREPROC EXE can be used to perform these substitutions and integrate multiple files into a single file The preprocessor program PREPROC EXE or the compiler program PLCC EXE can be obtained from Delta Tau s bulletin board system To execute the pre processor program that performs the define macro substitution
476. rol even with poor coupling In this case the sensor on the load is used to close the position loop it is addressed by Ix03 above The sensor on the motor is used to close the velocity loop it is addressed by Ix04 The vast majority uses only one feedback encoder whether it is on the motor or on the load For these Ix04 will be set to the same value as Ix03 addressing the same encoder If only using one feedback encoder ENC1 for the Motor 1 in the example make sure I104 is set to 1824 just as 1103 is this is the default Flag Address Now make sure the card knows where to look for its limit and home flag inputs which is controlled by 1125 remember that this is essential to command a move To use LIM1 LIMI and HMFL1 1125 should be set to C000 49152 This should be the value set at the factory If not using overtravel limit switches and the limit pins have not been wired to ground set 1125 to 2C000 instead If the amplifier is expecting sign direction and magnitude command disable the use of AENAn DIRn as an amplifier enable line so it can be used for direction For motor 1 set 1125 to 1C000 If the limits should be disabled set 1125 to 3C000 Reading Position Now start checking on some basic motor functions First try to read motor position With the Executive program in terminal mode type 1 lt CR gt to address motor 1 Next type P lt CR gt and PMAC should return a position value to the terminal screen Now tu
477. rred it will re enter the interrupt service routine immediately and re evaluate the condition If this occurs repeatedly background routines will be starved for time slowing PLCs and communications or in the worst case tripping the watchdog timer Usually this happens only if multiple coordinate systems are in simultaneous WHILE WAIT loops Of similar speed is an empty WHILE ENDWHILE loop or at least one with no motion commands inside Each RTI this will execute twice stopped by the double jump back rule Calculations resume at the next RTI or if this has occurred already they resume immediately with the same possible consequences for starving background calculations Using a WHILE condition DWELL single line loop helps to control the looping rate better giving time for background routines The condition is evaluated only once after each DWELL Implications of Calculating Ahead The need of the motion program to calculate ahead during a continuous sequence of moves means that non motion actions particularly the setting of outputs taken by the program happen before it is thought they would by one or two moves For variables that are only used within the program this is no problem because everything happens sequentially within the program It is possible to move these non motion actions to a point one or two moves later in the program to get the actions to occur when they are desired However this makes the program extremely d
478. rs NA YES YES jut All NL Read A1 interrupt vector characters and acknowledge interrupt sent a NO Wait for interrupt Read mailbox regs until 1 CR encountered 2 lt ACK gt encountered 3 lt BELL gt encountered 4 All 16 regs have been read Read A0 interrupt vector and acknowledge interrupt Write 00 into maibox reg 1 Figure 56 PMAC VME Communications Flow Diagram 17 24 Writing a Host Communications Program PMAC User Manual PMAC VME Interrupt Vector Assignments PMAC VME Interrupt Vector Pair Card Number 0 A0 A1 1 A2 A3 2 A4 AS 3 A6 A7 4 A8 A9 5 AA AB 6 AC AD 7 SAE SAF It is possible to keep all of the PMACs in a rack completely synchronized by sharing clock signals over extra lines on the serial port To do this simply daisy chain a cable between all the PMAC VME J4 connectors in the rack If this method is used one PMAC VME must have jumpers E40 through E43 configured so it becomes card 0 since card O outputs the synchronizing clock All the other PMACs must have E40 E43 set for higher card numbers card 1 2 etc which input the synchronizing clock If the PMACs are not sharing a common clock signal all PMAC VMEs in the rack must have jumpers E40 E43 configured for card 0 Without the common clock signal action on the different cards can
479. rs sent before it These control characters can be sent in the middle of a line of alphanumeric command characters without disturbing the flow of the command PMAC will respond first to the control character command storing the text string until the CR character is received Command Acknowledgement The exact nature of the PMAC acknowledgement of commands and its data response is controlled by I variables I3 I4 and I9 with I3 as the most important If I3 is 1 PMAC acknowledges a valid alphanumeric command by sending the line feed LF ASCII value 10 character back to the host If I3 is 2 or 3 it uses the lt ACK gt character ASCII value 6 instead If I3 is 0 it does not provide any acknowledging character Regardless of the setting of I3 PMAC responds to an invalid command by returning the BELL character ASCII value 7 When working interactively with PMAC in terminal mode it is often nice to use the lt LF gt as acknowledgement because it spaces commands and responses automatically on the terminal screen Data Response When the command received requires a data response PMAC will precede each line of the data response with a line feed character if I3 is set to 1 or3 It will not do so if I3 is set to 0 or 2 PMAC will terminate each line of the data response with a carriage return character regardless of the setting of I3 For these commands the command acknowledgement character LF or lt ACK gt is sent after
480. rt The JPAN connector J2 on PMAC PC Lite VME and top board of PMAC STD is a 26 pin connector with dedicated control inputs dedicated indicator outputs a quadrature encoder input and an analog input The control inputs are low true with internal pull up resistors They have predefined functions unless the control panel disable I variable I2 has been set to 1 If this is the case they may be used as general purpose inputs by assigning M variables to their corresponding memory map locations bits of Y address FFCO 6 10 Input Output Connecting PMAC to the Machine PMAC User Manual Discrete Inputs Command Inputs JOG JOG PREJ return to pre jog position and HOME affect the motor selected by the FDPn lines see below STRT run STEP STOP abort and HOLD feed hold affect the coordinate system selected by the FDPn lines Selector Inputs Caution Do not change the selector inputs while holding one of the jog inputs low Releasing the jog input then will not stop the previously selected motor This can lead to a dangerous situation The four low true BCD coded input lines FDPO LSBit FDP1 FDP2 and FDP3 MSBit form a low true BCD coded nibble that selects the active motor and coordinate system simultaneously These are usually controlled from a single 4 bit motor coordinate system selector switch The motor selected with these input lines will respond to the motor specific inputs
481. rvo Loop 9 13 PMAC User Manual demand value ACTUAL A EQU 07F3 Address for the temp storage of actual value DAC_A EQU 07F4 Address for dac value ORG P B800 CLR B B10 L DEMAND A Save the demand in memory MOVE 1 B1 Bl 1 MOVE X SAMP A A Al counter ADD B A Y SAMP A YO Counter counter l YO samp factor SUB YO A A1 X SAMP A Compare counter with factor amp save count JMI ESERVO Skip if counter lt samp factor MOVE Al X SAMP_A Clear and save the counter MOVE Y DEMAND_A B Load demand position assuming 24 bit MOVE X1 A Load Actual position assuming 24 bit SUB A B Form the 24 bit error k Now execute the low pass filter and exit with value of DAC in the upper 18 bits of Al integer RND B X COEF A X1 Round B adding 1 to bit 23 of BO MOVE X OLD UF A XO B Y1 PXO uf k 1 Yl error k Xl al MPY X1 Y1 B Y COEF A YO B al error k Y0 a2 MACR X0 YO B B al error k a2 uf k 1 MOVE B X OLD UF A Save uf k ESERVO MOVE X OLD UF A A LOAD SAVED DAC VALUE MOVE A0 A1 REP 6 ASL A JMP 23 RETURN TO SERVO END C Program to Convert LOD File to PMAC Format LOD TO PMC CONVERSION PROGRAM 09 04 90 V1 0 include lt string h gt include lt stdio h gt include lt stdlib h gt FILE infile outfile Char buf 81 bufr 32768 Int 1 m n x y void main argc argv int argc char argv m 0 x 0 i
482. s To implement such a function activate an extra motor Ix00 1 and tell it to use the user written servo 1x59 1 The motor must be in a closed loop enabled state for the algorithm to execute this will happen automatically if Ix80 1 or it can be brought into this state with a J command Do not worry about where to pick up and leave off the servo information but be careful not to disturb anything else Simple User Written Servo Example A ENTER B demand angle integer H X actual angle integer a EXIT upper 18 bits of Al DAC integer r This servo routine executes a low pass filter of 7 the form uf k al error k a2 uf k 1 r Prior to enabling this routine al amp a2 should be E initialized in L COEF A cells Also Sampling H period factor and its counter should be A initialized in L SAMP_A Notice the sampling E period counter always should be less than the sampling period factor The content of the E sampling period factor cell represents an integer multiple of the hardware selected PMAC servo gt sampling period In this way the sampling frequency A may be reduced from the the PMAC default value r OLD_UF_A EQU 0770 Old UVAL after filter COEF A EQU 07F0 Filter coef al x mem a2 y mem SAMP A EQU 07F1 Sampling period factor y mem amp counter x mem DEMAND A EQU 07F2 Address for the temp storage of Closing the Se
483. s outportb combase 4 0 Set port for output enable Re enable interrupts To read an entire line in a single routine turn around the port at the beginning and end of the line Host Port Bus PC STDbus Communications Host Port Structure The host port interface of PMAC used for communications over the PC ISA and STD busses occupies 11 consecutive addresses of a 16 address region in the I O space of the host computer it is not memory mapped On the host side these registers are accessed with byte write and byte read commands such as outportb inportb outp and inp On the PMAC side the PMAC firmware takes care of the direct access to these registers in response to commands from the host Base Address Selection The location of the first of these 11 registers in the host computer s I O space the base address is selected by the settings of jumpers E91 E92 E66 E71 on the PMAC PC and PMAC Lite by jumpers W11 to W22 on the PMAC STD Refer to the Jumper Descriptions section of the manual for actual setting information The addresses of these registers range from base address to base address 10 Register Functions Each of these 11 registers has a function for host communications although only a few of them are used commonly and some are not used at all The functions of the registers are Register Functions Base Register Function Base 0 Interrupt Contro
484. s The commands to jog a motor are on line immediate commands that are motor specific they act on the currently addressed motor A jog command to a motor will be rejected if the motor is in a coordinate system currently executing a motion program even if the motion program is not commanding that motor to move PMAC will report ERRO01 if I6 is set to 1 or 3 Basic Motor Moves 11 1 PMAC User Manual Indefinite Jog Commands J commands an indefinite positive jog for the addressed motor J commands an indefinite negative jog J commands an end to the jog leaving the motor in position control after the deceleration It is possible for the J command to leave the commanded position at a fractional count which can cause dithering between the adjacent integer count values If this is a problem the J command can be used to force the commanded position to the nearest integer count value Jogging To A Specified Position Jog commands to a specified position or of a specified distance can be given J commands a jog to the last pre jog position J2 constant commands a jog to the unscaled position specified in the command J constant commands a jog to the unscaled position specified in the command and makes that position the pre jog position J constant commands a jog of the specified distance from the actual position at the time of the command 3 0 can be useful to take up remaining following error J constant commands a jo
485. s available for the PMAC internal use If using this flag internally make sure that the signal is latched M111 1 or it will be missed For interrupting the host edge triggered make the signal transparent The output enable bit M112 here determines whether the compare equal flag will be output on the EQU line 1 enables This must be set to use the signal either to interrupt the host or to trigger an external event directly The output invert bit M113 here determines whether the EQUn output is high true or low true 1 inverts to low true For host interrupt purposes set this high true Interrupting the Host on a Compare Equals If using this EQUn line to interrupt the host jumper the line to PMAC PC s 8259 Programmable Interrupt Controller PIC The jumpers for this purpose are in the range E54 to E65 along the bottom edge of the PMAC PC board The output from this PIC must be jumpered to a PC interrupt line using one of the jumpers E76 E84 Refer to the jumper tables and the Using the PMAC PC to Interrupt the Host Computer section Directly Triggering External Action To use the EQU lines to trigger external action from a PMAC PC put a connector on the E points E53 E65 that would jumper these signals to the interrupt controller an IDC 26 pin connector can work nicely There is no other connector to bring these signals out These signals must be buffered the TTL drivers for these outputs on PMAC PC are very weak On the PMAC Lit
486. s 15 3 PMAC User Manual Ix05 Master HW Position Address amp Mode Ix06 Following Enable Encoder uae Ix07 Master Scale Factor Ix08 Position Loop Load Scale Factor Hw J Lae Ix09 Velocity Loop Motor Scale Factor x c Can b an be e O i Ix06 changed on the fly 0720 0739 Ix07 Trajectory Y CP FE t To DAC Command jog peer e PI gt Cannot be changed on AP the fly D Actual Motor Position Ix09 Actual Poston 1x08 Figure 52 Position Following Parameters Real Time Input Frequency The PMAC method for doing this leaves the language expressing position as a function of time but makes time proportional to the distance covered by the master This is done by defining a real time input frequency RTIF from the master s position sensor in units of counts per millisecond For example an RTIF of 32 cts msec is defined Then in time base mode when the program refers to a millisecond what it is really referring to is 32 counts of the master encoder whatever physical distance that is If move is programmed in the slave program to take 2 seconds it will really take 64 000 counts of the master encoder to complete Constraints on Selection of RTIF If PMAC had infinite resolution and infinite dynamic range in its time base calculations the choice of real time input frequen
487. s and integrates the include files type PREPROC F filename at the DOS prompt where filename is the full name of the main file including the extension This program creates an output file with the same name as the input file but with a SRC output file It also creates a MAP file of the same name that contains the cross references between macro names and PMAC code Link Address File In the same subdirectory that contains the cross compiler there must be a file called LISTLINK TXT that the compiler will reference as it runs This file must contain the ASCII text returned by PMAC in response to a LIST LINK command This text contains the PMAC addresses of key subroutines to which the cross compiler must link the compiled PLC code It is specific to a particular version of PMAC firmware Any change in PMAC firmware even a sub version change for a bug fix e g from V1 15A to V1 15B requires a new LISTLINK TXT file re compilation of the PLCs and re downloading of the compiled code Executing the Compiler The standalone compiler is executed by typing PLCC F filename at the DOS prompt where filename is the full name of the input file including the extension The compiler will then execute either until successful completion or until it finds an error In the PMAC Executive programs the compiler is integrated into the download routine as long as the Compile on Download option has been activated If the compiler can compile the e
488. s as inputs What are actually being shared are the phase clock and servo clock signals which are divided down from the master clock as determined by the settings of jumpers E29 E33 and E3 E6 When sharing clock signals only the settings of these jumpers on card 20 matter The I10 servo period parameter on every board in the chain should match the jumper settings on card 20 When multiple cards are communicating on the same serial port they must share a common clock signal This is because the same jumpers or switches that control the software addressing E40 E43 or SW1 1 SW1 4 also control whether the clock signal is input or output so only one card in the chain can use its own clock signals all others must receive theirs through the serial port connector When multiple cards are communicating at separate hardware addresses on a common bus or are operating standalone it is optional whether they share the same clock signals To have them share a common clock signal use the jumpers or switches to set up one card as 20 and the rest as higher numbered cards and tie together the clock signals on the serial ports of all cards It may be easiest to tie all of the lines of the serial port together from card to card These jumper settings will not affect bus communications protocol in any way If not sharing clock signals on multiple cards in a bus application every card must be set up as 90 Connections Clock signals can be shared simply b
489. s second 9000 full Position Correction Drive Motor H Bridge Drive H Bridge Drive Figure 17 PMAC PMAC2 Direct Microstepping System Setting the I Variables Setting up a motor for microstepping is simply a matter of setting motor I variables according to the following list Since there is no feedback there is no tuning necessary Commutation Positon Trajectory Generation Ix01 Set to 1 to enable PMAC commutation Ix02 Set bits 0 to 15 to the lower address of the pair of output DACs you wish to use C002 for DACI amp DAC2 C00A for DAC3 amp DACA Set bit 16 to 1 to tell PMAC it is microstepping this motor For example 1102 1C002 Ix03 Ix04 Set both of these to a register in the encoder conversion table that has processed data from the phase position register That entry in the table should be set up as follows Ist Y register 600041 60 is parallel X word source 0041 is motor 1 phase position Use 60007D for motor 2 Use 6000B9 for motor 3 8 14 Setting Up PMAC Commutation PMAC User Manual Use 6000F5 for motor 4 Use 600131 for motor 5 Use 60016D for motor 6 Use 6001A9 for motor 7 Use 6001E5 for motor 8 2nd Y register 0000FF Only use lowest 8 bits Remember to point Ix03 and Ix04 to the second line of the entry For example WY 720 600041 0000FF sets up the conversion table entry 11032 721 and 1104 721 point to it 721 1825 decimal Ix08 Ix0
490. s taken up smoothly over the course of the move This allows smooth compensation for round off errors For circles using the Radius center specification the R format as opposed to I J K format each coordinate system has an I variable Ix96 that determines the limit in distance difference for which this compensation will be done Above this limit a run time error will be generated and the program will stop This limit helps distinguish between round off errors and major mistakes Regardless of this limit if the distance from starting point to center or from ending point to center is zero an error will be generated and the program will stop If the specified vector does not lie in the plane of interpolation the projection of that vector into the plane is used Move Segmentation PMAC computes circular trajectories through a rapid and continuous cubic spline technique The spline segments are of a time specified by 113 in units of milliseconds Typically a value of 5 to 10 milliseconds will be used depending on the number of axes being controlled by the card When I13 is greater than zero all blended moves linear and circular are computed through this ongoing cubic spline 14 16 Writing Programs for PMAC PMAC User Manual technique If I13 is zero linear moves are not computed using this spline technique and circular moves are not permitted if a circular move is requested it will be done as a linear move The difference in the
491. s the old version in PMAC so the new version can replace it There is no reason in this process to upload the program from PMAC The program editor maintains its copy even after the download and it keeps comments with it The only reasons to upload a program are to confirm that it is downloaded properly and to restore a program that was lost by the host computer 2 16 Getting Started with PMAC PMAC User Manual Writing and Executing a PLC Program PLC programs are useful for doing monitoring and calculations in background asynchronously to any motion programs They are written much like motion programs and have much of the same language although no motion commands There can be up to 32 PLC programs which can be enabled and disabled individually The enabled programs cycle through continually in background as time allows Start by writing a simple PLC program that increments a variable each time through Using either Terminal mode or preferably the Program Editor in the Executive Program type the following CLOSE OPEN PLC 1 CLEAR P1 P1 1 CLOSE If using the Editor download what has been written to PMAC by selecting the Download Editor to PMAC menu option or by typing lt ALT D gt Now see if the program got to PMAC properly From the Terminal mode type LIST PLC 1 CR The following response should appear P1 P1 1 RETURN PMAC automatically adds a RETURN statement short form RET to the end of a
492. s therefore cannot be nested within each other however a single PRELUDE subprogram call may be nested within explicit subroutine and subprogram calls and explicit subroutine and subprogram calls may be nested with a single automatic PRELUDE subprogram call A new PRELUDE1 command supersedes the existing PRELUDE1 command A PRELUDEO command no arguments necessary turns off the PRELUDE function Running a Motion Program Once the motion program has been entered and the program buffer closed execute the motion program Since PMAC can store multiple programs at once the first thing to do is to tell the PMAC coordinate system which program to run remember that it is a coordinate system in PMAC that executes a motion program different coordinate systems may be executing other motion programs at the same time Pointing to the Program Pointing to the program is done with the B constant command where the constant represents the number of the motion program buffer Use the B command to change motion programs and after any motion program buffer has been opened Do not use it if repeatedly running the same motion program without modification When PMAC finishes executing a motion program the program counter for the coordinate system is set automatically to point to the beginning of that program ready to run it again Use the PC program counter command to see which program the coordinate system is pointing to at the time A response is rec
493. set to get the absolute position Ix75 specifies the difference between the sensor s zero position and the phase cycle s zero position in units of counts Ix70 After reading the power up reset position from the absolute sensor PMAC adds this value and writes the resulting sum to the phase position register Set up Phasing Search To set up for the absolute phasing first do a phasing search on the motor not utilizing the absolute power on position All of the directions for setting up the commutation with an incremental sensor apply here These tasks should be done with an unloaded motor for maximum accuracy Assure that a phasing search on the motor can be done consistently using the stepper motor method implemented in the PLC program shown in this manual and the motor can be turned in both directions with small open loop commands e g 05 0 5 This phasing search can also be done with four on line commands as shown below 8 6 Setting Up PMAC Commutation PMAC User Manual Once confident that the commutation algorithms with the stepper motor phasing search are working well determine the phasing offset required for phasing with the absolute sensor First define an M variable to read the absolute sensor For a resolver read through the ACC 8D Option 7 R D converter board this is a TWR form of M variable For a sensor such as an absolute encoder read as parallel bits usually through an ACC 14 I O board this is a Y form of M variabl
494. seven active background interpreted PLCs each background compiled PLC will execute seven scans for each scan of a background interpreted PLC 16 6 Writing a PLC Program PMAC User Manual Preparing Compiled PLCs Preparation of compiled PLCs is a multi step process The basic steps are as follows Write and debug the PLC programs in interpreted form e Change all references to PLCs to be compiled from PLC to PLCC e For integer arithmetic define L variables and substitute these for the old variable names in the programs Combine all of the PLC programs to be compiled into one file on the PC substituting true PMAC code for the macro names e With the Compile on Download feature of the Executive program active download the files to PMAC using the Download function e Activate the compiled PLCs If operation is not correct return to step 1 or 2 Each of the above steps is explained in detail below Preliminary Debugging It is advisable to do most of the debugging of PLC program code in interpreted form The ease of repeated editing downloading and execution makes multiple trials fast and easy using the PMAC Executive program and the PMAC Once debugging is substantially complete in interpreted form it is quite easy to change to compiled form Changing PLC References All references to the PLC programs that are to be compiled must be changed from PLC to PLCC Each PLC program that is to be compiled must be headed with a
495. should be used Backlash Hysteresis I99 controls for all motors on PMAC the number of counts in the new direction of the commanded position that must be seen before PMAC determines that a reversal has occurred and the backlash must be changed As such it acts as a hysteresis term It is particularly important if a master encoder is used to drive the motor so slight dithering in the master encoder does not cause repeated introduction and removal of backlash 199 has units of 1 16 count so the default value of 64 provides a 4 count hysteresis Backlash Tables A backlash compensation table created with the DEFINE BLCOMP command can be used to create backlash distances that vary with the position of the motor Most often this is used in conjunction with a leadscrew compensation table to create the effect of a bi directional leadscrew compensation table The value of backlash distance for a given motor position derived from the backlash table is added onto the Ix86 constant backlash parameter The backlash distance from the table at motor position O home position is zero by definition so if a backlash table is used Ix86 should contain the amount of backlash at the home position The table then should hold the differences from this amount Note Typically while the range and spacing of a backlash table will be the same as for the leadscrew compensation table for the same motor this is not required Even the presence of a leadscrew compens
496. sition value on the motor index pulse perform a power on phasing search move to establish a precise phase reference then read the value of the phase position register Mx71 at the index pulse monitoring the pulse either on an oscilloscope or the matching M variable on PMAC This value can be stored in the Ix75 phase position offset variable which is not used by the automatic firmware in this mode In actual operation this value can then be copied into the phase position register Mx71 after homing to the index pulse The full phase reference then consists of the following steps e Doarough phase reference using the hall effect sensors as specified by Ix81 either automatically on power up reset if Ix80 1 or on the command if Ix80 0 Do a homing search move on the motor using the index pulse as part of the home trigger e Wait for the motor to settle in position following error less than Ix27 at the home position using the motor in position status bit suggested M variable Mx40 WHILE M140 0 e Force the motor phase position register to the pre determined value at this point with a command like Mx71 1x75 Phase Advance A velocity phase advance gain term Ix76 allows the phasing sequence to be advanced in the direction of motion by an amount proportional to the velocity to counteract computational delays and current lags in the motor and amplifier This feature can significantly increase the top speed of the motor and greatl
497. sive Servo Loop Tuning The PMAC Executive Program for PC compatibles has a large section devoted to assisting the user in optimizing the servo loop parameters for a motor It allows performance of step moves and profiled moves and the response is plotted to the screen with key statistics calculated so that easy choices may be made about changing gains This process is documented in detail with examples in the manual for the PMAC Executive Program In addition there is an auto tuning feature that lets the Executive program make the decisions about what the gains should be The program excites the system evaluates the response and calculates the gains necessary to achieve the desired response Remember that precise tuning cannot be done until the load has been connected to the motor Our goal at this point is simply to get the motor moving reasonably well without a load Jogging Moves With these two parameters 1130 and 1131 at reasonable levels good performance in moves should be achieved Try a jog move first Before doing the move set up the jog speed I122 in counts msec acceleration time 1120 in milliseconds and S curve time 1121 in msec to desired values to be safe use low speed and high acceleration times at first Now type J CR the motor should turn in the positive direction Getting Started with PMAC 2 13 PMAC User Manual Type J CR and the motor should stop If it takes a while to stop either slow down
498. statement PMAC supports both simple and compound conditions A condition in a command line IF or WHILE must be surrounded by parentheses Simple Conditions A simple condition consists of three parts expression comparator expression If the relationship between the two expressions defined by the comparator is valid then the condition is true otherwise the condition is false Examples of simple conditions in commands are WHILE 1 2 always true IF P1 gt 5000 WHILE SIN P2 P1 gt P300 1000 Notice that parentheses are required around the condition itself Computational Features 13 21 PMAC User Manual Unlike in some high level languages a PMAC condition may not be simply a value evaluated for zero or non zero e g IF P1 is not valid It must explicitly be a condition with two expressions and a comparator Compound Conditions A compound condition is a series of simple conditions connected by the logical operators AND and OR The compound condition is evaluated from the values of the simple conditions by the rules of Boolean algebra In the PMAC AND has execution precedence over OR that is ORs operate on blocks of ANDed simple conditions PMAC will stop evaluating compound AND conditions after one false simple condition has been found Examples of compound conditions in command lines are IF P1 gt 20 AND P1 lt 20 WHILE P80 0 OR 1120 gt 300 AND I120 400 IF Q16 Q17 AND Q16 gt Q18 OR M136 lt
499. ster Itis a good idea in the initial set up to compute a timeout value related to the host computer s speed As the host polls PMAC to see if it is ready to communicate a counter increments if the counter exceeds the timeout value the host should give up on this attempt to talk to PMAC Depending on the circumstances it should either just try again later as when waiting for some asynchronous communications or assume there is an error condition A good equation for the timeout value is timeout 7 speed 100 where speed is 1 or 2 for a PC XT 3 or 4 for a 286 based computer 5 to 6 for a 386 based computer and 7 to 9 for a 486 based computer Sending a Character To send a character the host simply waits for the Write Ready Bit to go true and then writes the character to the output port as this sample C code segment shows i 0 Reset counter while 4 timeout amp amp inportb combase 2 amp 2 Loop until bit true if i lt timeout outportb combase 7 outchar Write character Reading a Character To read a character the host waits for the Read Ready Bit to go true then reads the character from the input port as this sample C code segment shows i 0 while i lt timeout amp amp inportb combase 2 amp 1 Loop until bit true if i lt timeout inchar inportb combase 7 Read character Using the PMAC PC STD to Interrupt the Host Computer The PMAC PC PMAC Lite
500. t be used between the second and third source entries This is accomplished by reading the output of the second entry the first summed entry with an entry using the 68 format This entry can then be summed into a third source entry using the standard technique PMAC Encoder Conversion Table X Memory Results Y Memory Set up 1 Single Line Entry Bits Bits Bits Bits 5 23 0 4 16 23 0 15 Result Integer Fraction Method Source Address 2 Multi Line Entry Bits Bits Bits Bits 5 23 0 4 16 23 0 15 Intermediate Result Method Source Address ecc Conversion Factors Result Integer Fraction ecc Figure 10 PMAC Encoder Conversion Table Principle Setting Up a Motor 7 15 PMAC User Manual Possible Conversion Formulas Y Word Conversion Type No of Bits 16 23 Rows 0x 1 T extension of incremental encoder 1 1x A D register no rollover 1 2y Parallel position from Y data word no filtering with rollover 2 3y Parallel position from Y data word with filtering with rollover 3 4x Time base conversion scaled digital differentiation 2 50 Integrated analog 2 6y Parallel position from X data word no filtering with rollover 2 7y Parallel position from X data word with filtering with rollover 3 8x Incremental encoder with parallel sub count extension 1 90 Triggered time base frozen 2 A0
501. t CR gt lt 72dec gt 72 10 49 13 lt LF gt 2 lt CR gt lt 73dec gt 73 10 50 13 lt ACK gt lt 3690r113dec gt 369 81 49 48 46 46 49 50 113 369 modulo 256 Data Gathering PMAC has a general purpose data gathering function for repetitive on the fly storage of real time data In this function PMAC can store the contents of up to 24 memory locations at specified intervals up to the servo interrupt frequency This data is stored in a buffer in open PMAC memory for later transmission to the host This feature is useful for filter tuning and motion problem solving Executive Program Data Gathering Usually this feature is used in conjunction with the PMAC Executive Program on the PC which handles the details of this function automatically Refer to the Executive Program manual for details It is possible although not trivial to write a custom host program to utilize this feature Gathering l Variables Specify up to 24 source addresses in I variables 121 to 144 The low 16 bits of these variables represent the word address itself The top 2 bits control whether the X word the Y word or both in fixed or floating format will be gathered A mask is set in I20 to specify which of these addresses will be collected and the gathering period is defined in servo interrupt cycles with I19 Writing a Host Communications Program 17 27 PMAC User Manual Gathering Commands The buffer in the PMAC memory is set up with the on li
502. t cannot be assigned to combinations of motors A rotary axis must be named A B or C The rollover is technically a motor function specified by Ix27 for motor X but it can only operate when the motor is assigned to a rotary axis Rollover permits the motor to take the shortest path around the rotary range when an absolute axis move is specified in a program Feedrate Axis A feedrate axis is an axis in a coordinate system that figures into the calculations of a feedrate specified move The time for a feedrate specified move is calculated as the vector distance for the feedrate axes divided by the feedrate itself If other axes are commanded to move in the same statement they will be linearly interpolated over this same computed time The default feedrate axes are the Cartesian axes X Y and Z This setting can be changed with the FRAX feedrate axis command Axis Motor Position Re matching There is only one type of calculation in which PMAC converts from commanded motor position to commanded axis position This is in the PMATCH position match function This is needed in only a few cases First when a motor function such as a jog move open loop move or a stop on abort or limit has changed the motor commanded position since the last axis move or home search move In other words the axis does not know where the motor has gone In order for the next axis programmed move to function properly the axis must be told where it is start
503. t cycle with a frequency specified by variable I8 every I8 1 servo cycles This program is meant for a few time critical tasks and it should be kept small because its rapid repetition can steal time from other tasks Caution A PLC 0 that is too large can cause unpredictable behavior and can even trip the PMAC Watchdog Timer by starving background tasks of time to execute PLC programs 1 through 31 operate continually in background as time allows effectively in an infinite loop They get interrupted by the higher priority tasks of motor phasing servo loop closure more planning and PLC 0 Writing a PLC Program 16 1 PMAC User Manual Entering a PLC Program The PLC program statements are entered as buffered command lines into PMAC In preparation it is a good idea to make sure no other buffers have been left open by issuing a CLOSE command It is also good practice to make sure that memory has not been tied up in data gathering or program trace buffers by issuing DELETE GATHER and DELETE TRACE commands Opening the Buffer For each PLC program the next step is to open the buffer for entry with the OPEN PLC n statement where n is the buffer number Next if there is anything currently in the buffer that should not be kept it should be emptied with the CLEAR statement PLC buffers may not be edited on the PMAC itself they must be cleared and re entered If the buffer is not cleared new statements will be added onto the en
504. t higher register as well with the most significant bit specifying whether the quantity is to be treated as a signed or unsigned value and the second most significant bit bit 22 specifying whether the data comes from an X register or a Y register Valid values for the number of bits in this mode are 8 to 48 08 to 30 If the most significant bit value 80 is set to 1 giving a range for the high eight bits of 88 to B0 the number read from the sensor is treated a signed quantity with a range of 2N 1 to 2N 1 where N is the number of bits If the MSBit of Ix10 is zero the sensor value is treated as an unsigned quantity with a range of O to 2 1 Virtually all parallel I O sources map into Y registers in PMAC so usually bit 22 X Y specification is set to 0 to specify a Y data source Example As an example for a 22 bit absolute encoder on Port B of the first ACC 14 Y FFD1 to be read as an unsigned quantity Ix 10 would be set to 16FFD1 16 hex is 22 decimal to be read as a signed quantity Ix10 would be set to 96FFD1 For a 32 bit absolute sensor with the low 24 bits at Port A of the first ACC 14 Y FEDO and the high eight bits at Port B Y FFD1 to be read as an unsigned quantity Ix10 would be set to 20FFDO 20 hex is 32 decimal to be read as a signed quantity Ix10 would be set to AOFFDO Note A sensor with parallel data output is not necessarily an absolute sensor Laser interferometers often present t
505. t n 1 Example Starting with the default encoder conversion table which occupies registers 0720 to 0729 to add a new entry to the table that filters the handwheel encoder that is wired into Encoder 5 on PMAC the filter is to have a time constant of eight servo cycles and the maximum velocity of the output is to be 16 counts per servo cycle In the default table the 1 T interpolation result for Encoder 5 is placed in register X 0724 This is the source address for the exponential filter Since the time constant of eight servo cycles is equal to 8 388 608 divided by filter gain K then K is equal to 1 048 576 The units LSBs of the source register are 1 32 count so the maximum change value is 32 16 or 512 LSBs per servo cycle These values can be entered into the interactive menu of the PMAC Executive program V3 0 or newer or they can be entered with a direct memory write command WY 072A D00724 512 1048576 Y 072A is the starting location of the entry in PMAC memory D0 specifies the exponential filter 512 or 200 specifies the maximum output change rate 1048576 or 100000 specifies the filter gain If the filtered value were to be used as a master encoder x05 would be set to 072C Setting Up the Encoder Conversion Table The encoder conversion table starts at address 720 1824 decimal in the PMAC memory It can continue through address 73F 1855 decimal The active part of the table is ende
506. t need all of these words are needed in the declaration the first void says that the routine will not return a value interrupt specifies this as an interrupt service routine far declares the address referred to in setvect to be a far pointer pmac comm is the name of the routine called in setvect the second void declares that this has no arguments since it cannot Writing a Host Communications Program 17 11 PMAC User Manual The interrupt routine should first disable PC interrupts for just long enough to make sure the necessary tasks can be done Then it should write an End of Interrupt byte to the PC PIC I O port address 20 hex This byte has a high nibble of six and a low nibble with the IRQ line number For instance if IRQA is used the TurboC statment to do this is outportb 0x20 0x64 As soon as possible the PC interrupts should be re enabled When this can occur depends on how the program is structured Now write an End of Interrupt byte to the PMAC PIC The byte is the same six in the high nibble hardware input IR line number in the low nibble For the PMAC PIC this byte is written to the card s base address plus eight in the PC s I O port space This could be done with an outportb command Of course somewhere in here take the action that needs to be taken on receiving the interrupt whether it is simply reading a character sending a command line or finding an error condition Restoring Previous
507. t not need Encoder Conversion Table entries 6 to 9 PLCO could maybe be done as PLCC1 or the RTI could be done every fourth or fifth servo cycle 13 2 Computational Features PMAC User Manual Second is to adjust the jobs at a priority level to give them less emphasis Large PLC programs can be split into a few shorter PLC programs This increases the frequency of housekeeping and communications by giving more breaks in PLC scans Motion program WHILE condition WAIT statements could be done as follows WHILE condition DWELL20 ENDWHILE This will give more time to other RTI jobs such as Move Planning and PLC PLCCO Numerical Values PMAC can store and process numerical values in many forms with both fixed point and floating point values The Motorola 56000 DSP that acts as the PMAC CPU is a fixed point processor with built in 24 bit and 48 bit arithmetic capability plus a 56 bit accumulator However the PMAC firmware implements a full set of floating point routines Internal Formats The internal servo interpolation and commutation routines all operate with fixed point arithmetic 24 bit and 48 bit for maximum speed The user programs motion and PLC use floating point arithmetic for maximum range and generality Even when reading from and or writing to fixed point registers the intermediate formats are all floating point values The only exception to this rule is the new compiled PLC programs in a statement containing
508. t physically separate from the motor power cable if at all possible Second both of these cables should be shielded the motor cable to prevent noise from getting out and the encoder cable to prevent noise from getting in These shields should be grounded at the inward end only that is to the device that is itself tied to a ground Twisted Pairs A third important noise mitigation technique is to twist the leads of the complementary pairs around each other With these twisted pairs what noise does get in tends to cancel itself out in opposite halves of the twist Encoder Signal Sampling After the front end processing through the differential line receivers the encoder signals are sampled digitally at a rate determined by the SCLK encoder sampling clock frequency SCLK is divided down from the master clock frequency by an amount determined by jumpers E34 to E38 The default setting is E34 ON which gives SLCK half the frequency of the master clock which on the standard board is about 10 MHz 6 4 Input Output Connecting PMAC to the Machine PMAC User Manual E35 ON gives it one fourth the frequency E36 one eighth and E37 one sixteenth Setting E38 ON provides an external SCLK signal on CHC4 and CHC4 inputs The SCLK frequency used sets the upper limit on the possible count rate in actual use the maximum count rate should be considered about 2096 lower allowing for imperfections in the input signals Digital Delay Filter E
509. tas enses enses sone ta coc rco non noc conose snae 1 QV ELVIS W E 1 Preparing the Card siii iii di cr doe suueevos ER SO EEE 1 EXPOME JUMPE S igisining nni p e so ddevwesdedead senesced oassnbeadedeisuaced sacs dsneadeesiedwecseseady 1 Card Number Jumpers eese ee ese esee eee teeth then nennen a nn RR RRA RARA RR NARRAR ARAN RR ne enee trennt teint tnen tenente enne trennen nnne 1 Communications Baud Rate Jumpers eee esee esee entente teen tnene then nnne trennt tee nennen etre trennen enne nnsn nete 2 PEDUS Address JUmpers ad eines iun drid 2 STDbus Address Jumpers esee eene tete nee enne then RR RR enn RRA RR RR tritt teet ne tnee trennt te enne teste tenete enne te innen nnne 2 PMAC VME Interface Setup eret reete R ete a RE EE lee a SERERE e aep aeg eus eode usd casei gn 2 Encoder Jumpers ELE 2 Analog Circuit JUMPErS visitada cir cid E E EEE R EEE I a E E E EE i ii 3 Re initialization JUMPED E centona asii e se ioe aenta E ERA EEEE N E EEEE Eaa E EERS 3 Standard and Option 5 IN AAA 3 PMAC with Options 4A SA and 5B eee RRA Ranas 3 Connecting PMAC to the Host Computer nete ener nenne nre netten etes nete nete en nr nan trennen 4 Bus COMME CHON MEN EERS 4 Serial Port COMME CHON m X w MM 4 Installing the PMAC Executive Program e
510. te 1 Occurs Home Search in Progress 0 Home Complete 0 Home Search In Progress 1 Net distance from trigger position 1x26 Time gt x21 x21 A x x20 A Hate of acceleration limited by Ix19 can override 2t M pet p Ix21 Ix20 and Ix21 Ix20 Ix20 Desired Velocity Zero 1 In Position 1 when FE in range A Figure 22 Homing Search Move Trajectory Trigger Signal s amp Edge s Once the set of flags for the motor have been specified with Ix25 use Encoder Flag I variable 2 1902 1907 etc to tell PMAC whether to use a flag the index channel or both as the capture trigger and which edge of the flag and or the index channel to use Next use Encoder Flag I variable 3 1903 1908 etc to specify which of the four flags HMFLn LIMn LIMn FAULTn is to use for the capture If using a limit or a fault flag for home capture disable the normal function of that input by setting high bits of Ix25 at least for the duration of the homing search move Torque Mode Triggering Normally the trigger condition for homing search moves jog until trigger moves and motion program move until trigger moves is an input flag signal transition Sometimes it is desired that a trigger occur when an obstruction such as a hard stop is encountered To support this type of functionality PMAC permits triggering on a warning following error condition instead of an input flag This is s
511. tection PMAC can be set up to fault a motor if the time integrated current levels exceed a certain threshold This can protect the amplifier and or motor from damage due to overheating This type of protection is commonly known as TT eye squared tee because it measures integrates the square of current over time power dissipation is proportional to the square of current Some amplifiers have their own internal TT protection but many others do not The PMAC TT protection can be used in either case It reads the PMAC commanded current registers to determine current levels so it can be used without bringing actual current measurement signals into PMAC It can be used with any amplifier for which PMAC computes current commands whether or not PMAC also performs the commutation and or digital current loop functions It is not suitable for use in systems where PMAC outputs a velocity command either analog velocity or a pulse frequency Note The PT protection feature is not available on PMACS with the Option 6 Extended Servo Algorithm firmware Ix57 and Ix58 have other functions in that firmware version Two I variables control the functioning of the TT protection for each motor Ix57 is the continuous current limit magnitude It has the same units as the Ix69 instantaneous output limit bits of a 16 bit DAC even if some other output device is used Both have a range of 0 to 32 767 where 32 767 is the PMAC maximum possible output magni
512. tells it where to look for its time base information This variable is Ix93 for Coordinate System x The default values for Ix93 are the addresses of registers that are under software control not the control of an external frequency For a coordinate system to be under external time base control put the address of the scaled time base value determined above For instance in the default conversion table this value is at address 729 1833 decimal so if Coordinate System 1 were to be controlled by this frequency 1193 would be set to 1833 this is always an X memory word so X does not need to be specified Once this I variable has been set up all motors assigned to this coordinate system will be under the control of the external frequency in programmed and non programmed moves I variable Ix94 controls the maximum rate of change of the time base value for Coordinate System x When commanding the time base value from the host with a n command this value should be set fairly low to produce a nice slewing to the new commanded value However to keep synchronized to an external signal as time base source this value should be set as high as possible maximum value is 8 388 607 so the time base can always slew as fast as the signal Setting the value low can improve following smoothness at the cost of some slip in the following If the Ix94 limit is ever used in external time base position synchronization to the master is lost Step 5 Writing t
513. tem because motors that are not in any coordinate system use Coordinate System 1 s time base control feedrate override Spindle speed values simply are scaled and put into jog speed I variables Ix22 and the spindle on off functions simply command jog starts and stops see M03 M04 and M05 Open Loop Spindle If using the open loop spindle write directly to an otherwise unused DAC output register by use of an M variable For instance the definition M425 gt Y C00A 8 16 S matches the variable M425 to the DAC4 output register Any value given to this M variable will cause a corresponding voltage on the DAC4 output line In this method a spindle on command see M03 M04 could be M425 P10 or M425 P10 where P10 has been set previously by an S code The spindle off command see MO5 could be M425 0 Switching Between Spindle and Positioning There are cases where the spindle motor is sometimes used as a regular axis doing position moves instead of steady velocity and sometimes as a regular spindle In this case the spindle motor will be made an axis in the main coordinate system so it can do coordinated moves When real spindle operation is desired a pseudo open loop mode can be created by setting the motor s proportional gain to zero and writing to the output offset register Ix29 In this method Ix29 would be treated just as M425 was in the 14 48 Writing Programs for PMAC PMAC User Manual above paragraph Of course a v
514. tem Variables 14 4 Writing Programs for PMAC PMAC User Manual SPECIFY t AND t AND ACCELERATION LIMIT ACCELERATION gt Parabolic E Sinusoidal For Comparison 4 t L 0 gt 3 2a f og 3 Ucca 7 2 2 gt t amp 2 ts 0 1 gt t acol 24 0 TIME gt Parabolic sinusoidal VELOCITY t ten gt 26 for comparison em lt t gt lt t t gt s j i s j MAX gt 3 np 2ts gt t k 2 ts 0 1 E accer t 0 TIME ACCEL taccer 2k t Figure 27 Automatic S Curve Acceleration 14 5 Writing Programs for PMAC PMAC User Manual Feedrate or Move Time Specification The target velocity feedrate for the move can be specified with an F command or the move time with the TM command If F is specified the move time is calculated and if TM is specified the feedrate is calculated The relationship between the two values is reciprocal for a given move distance In either type of specification remember that there is an extra TA time at the end of a move or move sequence to decelerate to a stop That is a single move with a specified TM will take TM TA time from start to stop An N segment move will take SUM 1 1 to N ITMj TA 2 TAN 2 to complete The same is true of feedrate specified moves except that TM is calculated as distance divided by feedrate for each segment instead of specified directly Note Feedrate is a magnitu
515. tem the host is addressing Changing the host s addressing mode s does not affect the program s or vice versa Also independent of the host addressing the control panel selects a motor and coordinate system for its hardwired inputs to affect with its BCD coded low true FDPn lines determined by a rotary switch on Delta Tau s ACC 16 Control Panel Talking to PMAC 4 5 PMAC User Manual Motor Commands There are only a few types of motor specific commands These include the jogging commands a homing command an open loop command and requests for motor position velocity following error and status Coordinate System Specific Commands Coordinate System Addressing A coordinate system is addressed by a amp n command where n is the number of the coordinate system with a range of 1 to 8 inclusive This coordinate system remains the one addressed until another amp n command is received by the card For instance the command line amp 186R amp 2B8R tells Coordinate System 1 to run Motion Program 6 and Coordinate System 2 to run Motion Program 8 Coordinate System Commands There are a variety of types of coordinate system specific commands Axis definition statements act on the addressed coordinate system because motors are matched to an axis in a particular coordinate system Since it is a coordinate system that runs a motion control program all program control commands act on the addressed coordinate system Q variable assig
516. ter Arc AIC ol Center enter Path 7 Path Right Path Left Line to Line Line to Arc Inside and Outside Tool Center 9 Path Arc N ua pi Programmed Path xcd gt Programmed A ee A Path BW La Kat teo nentar Siy Arc to Arc Outside Arc to Arc Inside Figure 43 Reversal in Cutter Compensation Note on Full Circles If a full circle move is executed while in cutter compensation and one or both of the ends produces a shallow outside corner that is directly blended no added arc see the previous section Treatment of Outside Corners the compensated arc move will be extended beyond 360 and PMAC may produce just a very short arc 360 shorter than what is desired making it appear that the circle has been skipped Typically while this is the result of sloppy programming an outside corner with a full circle causes an overcut into the circle many machine designers may want to permit slight cases of this Coordinate system parameter Isx97 defines the shortest arc angle that may be executed the longest arc angle is 360 plus this angle The default value of Isx97 sets a minimum arc angle of one millionth of a semi circle enough to account for numerical round off but sometimes not enough for compensated full circles To handle these cases Isx97 should be set to a somewhat larger value 14 28 Writing Programs for PMAC PMAC User Manual Failure When Compensation Extends Full Circle Tool Cent
517. ter position that occurred when the starting trigger occurred usually the index channel of the master encoder This provides a complete position lock of the slave to the master there is no need for subsequent adjustment to make sure that they are phased in as would be the case for normal untriggered time base control Entry Format Unlike the normal untriggered time base conversion the source address must be that of the encoder registers in the DSP GATE with the raw unprocessed data The triggered time base conversion does the 1 T interpolation itself The valid addresses for triggered time base entries are the same as those for the Incremental Encoder Entries C000 for Encoder 1 C004 for Encoder 2 and so on to C03C for Encoder 16 Triggered Time Base Conversion X Words Y Words 1 Lastcycle s source data 1 Source and process Bits 0 4 Fractional bits Bits 0 15 Address of source always a set of Bits 5 23 Integer Bits DSPGATE encoder registers Bits 16 23 90 frozen for preparation BO armed waiting for trigger SAO running post trigger 3 Actual time base value Whenrunning 2 Time base scale factor supplied by user the product of scale factor and difference equal to 131 072 real time input frequency between last two source values in cts msec Setting the Trigger State The process bits bits 16 to 23 of the first Y word in the conversion table entry of a single t
518. tes the memory that had been reserved for it How PMAC Executes a Motion Program It can be important to know how PMAC works its way through a motion program A motion program differs fundamentally from a typical high level computer program in that it has statements moves DWELLs and DELAYs that take time there is an important difference between the calculation time and the execution time Basically a PMAC program exists to pass data to the trajectory generator routines that compute the series of commanded positions for the motors every servo cycle The motion program must be working ahead of the actual commanded move to keep the trajectory generators fed with data If the program fails to keep ahead and the time for the next move comes without the proper data in place for the trajectory generators PMAC will abort the program and bring all motors in the coordinate system to a stop Calculating Ahead PMAC processes program lines either one or two moves including DWELLs and DELAYs ahead Calculating one move ahead is necessary in order to be able to blend moves together calculating a second move ahead is necessary if proper acceleration and velocity limiting is to be done or a three point spline is to be calculated SPLINE mode For linear blended moves with 113 move segmentation time equal Writing Programs for PMAC 14 53 PMAC User Manual to zero disabled PMAC calculates two moves ahead because the velocity and acceler
519. that was done during development Setting bit 23 of Ix81 to 1 specifies a hall effect power on phase reference In this case the address portion of Ix81 specifies a PMAC X address usually that of an otherwise unused flag register matching the second DAC output for the motor For example a motor using DACs 1 amp 2 for the commutated outputs would use Flags 1 at X C000 for its main flags and Flags 2 at X C004 for its hall effect inputs 8 8 Setting Up PMAC Commutation PMAC User Manual PMAC expects to find the hall effect inputs at bits 20 21 and 22 of the specified register In a flag register these bits match the HMFLn LIMn and LIMn inputs respectively Traditionally hall effect inputs are labeled U V and W The U input is bit 22 LIMn V is bit 21 LIMn and W is bit 20 HMFLn The hall effect signals must each have a duty cycle of 50 180 PMAC can use hall effect commutation sensors separated by120 e There is no industry standard with hall effect sensors as to direction sense or zero reference so this must be handled with software settings of Ix81 Bit 22 controls the direction sense of hall effect sensors as shown in the following diagram where a value of 0 for bit 22 is standard and a value of 1 is reversed 1 3 2 6 4 5 1 U 0 1 V 0 1 W 0 Standard 30 30 90 150 150 90 Reversed 30 30 90 150 150 90 Figure 16 Hall Effect Waveform Diagram Hall Diagram This diagram shows the hall effect w
520. the LSBit of the 16 bit A D converter For example if there were an offset in 16 bit ADC of five LSBits this term would be set to 1280 If no bias is desired a zero value should be entered here This term permits reasonable integration even with an analog offset Setting Up a Motor 7 17 PMAC User Manual Result Format The integrated result is placed in the X register of the second line of the entry with 19 bits of integer and five bits of fraction the fraction is always zero Because the input data has 16 bits this high 16 bits of a 24 bit word at the maximum range of the input there is only a 3 bit 8 times extension of the input into this integrated register with the integration performed every servo cycle Therefore whatever task uses this information must look at the integrated register at least once every eight servo cycles to handle potential rollover situations This is no problem for the automatic servo loop uses of the information master or feedback but it could be a problem in a background task The integrated result is set to zero automatically on power up reset and the integration function starts immediately afterward Any value may be written to the result register at any time usually through an M variable make sure that nothing using the register at the time could be adversely affected by changing the value of this register Integrated Analog Feedback X Words Y Words 1 Intermediate data 1 Source and
521. the Servo Loop PMAC User Manual Restrictions The following restrictions must be observed in the user written code Only one level of stack use is allowed Do not write to 56000 address registers R2 R3 R6 or R7 modifier registers M2 M3 M6 or M7 or offset registers N2 N3 N6 or N7 Other R M and N registers may be written to but must be restored before exiting the user written code e Apart from the A B X and Y registers all other 56000 registers must be restored before exiting the user written code Alternative Uses for User Written Servo This calculation does not have to be used to close the servo loop for a motor or motors It can be thought of simply as a very fast software routine that executes every servo cycle without fail As such it can be used as a super fast PLC program better by far in speed than PLC 0 The most common use for this user written non servo is for the very fast setting and clearing of many outputs based on position when more is needed than just the hardware position compare output Using this routine for such a function has several advantages over a PLC program First it is written in assembly language so there are no compilation inefficiencies or interpretation delays Second it can use simple fixed point arithmetic rather than the floating point arithmetic that the PLC and motion programs use Third it is guaranteed to run at a fixed rate even PLC 0 can be delayed by motion program
522. the data response serving as an end of transmission character For computer parsing of the response the lt ACK gt should serve as a unique EOT character Data Integrity Variable I4 determines some of the data integrity checks PMAC performs on the communications the most important of which is a line by line checksum The Writing a Host Communications Program section covers this feature in detail 4 4 Talking to PMAC PMAC User Manual Data Response Format Variable I9 controls some aspects of how PMAC sends data to the host Its setting determines whether PMAC lists program lines back to the host in long or short form whether it reports I variable values and M variable definitions as full command statements or not and whether address I variable values are reported in decimal or hexadecimal form On Line Immediate Commands Many of the commands given to PMAC are on line commands that is they are executed immediately by PMAC to cause some action change some variable or report some information back to the host The command itself is thrown away after executing so cannot be listed back although its effects may stay in PMAC Some commands such as P171 are executed immediately if there is no open program buffer but are stored in the buffer if one is open Other commands such as X1000 Y1000 cannot be on line commands there must be an open buffer even if it is a special buffer for immediate execution These commands wil
523. the move next time or increase 1130 to reduce the error J lt CR gt should cause the motor to turn in the negative direction and J CR should stop it again J2 CR should cause the motor to jog to the last pre jog position and stop there automatically Optimizing Jog Performance If your jog speed seems slower than desired one or more of PMAC automatic safety limit parameters may have been used particularly if there is a fine resolution system The first of these is I119 which is the maximum permitted motor jog acceleration expressed in counts msec The default value is quite low for most systems Increase it several orders of magnitude for now to get it out of the way Velocity Feedforward Gain When jogging at constant speed monitor following error and increase velocity feedforward gain 1132 to minimize the following error If there is a current loop amplifier set 1132 equal to 1131 or just slightly greater Integral Gain To eliminate steady state error bring in some integral gain Set 1133 to 10 000 This should provide weak integral action but enough to eliminate steady state error over a few seconds Now try increasing 1133 some more to get quicker action It should be safe to raise it in increments of 10 000 to get the performance needed quick restoration of commanded position without introducing oscillation If there is oscillation reduce the integral gain until the oscillation is eliminated If there is no effect from
524. the subroutine in the subroutine call if it has not nothing will be done with that parameter see the previous Passing Arguments to Subroutines section In the case of the S argument the value is stored for later use by other routines so that a commanded spindle speed will not exceed the limit specified here In the case of the R argument the routine calculates the difference between the current commanded X axis position M165 and the declared radial position R argument Q118 to get an offset value P98 This offset value can be used by the spindle program to calculate a real time radial position G94 Inches Millimeters per Minute Mode This code sets up the program so that F values feedrate are interpreted to mean length units inches or mm per minute In PMAC F values are interpreted to mean a speed length per time where the length units are set by the axis definition statements and the time units are set by the coordinate system variable Ix90 Since the units of Ix90 are milliseconds this routine should set Ix90 to 60 000 Also because G94 is used usually to cancel G95 which interprets F values as inches mm per spindle revolution by using the spindle encoder as an external time base source this routine should return the coordinate system to internal time base A typical routine would be N94000 I190 60000 Feedrate is per minute 1193 2054 Use internal time base RET 14 46 Writing Programs for PMAC PMAC User
525. ting Up a Coordinate System PMAC User Manual Axis Types An axis can have several attributes as specified below Note that for most axis functions it does not matter what type of axis is used or what letter is given it However for some features only particular axis names may be used Cartesian Axis A Cartesian axis is one that may be put into a grouping of two or three axes so that movement along an axis is a linear combination of motion on two or three motors X Y and Z form one set of Cartesian axes U V and W form the other In addition there are several commands NORMAL circular move which can reference the X Y and Z axes through the use of I J and K vectors respectively To make a cartesian axis a linear combination of several motors use an extended form of the axis definition statement For instance to get a 300 rotation of the axes from the motors with the following axis definition statements 1 gt 8660 25X 5000Y 2 gt 5000X 8660 25Y In this case a request for a Y axis or an X axis move would cause both motors 1 and 2 to move Only the X Y and Z cartesian axes may be used for the PMAC circular interpolation routines cutter radius compensation routines and matrix axis transformation routines To do circular interpolation on other axes do it through blended short moves and trigonometry in subroutines See example program CIRCTRY PMC Rotary Axis A rotary axis is one that permits rollover bu
526. ting of the sensor and subsequent position readings are incrementally referenced to this zero position For more information refer to the Absolute Power Up Position section in this manual the Ix10 description in the Software Reference manual and the ACC 29 MLDT Interface manual It is important with this type of feedback device to perform a PMATCH position match function before the first programmed move after power up reset Usually this is done automatically by having I14 equal to 1 If this is not done PMAC will calculate the first move for the motor assuming a starting point of Zero instead of the true position leading to unexpected performance on the first move Analog Position Feedback If analog feedback is desired for instance from a potentiometer or an LVDT PMAC can accept high band width analog feedback through one of its analog to digital converter boards ACC 23 or ACC 28 Any modulated analog position signal must be demodulated before it is presented to the PMAC system so that a fixed position is represented by a DC voltage PMAC does not support the software extension of analog position feedback through its accessory cards so no rollover should be permitted Analog feedback through ACC 23 or ACC 28 requires conversion format 10 see below If the analog data is converted to digital form external to PMAC or its accessory boards then it will be fed into PMAC as a parallel data word and PMAC will treat it like an absolute enco
527. tion PMAC has many program buffers 256 regular motion program buffers 8 rotary motion program buffers 1 for each coordinate system and 32 PLC program buffers Before commands can be entered into a buffer that buffer must be opened e g OPEN PROG 3 OPEN PLC 7 Each program command is added onto the end of the list of commands in the open buffer to replace the existing buffer use the CLEAR command immediately after opening to erase the existing contents before entering the new ones After finishing entering the program statements use the CLOSE command to close the opened buffer 4 6 Talking to PMAC PMAC User Manual Rotary Motion Program Buffer The rotary motion program buffer is a special program buffer that can execute motion programs at the same time it is open for entry of program commands from the host computer If an open rotary program buffer is executing but has already executed every command sent to it it will execute the next buffered program command sent to it almost immediately Multiple Card Applications If there are several cards communicating with the host there must be a way for the host to distinguish between the different cards The host computer must be able to talk to each of the cards individually and sometimes to talk to the cards collectively Therefore the host must have a means of addressing the cards This section covers the basic concepts of communications issues dealing with multiple ca
528. tion each axis can be put in its own coordinate system for eight completely independent operations any intermediate arrangement of axes into coordinate systems is also possible The PMAC CPU communicates with the axes through specially designed custom gate array ICs referred to as DSPGATES Each of these ICs can handle four analog output channels four encoders as input and four analog derived inputs from accessory boards One PMAC can utilize from one to four of these gate array ICs so specifying the hardware configuration amounts to counting the numbers and types of inputs and outputs Up to 16 PMAC may be ganged together with complete synchronization for a total of 128 axes PMAC Is a Computer It is important to realize that PMAC is a full computer in its own right capable of standalone operation with its own stored programs Furthermore it is a real time multitasking computer that can prioritize tasks and have the higher priority tasks pre empt those of lower priority most personal computers are not capable of this Even when used with a host computer the communications should be thought of as those from one computer to another not as computer to peripheral In these applications the ability of to run multiple tasks simultaneously properly prioritized can take a tremendous burden off the host computer and its programmer both in terms of processor time and of task switching complexity Introduction 1 1 PMAC User Manual
529. tion Feedback Conversion eee eese eese teen tenente etne teen tne teens nnne 19 Time Base Conversi n Entries iuit atu eg cand bate be E y ins sip ree Pr b e iit cei pepe eva ern lop tento 22 Triggered Time Base Conversion Entries eese coronan canon neon en eene tne tete teee tree teen trennen rennen 23 Exponential Filter Entries ueritas eati in tetris ries EH iii 24 Setting Up the Encoder Conversion Table eee esee eene enne nennen then nana nennen teen 25 Further Position gue du saa 27 Software Position Extension etae E etate Rep Dite t ii Hoe pH Hla deoa 27 AXIS POSTION Scaling isis odia 28 Leadscrew Compensaci n 28 Backlash Compensation iicet eue ee vp te vuv edes ule ike nene petu pec e ud p baee u e een 32 Torque Compensation Tables dci e putet ec ote HE tees eR ue E rete DRE ee E dents 34 Table of Contents 7 i PMAC User Manual 7 ii Table of Contents PMAC User Manual SETTING UP A MOTOR What is a Motor A motor to PMAC is a unit that has feedback output flags and potentially a master A motor is set up by assigning it these attributes and activating it This is done through the use of I initialization variables Position information is typically pre processed through a structure known as the Encoder Conversion Table explained below Defining the Motor The settings of a few I variables d
530. to a single file before the compiler can run A compiler running as part of the CNC Executive or the PMAC Executive will combine these automatically if using a single main load file which includes all of the other files For variables referencing fixed locations in the PMAC memory and I O space the L variables will simply replace M variables and the L variable definition will be made exactly like the M variable definitions It is acceptable to retain the M variable definition as well Retain the M variable definitions for debugging purposes because PMAC will not accept a query command for the value or definition of an L variable For example Machine Output 1 and Machine Input 1 on the JOPTO port are typically referenced by the following definitions in uncompiled programs M1 gt Y SFFC2 8 Machine Output 1 M11 gt Y SFFC2 0 Machine Input 1 For the compiled PLC programs you could create equivalent M variable definitions L1 gt Y SFFC2 8 Machine Output 1 L11 gt Y FFC2 0 Machine Input 1 A small routine in a compiled PLC to make Machine Output 1 follow Machine Input 1 would be IF L11 1 L1 1 ELSE L1 0 ENDIF It is acceptable to access a register in one program statement with an L variable and then access the same register even the same part of the register in another program statement with an integer M variable or I variable Mixing L variable access and P or Q variable access to a P or Q variable register will yield
531. to the JMACHI connector for two to four more axes It is only present if the PMAC card has been fully populated to handle eight axes Option 1 because it interfaces the optional extra components Note While the numbering scheme for the pins on machine connectors on PMAC VME is different from that for PMAC PC the physical arrangement is the same and PMAC VME can use the same terminal numbers on the terminal block board Connecting the Analog Power Supply The analog output circuitry on PMAC is optically isolated from the digital computation circuitry and so requires a separate power supply This is brought in on the JMACH connector The positive supply 12 to 15 volts should be brought in on the A 15V line on pin 59 The negative supply 12 to 15V should be brought in on the A 15V line on pin 60 The analog common should be brought in on the AGND line on pin 58 Typically this supply can come from the servo amplifier Many commercial amplifiers provide such a supply If this is not the case an external supply may be used Even with an external supply the AGND line should be tied to the amplifier common As mentioned before it is possible to get the power for the analog circuits from the bus but doing so defeats optical isolation In this case no new connections need to be made However be sure jumpers E85 E87 E88 E89 and E90 are set up for this circumstance as explained previously in the Preparing the Card section The car
532. tor entries defines the number of points in the table and count length defines the span of the table in counts of the motor The spacing between entries in the table is therefore count length entries The first entry in the table defines the correction at one spacing from the zero position of the motor the second entry at two spacings and so on The correction at motor zero position is zero by definition The correction is defined directly for the range of motor positions 0 to count length For motor positions outside this range the position is rolled over to within this range before the correction is applied In this way cyclic disturbances such as motor cogging torque can be compensated for The correction at the end of the table is equivalent to the correction at zero position because the correction at Zero position is zero by definition the last entry of any table intended to be rolled over should be zero also After the table definition command the next ent ries constants sent to PMAC are put into the table as table entries The units of the entries in the table are the units of a 16 bit DAC with range 32 768 to 32 767 even if an output device of a different resolution is used Corrections at points in between entries of the table are linearly interpolated from the adjacent values in the table If the following table were entered 1 DEFINE TCOMP 8 2000 Table of 8 entries over 2000 counts for
533. tor 10 AXIS E apran aoee os a Ni S EE E RAE rE E EE N i ee aE 2 Scalme and STO 2 ARIS LPS ninia ia E AE Sae 3 Cartestan Axis iet tutes Get ri dites a e ii vade abe Ese EL U bees Sedan Goods evo td se aa last duse pes di cin 3 IA ON 3 IU A RPERERR 3 Axis Motor Position Re matching seeeesseeeeeeeeeeee nennen trennen eene ea a enne tenete tenete nete ne trente ente enne 3 What Is Coordinate System Time Base esee eene eene enne adnek iet pionie tenente enee iiei ekini 6 Table of Contents 12 1 PMAC User Manual 12 2 Table of Contents PMAC User Manual SETTING UP A COORDINATE SYSTEM Coordinating Multiple Motions Once the motors have been set up and they are well tuned and doing controlled jogging and homing search moves assemble one or more coordinate systems so that motion programs can be run PMAC has several methods of coordinating multiple motions whether they are all under the PMAC direct control or not Depending on needs one of the coordination strategies below can be implemented What is a Coordinate System A coordinate system in PMAC is a grouping of one or more motors for the purpose of synchronizing movements A coordinate system even with only one motor can run a motion program a motor cannot PMAC can have up to eight coordinate systems addressed as amp 1 to amp 8 in a very flexible fashion e g eight coordinate systems of one mo
534. tor each one coordinate system of eight motors four coordinate systems of two motors each etc In general if certain motors should move in a coordinated fashion put them in the same coordinate system To have them move independently of each other put them in separate coordinate systems Different coordinate systems can run separate programs at different times including overlapping times or even run the same program at different or overlapping times A coordinate system must first be established by assigning axes to motors in Axis Definition Statements A coordinate system must have at least one motor assigned to an axis within that system or it cannot run a motion program even non motion parts of it When a program is written for a coordinate system if simultaneous motions are desired of multiple motors their move commands are simply put on the same line and the moves will be coordinated What is an Axis An axis is an element of a coordinate system It is similar to a motor but not the same thing An axis is referred to by letter There can be up to eight axes in a coordinate system selected from X Y Z A B C U V and W An axis is defined by assigning it to a motor with a scaling factor and an offset X Y and Z may be defined as linear combinations of three motors as may U V and W The variables associated with an axis are scaled floating point values One to One Matching In the vast majority of cases there wi
535. ts The radius value will not scale with the axes Writing Programs for PMAC 14 15 PMAC User Manual END Y 25 30 7 NORMAL K 1 Defaults ABS X Y INC R CIRCLE2 CIRCLE1 CENTER START TM1000 gt F10 15 20 25 20 X15Y101 10 X25Y30120J5 END 15 10 CIRCLE1 O M2000 F25 XOY10R10 X30Y101 10J10 END er TT 0 10 CIRCLE2 TM2000 yc o XOY10R 10 PEN S START END L 30 10 0 START 10 0 X Figure 32 PMAC Circular Interpolation No Center Specification If there is neither a vector specification nor a radius specification on a given move command line the move will be linearly interpolated between start and end points even if the program is in circular move mode However cutter compensation will not work properly if this is done LINEAR move mode must be explicitly declared if cutter compensation is on Feedrate Axes Any axes used in the circular interpolation are automatically feedrate axes for circular moves even if they were not so specified in a FRAX command Other axes may or may not be feedrate axes Any non feedrate axes commanded to move in the same move command will be linearly interpolated so as to finish in the same time This permits easy helical interpolation See the Feedrate Axes section in this manual Circle Radius Errors If the endpoint is not the same distance from the center as the starting point the change in radius i
536. tten commutation algorithm at power on reset so in order to change which algorithm is used Ix59 must be changed the value must be stored to non volatile memory with the SAVE command and the card must be reset Memory Space Software Interface and Program Restrictions The program space allocated for a user written commutation is Program code starting address P BB00 e Maximum continuous program length is 256 24 bit words P BBO0 to P SBBFF With jump instructions other program memory reserved for user use P 8000 P B AFF can be accessed Compiled PLC code if present starts at P 8000 user written servo if present starts at B800 Memory in this range not used for these purposes may be used for user written commutation The data spaces easily available for variables used in the user written servo are Zero value initialized registers L 0770 to L 077F Uninitialized user registers L 07F0 to L 07FF These registers retain the last values written to them before power down reset in battery backed PMACs then power up with the last values saved to flash memory in flash backed PMACs e Registers reserved with the DEFINE UBUFFER command from L 9FFF with decreasing address values to the declared length of the buffer The user written commutation algorithm must directly access memory and memory mapped I O registers Unlike the user written servo no special data is placed into or removed from internal DSP registers Common r
537. tude Generally Ix57 will be 1 4 to 1 2 of the value of Ix69 Ix58 is the integrated current limit parameter If Ix58 is set to O this function is disabled If Ix58 is greater than 0 PMAC will compare the integrated current value to Ix58 When the integrated current value exceeds this value PMAC will fault this motor as if an amplifier fault had occurred The offending motor is killed if it was in a coordinate system running a motion program that motion program aborted other motors are killed according to the setting of bits 21 and 22 of Ix25 10 4 Making Your Application Safe PMAC User Manual The PMAC I T function works according to the following equation 2 2 2 I I Sum Sum 4 q i d J37 At 32768 32768 32768 where a I quadrature current is the commanded torque producing output of the PID filter in 7 units of a 16 bit DAC b I direct current is the magnetization current command as set by Ix77 This is usually zero except when PMAC is doing vector control of induction motors ce At is the time since the last sample in servo cycles If Sum exceeds Ix58 an PT fault will occur When commanded current levels are below Ix57 Sum will decrease but it will never go below zero Example With command output limit Ix69232767 maximum integrated current limit Ix57 16384 half of maximum and magnetization current Ix77 0 the motor hits an obstruction and the command output saturates at 32767 The PT function will c
538. uitry This circuitry which creates digital quadrature and the parallel fractional bits must be external to PMAC either on Delta Tau s ACC 8D Opt 8 Analog Encoder Interpolator board or on user provided circuitry PMAC provides simultaneous latching of the quadrature counter and the parallel inputs to ensure synchronicity of the data This interpolation method unlike the 1 T method provides accurate interpolation at rest as well as during movement If the A D conversion circuitry does not provide accurate interpolation at high speeds it is possible to change on the fly between 1 T and parallel interpolation This type of sub count extension may be done only on odd numbered encoders The five bits are the five inputs associated with the next higher numbered encoder FAULT MSBit LIM LIM HMFL and CHC LSBit Parallel sub count extension requires the 80 conversion format see below Setting Up a Motor 7 5 PMAC User Manual Servo Interrupts i ll A B NH Tp h T K Velocity Estimation Vp E 1 T Position Estimation Pn Counter Figure 6 PMAC 1 T Extension Hardware Changes To implement this type of feedback properly several settings in hardware and software must be changed from the default First the socketed opto isolators for the flag bits being used as interpolated bits must be removed and replaced with hard wired shunts so the signals are not delay
539. uncompiled PMAC programs can also be used in integer operations in compiled PLCs The priorities of these operations are the same as for the floating point operations Integer Division The result of the integer divide is rounded toward the nearest integer unlike the integer divide in the PCs Intel 80x86 in which it is truncated toward zero In the case where the fraction is exactly 0 5 it will round to the next more positive integer e g 7 5 to 7 and 7 5 to 8 In PMAC floating point operations all intermediate values have floating point resolution and range if the final value is stored in an integer register as an I or M variable the rounding rules above apply for this final value The following table illustrates the effect of integer division round off Integer Division Round Off Effect Platform Statement Resulting value PC x 10 2 3 6 PMAC L1 10 2 3 7 PMAC M1 10 2 3 7 PC x 10 2 3 0 PMAC L1 10 2 3 10 PMAC M1 10 2 3 7 Writing a PLC Program 16 9 PMAC User Manual Bit Inversion The logical NOT operation to invert bits can be executed by operating on the quantity with the exclusive or operator and a constant value that contains all bits 2 1 A single bit L variable can be toggled with 1 for example L12L1 1 All bits of a 24 bit L variable can be changed with FFFFFF for example L3562L355 FFFFFF No Functions It is not acceptable to use any functions in int
540. urce in Y memory space 6x and 7x get it from X memory space Usually this data is brought in on an Accessory 14 board which is in the Y memory space so the 6x and 7x formats are rarely used If the x value in the conversion format is 0 or 1 format word bit 19 0 the resulting data is shifted left five bits so that the least significant bit of the source data appears as one count to the servo algorithms which expect five bits of fraction If the x value is 8 or 9 format word bit 19 1 the resulting data is not shifted and the LSB appears as 1 32 count to the servo algorithms see the Unshifted Conversion section in this manual If x is 1 or 9 format word bit 16 1 the resulting data is summed with the result of the previous table entry If x is 0 or 8 format word bit 16 0 no summing is performed ACC 14 Source Registers When using ACC 14 to bring in the data the following source addresses would be used Ist ACC 14 Port A J7 FEDO 1st ACC 14 Port B J15 FFD1 2nd ACC 14 Port A J7 FFD8 2nd ACC 14 Port B J15 FFD9 3rd ACC 14 Port A J7 FFEO 3rd ACC 14 Port B J15 FFE1 4th ACC 14 Port A J7 FFES 4th ACC 14 Port B J15 FFE9 5th ACC 14 Port A J7 FFFO 5th ACC 14 Port B J15 FFF1 6th ACC 14 Port A J7 FFF8 6th ACC 14 Port B J15 FFF9 A typical setup word for this type of feedback is 20FFDO which provides for non filtered conversio
541. ure 28 Figure 29 Figure 30 Figure 31 Figure 32 Figure 33 Figure 34 Figure 35 Figure 36 Figure 37 Figure 38 Figure 39 Figure 40 Figure 41 Figure 42 Figure 42 Figure 44 Figure 45 Figure 46 Figure 47 Figure 48 Figure 49 Figure 50 Figure 51 Figure 52 Figure 53 Figures PMAC Motion Controller Custom Gate Array IC nennen nennen 6 2 PANCARTA 6 3 Encoder Digital Delay Pta ties 6 5 Using the PMAC Control Panel Analog Wiper Input esee enne 6 13 PMAC Pulse and Direction Output ener ene issen tren teste enne en eene enne ens 7 3 PMAC V T Extension tenete ect teret re lee oes Ee eset cep Ub re Eres eee bebes E EIE Eee pes 7 6 Interpolated Encoder Feedback eee a a EE nete rese a 7 7 Encoder Conversion Table Process eene teet Ire iere erbe cascassseuaresuscubcescecsctensesssteacesss 7 13 Configure Encoder Conversion Table Editing Screen ci eecsesceeeccsecseeeceeeeeeaeeecsaeeaeeaecneeeesaeeeeeas 7 14 PMAC Encoder Conversion Table Principle esee eene 7 15 Conversion Table Example for Time Base Entry esee rennen 7 23 PMAC Position Processing caian ea 7 28 PMA Compensation Tables 2 rte tester iaa 7 31 Two Dimensional Compensation Table sess nennen retener ens 7 31 PMAG Commutation iia ide 8 2 Hall Effect Waveform Diari rails ele eee 8 9 PMAC PMAC2 Direct Microstepping System sess 8 14 PMAC PID and N
542. ure on rising flag and rising index I913 0 Use HMFL3 as flag HOME3 Do actual homing move CLOSE End of program 7 RKKKKKKKKKEKKKKKPLC Set up variables to be saved k iik ikk dkk kk kkk k CLOSE M320 X C008 20 1 Variable for HMFL3 input 1325 C008 Use Flags3 for Motor 3 M333 X 00B5 13 1 Desired Velocity Zero bit M345 gt Y 0994 10 1 Home complete bit M350 gt D 009E Present Desired Velocity OOOO RRA RA RAR ARA PLC program to execute routine 9e kkk k kok kikk kk kkk OPEN PLC 12 CLEAR IF M320 1 Already in trigger 1323 10 Home speed 10 cts msec positive direction I326 1600 Home offset 100 counts to make sure clear 1912 11 Capture on falling flag and rising index I913 0 Use HMFL3 as flag CMD 3HM Home out of switch WHILE M345 1 Waits for Home Search to start ENDWHILE WHILE M333 0 Waits for Home motion to complete ENDWHILE ENDIF 1323 10 Home speed 10 cts msec negative direction I326 0 No home offset 1912 3 Capture on rising flag and rising index I913 0 Use HMFL3 as flag CMD 3HM Do actual homing move WHILE M345 1 Waits for Home Search to start ENDWHILE 11 12 Basic Motor Moves PMAC User Manual WHILE M333 0 Waits for Home motion to complete ENDWHILE DIS PLC12 Disables PLC once Home is found CLOSE End of program Storing the Home Position PMAC stores the encoder position that was captured during the latest homing search
543. utting multiple cards together in a single application To get the cards working together properly in a coordinated fashion several factors must be considered e Host communications addressing Clock timing e Motion program timing The host communications addressing is covered in the previous Talking to PMAC section and the following Writing a Host Communications Program section The timing synchronization issues are covered immediately below Clock Timing PMAC cards use a crystal clock oscillator the master clock as their fundamental time measuring device Each PMAC has its own crystal oscillator Although these crystals are made to a very tight tolerance 50 ppm accuracy standard 10 ppm with Option 8 they are not exactly the same from card to card This can cause cards to lose synchronicity with each other over long move sequences if they are each using their own master clock Generally this will be noticeable only if a continuous move sequence lasts more than 10 minutes For example in the worst case with 100 ppm difference between two cards at the end of a 10 minute continuous sequence the cards will be off by 60 msec Synchronizing PMAC to External Events 15 11 PMAC User Manual Sharing Clock Signals The solution to this problem is to have all the cards share a common clock signal With PMAC this is done over spare lines on the serial connector Card 0 outputs its clock signals all other cards take the clock signal
544. value is used as the trigger position suitable for incremental encoder signals real or simulated or the software read position is used instead suitable for other types of feedback O hardware 1 software The software read position must be used if the following error status is used for the trigger PMAC will use the jog parameters Ix19 Ix22 in force at the time of the command for the pre trigger move and the values of these parameters in force at the time of the trigger for the post trigger move The captured value of the sensor position at the trigger is stored in a dedicated register if later access is needed The units are in counts for incremental encoders they are relative to the power up reset position PMAC sets the motor home search in progress status bit bit 10 of the first motor status word returned on a command true 1 at the beginning of a jog until trigger move The bit is set false 0 either when the trigger is found or at the end of the move PMAC also sets the motor trigger move status bit bit 7 of the second motor status word returned on a command true at the beginning of a jog until trigger move and keeps it true at least until the end of the move If a trigger is found during the move this bit is set false at the end of the post trigger move however if the pre trigger move finishes without finding a trigger the bit is left true at the end of the move Therefore this bit can be used at the end of the
545. ved from the socket Sourcing Drivers On newer hardware versions of PMAC those with jumpers E101 and E102 a UDN2981A open emitter sourcing driver can be substituted for the standard sinking driver This is done by exchanging the IC in the socket and changing the placement of jumpers E101 and E102 Polarity Control Jumper E17 controls the polarity of these outputs For PMAC PC a jumper ON means low true enable default a jumper OFF means high true enable PMAC PC has a single jumper E17 for all four or eight lines PMAC Lite VME and STD have separate jumpers E17A to E17H for each channel For PMAC Lite VME and STD a jumper OFF means low true enable default for PMAC Lite and VMB a jumper ON means high true enable default for PMAC STD The reason that the polarity is under hardware not software control is that it is important to make sure the amplifiers are properly disabled even if the software fails Failsafe Polarity With the default sinking drivers for the amplifier enable signals using the low true enable polarity low voltage conducting is enable high voltage non conducting is disabled provides better failsafe protection against loss of power supply If either the 5V supply for the PMAC computational section or the 15V analog supply is lost the amplifier will be disabled automatically because the output transistor will go into its non conducting state To use this failsafe protection without connect
546. vents section of this manual PMAC PC On the PMAC PC there is not a framed connector for the EQU outputs However these signals may be brought out by placing a 26 pin IDC connector over the 13 E point pairs E53 to E65 which include the eight EQU lines These outputs are TTL level with very low drive capability they must be buffered externally before they can drive any real devices ACC 27 normally used as an I O buffer for the thumbwheel multiplexer port can be used to drive several of these EQU lines The 26 pin cable provided with the ACC 27 fits over the 13 jumper pairs E53 E65 PMAC VME On PMAC VME these signals are brought out on connector J7 JEQU referenced to digital ground GND As shipped from the factory they are open collector sinking outputs with a ULN2803A driver IC rated to 24V and 100mA each They may be changed to open emitter sourcing drivers by replacing this chip in U28 with a UDN2981A driver IC and changing jumpers E93 and E94 PMAC Lite On PMAC Lite these signals are brought out on connector J8 JEQU optically isolated from the digital circuitry referenced either to analog ground AGND or an external flag supply ground As shipped from the factory they are open collector sinking outputs with a ULN2803A driver IC rated to 24V and 100mA each They may be changed to open emitter sourcing drivers by replacing this chip in U54 with a UDN2981A driver IC and changing jumpers E101 and E102 PMAC STD On
547. verride When PMAC is segmenting moves 113 gt 0 automatically which is required for Circular Interpolation the Ix17 accelerations are not observed Ix17 is particularly useful to prevent unreasonable moves early in system development when it is easy to make large mistakes in scaling In some systems it can be used during the actual application to make sure that accelerations always happen in the minimum time In these applications the TA and TS acceleration times are set very small so that the Ix17 limit is always used Sometimes the Ix17 limit is too effective limiting when it is not wanted other times it is not effective enough permitting the trajectory to violate the limit For more details reference Chapter 14 Writing Programs for PMAC Making Your Application Safe 10 3 PMAC User Manual Command Output Limits PMAC has a programmable output limit on the command PMAC sends to the amplifier for each axis 1x69 which acts as a torque limit for current loop amplifiers or an actual velocity limit for tachometer amplifiers If this limit is engaged to change what the servo loop commands the PMAC anti windup protection activates to prevent oscillation when coming out of the limiting condition In addition there is a limit on the size of the error that the feedback filter is permitted to see Big Step limit Ix67 which has the effect of slowing down too sudden a move in a controlled fashion Integrated Current IT Pro
548. will be I8 1 servo cycle length us later If PLC programs are enabled the starting offset between cards could be as much as the amount of time the longest PLC requires to run and be translated A good method for eliminating an initial execution offset is as follows e Initialize all program counters on all PMAC cards For the case of the same program with the same name on each card enter B1 lt CR gt For a more complicated case enter 0B1 1 amp 3B2 lt CR gt e Disable all PLC programs using CTRL D This will give the fastest possible response to a command Set I8 to 0 which forces a real time interrupt every servo cycle If not running a PLC O leave this at zero permanently e Begin the programs using R CR if has been issued as in the simple case or use CTRL R which is the global run command e To run a PLC O set I8 back to its original value usually 2 Leaving I8 at 0 will probably cause PLC 0 to starve the background tasks for processor time causing loss of communications or even a watchdog timer failure e Enable the PLC programs required Have the first line of each motion program enable the PLC programs for its respective PMAC card For example OPEN PROG 1 CLEAR ENA PLC 1 31 TM 1000 Synchronizing PMAC to External Events 15 13 PMAC User Manual Position Capture Functions The position capture function latches the current encoder position at the time of an external event into a special
549. x This structure permits the creation of special subprograms either as a single subroutine or as a collection of subroutines that can be called from other motion programs Passing Arguments to Subroutines These subprogram calls are made more powerful by use of the READ statement The READ statement in the subprogram can go back up to the calling line and pick off values associated with other letters to be used as arguments in the subprogram The value after an A would be placed in variable Q101 for the coordinate system executing the program the value after a B would be placed in Q102 and so on Z value goes in Q126 This structure is useful for creating machine tool style programs in which the syntax must consist solely of letter number combinations in the parts program Since PMAC treats the G M T and D codes as special subroutine calls see below the READ statement can be used to let the subroutine access values on the part program line after the code Example For example the command CALL500 X10 Y20 causes a jump to the top of PROG 500 If at the top of PROG 500 there is the command READ X Y the value with X will be assigned to Q124 X is the 24th letter and the value with Y will be assigned to Q125 Now the subroutine can work with the values of Q124 and Q125 in this case 10 and 20 respectively processing them as needed What Has Been Passed The READ statement also provides the capability of seeing what arguments
550. xecution This PLC program can be used to prevent other PLC programs from executing immediately on power up with DISABLE PLC and DISABLE PLCC commands In this way power up can be done with only a choice of PLC programs enabled Sending the CONTROL D character is a quick way of disabling all PLC programs compiled and interpreted 16 14 Writing a PLC Program PMAC User Manual Note It is never advisable to have PLC 0 or PLCC 0 running on power up Therefore do not save an I5 value of 1 or 3 Instead save I5 as 2 then in PLC 1 reset PLC use a command sequence like DISABLE PLCC 0 DISABLE PLC 0 I5 3 The PLC 0 and or PLCC 0 can then be enabled as needed Writing a PLC Program 16 15 PMAC User Manual 16 16 Writing a PLC Program PMAC User Manual 17 Writing a Host Communications Program Table of Contents WRITING A HOST COMMUNICATIONS PROGRAM eee seen eese te enean staat es sosta sone ta sens enses suse te suse ta suu 1 Communicating From a Host Computer cocooconoccconnnononononononnonnnonnnonnnonnnnnn corno nec neen eene enne enne enne tene tene nte et reete etre ens 1 Polled vs Interrupt Based Communications eee eee nono cnn rnn canon te enne tnen etre trennen enne nee nennen 1 Serial Port Communications esee esee eee eee tnen teen teen teen tret RR ets enne entes tenete tene tret tese testet rennen 1 SOUS UP TNE INLET cm 1 Host Port Bus PC STDbus
551. y If a particular card in the chain has not been sent a command when it sees the carriage return command it will process a no operation command Example The command string 0 amp 1B4R 1 amp 3B25R lt CR gt will cause card 20 s coordinate system 1 to start executing motion program 4 and card 1 s coordinate system 3 to start executing motion program 25 Control character commands that require a data response are accepted and processed by the currently addressed card and ignored by the other cards They will be rejected in the addressing mode Commands in this category are CTRL B Report all motor status words lt CTRL C gt Report all coordinate system status words lt CTRL E gt Report data gathering address contents in binary lt CTRL F gt Report all following errors lt CTRL G gt Report global status words lt CTRL P gt Report all motor positions lt CTRL V gt Report all motor velocities lt CTRL Y gt Report and repeat last command line A control character command requiring a data response will be acted on by the card addressed by the most recently processed addressing command Since an addressing command is not processed until the next carriage return character but a control character command is acted on before a carriage return it 1s important to send a carriage return character between the addressing and the control character command Other control character commands and their properties in multiple card applicati
552. y increase the energy efficiency of the system It is not possible when commutating off hall effect sensors This parameter is usually set interactively by running the motor at high speed and finding the setting that minimizes current draw Switched Reluctance Motor Commutation To the PMAC commutation algorithm a switched variable reluctance motor can look the same as a permanent magnet DC brushless motor The difference is in the amplifier Because the phases of an SR motor are driven unidirectionally the power stage can be simpler However the analog pre driver circuitry must convert the bidirectional nature of the PMAC outputs First the extra phase s is generated from the commands alone not from any actual current information as is desirable for DC brushless and AC induction motors Then each of the phase current command signals must be half wave rectified before being sent to the current loop because in an SR motor during half of the commutation cycle any current in either direction in a phase works against you AC Induction Motor Commutation PMAC can drive standard AC induction motors as position servos by a technique known as indirect vector control PMAC continually estimates the orientation of the rotor magnetic field and orients the current in the stator phases in order both to induce rotor current and to create torque The algorithm turns out to be the same as that for the DC brushless motor but with the addition
553. y Ix03 Selecting the Power Up Mode Variable Ix80 determines whether the motor will be enabled or disabled at the end of the power up reset cycle If Ix80 is 1 the motor will be enabled automatically at the end of the power up reset cycle in a closed loop zero velocity state with the commanded position set equal to the actual position at the time If a phasing search is required for a PMAC commutated motor it will be done automatically If Ix80 is 0 the motor will be left disabled killed a command will be required to enable the motor for a PMAC commutated motor the command must be used for a motor not commutated by PMAC either the or J command may be used or the A command for all the motors in a coordinate system or the CTRL A command for all PMAC motors 7 4 Setting Up a Motor PMAC User Manual Types of Position Sensors PMAC is designed to take incremental encoder feedback without any accessories With the appropriate accessories it can also take resolver absolute encoder analog or magnetostrictive linear displacement transducer feedback These features are explained in further detail below Quadrature Encoder Feedback PMAC can take quadrature encoder signals as position feedback with software programmable decode selection of x1 x2 or x4 decode pulse and direction decode is also possible Encoder I variable O 1900 I905 etc determines the decode method and direction sense for each encoder The 24
554. y available Motorola s DSP56001 is the CPU for PMAC and it handles all the calculations for all eight axes There are four hardware versions of PMAC the PMAC PC the PMAC Lite the PMAC VME and the PMAC STD These cards differ from each other in their form factor the nature of the bus interface and in the availability of certain I O ports All versions of the card have identical on board firmware so PMAC programs written for one version will run on any other version The PMAC STD has a different memory mapping of some I O Any version of PMAC may run as a standalone controller or it may be commanded by a host computer either over a serial port or over a bus port Flexibility As a general purpose controller PMAC can serve in a wide variety of applications from those requiring sub micro inch precision to those needing hundreds of kilowatts or horsepower Its diverse uses include robotics machine tools paper and lumber processing assembly lines food processing printing packaging material handling camera control automatic welding silicon wafer processing laser cutting and many others Configuration for a Task PMAC is configured for a particular application by choice of the hardware set through options and accessories configuration of parameters and the writing of motion and PLC programs Each PMAC possesses firmware capable of controlling eight axes The eight axes can be associated all together for completely coordinated mo
555. y byte address the following equation should be used Host address DPRAM base address 0800 4 Pointer value The value of the storage pointer will wrap back to 0 PMAC address D200 when it becomes greater than or equal to the value of the buffer end pointer No item will be stored in the DPRAM starting at the PMAC word address shown by the buffer end pointer although if a long item would start to be stored in the previous DPRAM word the second half would be placed in the actual buffer end word Data Format Data is stored in the buffer in 32 bit sign extended form That is each short 24 bit word gathered from PMAC is sign extended and stored in 32 bits of DPRAM LSByte first The most significant byte is all ones or all zeros matching bit 23 Each long 48 bit word is treated as 2 24 bit words with each short word sign extended to 32 bits The host computer must re assemble these words into a single value To reassemble a long fixed point word in the host take the less significant 32 bit word and mask out the sign extension top eight bits In C this operation could be done with a bit by bit AND LSW amp 16777215 Treat this result as an unsigned integer Next take the more significant word and multiply it by 16 777 216 Finally add the two intermediate results together To reassemble a long floating point value in the host first split the 64 bit value into its pieces Bits O to 11 of the 32 bit word at the lowe
556. y tying identical pins on the PMACs together Accessory 3D or 3L cables with extra PMAC connectors one Accessory 3E for each extra PMAC can be used to share the clock signals in either bus or serial communications applications and of course for actual serial communications In a standalone or bus communications application there is no need for a host drop on the cable As is the case for the communications lines you cannot tie the clock lines from the RS 422 port of a PMAC PC to the RS 232 port of a PMAC Lite With the RS 422 option on the PMAC Lite Opt 9L connection to a PMAC PC is possible but the connector pinouts are different If no serial communication is being used but the serial data lines are connected along with the clock signals it may be desirable to deactivate the serial port to prevent noise on the lines from creating input command characters to PMAC On PMAC PC PMAC Lite and PMAC VME this is done by making jumpers E44 E47 all ON on PMAC STD by making DIP switches SW1 5 to SW1 8 all OFF External Time Base If synchronicity is desired in an application where axes on several cards are tied to an external frequency time base the same frequency signal must be brought into encoder counters on all cards If it is not also required to have complete synchronicity when on an internal time base there is no need to tie the PMAC clock signals together because the external frequency will effectively provide the common clock Motio

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