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82-0074-000--Manual, User`s

1. or Figure 2 8 Grounding the Guard Terminal Chapter 2 Field Wiring 41 Connecting the On Board Thermistor The following figures show how to use the A D module to make temperature measurements with or without using the on board Thermistor The Thermistor is used for reference junction temperature sensing in thermocouple measurements Figure 2 9 shows the configuration for the VT1415A Terminal Module Under Cover ON BOARD S Place both J1 jumpers here to connect current source to on board thermistor RT1 Sense Jd d RT1 by connecting any sense channels to terminals HTS and Es 1 J1 L
2. analog input SCP config analog output SCP programming digital SCP 1 0 and config ALG DEF GLOBALS Ch 00 SS is ALG DEF ALGn Algorithm eer ALG ARRay Memory ALG SCALar o STATus ALG SCAN RATio S 8 ALG UPDate 5 SENSe FUNCtion RESistance SCP a OUS SENSe FUNCtion STRAIN 1 ES SENSe FUNCtion TEMPerature v 5 SENSe FUNCtion VOLTage v a 2 SYsTom ERROr SENSe DATA CVTable Current P 3 RESet Value writecvt A Table 4 E c Formotter writeboth Control Processor uy EU Conversion Le A D id SCP 2 3 FIFO E E Reading writefifo e uffer c o j 5 g Ch 23 FORMat DATA SENSe DATA FIFO ALL 64K E EU table 5 COUNt PN B ue 2 HALF E E Channel e i a o f E PART 3 Function range selection a HALF 8 i RESet SENSe DATA FIFO MODE g Ch 55 SCPI CSCPI Driver 3 pum SCP E ri Scan Multiplexer E next channel Control Ch 63 E zh ARM SOURce sj 172 El Ez m zt TRIGger TIMer 5 2 o a s Lie 2 INITiate IMMediate 2 z 2
3. QUO AO Ca A LILILI HUW LILIL LILILI OOL cx w o a 09 11 12 13 L E HLGHL m JL JL ILLE S E EDEN EN ER UNO UN Sockets for Guard to _ Ground Connections QU Terminal Block for Input Connections E Jumper to select for On board or Remote Temperature Sensing QIU Remote Temperature Sensing Trigger and other Connections Terminal Block with e Figure 2 3 VT1415A Terminal Module
4. 2 V HEN TRICE GN CUN HCALM E Lov M B HT GN L O z O for Temperature Sensing Chapter 2 36 Field Wiring Reference Temperature Sensing with the VT1415A The Terminal Module provides an on board thermistor for sensing isothermal reference temperature of the terminal blocks Also provided is a jumper set J1 in Figure 2 3 to route the VT1415A s on board current source to a thermistor or RTD on a remote isothermal reference block Figures 2 5 and 2 4 show connections for both local and remote sensing VT1415A Terminal Module Field Wiring TUN ON E REM BOARD S On Board G HTS Current Source O Q O LTS J1 Any Sense m Channel O Figure 2 4 On Board Thermistor Connections VT1415A Terminal Module Field Wiring tum x EE ON me e REM BOARD S On Board HT Current Source o O amp J1 LTS Any Sense Channel m Q Lnn Figure 2 5 Remote Thermistor or RTD Connections Chapter 2 Field Wiring 37 Terminal Module Considerations for TC Measurements The isothermal characteristics of the VT1415A Terminal Module are crucial for good TC readings and can be affected by any of the following factors Th
5. Top SEDI DESCR ETUR ien 33 28 CLELOLELLOGLTDLL LOO DIL H08 HOO L08 Loo E G08 G00 H09 H01 L09 L01 G09 G01 H10 H02 L10 L02 G10 G02 H11 H03 L11 L03 G11 G03 H12 H04 L12 L04 E G12 G04 v H13 HO5 L13 L05 G13 G05 H14 H06 cmd L14 L06 j G14 G06 H15 H07 as L15 L07 G15 G07 gt ge GND a GND Een LTS ca CER 8 Q All wiring entering Terminal LTI O HTI Module passes under ths gt GND strain relief bar O us O LCAL HCAL LOHM O GND al GND G56 AY L56 A H56 AY JE G57 L57 Ej H57 G58 L58 L59 H59 3 7 G61 L61 H61 L2 G62 L62 e H62 a Menu G63 n Heavy line indicates the side L63 of the terminal block on H63 1 d Er which the wire enters c DELETED L RULE SUBE BSBRGABR 5 99 22 O Figure 2 16 VT1415A Terminal Module Map 48 Field Wiring Chapter 2 Terminal Module Option Option A3F Option A3F allows a VT1415A to be connected to a VT1586A Rack Mount Terminal Panel The option provides four SCSI plugs on a Terminal Module to make connections to the Rack Mount Terminal Panel using four separately ordered SCSI cables Option A3F Is shown in Figure 2 17 Figure 2 17 Option A3F Rack Mount Terminal There are two different cables available for connecting the VT1586A Ra
6. HENS i Be See figure on page 43 to remove the cover Figure 2 9 Temperature Sensing for VT1415A Terminal Module 42 Field Wiring Chapter 2 Wiring and Attaching the Terminal Module Figures 2 10 and 2 11 show how to open wire and attach the terminal module to a VT1415A O Remove Clear Cover Q Remove and Retain Wiring Exit Penal a A Release Screws B Press Tab Forward and Release Remove 1 of the 3 wire exit panels G Make Connections Special tool P N 8710 2127 size 00 06 shipped with Terminal ia Use wire Tighten wraps to secure wires VW1 Flammability Rating Push down on lever insert wire into terminal and release Figure 2 10 Wiring and Connecting the VT1415A Terminal Module Chapter 2 Field Wiring 43 5 Replace Wiring Exit Panel 6 Replace Clear Cover A Hook in the top cover tabs onto the fixture 5 B Press down and ap Cut required Keep wiring exit panel holes in panels hole as small as for wire exit possible 070 07 970 070 Install the Terminal Push in the Extraction Levers to Lock the Module Terminal Module onto the VT1415A Sy VID Install Mylar Thermal Barrier on Terminal Module b connectors VATS OOO IAN D e o REER X SNSSSSNSSNSSSN
7. VTIA415A Count Count From From Top Bottom d LI 1 GND H0O L00 32 2 GND H01 L01 31 Technology 3 GND H02 L02 30 ET 4 GND H03 L03 29 5 GND H04 L04 28 Closed Loop 6 G0 H05 L05 27 Controller 7 G1 H06 L06 26 8 HO8 H07 L07 25 Da 9 LOB H08 L09 24 cans 10 H11 H10 LOO 23 m 11 L11 H12 L02 22 eis 12 H14 H13 H03 21 iV 13 L14 L15 L05 20 as 14 H17 H16 H06 19 us 15 L17 H18 L08 18 ss 16 H20 H19 H09 17 wea 17 L20 H21 L10 16 eas 18 H23 H22 H22 15 El 19 L23 124 L24 14 wu 20 G2 H25 L25 13 eas 21 H27 H26 L26 12 vaa 22 L27 H28 L28 11 d 23 H30 H29 H29 10 a 24 L30 131 L31 9 en 25 G3 G3 G3 8 ix 26 G3 G3 G3 7 wag 27 GND GND GND 6 sus 28 GND HOHM LOHM 5 cia 29 GND HCAL LCAL 4 Ea 30 GND GND GND 3 ses 31 GND HI LI 2 esac 32 GND GND GND 1 ww H 1 HCAL HCAL 6 V fe alL 2 LCAL LCAL 5 le a 6 CAL 3 GND GND 4 fr sm BUS 4 HOHM HOHM 3 1 H 5 LOHM LOHM 2 LO 6 GND GND 1 ee 1 GND GND GND 32 eee 2 GND TRG GND 31 pes 3 GND GND GND 30 sas 4 TST A SYSF GND 29 aoe 5 GND GND GND 28 inia 6 G4 G4 G4 27 aux 7 G4 G4 G4 26 aoe 8 G4 G4 G4 25 uu 9 L33 H32 132 24 vr 10 H33 H34 L34 28 ut 11 L36 H35 L35 22 nuu 12 H36 H37 L37 21 KES 13 G5 L38 138 20 eos 14 L40 L39 L39 19 Swa 15 H40 L41 L41 18 sine 16 L43 L42 142 17 RE 17 H43 H44 L44 16 an 18 L46 L45 L45 15 suu 19 H46 H47 L47 14 de 20 L49 H48 L48 13 uc 21 H49 H50 L50 12 eee 22 L52 H51 L51 11 ecg 23 H52 H53 L53 10 2 L55 H54 L54 9 5 H55 H56 L56 8 laa
8. Pd NS sense Hi i Note Each channel line sense Lo represents both a Hi and Lo input 9 I g 3 aj LT A Ch 24 SCP Za f D 3 lt 1 o sense PE a al a 5 Ch 31 gt BD Ch 32 o scp See ee 4 E 7777 y output gt FC Ch 39 Terminal Module Figure 2 2 Pairing Output and Sense SCP Channels Chapter 2 Field Wiring 33 Planning for Thermocouple Measurements NOTE IMPORTANT Thermocouples and thermocouple reference temperature sensors can be wired to any of the VT1415A s channels When the scan list 1s executed make sure that the reference temperature sensor is specified in the channel sequence before any of the associated thermocouple channels External wiring and connections to the VT1415A are made using the Terminal Module see page 43 The isothermal reference temperature measurement made by a VT1415A applies only to thermocouple measurements made by that instrument In systems with multiple VT1415As each instrument must make its own reference measurements The reference measurement made by one VT1415A can not be used to compensate thermocouple measurements made by another VT1415A To make good low noise measurements shielded wiring must be used from the device under test to the Terminal Module at the VT1415A The shield must be continuous through any wiring panels or isothermal reference connector blocks and must be grounded at a single po
9. Switch Jumper Setting Logical Address Switch 208 Input Protect Jumper Protected Flash Memory Protect Jumper PROG NOTE Setting the V XIbus Interrupt Level The VT1415A uses a default VXIbus interrupt level of 1 The default setting is made at power on and after RST command The interrupt level can be changed by executing the DIAGnostic INTerrupt LINe command in the application program Chapter 1 Getting Started 19 Setting the Logical Address Switch Follow the next figure and ignore any switch numbering printed on the Logical Address switch When installing more than one VT1415A ina single VXIbus Mainframe set each instrument to a different Logical Address ZA A oF ost Setting Logical Address Switch VT1415A p ww SLISA ESA f KRAY Set Switch As Shown n SS p s y a L L D N ID LOGICAL ADDRESS 208 x AEE pA ACA OPEN SWITCH SET TO 0 OFF m od 8 CLOSED SWITCH SET TO 1 ON uu Cu LE i pd Pea p a Zu C Zw O AS prd uu uw AS P ud Z a X Es ij AP Y SS 3 e Z ad f 7 A b ud p d 3s P Z P Z P Z a 2 p A pd J p d lt d CN A a xl Q p M ad SS A P QS V B 20 Getting Started Chapter 1 Installing SCPs The following illustrations show the steps used to install Signal Conditioning Plug on Modules SCPs Before installing the SCPs read Separating Digital and Analog SCP Signals in A
10. Parameters Parameter Parameter Range of Default Name Type Values Units alg name string ALGI ALG32 GLOBALS none swap size numeric uint16 0 Max Available Algorithm Memory words source code string or block data PIDA PIDB algorithm source none see Comments Comments e The alg name gt must be one of ALG1 ALG2 ALG3 etc through ALG32 or GLOBALS The parameter is not case sensitive ALGI and algl are equivalent as are GLOBALS and globals e The swap size parameter is optional Include this parameter with the first definition of alg name gt to make it possible to change a g name gt later while it is running The value can range up to about 23k words ALG DEF will then allocate 46k words as it creates two spaces for this algorithm If included swap size specifies the number of words of memory to allocate for the algorithm specified by alg name gt The VT1415A will then allocate this much memory again as an update buffer for this algorithm Note that this doubles the amount of memory space requested Think of this as spacel and space2 for algorithm a g name gt When a replacement algorithm is sent later must be sent without the swap size parameter it will be placed in space2 An ALG UPDATE command must be sent for execution to switch Chapter 6 VT1415A Command Reference 165 ALGorithm from the original to the replacement algorithm If th
11. Parameters Parameter Parameter Range of Default Name Type Values Units mode boolean uint 16 0 1 volts Comments Chapter 6 VT1415A Command Reference 193 DIAGnostic e When lt mode gt is set to 1 the RST Default channels are calibrated using the Least Squares Fit method to provide the minimum error overall over the entire output range When lt mode gt is 0 channels are calibrated to provide the minimum error at their zero point See the SCPs User s Manual for its accuracy specifications using each mode e Related Commands CAL CAL SET DIAG CAL SET MODE e RST Condition DIAG CAL SET MODE 1 Usage setanalog DAC SCP cal mode for best zero accuracy DIAG CAL SET MODE 0 Set mode for best zero cal CAL Start channel calibration DIAGnostic CALibration SETup MODE DIAGnostic CALibration SETup MODE returns the currently set calibration mode for analog output DAC SCPs Comments Returns a 1 when channels are calibrated using the Least Squares Fit method to provide the minimum error overall over the entire output range Returns a 0 when channels are calibrated to provide the minimum error at their zero point See the SCPs User s Manual for its accuracy specifications using each mode The C SCPI type is int16 e Related Commands DIAG CAL SET MOD CAL CAL SET e RST Condition DIAG CAL SET MODE 1 DIAGnostic CALibration TARE OTDetect MODE DIAGnostic CALibration TARE OTDetect MODE m
12. Input Protect Jumper Warning Cutting this Jumper Voids Your Warranty 26 Getting Started Chapter 1 Instrument Drivers If using the VT1415A with C SCPI compiled SCPI the driver needed is supplied as an option to the C SCPI product Follow the C SCPI documentation for use The Agilent HP E1405B 06A downloadable driver is supplied with the VTI415A See the manual for the Agilent HP Command Module Mainframe for down loading procedures About Example Programs Examples on Disc Example Command Sequences Typical C SCPI Example Program All example programs mentioned by file name in this manual are available on the VXIplug play Drivers amp Product Manuals CD supplied with the VTI415A Where programming concepts are discussed in this manual the commands to send to the VT1415A are shown in the form of command sequences These are not example programs because they are not written in any computer language They are meant to show the VT1415A SCPI commands in the sequence they should be sent Where necessary these sequences include comments to describe program flow and control such as loop end loop and if end if See the code sequence on page 88 for an example The Verify program file name verif cs is printed below to show a typical C SCPI program for the VT1415A Verifying a Successful Configuration An example C SCPI program source is shown on the following pages This program is included with the
13. Trigger Input Channel Buffer 1100 1163 Execution Phases o i 3 3 ES 3 3 o 1 2 3 4 I ALG OUTP DELAY gt PHASE 3 PHASE 2 CALCULATE UPDATE Update Queue For Variables and Algorithms Global Variables main function Local and Global driver generated Query ALG1 Local Variables im lim PHASE 2 UPDATE Algorithm Code Current Value Table elements 10 511 FIFO 64 K values FIFO CVT Buffer PHASE 3 CALCULATE iagram Sequence Di ing Algorithm Operati Figure 4 2 Chapter 4 122 Creating and Running Custom Algorithms Defining Custom Algorithms ALG DEF This section discusses how to use the ALG DEFINE command to define custom algorithms Later sections will discuss what to define ALG DEFINE in the RST erases all previously defined algorithms All algorithms must be erased Prog ramming before beginning to re define them except in the special case described in Sequen ce Changing an Algorithm While it s Running later in this section ALG DEFINE s Forcustom algorithms the ALG DEFINE lt alg name source code Three Data Formats command sends the algorithm s source code to the VT1415A s driver for translation to executable code The source code parameter can be sent in one of three forms 1 SCPI Quoted String For short segments
14. Comments e SENS CHAN SETTLING causes each channel specified in lt ch_list gt that is also referenced in an algorithm to appear num samples times in the analog input Scan List Channels that do not appear in any SENS CHAN SETT command will be entered into the scan list only once when referenced in an algorithm Since the scan list is limited to 64 entries an error will be generated if the number of channels referenced in algorithms plus the additional entries from any SENS CHAN SETTLING commands that coincide with algorithm referenced channels exceeds 64 The SAMPLE TIMER command can change the effect of the SENS CHAN SETTLING command since SAMPLE TIMER changes the amount of time for each measurement sample When Accepted Not while INITiated Related Commands SENSe CHANnel SETTling SAMPLE TIMER RST Condition SENS CHAN SETTLING 1 100 163 Usage SENS CHAN SETT 4 144 156 settle channels 44 and 56 for 4 measurement periods SENSe CHANnel SETTling SENSe CHANnel SETTling lt channel gt returns the current number of samples to make on lt channel gt Parameters Parameter Parameter Range of Default Name Type Values Units channel string 100 163 none Comments e lt channel gt must specify a single channel Related Commands SENS CHAN SETT SAMP TIMER Chapter 6 VT1415A Command Reference 229 SENSe e RST Condition will return 1 for all channel
15. Example algorithm that calculates 4 Mx B values upon signal that sync 1 M and B terms set by application program filename mxplusb E static float M B x sync if First loop sync 0 if sync 1 writecvt M x B 10 writecvt M x B J3 ee writecvt M x B 2 12 writecvt 2 M x B 13 sync 2 Results from running this program with the following syntax lt progname gt mxplusb Array contents 5 678000 5 678000 Array contents 6 912000 6 912000 Array contents 8 146000 8 146000 073000 16 292000 Array contents 9 379999 9 379999 690000 18 759998 Array contents 10 613999 10 613999 5 307000 21 227999 Array contents 11 848000 11 848000 5 924000 23 695999 Array contents 13 082000 13 082000 6 541000 26 164000 Array contents 14 315999 14 315999 7 158000 28 631998 7 8 839000 11 356000 456000 13 823999 A AUN Array contents 15 549999 15 549999 775000 31 099998 Array contents 16 783998 16 783998 391999 33 567997 endif Header C SCPI Example program for the E1415A Algorithmic Closed Loop Controller swap cs This example shows how to perform algorithm swapping This is an extension of th xample file file alg cs This is a template for building E1415A C programs that may use C SCPI or SICL to control instruments Standard include files includ
16. char errorbuf 255 Holds instrument error message char idbuf 255 Holds instrument response to IDN cscpi exe id IDN n 6 idbuf 255 cscpi exe id SYST ERR n 10 errorbuf 255 void fprintf stderr Instrument error s from s n errorbuf idbuf endif The following routine allows you to type SCPI commands and see the results If you don t call this from your program set the following if 1 to dif 0 if 1 Set to 0 to skip this routine void do interactive void char command 5000 char result 5000 int32 error char string 256 for void printf SCPI command void fflush stdout repeat until it actually gets something while gets command if command break result 0 0 cscpi exe el415 command strlen command result sizeof result INST QUERY e1415 syst err d s error string while error 380 Example Program Listings Appendix G void printf syst err d s NMn error string INST QUERY el415 syst err d s amp error string if result 0 void printf result s n result Hendif Print usage information void usage char prog_name void fprintf stderr usage s algorithm file n prog name Get an algorithm from a filename static char get algorithm char file name FILE and Algorithm
17. 0 0 eee eee ee 27 Chapter 2 Field Wiring cc cece cece cece ence nn nnn 31 About This Chapter za oo Libo 088 ete yee Seta eek eda ease Mea AER 31 Planning the Wiring Layout 00 eee eee eee 31 SCP Positions and Channel Numbers 0000 00 o 31 Sense SCPs and Output SCPs osser scisirieri ere iotr r ie ea 33 Planning for Thermocouple Measurements 004 34 Terminal Modules 00 0c aa aa cee a 35 The SCPs and Terminal Module 2 0 0 cee ee eee 35 Terminal Module Layout penran ea E eee 35 Reference Temperature Sensing with the VT1415A 37 Preferred Measurement Connections 39 Connecting the On Board Thermistor 0 000 cee eee eee 42 Wiring and Attaching the Terminal Module 004 43 Attaching Removing the VT1415A Terminal Module 45 Adding Components to the Terminal Module 4 47 Terminal Module Wiring Maps 0 002 eee ee 48 Terminal Module Option 49 OptionABE oro Rua REEL e e EXTR Y GR AC e 49 Faceplate Connector Pin Signal Lists ooooooooocooooooooooo 51 Chapter 3 Programming the VT1415A for PID Control 53 About This Chapter i22 coran cone pa cda di EFE ER RU 53 Overview of the VT1415A Algorithmic Loop Controller 54 Operational Overview 0 0 0 ccc ccc teens 54 Programming Modelo creses vow eae su es dele sea RAUS 55
18. is sent to the FIFO first Ap Fe Location Value t po 0 Input ay gl Error 2 Output es 3 Status 4 Setpoint Fy 5 Proportional term y 6 Integral term 7 Derivative term Je 8 Setpoint Derivative term J KCKCKCKCKCKCk KK RARA RARA RRA A KK A A KK KK KK KK KK KK KK KK KK KK KC KK kk kk e ke e ke ke ke e e ek E e User determined control parameters static float Setpoint 0 The setpoint E static float P factor 1 Proportional control constant y static float I_factor 0 Integral control constant static float D factor 0 Derivative control constant static float Error max 9 9e 37 Error alarm limits static float Error min 9 9e 37 static float PV max 9 9e 37 Process Variable alarm limits E static float PV min 9 9e 37 static float Out max 9 9e 37 Output clip limits e static float Out min 9 9e 37 static float D max 9 9e 37 Derivative clip limits static float D min 9 9e 37 static float I max 9 9e 37 Integral clip limits e static float I min 9 9e 37 static float Man state 0 Activates manual control e static float Man out 0 Target Manual output value mur Appendix D PID Algorithm Listings 347 static float Man inc 0 Manual outout change increment X static float SD factor 0 Setpoint Derivative constant static float SD max 9 9e 37 Setpoint Derivativ
19. STATus OPERation CONDition STATus OPERation CONDition returns the decimal weighted value of the bits set in the Condition register Comments The Condition register reflects the real time state of the status signals The signals are not latched therefore past events are not retained in this register see STAT OPER EVENT 262 VT1415A Command Reference Chapter 6 e Returned Value Decimal weighted sum of all set bits The C SCPI type is uint16 e Related Commands CAL CAL ZERO INITiate IMMediate STAT OPER EVENT STAT OPER ENABLE STAT OPER ENABLE e RST Condition No Change Usage STATUS OPERATION CONDITION Enter statement will return value from condition register STATus OPERation ENABle STATus OPERation ENABle lt enable_mask gt sets bits in the Enable register that will enable corresponding bits from the Event register to set the Operation summary bit Parameters Parameter Parameter Range of Default Name Type Values Units enable_mask numeric uint16 0 32767 none Comments enable mask may be sent as decimal hex H octal Q or binary 4B e VXI Interrupts When Operation Status Group bits 4 8 9 10 or 11 are enabled VXI card interrupts will occur as follows When the event corresponding to bit 4 occurs and then is cleared the card will generate a VXI interrupt When the event corresponding to bit 8 9 10 or 11 occurs the card will generate
20. e v E 3 Specifications 311 Appendix A Type S filter off VT1508A 09A 0 1 001 Ol XD Baq TT a a A A tue h A PE a C 440 39114 61 140 V6eOSLLA rr A dm AJO 39114 81 140 V8OSTLA Appendix A 312 Specifications Type T filter off 00 00t 23 Bog vs ce e ee pos e 070 EET 4s mem ee e i TERE B bad Ly gt Sn AA LA n 1 T teta ua arta MI MEE J40 PHA pox c1 l0 VEOSLLA 440 494 z1 WO VZOSTLA Pee bee AA EN ed ee OT OPES ESE Ed J40 Joa E1300 VIOSILA Specifications 313 Appendix A Type T filter off VT1508A 09A 2 321 AAO 43or4 81 340 VROSTLA dO PUL 61 ISO V60SLLA peter tiere terete AN o0 00P 0000t 00002 00001 000 00 001 00 00C 000 OFO oro 0t 0 Oro 00 Pore na 090 mes DLO 080 060 pee DIE JoadAL Appendix A 314 Specifications Reference Thermistor 5 KQ filter off 0008 00 09 000b 00 07 000 9 82d GOT 08 E OO p Mr dT el Qoi 08 0 09 0 QO cn 40 upd FOX E1130 VEOSILA OCC PME AJO JONA BX 1110 VEOSTLA ou LO PUT 21 IO VZOSTLA a 0
21. make 10 changes to x INST SEND el1415 alg scal algl x f n float32 i INST SEND el415 alg scal algl sync f n 1 set sync INST SEND e1415 alg upd n The following alg scal command will not complete if the update has not occured Then it s a matter of waiting for the algorithm to complete and set sync 2 This should happen almost instantly since the algorithm is executing every lmsec based upon trig timer 001 above sync 0 while sync 2 0 wait until algorithm sets sync to 2 INST QUERY el415 alg scal algl sync f amp sync read results of Mx B calculations INST QUERY e1415 data cvt 810 13 f amp array printf Array contents f Sf sf f n array 0 array 1 array 2 array 3 if 0 Set to 1 if using User interactive commands to E1415 Call this function if you want to be able to type SCPI commands and s their responses NOTE switch to FORM ASC to retrieve ASCII numbers during interactive mode EJ do _ interactive Calls cscpi exe in a loop endif dif 0 C CSPI way to check for errors INST QUERY e1415 syst err n d S if error void printf syst err d s n error string amp error string exit 1 endif return 0 Normal end of program dif 0 390 Example Program Listings Appendix G
22. out Error factor Error old 7 Error else not First trigger out Error factor out output channel hard coded here 0116 Error P factor out D factor Error Error old Error old Error 130 Creating and Running Custom Algorithms Chapter 4 Non Control Algorithms Data Acquisition The VT1415A s Algorithm Language includes intrinsic functions to write Algorithm values to the CVT the FIFO or both Using these functions it is possible to create algorithms that simply perform a data acquisition function The following example shows the acquisition of eight channels of analog input from SCP position 0 and one channel 8 bits of digital input from a VT1533A in SCP position 2 The results of the acquisition are placed in the CVT and FIFO Data acquisition to CVT and FIFO writeboth 1100 330 channel 0 to FIFO and CVT element 330 writeboth 1101 331 channel 1 to FIFO and CVT element 331 writeboth 1102 332 channel 2 to FIFO and CVT element 332 writeboth 1103 333 channel 3 to FIFO and CVT element 333 writeboth 1104 334 channel 4 to FIFO and CVT element 334 writeboth 1105 335 channel 5 to FIFO and CVT element 335 writeboth 1106 336 channel 6 to FIFO and CVT element 336 writeboth 1107 337 channel 7 to FIFO and CVT element 337 writeboth 1116 338 channel 16 to FIFO and CVT element 338 c
23. compute 2 n float64 r 1 int32 i for i 0 i lt n i r 2 return r BK KK KK RARA RARA A KK KK CK CK KK KC KK KC KK KC CK KC SK KG KG KG e ke e ke K kk NAME static int32 round32f TASK Rounds a 32 bit floating point number static int32 round32f float64 number add or subtract 0 5 to round based on sign of number float64 half number gt 0 0 0 5 0 5 Appendix F Generating User Defined Functions 365 return int32 number half J EK kk A RAR RR RARA RARA A I A Ck A A kk e ke e ke e ke ek ke NAM TAS HAV Be 5 K ERSINI static float64 my function ee User supplied function for calculating desired results of f x rj float64 my function float64 input float64 returnValue return returnValue returnValue sin input J BK kkk A A A Kk CK IA IIIA I A A IA A A A kk kk e ke e ke e ke e e e NAME void Build table TASK Generates tables of mx b values used for Custom Functions in the E1415A Generate the three coefficients for the CUSTOM FUNCTION algorithm a The exponent value Ei b The slope or M value C The intercept or B value INPUT PARAMETERS float64 max input maximum input expected float64 min input minimum input expected float64 custom function float
24. Using SENS DATA FIFO and the SENS DATA CVT commands the application program can access the data Process Monito ring Another function the VT1415A performs well is monitoring input values Algorithm and testing them against pre set limits If an input value exceeds its limit the algorithm can be written to supply an indication of this condition by changing a CVT value or even forcing a VXIbus interrupt The following example shows acquiring one analog input value from channel 0 and one VT1533A digital channel from channel 16 and limit testing them Limit test inputs send values to CVT and force interrupt when exceeded static float Exceeded static float Max chan0 Min chan0 Max chan1 Min chan1 static float Max chan2 Min chan2 Max chan Min chan3 static float Mask chan16 if First loop Exceeded 0 initialize Exceeded on each INIT writecvt 1100 330 write analog value to CVT Exceeded 1100 gt Max chan0 1100 lt Min chan0 limit test analog writecvt 1101 331 write analog value to CVT Exceeded Exceeded 1101 gt Max chan 1101 lt Min chan1 writecvt 1102 332 write analog value to CVT Exceeded Exceeded 1102 gt Max chan2 1102 lt Min chan2 writecvt 1103 333 write analog value to CVT Exceeded Exceeded 1103 gt Max chan3 1103 lt Min chan3 writecvt 1116 334 write 8 bit value to CVT
25. 0 002 0 e sees 120 Operating Sequence 120 Overall Sequence i i issu cuam aaa EE 121 Algorithm Execution Order esses 121 Defining Custom Algorithms ALG DEF lsseseeseee ees 123 ALG DEFINE in the Programming Sequence 123 ALG DEFINE s Three Data Formats 0 0000 123 Changing a Running Algorithm llle 124 A Very Simple First Algorithm i eee esee 126 Writing the Algorithm lesser 127 Running the Algorithm ssie ees iiaae nee keie daa ea i o eaa 127 Modifying a Standard PID Algorithm llle ese 127 PIDA with Digital On Off Control 0 0 0 00005 127 Algorithm to Algorithm Communication 0 0000 eee 128 Communication Using Channel Identifiers 128 Communication Using Global Variables 129 Non Control Algorithms cece eens 131 Data Acquisition Algorithm 0 0 0 c eee ee eee 131 Process Monitoring Algorithm 00 0000 e ee eee 131 Implementing Setpoint Profiles 00 0 00 cee eee eee 132 Chapter 5 Algorithm Language Reference o oooooomomo o o 135 Language Reference nici eras Uie br E eR UR RE 135 Standard Reserved Keywords 00 cece cece eee o 136 Special VT1415A Reserved Keywords 2 0200 000 136 Table of Contents ix Identifiers oioommmm momen me erem ek 136 Special Identifiers for Channels 00 0000 ee eee eee 137 O
26. 20 30 37 Remove all SCPs and see if TST passes If so replace SCPs one at a time until the one causing the problem is found 38 71 VXI Technology Service 72 74 76 80 93 re seat the SCP that the channel number s points 301 354 to or move the SCP and see if the failure s follow the SCP If the problems move with the SCP replace the SCP 73 T1 79 94 99 VXI Technology Service Must send module to a VXI Technology Service Center for repair Record information found in FIFO to assist the VXI Technology Service Center in repairing the problem Refer to the Command Reference under TST for a list of module functions tested During the first 5 minutes after power is applied TST may fail Allow the module to warm up before executing TST 3053 3056 Corrupt on board Flash memory Custom EU not loaded May have erased custom EU conversion table with RST May have linked channel with standard EU after loading custom EU this erases the custom EU for this channel Reload custom EU table using DIAG CUST LIN or DIAG CUST PIEC 330 Error Messages Appendix B 3057 3058 3067 3068 3069 3070 3071 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 Invalid ARM or TRIG source when S H SCP s enabled Don t set TRIG SOUR or ARM SOUR to SCP with VTI510A or VT1511A installed Hardware does not have D32 S H or new trigg
27. All variables must be declared static float Array variables cannot be assigned a value when declared 3 AII variables declared within an algorithm are local to that algorithm If a variable is declared locally with the same identifier as an existing global variable the algorithm will only access the local variable Ne The VT14154A always declares the global variable First loop First loop is set to 1 each time INIT is executed After main calls all enabled algorithms it sets First loop to 0 By testing First loop an algorithm can determine if it is being called for the first time since an INITiate command was received Example static float scalar var static float array var 4 assign constants to variables on first pass only if First loop scalar_var 22 3 array_var 0 0 array var 1 0 array_var 2 1 2 array var 3 4 Chapter 4 Creating and Running Custom Algorithms 117 Initializing Variables Variable initialization can be performed during three distinct VT1415A operations 1 When algorithms are defined with the ALG DEFINE command A declaration initialization statement is a command to the driver s translator function and doesn t create an executable statement The value assigned during algorithm definition is not re assigned when the algorithm is run with the INIT command Example statement static float my variable 22 95 tells translator to allocate space for thi
28. DIN selects the Digital Input channel list DOUT selects the Digital Output channel list e Returned Value Definite Length Arbitrary Block Data format This data return format is explained in Arbitrary Block Program Data on page 158 of this chapter Each value is 2 bytes in length the C SCPI data type is an int16 array e RST Condition To supply the necessary time delay before Digital inputs are read the analog input AIN scan list contains eight entries for channel 0 100 This minimum delay is maintained by replacing these default channels as others are defined in algorithms After algorithm definition if some delay is still required there will be repeat entries of the last channel referenced by an algorithm The three other lists contain no channels Usage ROUT SEQ DEF AIN query for analog input Scan List sequence 224 VT1415A Command Reference Chapter 6 ROUTe ROUTe SEQuence POINts ROUTe SEQuence POINts type returns the number of channels defined in each of the four channel list types Parameters Parameter Parameter Range of Default Name Type Values Units type string AIN AOUT DIN DOUT none Comments The channel list contents and sequence are determined by channel references in the algorithms currently defined e The type parameter selects which channel list will be queried AIN AOUT DIN DOUT selects t
29. Does the E1415 pass self test int test_result Result of E1415 self test test_result 1 Make sure it gets assigned INST QUERY e1415 TST n Sd amp test result if test_result void fprintf stderr E1415A failed self testin exit 1 388 Example Program Listings Appendix G fendif Tif Setup SCP functions INST SEND e1415 sens func volt 116 n Analog in volts INST SEND e1415 sour func cond 8141 Nn Digital output 0 fendif dif INST Sl INST SEND e1415 samp timer 10e 6in default INST Si il Set to 1 to do calibration Perform Calibrate if necessary int cal result Result of E1415 self test cal result 1 Make sure it gets assigned INST QUERY e1415 CAL n Sd amp cal result if cal result void fprintf stderr E1415A failed calibration Nn void fprintf stderr Check FIFO for channel errors Nn exit 1 Configure Trigger Subsystem and Data Format END e1415 trig sour timer trig timer 001 n END el415 form real 321n Download Globals INST SEND el415 alg def globals static float x Nn Download algorithms Set to 1 if algorithms passed in as files Get an algorithm s from the passed filename s We assign sequential algorithm number
30. Illegal program name System error Query INTERRUPTED Out of memory Invalid channel number Invalid word address Bus error Scan list not initialized Too many channels in channel list Byte count is not a multiple of two Illegal while initiated Operation must be performed before INIT or INIT CONT ON Appendix B Error Messages 327 3004 3005 3006 3007 3008 3012 3015 3019 3020 3021 3026 3027 3028 3030 3032 3033 Illegal command CAL CONF not sent Incorrect sequence of calibration commands Send CAL CONF VOLT command before CAL VAL VOLT and send CAL CONF RES command before CAL VAL RES Illegal command Send CAL VAL RES The only command accepted after a CAL CONF RES is a CAL VAL RES command Illegal command Send CAL VAL VOLT The only command accepted after a CAL CONF VOLT is a CAL VAL VOLT command Invalid signal conditioning module The command sent to an SCP was illegal for its type Too few channels in scan list A Scan List must contain at least two channels Trigger too fast Scan list not completed before another trigger event occurs Channel modifier not permitted here TRIG TIM interval too small for SAMP TIM interval and scan list size TRIG TIM interval must allow for completion of entire scan list at currently set SAMP TIM interval See TRI
31. lt ch_list gt HBENding lt range gt lt ch_list gt HPOisson lt range gt lt ch_list gt QUARIer lt range gt lt ch_list gt TEMPerature lt sensor_type gt lt sub_type gt lt range gt lt ch_list gt TOTalize lt ch_list gt VOLTage DC lt range gt lt ch_list gt REFerence lt sensor_type gt lt sub_type gt lt ch_list gt CHANnels W lt ref_channel gt lt ch_list gt TEMPerature degrees celsius STRain EXCitation lt excite_v gt lt ch_list gt EXCitation lt channel gt GFACtor lt gage_factor gt lt ch_list gt GFACtor lt channel gt POlSson lt poisson_ratio gt lt ch_list gt POlSson W lt channel gt UNSTrained lt unstrained_v gt lt ch_list gt UNSTrained lt channel gt TOTalize RESet MODE INIT TRIGger lt ch_list gt TOTalize RESet MODE lt channel gt 228 VT1415A Command Reference Chapter 6 SENSe SENSe CHANnel SETTling SENSe CHANnel SETTling lt num_samples gt lt ch_list gt specifies the number of measurement samples to make on channels in lt ch_list gt SENS CHAN SETTLING 1s used to provide additional settling time only to selected channels that might need it See the Settling Characteristics discussion on page 108 Parameters Parameter Parameter Range of Default Name Type Values Units settle time numeric int16 to 64 none ch list string 100 163 none
32. o oooooooooooomoooo page 131 Data Acquisition Algorithm 02 0 0000s page 131 Process Monitoring Algorithm 00 page 131 e Implementing Setpoint Profiles o ooo oooooomoo page 132 Creating and Running Custom Algorithms 111 Describing the VT1415A Closed Loop Controller The VT1415A is a self contained data acquisition and control platform in a single C size VXIbus module Once configured for operation and initiated with its SCPI command set the module is controlled by the algorithm s it Is executing It is the algorithms that have exclusive access to acquired data from input channels and it is the algorithms that generate values that control the analog and digital output channels It is the calculation and decision making capability provided by its Algorithm Language that makes the VT1415A a closed loop controller By placing the control computer the algorithm inside the data acquisition and control instrument the data acquisition the control decision making and the data output phases are as tightly coupled as they can be The time required for the system to respond to changing input values is at most one execution of the control algorithm No data exchange to or from an external computer is required in this cycle What is a Custom Algorithm The only thing that separates the VT1415A s standard PID algorithms from custom algorithms is that the standard PIDs are built in
33. C language The program that runs in the VXIbus controller either embedded within the VXIbus mainframe or external and interfaced to the mainframe The application program typically sends SCPI commands to configure the VTI1415A define its algorithms then start the algorithms running Typically once the VT1415A is running algorithms the application need only oversee the control application by monitoring the algorithms status During algorithm writing debugging and tuning the application program can retrieve comprehensive data from running algorithms In this manual a buffer is an area in RAM memory that is allocated to temporarily hold Data input values that an algorithm will later access This is the Input Channel Buffer Data output values from an algorithm until these values are sent to hardware output channels This is the Output Channel Buffer Data output values from an algorithm until these values are read by the application program This is the First In First Out or FIFO buffer A second copy of an array variable containing updated values until it is activated by an update This is double buffering A second version of a running algorithm until it is activated by an update This is only for algorithms that are enabled for swapping This is also double buffering Appendix C Glossary 335 Control Processor DSP EU EU Conversion FIFO Flash or Flash Memory
34. Note that the delay value returned by ALG OUTP DEL is valid only until another algorithm is loaded After that re issue the ALG OUTP DEL AUTO and ALG OUTP DEL commands to determine the new delay that includes the added algorithm e When Accepted Before INIT only e RST Condition ALG OUTP DELAY AUTO Chapter 6 VT1415A Command Reference 175 ALGorithm ALGorithm OUTPut DELay ALGorithm OUTPut DELay returns the delay setting from ALG OUTP DEL Comments The value returned will be either the value set by ALG OUTP DEL delay or the value determined by ALG OUTP DEL AUTO e When Accepted Before INIT only e RST Condition ALG OUTP DEL AUTO returns delay setting determined by AUTO mode e Returned Value number of seconds of delay The type is float32 ALGorithm UPDate IMMediate ALGorithm UPDate IMMediate requests an immediate update of any scalar array algorithm code ALG STATE or ALG SCAN RATIO changes that are pending Comments e Variables and algorithms can be accepted during Phase 1 INPUT or Phase 2 UPDATE in Figure 6 1 when INIT is active All writes to variables and algorithms occur to their buffered elements upon receipt However these changes do not take effect until the ALG UPD IMM command is processed at the beginning of the UPDATE phase The update command can be received at any time prior to the UPDATE phase and will be the last command accepted Note that the ALG UPD WINDow command specifies the
35. OUTPut VOLTage AMPLitude 222 OUTPut VOLTage AMPLitude 223 VT1413C declaration of conformity v VT1415A background operation 100 VT1415A configuring the 19 W Warranty iii Voided by cutting Input Protect Jumper 25 What CAL does 74 What is a custom algorithm 112 When to make shield connections 355 When re execute CAL 75 Where to go next 149 Which FIFO mode 87 WIDTh SOURce PULSe WIDTh 259 WIDTh SOURce PULSe WIDTh 259 WINDow ALGorithm UPDate WINDow 178 WINDow ALGorithm UPDate WINDow 179 Wiring planning for thermocouple 34 planning layout 31 signal connection 39 Wiring and attaching the terminal module 43 Wiring maps Terminal Module 48 Wiring techniques for noise reduction 354 424 Index Wiring the terminal module 43 writeboth expression cvt element 138 writecvt expression cvt element 118 138 writefifo expression 119 138 Writing the algorithm 127 Writing values to CVT elements 118 Writing values to the FIFO 119 Z ZERO CAL ZERO 192 Index 425
36. OUTPut CURRent AMPLitude OUTPut CURRent AMPLitude lt channel gt returns the range setting of the Current Source SCP channel specified by lt channel gt Parameters Parameter Parameter Range of Default Name Type Values Units channel channel list string 100 163 none Comments e lt channel gt must specify a single channel only If lt channel gt specifies an SCP which is not a Current Source a 3007 Invalid signal conditioning plug on error is generated Returned Value Numeric value of amplitude set The C SCPI type is float32 Related Commands OUTP CURR AMPL Usage OUTP CURR AMPLITUDE 163 Check SCP current set for channel 63 returns 3 0E 5 or 4 88E 4 216 VT1415A Command Reference Chapter 6 OUTPut OUTPut CURRent STATe OUTPut CURRent STATe lt enable gt lt ch_list gt enables or disables current source on channels specified in cA list Parameters Parameter Parameter Range of Default Name Type Values Units enable boolean uint16 1 0 ON OFF none ch_list channel list string 100 163 none Comments OUTP CURR STAT does not affect a channel s amplitude setting A channel that has been disabled when re enabled sources the same current set by the previous OUTP CURR AMPL command e OUTP CURR STAT is most commonly used to turn off excitation current to four wire resistance and resistance temperatu
37. Usage ALGorithm EXPLicit ARRay lt alg_name gt lt array_name gt lt array_block gt places values of lt array_name gt for algorithm lt alg_name gt into the Update Queue This update is then pending until ALG UPD is sent or an update event as set by ALG UPD CHANNEL occurs ALG ARRAY places a variable update request in the Update Queue Do not place more update requests in the Update Queue than are allowed by the current setting of ALG UPD WINDOW or a Too many updates send ALG UPDATE command error message will be generated Parameter Parameter Range of Default Name Type Values Units alg name string ALGI ALG32 GLOBALS none array name string Valid C variable name none array block block data Block of IEEE 754 64 bit floating none point numbers e To send values to a Global array set the alg name parameter to GLOBALS To define a global array see the ALGorithm DEFine command e An error is generated if alg name or array name is not defined e When an array is defined in an algorithm or in GLOBALS the VT1415A allocates twice the memory required to store the array When the ALG ARRAY command is sent the new values for the array are loaded into the second space for this array When ALG UPDATE or ALG UPDATE CHANNEL commands are sent the VT1415A switches a pointer to the space containing the new array values This is how even large arrays can be upda
38. Zero the I term and start integrating I out Error I factor Zero the derivative term Error old Error On subsequent triggers continue integrating else not First trigger I out Error I factor I out Sum PID terms outchan Error P factor I out D factor Error Error old Save values for next pass Error old Error 340 PID Algorithm Listings Appendix D PIDB AEREA RR RAR RARA CK A CK KK KK KK KK KK KK KK KK KK KIC KK KK KK KK SK KC kk kk ke ke ke e ke e ke e e ek PIDB J KCKCKCKCKCKCk kk Ck RR RR RAR KK KK KK KK a KK KK KK KK KK KK KK KC KK KK KK KC Sk kk kk e ke e ke e ke e e ek I O Channels Must be defined by the user RY e E inchan Input channel name Fl outchan Output channel name alarmchan Alarm channel name pe VE AA A rac Tu J KCKCKCKCkC Ck Ck kk kk Ck kk Ck CK Ck CK Kk CK Kk KK Kk KK Kk KK Ck KC Ck KK Kk KC Sk A Ck kk kk kk e ke ke ke e ke ke ko ke ke ke oe A PID algorithm for E1415A controller module This algorithm is called once per scan trigger by main It performs Proportional Integral and Derivative control E pe yt mu The output is derived from the following equations ay yes D PID out P out I out D out SD out x P out Error P factor I out I out Error I factor qu D out PV ol
39. ee page 245 SENSe REFerence lt sensor_type gt lt sub_type gt lt range gt lt ch_lis gt page 246 SENSe REFerence CHANnels lt ref_channel gt lt tc_channels gt ooo page 248 SENSe REFerence TEMPerature degrees c ee page 248 SENSe STRain EXCitation excite v Q ch list 2 o page 249 SENSe STRain EXCitation lt channel gt sa s ecc e sa eaea e e r aa ea D page 249 SENSe STRain GFACtor lt gage factor gt DSCh_liSt gt ooo page 250 SENSe STRain GFACtor lt channel gt ooo page 250 SENSe STRain POISson lt poisson_ratio gt lt ch_list gt ee page 251 SENSe STRain POISson lt channel gt 22s page 251 SENSe STRain UNSTrained unstrained v Q amp ch list 2222 page 251 SENSe STRain UNSTrained lt channel gt o page 252 SENSe TOTalize RESet MODE INIT TRIGger Q ch list lens page 252 SENSe TOTalize RESet MODE lt channel gt nonna page 254 SOURce FM STATe 1 0 O OFF lt ch list page 255 SOURce FM STATe lt channel gt ee page 256 SOURce FUNCtion SHAPe CONDition g ch list 2 ee ee page 256 SOURce FUNCtion SHAPe PULSe Q ch list 2 2 ee page 256 SOURce FUNCtion SHAPe SQUare lt ch_list gt 2 ee page 257 SOURce PULM STATe 1 0 ON OFF lt ch_ list 2 ee page 257 SOURce PULM STATe lt channel gt oo page 257 SOURce PUL
40. int32 error Holds error number if 0 Set to 1 if reading algorithm files Check pass parameters if arge lt 2 argc gt 33 Must have 1 to 32 algorithms usage argv 0 exit 1 endif INST STARTUP Initialize the C SCPI routines dif 0 Set to 1 to open interface session If you need to open a VXI device session here s how to do it You need a VXI device session if the V382 is to source or respond to VXI backplane triggers SICL ixtrig or ionintr calls y if vxi iopen vxi void fprintf stderr SICL error failed to open vxi interface Nn void fprintf stderr SICL error d s Nn igeterrno igeterrstr igeterrno exit 1 Hendif Open the E1415 device session with error checking Copy and modify these lines if you need to open other instruments INST OPEN e1415 E1415 ADDR Open the E1415 if el415 Did it open void fprintf stderr Failed to open the E1415 at address s n E1415 ADDR void fprintf stderr C SCPI open error was d n cscpi open error void fprintf stderr SICL error was d s Wn igeterrno igeterrstr igeterrno exit 1 Check for startup errors INST QUERY e1415 syst err n d 5 amp error string if error void printf syst err d s n error string exit 1 Usually you ll want to start f
41. 240 VT1415A Command Reference Chapter 6 Usage SENS FUNC FREQ 144 SENSe Use the SENSe FREQuency APERture command to set the gate time for the frequency measurement Related commands SENS FREQ APER RST Condition SENS FUNC COND and INP POL NORM for all digital SCP channels set channel 44 s sense function to frequency SENSe FUNCtion RESistance Parameters Comments SENSe FUNCtion RESistance lt excite_current gt lt range gt lt ch_list gt links the EU conversion type for resistance and range with the channels specified by ch list Parameter Parameter Range of Default Name Type Values Units excite current discrete string 30E 6 488E 6 MIN MAX amps range numeric float32 see first comment V dc ch list channel list string 100 163 none The range parameter The VT1415A has five ranges 0 0625 V dc 0 25 V dc 1 V dc 4 V dc and 16 V dc To select a range simply specify the range value for example 4 selects the 4 V dc range Ifa value larger than one of the first four ranges is specified the VT1415A selects the next higher range for example 4 1 selects the 16 V dc range Specifying a value larger than 16 causes an error Specifying 0 selects the lowest range 0 0625 V dc Specifying AUTO selects auto range The default range no range parameter specified is auto range If amplifier SCPs set them first and keep their settings in mind when s
42. 3 Chapter 4 Creating and Running Custom Algorithms 119 This code writes PID values into CVT elements 10 through 13 for ALGI CVT elements 20 through 23 for ALG2 CVT elements 30 through 33 for ALG3 etc Using ALG NUM allows identical code to be written that can take different actions depending on the name it was given when defined Calling USer Access to user defined functions is provided to avoid complex equation Defined Functions calculation within an algorithm Essentially what is provided with the VT1415A is a method to pre compute user function values outside of algorithm execution and place these values in tables one for each user function Each function table element contains a slope and offset to calculate an mx b over the interval x is the value the function is provided This allows the DSP to linearly interpolate the table for a given input value and return the function s value much faster than if a transcendental function s equation were arithmetically evaluated using a power series expansion User functions are defined by downloading function table values with the ALG FUNC DEF command and can take any name that is a valid C identifier like haversine sqr log10 etc To find out how to generate table values from function equation see Generating User Defined Functions in Appendix F For details on the ALG FUNC DEF command see page 174 in the Command Reference User defined functions are
43. 7 and the ending point would be at 4 With the desired range spread over 7 the 128 segments are actually divided over the range of 2 Therefore the 128 Mx B line segments are divided equally on both sides of X 0 64 segments for 0 2 and 64 segments for 2 0 360 Generating User Defined Functions Appendix F Figure F 1 A Haversine Function A typical use of this function would be to output an analog voltage or current at each Scan Trigger of the VT1415A and over the range of the haversine For example suppose a new position of an analog output is needed to move from 1 mA to 3 mA over a period of 100 ms If the TRIG TIMER setting or the EXTernal trigger was set to 2 ms then force 50 intervals over the range of the haversine This can be easily done by using a scalar variable to count the number of times the algorithm has executed and to scale the variable value to the 7 2 to 1 2 range 3 mA is multiplied times the custom function result over each interval which will yield the shape of the haversine 0 003 sin x 0 001 This is illustrated in the example shown in Figure F 1 The program listings on the disc and printed later in this appendix illustrate the actual program used to generate this haversine function Simply supply the algebraic expression in my function the desired range over which to evaluate the function which determines the table range and the name of the function The Build table routine see
44. Command Bridge Type FBENding Full Bending Bridge FBPoisson Full Bending Poisson Bridge FPOisson Full Poisson Bridge HBENding Half Bending Bridge HPOisson Half Poisson Bridge QUARter Quarter Bridge default e The lt ch_list gt parameter specifies which sense SCP channel s to link to the strain EU conversion lt ch_list gt does not specify channels on the VT1506A 07A Strain Bridge Completion SCPs but does specify one of the lower four channels of a VT1511A SCP 68 Programming the VT1415A for PID Control Chapter 3 Custom EU Conversions Linking Output Channels to Functions e The optional range parameter can be used to choose a fixed A D range When not specified defaulted the module uses auto range To link channels 23 through 30 to the quarter bridge strain EU conversion SENS FUNC STR QUAR 123 130 uses autorange Other commands used to set up strain measurements are SENSe STRain POISson SENSe STRain EXCitation SENSe STRain GFACtor SENSe STRain UNSTrained See the Command Reference Chapter 6 and the VT1506A 07A and VT1511A User s Manuals for more information on strain measurements See Creating and Loading Custom EU Conversion Tables on page 101 Analog outputs are implemented either by a VT1531A Voltage Output SCP or a VT1532A Current Output SCP Channels where these SCPs are installed are automatically considered outputs No SOURce FUNCtion command is required since the VT1531A
45. Comments e The frequency control for these channels is provided by the algorithm language function 0143 2000 set channel 43 to 2 kHz SOURce PULM STATe SOURce PULM STATe lt enable gt lt ch_list gt enable the pulse width modulated mode for the PULSe channels in lt ch_list gt Parameters Parameter Parameter Range of Default Name Type Values Units enable boolean uint16 1 0 ON OFF none ch list string 100 163 none Comments This command is coupled with the SOURce FM command If the FM state is enabled then the PULM state 1s disabled If the PULM state is enabled then the FM state is disabled If both the FM and the PULM states are disabled then the PULSe channel is in the single pulse mode e f the channels specified are not on a Frequency Totalize SCP an error will be generated e RST Condition SOUR PULM STATE OFF SOURce PULM STATe SOURce PULM STATe lt channel gt returns the pulse width modulated mode state for the PULSe channel in lt channel gt Chapter 6 VT1415A Command Reference 257 SOURce Parameters Parameter Parameter Range of Default Name Type Values Units channel string 100 163 none Comments lt channel gt must specify a single channel e Returned Value returns ON or OFF The type is string SOURce PULSe PERiod SOURce PULSe PERiod lt period gt lt ch_list gt sets the fixed pulse p
46. EX jj uint16 Xofst Xfactor M jj uint16 Mfactor OxFFFFE remove leading 1 s B round32f two to the N Xfactor result ii 1 Bhigh jj uint16 B gt gt 16 amp Ox0000FFFF Blow jj uint16 B amp OxOO00FFFF end for for ii20 ii 264 iit 0 to FS input ii center tbl range 64 0 float64 ii result ii custom_function input ii if ii 0 continue This is the first point skip slope jj ii 1 generate numbers for prev segment for second and subsequent points t result ii 1 using prev seg base if t 0 0 t 1 0 use abs value magnitude of t compute the exponent of the offset B is 31 bits if t 0 0 don t take log of zero exponent 31 0 log10 t 1lo0g10 2 0 take log base 2 else exponent 100 0 compute slope in bits each tabl ntry represents 512 bits slope result ii result ii 1 512 0 don t take the log of a negative slope absslope slope 0 slope slope compute the exponent of the slope M is 16 bits if absslope 0 404 Example Program Listings Appendix G exponent2 15 0 10g10 absslope 10g10 2 0 else exponent2 100 0 Choose the smallest exponent maximize resolution if exponent2 lt exponent xponent exponent2 Xfactor int32 exponen
47. Usage INPUT FILTER LPASS FREQUENCY 155 Check cutoff freq on channel 55 INP FILT FREQ 100 Check cutoff freq on channel 0 INPut FILTer LPASs STATe INPut FILTer LPASs STATe lt enable gt lt ch_list gt enables or disables a programmable filter SCP channel When disabled enable 0FF these channels are in their pass through mode and provide no filtering When re enabled enable ON the SCP channel reverts to its previously programmed setting Parameters Parameter Parameter Range of Default Name Type Values Units enable boolean uint16 1 0 ON OFF none ch list channel list string 100 163 none Comments e Ifthe SCP has not yet been programmed ON enables the SCP s default cutoff frequency 206 VT1415A Command Reference Chapter 6 INPut e When Accepted Not while INITiated e RST Condition ON Usage INPUT FILTER STATE ON 115 117 Channels 115 and 117 return to previously set or default cutoff frequency INP FILT OFF 100 115 Set channels 0 15 to pass through state INPut FILTer LPASs STATe INPut FILTer LPASs STATe lt channel gt returns the currently set state of filtering for the specified channel If the channel is not on an input SCP the query will return zero Parameters Parameter Parameter Range of Default Name Type Values Units channel channel list string 100 163 none Comments Returned
48. all algorithms every second TRIGger TIMer PERiod TRIGger TIMer PERiod returns the currently set Trigger Timer interval Comments Returned Value Numeric 1 through 6 5536 The C SCPI type is float32 e Related Commands TRIG TIMER e RST Condition 1 0E 4 Usage TRIG TIMER Query trig timer enter statement Returns the timer setting Chapter 6 VT1415A Command Reference 277 Common Command Reference Common Command Reference CAL NOTE The following reference discusses the VT1415A IEEE 488 2 Common commands Calibration command The calibration command causes the Channel Calibration function to be performed for every module channel The Channel Calibration function includes calibration of A D Offset and Gain and Offset for all 64 channels This calibration is accomplished using intemal calibration references The CAL command causes the module to calibrate A D offset and gain and all channel offsets This may take many minutes to complete The actual time it will take the VT1415A to complete CAL depends on the mix of SCPs installed CAL performs literally hundreds of measurements of the intemal calibration sources for each channel and must allow seventeen time constants of settling wait each time a filtered channel s calibrations source value is changed The CAL procedure is internally very sophisticated and results in an extremely well calibrated module To perform Channel Calibration on multiple VT1415As us
49. break INST SEND el415 alg scal algl Setpoint f n setpoint INST SEND e1415 alg upd n for i 0 i lt 10 i read CVT 10 times ALG1 has elments 10 13 in CVT INST QUERY e1415 data cvt 8010 13 f amp process info printf Process variable sf bf bf f n process info 0 process info 1 process info 2 process info 3 Hif 0 Set to 1 if using User interactive commands to E1415 Call this function if you want to be able to type SCPI commands and MES their responses NOTE switch to FORM ASC to retrieve ASCII numbers during interactive mode T do interactive Calls cscpi exe in a loop endif if 0 C CSPI way to check for errors INST QUERY e1415 syst err n d 5 amp error string if error void printf syst err d s n error string exit 1 endif return 0 Normal end of program dif 0 C CSPI program Example of changing from Setpoint 3 to Setpoint 9 over a trigger event period of 1msec using PIDB Setpoint error output and status are shown 384 Example Program Listings Appendix G Enter desired setpoint 9 Process variable 3 000122 0 000122 0 001538 0 000000 Process variable 2 998657 6 001343 0 003638 0 000000 Process variable 5 744141 3 255859 0 004178 0 000000 Process variable 7 165039 1 834961 0 004494 0 000000 Process variable 8
50. input ii center tbl range 64 0 float64 ii result ii custom_function input ii 368 Generating User Defined Functions Appendix F if ii 0 continue This is the first point skip slope jj ii 1 generate numbers for prev segment for second and subsequent points t result ii 1 using prev seg base if t 0 0 t 1 0 use abs value magnitude of t compute the exponent of the offset B is 31 bits if t 0 0 don t take log of zero exponent 31 0 10og10 t 10g10 2 0 take log base 2 else exponent 100 0 compute slope in bits each tabl ntry represents 512 bits slope result ii result ii 1 512 0 don t take the log of a negative slope absslope slope lt 0 slope slope compute the exponent of the slope M is 16 bits if absslope 0 exponent2 15 0 10g10 absslope 10g10 2 0 else exponent2 100 0 Choose the smallest exponent maximize resolution if exponent2 lt exponent xponent exponent2 Xfactor int32 exponent if t 0 m ltemp round32f log10 t 1og10 2 0 if Xfactor ltemp gt 30 Xfactor 30 ltemp Mfactor round32f two to the N Xfactor slope if Mfactor 32768 There is an endpoint problem Re compute if on endpoint Xfactor Mfactor round32f two to the N
51. page 100 Creating and Loading Custom EU Tables page 101 Compensating for System Offsets o oooooooooo page 104 Chapter 3 Programming the VT1415A for PID Control 53 e Detecting Open Transducers 000 e eee eee page 106 e More on Auto Ranging 00 cece eee ene page 108 e Settling Characteristics page 108 Overview of the VT1415A Algorithmic Loop Controller The first part of this chapter will provide an overview ofthe VT1415A s operating model and programming This is intended to facilitate understanding the affects of programming commands that are seen in later examples and detailed discussions Operational This section describes how the VT1415A gathers input data executes an Overview 2 gorithm and outputs control signals Figure 3 1 shows a simplified functional block diagram Trigger Timer Digital Signal Processor DSP Output nput Buffer EU Conversion EU System Algorithm Program Memory Voltage Current Temperature alg1 Resistance static float input val val out input val 1100 pid algorithm Strain Jexe dninjg Bojeuy SdOS 1ndino Bojeuy Sample Hold Voltage O108 val out alg2 Digital State static float input_val val_out Static States input_val 1101 pid algorithm Pulse per Trigger Frequency O109 val out alg3 Totalize Pulse Width Modulation SdOS 1ndino eya Frequency Modulati
52. 0 i lt 10 i make 10 changes to x SEND el415 alg scal algl x f n float32 i SEND el415 alg scal algl sync f n 1 set sync SEN D e1415 alg upd n not complete if the a matter of waiting for set sync 2 This should lgorithm is executing Then it s the algorithm to complete and 001 above sync 0 while sync 2 0 wait until algorithm sets sync to 2 INST QUERY e1415 alg scal algl sync f amp sync read results of Mx B calculations INST QUERY e1415 data cvt 810 13 f amp array printf Array contents f f array 1 array 2 array 3 if 1 Set to 1 if using User interactiv Sf f n array 0 commands to E1415 Call this function if you want to be able to type SCPI commands and us th ASCII n TE do interactive Hendif dif 0 C CSPI way to check for errors INST QUERY ir responses E NOTI switch to FORM ASC to retrieve umbers during interactive mode Calls cscpi exe in a loop Xf e1415 syst err n 3959 5 wo amp error string if error void printf syst err d s n error string exit 1 endif Appendix G Example Program Listings 397 return 0 if 0 signal that sync 1 program filename mxplusb static float M B X sy
53. 0 lt byte gt lt byte gt lt byte gt lt byte gt lt NL END gt 158 VT1415A Command Reference Chapter 6 Linking Commands Optional Parameters Parameters shown within square brackets are optional parameters Note that the brackets are not part of the command and should not be sent to the instrument If a value for an optional parameter is not specified the instrument chooses a default value For example consider the FORMAT DATA lt type gt lt ength gt command If the command is sent without specifying lt ength gt a default value for lt ength gt will be selected depending on the lt type gt of format specified For example FORMAT DATA ASC will set lt ength gt to the default for ASC of 7 FORMAT DATA REAL will set lt ength gt to the default for REAL of 32 FORMAT DATA REAL 64 will set lt ength gt to 64 Be sure to place a space between the command and the first parameter Linking commands provides a way to send more than one complete command in a single command statement Linking IEEE 488 2 Common Commands with SCPI Commands Use a semicolon between the commands For example RST OUTP TTLT3 ON or TRIG SOUR IMM TRG Linking Multiple complete SCPI Commands Use both a semicolon and a colon between the commands For example OUTP TTLT2 ON TRIG SOUR EXT The semicolon as well as separating commands tells the SCPI parser to expect the command keyword following the semicolon to be at the s
54. 710 PRINT HPIB TIMEOUT 720 STOP 730 Err check REPEAT l Check for any errors 740 OUTPUT QE1415 SYST ERR 750 ENTER QE1415 Error String 760 IF Error THEN 770 OUTPUT Err Error returned amp VALS Error amp amp String 780 END IF 790 UNTIL Error 0 800 RETURN 810 END 820 HHPEREREREE REHEARSE EEE EERE EERE it EEE EESEEEEEEEEEEEEE 830 840 Subprogram Build eu table 850 TASK Generates tables of mx b values for downloading to E1415 DSP 860 870 Generate the thr coefficients for the EU algorithm 880 a The exponent value 890 b The slope or M value 900 C The intercept or B value 910 920 INPUT PARAMETERS 930 REAL Min input lowest expected value 940 REAL Max input largest expected valu 950 zero generates piecewise table 960 OUTPUT PARAMETERS 970 REAL Table range returned table rang 980 1 REAL Table offset how much to adjust X for shifted function 990 INTEGER Coef array returned coeficient array 1000 512 values 1010 1020 Build eu table SUB Build table REAL Min input Max input Table range Table offset INTEGER Coef array 1030 INTEGER M 128 Ex 128 Bhigh 128 B10w 128 Xofst Shift Ii Jj 1040 INTEGER Xfactor Ltemp 1050 REAL Input 129 Result 129 Test range T Exponent Exponent2 1060 REAL Slope Absslope Mfactor B Bl 1070 1080 Calculate the mid point of the range 1090 l 1100 Center Min input Max input Min input 2 1110 Table offse
55. CHANnel lt channel gt WINDow lt num_updates gt WINDow ARM IMMediate SOURce BUS EXT HOLD IMM SCP TTLTrg lt n gt SOURce CALibration CONFigure RESistance VOL Tage lt range gt ZERO FSCale SETup SETup STORe ADC TARE SCPI Command Quick Reference Description Stops scanning immediately and sets trigger system to idle state scan lists are unaffected Subsystem to define configure and enable loop control algorithms Defines contents of array lt array_name gt in algorithm lt alg_name gt or if lt alg_name gt is GLOBALS defines values global to all algorithms Returns block data from lt array_name gt in algorithm lt alg_name gt or if lt alg_name gt is GLOBALS returns values from a global array Defines algorithms or global variables program data is C source of algorithm or global declaration Defines value of variable var name in algorithm alg name or if alg name is GLOBALS defines a value global to all algorithms Returns value from var name in algorithm alg name gt or if alg name is GLOBALS returns a value from global variable Sets scan triggers per execution of alg name gt send also ALG UPD Returns scan triggers per execution of alg name Returns size in words of named algorithm Enables disables named algorithm after ALG UPDATE sent Returns state of named algorithm Returns worst case alg execution time Use MA
56. Controls Open Transducer Detect on SCPs contained in cA list Returns current state of OTD on SCP containing channel Returns value from an SCP register Returns manufacturer model serial flash revision and date e g Agilent E1415B US34000478 A 04 00 Wed Jul 08 11 06 22 MDT 1994 Return readings stored in VME Memory format set by FORM cmd Set format for response data from SENSe DATA Seven bit ASCII format not as fast as 32 bit because of conversion Same as REAL 64 except NaN INF and INF format compatible with Agilent BASIC IEEE 32 bit floating point requires no conversion so is fastest IEEE 64 bit floating point not as fast as 32 bit because of conversion Returns format REAL Put module in Waiting for Trigger state ready to make one scan Control filter Signal Conditioning Plug Ons Sets the cutoff frequency for active filter SCPs Returns the cutoff frequency for the channel specified Chapter 6 VT1415A Command Reference 289 Command Quick Reference Command STATe ON OFF lt channel gt STATe lt channel gt GAIN lt chan_gain gt lt ch_list gt GAIN lt channel gt LOW lt wvolt_type gt lt ch_list gt LOW lt channel gt POLarity NORmal INVerted lt ch_list gt POLarity lt channel gt MEMory VME ADDRess mem address ADDRess SIZE mem size SIZE STATe 1 0 ON OFF STATe OUTPut CURRent AMPLi
57. If SCP settings are 244 VT1415A Command Reference Chapter 6 SENSe changed those channels are no longer calibrated CAL must be executed again e See Linking Input Channels to EU Conversion on page 62 for more information e When Accepted Not while INITiated e Related Commands CAL OUTP CURR for RTDs and Thermistors SENS REF and SENS REF TEMP for Thermocouples e RST Condition SENSE FUNC VOLT AUTO 100 163 Usage Link two channels to the K type thermocouple temperature conversion SENS FUNC TEMP TCOUPLE K 101 102 Link channel 0 to measure reference temperature using 5 k thermistor SENS REF THER 5000 100 SENSe FUNCtion TOTalize SENSe FUNCtion TOTalize lt ch_list gt sets the SENSe function to TOTalize for channels in cA list Parameters Parameter Parameter Range of Default Name Type Values Units ch list string 100 163 none Comments The totalize function counts rising edges of digital transitions at Frequency Totalize SCP channels The counter 1s 24 bits wide and can count up to 16 777 215 e The SENS TOT RESET MODE command controls which events will reset the counter e Ifthe channels specified are not on a Frequency Totalize SCP an error will be generated e Related Commands SENS TOT RESET MODE INPUT POLARITY e RST Condition SENS FUNC COND and INP POL NORM for all digital SCP channels Usage SENS FUNC TOT 9134 channel 34 is
58. P out I out D out f P out Error P factor dy I out I out Error I factor D out Error Error old D factor Error Setpoint PV E e where Setpoint is the desired value of the process variable user supplied Ef PV is the process variable measured on the input channel PID out is the algorithm result sent to the output channel JF P factor I factor and D factor are the PID constants user supplied Je E pe E At startup the output will abruptly change to P factor Error A pe E y RARA RAR Ck Kk CK Ck KC KC RRA RRA KC KK KK KK KK KK KK KK KK KK KC KK KK KK kk Sk kk ke ke e ke ke ke ke ke ke ke ek red p User determined control parameters El Appendix D PID Algorithm Listings 339 static float Setpoint 0 The setpoint e static float P factor 1 Proportional control constant static float I factor 0 Integral control constant static float D factor 0 Derivative control constant e E yr Other Variables y static float I out Integral term static float Error Error term El static float Error old Last Error for derivative E PID algorithm code Begin PID calculations First find the Process Variable error This calculation has gain of minus one 1 Error Setpoint inchan On the first trigger after INIT initialize the I and D terms if First loop
59. SENSe DATA CVTable 230 CUSTom SENS FUNC CUSTom 237 Custom Algorithm what is a 112 Custom EU conversion tables creating 101 loading 101 Custom EU conversions 69 Custom EU operation 102 Custom EU tables 102 Custom reference temperature EU conversions 102 Custom thermocouple EU conversions 102 CVT Resetting the CVT 86 SENSe DATA CVTable 230 CVT elements reading 118 CVT elements writing value to 118 CVT organization of the 85 CVT reading algorithm values from the 85 CVT sending data to 118 D DATA FORMat DATA 201 FORMat DATA 203 Data acquisition algorithm 131 Data structures 139 Data types 138 DATA FIFO ALL 231 Decimal constant 141 Declaration initialization 141 Declaration of Conformity VT1413C v Declaration 143 Declarations 144 Declarator 143 Declaring variables 145 Default settings power on 57 DEFine ALGorithm EXPLicit DEFine 165 ALGorithm FUNCtion DEFine 174 ROUT SEQ DEF 224 Defined input and output channels 116 Defining a PID with ALG DEFINE 78 Defining an algorithm for swapping 124 Defining and accessing global variables 117 Defining custom algorithms 123 Defining data storage 79 Defining standard PID algorithms 75 Definite length block data example 124 DELay ALGorithm OUTPut DELay 175 DELay ALGorithm OUTPut 176 Describing the VT1415A closed loop controller 112 Detecting open transducers 106 Determining an algorithm s size 125 Determinin
60. Storage for algorithm Use as array index Read the algorithm Null terminate Appendix G Example Program Listings 393 return algorithm Return algorithm string Main program ARGSUSED Keeps lint happy int main int argc char argv Main program local variable declarations char algorithm Algorithm string int alg num Algorithm number being loaded char string 333 Holds error information int32 error Holds error number if 0 Set to 1 if reading algorithm files Check pass parameters if arge lt 2 arge gt 33 Must have 1 to 32 algorithms usage argv 0 exit 1 endif INST STARTUP Initialize the C SCPI routines dif 0 Set to 1 to open interface session If you need to open a VXI device session here s how to do it You need a VXI device session if the V382 is to source or respond to VXI backplane triggers SICL ixtrig or ionintr calls xy if vxi iopen vxi void fprintf stderr SICL error failed to open vxi interface n void fprintf stderr SICL error d s n igeterrno igeterrstr igeterrno exit 1 Hendif Open the E1415 device session with error checking Copy and modify these lines if you need to open other instruments INST OPEN el415 E1415 ADDR Open the E1415 if e1415 Did it open vo
61. Table offset Coef array 400 410 Download the function table and define the function 420 430 Ipiec 0 2256 NUM 4 NUM 4 build block 440 Ipiec 1 256 NUM 1 NUM 0 11024 bytes 450 Ipiec 2 2256 NUM 2 NUM 4 1512 Integers 460 FOR Ii 0 TO 511 470 Ipiec Iit 3 Coef array Ii 480 NEXT Ii 490 GOSUB Err check 500 OUTPUT QE1415 ALG FUNC DEF sin Table range Table offset 510 OUTPUT GBus Ipiec ladd block 520 OUTPUT QBus CHR 10 END terminate 530 3 374 Generating User Defined Functions Appendix F 540 GOSUB Err check 550 560 Now define an algorithm to use sin x and tests its functionality 570 580 OUTPUT GE1415 alg def algl static float y radians 0 y sin radians 590 OUTPUT GE1415 form ascii trig timer 001 init 600 RAD use radians 610 GOSUB Err check 620 FOR Radians PI 2 TO PI 2 STEP PI 10 630 OUTPUT QE1415 alg scal algl radians Radians upd 640 OUTPUT QE1415 alg scal algl y 650 ENTER QE1415 Y 660 PRINT USING This RMB sin radians SIN Radians E1415A sin Radians Y 670 This IMAGE K SD DDDD K SD DDDD 680 NEXT Radians 690 STOP 700 End
62. Trigger system is in the Idle state Both versions same function INITIATE IMMEDIATE 204 VT1415A Command Reference Chapter 6 INPut INPut The INPut subsystem controls configuration of programmable input Signal Conditioning Plug Ons SCPs Subsystem Syntax INPut FILTer LPASs FREQuency lt cutoff_freq gt lt ch_list gt FREQuency lt channel gt STATe 1 0 ON OFF lt channel gt STATe lt channel gt GAIN lt chan_gain gt lt ch _list gt GAIN lt channel gt LOW lt wvolt_type gt lt ch_list gt LOW lt channel gt POLarity NORMal INVerted lt ch_list gt POLarity lt channel gt INPut FILTer LPASs FREQuency INPut FILTer LPASs FREQuency lt cutoff_freq gt lt ch_list gt sets the cutoff frequency of the filter on the specified channels Parameters Parameter Parameter Range of Default Name Type Values Units cutoff freq numeric float32 see comment Hz string MIN MAX ch_list channel list string 100 163 none Comments e lt cutoff_freq gt may be specified in kilohertz khz A programmable Filter SCP has a choice of several discrete cutoff frequencies The cutoff frequency set will be the one closest to the value specified by cutoff freq7 Refer to Chapter 6 for specific information on the SCP being programmed Sending MAX for the cutoff freq selects the SCP s highest cutoff fr
63. While the VT1415 can auto range measure and convert a reading to engineering units as fast as once every 10 us measuring a high level signal followed by a very low level signal may require some extra settling time As seen from the point of view of the VT1415A s Analog to Digital converter and its Range Amplifier this situation is the most difficult to measure For example look at two consecutive channels The first measures a power supply at 15 5 volts the next measures a thermocouple temperature First the input to the Range Amplifier is at 15 5 volts near its maximum with any stray capacitances charged accordingly then it immediately is switched to a thermocouple channel and down ranged to its 0 0625 volt range On this range the resolution is now 1 91 uV per Least Significant Bit LSB Because of this sensitivity the time to discharge these stray capacitances may have to be considered Thus far in the discussion it has been assumed that the low level channel measured after a high level channel has presented a low impedance path to discharge the A D s stray capacitances path was the thermocouple wire The combination of a resistance measurement through a VT1501A Direct Input SCP presents a much higher impedance path A very common measurement like this would be the temperature of a thermistor If measured through a Direct Input SCP the source impedance of the measurement is essentially the value of the thermistor the output imped
64. channels specified and stores the value in on board RAM as a calibration constant for those channels Future measurements made with these channels will be compensated by the amount of the tare value Use CAL TARE to compensate for voltage offsets in system wiring and residual sensor offsets Where tare values need to be retained for long periods they can be stored in the module s Flash Memory Electrically Erasable Programmable Read Only Memory by executing the CAL STORe TARE command For more information see Compensating for System Offsets on page 104 Note for Thermocouples Do not use CAL TARE on field wiring that is made up of thermocouple wire The voltage a thermocouple wire pair generates cannot be removed by introducing a short anywhere between its junction and its connection to an isothermal panel either the VT1415A s Terminal Module or a remote isothermal reference block Thermal voltage is generated along the entire length of a thermocouple pair where there is any temperature gradient along that length To CAL TARE thermocouple wire this way would introduce an unwanted offset in the voltage temperature relationship for that channel If a thermocouple wire pair is inadvertently CAL TARE d use CAL TARE RESET to reset all tare constants to zero Do use CAL TARE to compensate wiring offsets copper wire not thermocouple wire between the VT1415A and a remote thermocouple reference block Disconnect the thermocouples and intro
65. command Unlike standard EU conversions the custom EU conversions are already linked to their channels tables loaded before the SENSe FUNC CUST command is executed but the command allows the A D range for these channels to be specified NOTE The RST command clears all channel Table RAM segments Custom EU conversion tables must be re loaded using the DIAG CUST commands Custom EU Tables The VT1415A uses two types of EU conversion tables linear and piecewise The linear table describes the transducer s response slope and offset y mx b The piecewise conversion table gets its name because it is actually an approximation of the transducer s response curve in the form of 512 linear segments whose end points fall on the curve Data points that fall between the end points are linearly interpolated The built in EU conversions for thermistors thermocouples and RTDs use this type of table Custom Thermocouple EU The VT1415A can measure temperature using custom characterized Conversions thermocouple wire of types E J K N R S and T The custom EU table generated for the individual batch of thermocouple wire is loaded to the appropriate channels using the DIAG CUST PIEC command Since thermocouple EU conversion requires a reference junction compensation of the raw thermocouple voltage the custom EU table is linked to the channel s using the command SENSe FUNCtion CUSTom TCouple lt type gt lt range gt ch list The
66. data end with a null 0 byte The null byte must be appended to the end of the block s lt data byte s gt and account for it in the byte count lt digit s gt from above If the null byte is not included or lt digit s gt doesn t include it the error Algorithm Block must contain termination 0 will be generated Indefinite Length Block Program Data this form terminates the data transfer when it receives an End Identifier with the last data byte Use this form only when it is certain that the controller platform will include the End Identifier If it Is not included the ALG DEF command will swallow whatever data follows the algorithm code The syntax for this parameter type is 0 lt data byte s gt lt null byte with End Identifier Example from Quoted String above ALG DEF ALG1 00108 1100 2 where is a null byte For Block Program Data the Algorithm Parser requires that the lt source_code gt data end with a null 0 byte The null byte must be appended to the end of the block s lt data byte s gt The null byte is sent with the End Identifier If the null byte is not included the error Algorithm Block must contain termination 0 will be generated If alg name gt is not enabled to swap not originally defined with the lt swap_size gt parameter included then both of the following conditions must be true a Module is in Trigger Idle State after RST or ABORT and befo
67. e1415 syst err n d 5 amp error string if error void printf syst err d sWMn error string exit 1 endif return 0 Normal end of program dif 0 Example of results from program C sin 1 570798 1 000000 E1415A sin 1 570798 0 999905 C sin 1 256639 0 951057 E1415A sin 1 256639 0 950965 C sin 0 942479 0 809018 E1415A sin 0 942479 0 808944 C sin 0 628319 0 587786 E1415A sin 0 628319 0 587740 C sin 0 314160 0 309017 E1415A sin 0 314160 0 308998 C sin 0 000000 0 000000 E1415A sin 0 000000 0 000000 C sin 0 314160 0 309017 E1415A sin 0 314160 0 308998 C sin 0 628319 0 587786 E1415A sin 0 628319 0 587740 C sin 0 942479 0 809018 E1415A sin 0 942479 0 808944 C sin 1 256639 0 951057 El415A sin 1 256639 0 950965 Appendix F Generating User Defined Functions 373 C sin 1 570798 1 000000 E1415A sin 1 570798 0 999905 o fendif RMB Version 10 RE SAVE SINE FN ASC 20 30 DESCRIPTION Example program to illustrate the use of Custom Functions 40 in the E1415A This example shows the use of RMB 50 This example shows the creation of a Haversine function 60 70 The Build table subprogram receives the minimum and maximum ranges 80 over which the function it to be built You supply the algebraic 90 expression f
68. example file sine fn cs creates the table for the function and the ALG FUNC DEF writes that table into VT1415A memory The table MUST be built and downloaded BEFORE trying to use the function The following is a summary of what commands and parameters are used in the program examples Table F 1 shows some examples of the accuracy of custom function with various input values compared to an evaluation of the actual transcendental function found in C or RMB Please note that the Mx B segments are located on boundaries specified by 2 64 on each side of X 0 This means that if the exact input value is selected that is used for the beginning of each segment the exact calculated value of the function at that point will be provided Any point between segments will be an approximation dependent upon the linearity of that segment Also note that values of X 2 and X 2 will result in Y infinity Appendix F Generating User Defined Functions 361 Limitations C sin 1 570798 1 000000 VT1415A sin 1 570798 0 999905 C sin 1 256639 0 951057 VT1415A sin 1 256639 0 950965 C sin 0 942479 0 809018 VT1415A sin 0 942479 0 808944 C sin 0 628319 0 587786 VT1415A sin 0 628319 0 587740 C sin 0 314160 0 309017 VT1415A sin 0 314160 0 308998 C sin 0 000000 0 000000 VT1415A sin 0 000000 0 000000 C sin 0 314160 0 309017 VT1415A sin 0 314160 0 308998 C sin
69. n values 2 147 483 647 maximum This command completes only after n values have been transferred 86 Programming the VT1415A for PID Control Chapter 3 FIFO Status Commands SENSe DATA FIFO COUNt returns a count of the values in the FIFO buffer Use with the DATA FIFO PART or DATA FIFO ALL commands SENSe DATA FIFO COUNt HALF returns a 1 if the FIFO is at least half full 32 768 values or a 0 if not Use with the DATA FIFO HALF command All of the FIFO commands except SENS DATA FIFO ALL can execute while the module continues to run algorithms Once a FIFO Transfer command is executed the instrument cannot accept other commands until the transfer is complete as specified for each command above The FIFO Status commands allow the instrument to be polled for availability of values before executing a transfer command Which FIFO Mode The way the FIFO is read depends on how the FIFO mode is set in the programming step Setting the FIFO Mode on page 80 Continuously Reading the FIFO FIFO mode BLOCK If reading the FIFO while algorithms are running the FIFO mode must be set to SENS DATA FIFO MODE BLOCK In this mode if the FIFO fills up it stops accepting values from algorithms The algorithms continue to execute but the latest data is lost To avoid losing any FIFO data an application needs to read the FIFO often enough to prevent overflow The flow diagram below shows where and when to use the FIFO commands Be
70. only 5000 See previous note on page 65 For CUSTom only 1 e The optional range parameter can be used to choose a fixed A D range When not specified defaulted or set to AUTO the module uses auto range Reference Measurement Before Thermocouple Measurements At this point the concept of the Scan List will be introduced As each algorithm is defined the VT1415A places any reference to an analog input channel into the Scan List When the algorithms are run the scan list tells the VT1415A which analog channels to scan during the Input Phase The SENSe REFerence CHANnels lt ref_chan gt lt meas_ch_list gt is used to place the lt ref_chan gt channel in the scan list before the related thermocouple measuring channels in lt meas_chan gt Now when analog channels are scanned the VT1415A will include the reference channel in the scan list and will scan it before the specified thermocouples are scanned The reference measurement will be stored in the Reference Temperature Register The reference temperature value is applied to the thermocouple EU conversions for thermocouple channel measurements that follow Chapter 3 Programming the VT1415A for PID Control 67 A Complete Thermocouple Measurement Command Sequence The command sequence performs these functions e Configures reference temperature measurement on channel 15 e Configures thermocouple measurements on channels 16 through 23 e Instructs the VT1415
71. printf All d algorithm s loaded without errors n n alg num 1 else Download algorithms with in line code algorithm n Example algorithm that calculates 4 Mx B values uponin signal that sync 1 M and B terms set by applicationin program n v n static float M B x sync n if First loop sync 0 Wn if sync 1 n Y writecvt M x B 10 An y writecvt M x B 11 n y writecvt M x B 2 12 n writecvt 2 M x B 13 n sync 2 n wp Ann INST SEND e1415 alg def ALG1 500 B n strlen algorithm 1 algorithm Hendif algorithm n Example algorithm that calculates 4 Mx B values upon n signal that sync 1 M and B terms set by application n program Calculations are different than above n Ww n static float M B x sync Mn if First loop sync 0 n if sync Nm Y writecvt M x B 10 n x writecvt M x B 11 n y writecvt 2 M x B 12 n Y writecvt M x B 2 13 n 2 sync 2 n wo Nutr Preset Algorithm variables INST SEND el415 alg scal alg1 M f n 1 234 INST SEND el415 alg scal algl B Sf n 5 678 INST SEND el1415 alg upd Nn Sl Initiate Trigger System start scanning and running algorithms INST SEND e1415 initNn Alter run
72. static float SD min 9 9e 37 static float History mode 0 Activates fifo data logging fe Other Variables static float I out Integral term Ef static float D out Derivative term x static float Error Error term EJ static float PV old Last process variable p static float Setpoint old Last setpoint for derivative EJ static float SD_out Setpoint derivative term y static float Status 0 Algorithm status word J 7 342 PID Algorithm Listings Appendix D BO PID out at clip limit 47 Bl I out at clip limit ad B2 D out at clip limit X B3 SD out at clip limit B4 in Manual control mode B5 Error out of limits Ef B6 PV out of limits others unused pe Tur PID algorithm code d Test for Process Variable out of limits if inchan gt PV max PV min gt inchan PV alarm test if Status B6 Status B6 1 alarmchan 1 interrupt else Status B6 0 Do this when in the Manual control mode if Man state Slew output towards Man out if Man out gt outchan abs Man inc outchan outchan abs Man inc else if outchan gt Man out abs Man inc outchan outchan abs Man inc else outchan Man out Set manual mode bit in status word Status B4 1 No error alarms while in Manual mode Status B5 0 In case we exit manua
73. t take log of zero exponent 31 0 1og10 t 10g10 2 0 take log base 2 else exponent 100 0 compute slope in bits each tabl ntry represents 512 bits slope result ii result ii 1 512 0 don t take the log of a negative slope absslope slope 0 slope slope compute the exponent of the slope M is 16 bits if absslope 0 exponent2 15 0 10g10 absslope 10g10 2 0 else exponent2 100 0 Choose the smallest exponent maximize resolution if exponent2 lt exponent xponent exponent2 Xfactor int32 exponent if t 0 int32 ltemp round32f log10 t 1og10 2 0 if Xfactor ltemp gt 30 Xfactor 30 ltemp Mfactor round32f two to the N Xfactor slope if Mfactor 32768 There is an endpoint problem Re compute if on endpoint Xfactor Mfactor round32f two to the N Xfactor slope if Mfactor lt 32767 amp amp Mfactor gt 32768 only save if M is within limits Adjust EX to match runtime asm EX jj uint16 Xofst Xfactor M jj uinti16 Mfactor OXFFFF remove leading 1 s B round32f two to the N Xfactor result ii 1 Bhigh jj uint16 B gt gt 16 0OxOOO00FFFF Blow jj uint16 B amp OxOO00FFFF end for for ii20 ii 264 iit 0 to FS
74. the Function will figure out which instrument generated th rror retrieve the error print a message and exit You may want to modify the way the error is printed or comment out the exit if you want the program to continue Note that this works only on REGISTER based instruments because it was a C SCPI register based feature not a general programming improvement If you re using MESSAGE instruments you ll still have to do SYST ERR If your test program generates errors on purpose you probably don t want this error function If so set the following if 1 to fif 0 This function is most useful when you re trying to get your program running if 1 Set to 0 to skip trapping errors ARGSUSED Keeps lint happy void cscpi error INST id int err ok CACA Xo F X Ro F HF x char errorbuf 255 Holds instrument error message char idbuf 255 Holds instrument response to IDN cscpi exe id IDN n 6 idbuf 255 cscpi exe id SYST ERR n 10 errorbuf 255 void fprintf stderr Instrument error s from s n errorbuf idbuf endif The following routine allows you to type SCPI commands and see the results If you don t call this from your program set the following fif 1 to Me 0 wf if 1 Set to 0 to skip this routine void do interactive void char command 5000 392 Example Program Listi
75. the names of the variables must be known The working variables for PIDA and PIDB are listed in the section Defining Standard PID Algorithms starting on page 75 To read the values of these variable use the command ALGorithm SCALar lt alg name lt var_name gt The command returns the current value of the variable var name from the algorithm alg name With this command it is possible to look at PIDB variables that are not automatically placed in the CVT Since the PIDA algorithm doesn t send values to the CVT ALG SCALAR is the only way to view the contents of its working variables Example for PIDA To return the value of the error term variable from the PIDA ALG3 ALG SCALAR ALG3 Error program executes enter statement now input the value The Current Value Table CVT contains the latest operating parameter values from executing PIDB algorithms The algorithms copy these values to specific elements of the CVT each time they execute The CVT is fast because it is a hardware state machine that does not require the DSP to be involved in the data transaction Further a single SCPI command can return some or all of the CVT s values thus reducing the I O load on an application program There is a pre defined organization for the CVT Standard PID algorithms are allocated 10 CVT elements With up to 32 PIDs possible 320 elements are allocated for Standard PIDs ALGI can use elements 10 19 ALG2 can us
76. 0 628319 0 587786 VT1415A sin 0 628319 0 587740 C sin 0 942479 0 809018 VT1415A sin 0 942479 0 808944 C sin 1 256639 0 951057 VT1415A sin 1 256639 0 950965 C sin 1 570798 1 000000 VT1415A sin 1 570798 0 999905 Table F 1 C Sin x Vs VT1415A Haversine Function for Selected Points As stated earlier there are limitations to using this custom function technique These limitations are directly proportional to the non linearity of the desired waveform For example suppose that the function X X X or X2 is to be represented over a range of 1000 The resulting binary range would be 1024 and the segments would be partitioned at 1024 64 intervals This means that every 16 units would yield an Mx B calculation over that segment As long as numbers are inputted that are VERY close to those cardinal points good results are yielded Strictly speaking perfect results can be received only if calculations are performed at the cardinal points which may be reasonable for an application if the input values are limited to exactly those 128 points The waveform may also be shifted anywhere along the X axis and Build_table will provide the necessary offset calculations to generate the proper table Be aware too that shifting the table out to greater magnitudes of X may also impact the precision of the results dependent upon the linearity of the waveform Suffice it to say that the best results will be attained and it w
77. 0 Input PE 1 Error A FF 2 Output pm 3 Status d History mode 1 Summary to CVT and FIFO In this mode the four ii summary values are written to both the CVT and FIFO A header tag 256 n 4 is sent to the FIFO first where n is the Algorithm number 1 32 red KK HK KK Ck Ck RR RARA RRA A A RRA KC KK KK KK A KK KC KK KK KK KC KK kk e ke ke ke e ke ke AAA User determined control parameters static float Setpoint 0 The setpoint E static float P factor 1 Proportional control constant static float I factor 0 Integral control constant static float D factor 0 Derivative control constant e static float Error max 9 9e 37 Error alarm limits static float Error min 9 9e 37 static float PV max 9 9e 37 Process Variable alarm limits ii static float PV min 9 9e 37 static float Out max 9 9e 37 Output clip limits EJ static float Out_ min 9 9e 37 static float D max 9 9e 37 Derivative clip limits E static float D min 9 9e 37 static float I max 9 9e 37 Integral clip limits static float I min 9 9e 37 static float Man state 0 Activates manual control e static float Man out 0 Target Manual output value static float Man inc 9 9e 37 Manual outout change increment static float SD factor 0 Setpoint Derivative constant y static float SD max 9 9e 37 Setpoint Derivative clip limits ef
78. 086914 0 383301 0 004673 0 000000 Process variable 9 018555 0 018555 0 004655 0 000000 Process variable 9 056152 0 056152 0 004637 0 000000 Process variable 9 054688 0 054688 0 004623 0 000000 Process variable 9 046387 0 046387 0 004612 0 000000 Process variable 9 010254 0 010254 0 004601 0 000000 endif file alg cs SHeader C SCPI Example program for the E1415A Algorithmic Closed Loop Controller file alg cs This example shows how to load algorithms from files This example works properly with the file mxplusb which contains the E1415A algorithm for calculating various combinations of Mx B This is a template for building E1415A C programs that may use C SCPI or SICL to control instruments Standard include files include lt stdlib h gt Most programs use one or more functions from the C standard library include lt stdio h gt Most programs will also use standard I O functions include lt stddef h gt This file is also often useful include lt math h gt Needed for any floating point fn s Other system include files Whenever using system or library calls check the call description to see which include files should be included ird Instrument control include files include lt cscpi h gt C SCPI include file Declare any constants that will be useful to the pro
79. 1100 A where is a null byte Chapter 4 Creating and Running Custom Algorithms 123 NOTE For Block Program Data the Algorithm Parser requires that the source code data end with a null 0 byte The null byte must be appended to the end of the block s data byte s gt For Definite Length Block Data the null byte must be accounted for in the byte count lt digit s gt If the null byte is not included within the block the error Algorithm Block must contain termination 0 will be generated Indefinite Length Block Data Example Retrieve algorithm source code from file and send to VT1415A in indefinite length format using VISA instrument I O libraries int byte count file handle char source buffer 8096 null 0 file handle open lt filename gt O RDONLY O BINARY byte count read file handle source buffer sizeof source buffer close file handle source buffer byte count 0 null to terminate source buffer string viPrintf e1415 ALG DEF ALG8 0 s c n source buffer null Definite Length Block Data Example Retrieve source code from text file determine length of file create a Definite Length Block header and send algorithm to VT1415A using VISA instrument I O Libraries int byte count file handle char header string 12 source buffer 8096 null 0 file handle open filename O RDONLY O BINARY byte count read file handle sou
80. 114 T1140 VZOSTLA y A30 19414 11140 VIOSLLA 3 Fq Appendix A 308 Specifications Type R filter off 0i XO 89g AIO 1931 POX 1 110 VEOSILA E qam Hk TED me Gs Hn CHR RH o un ud uk JAO 19184 8X 1 1d0 VEOSLLA oe te rz dJO 19114 21 HO VZOSTLA MeRRARRASAZSATATAAUAARUATUXATTEAA quA Aira J40 22184 11140 VIOSLLA 070 000 000 4 APS S oso aiaa PE MAMAN AUN A A P ip he w tod O01 in a mo u M M P i EIR Os I Er va a 007 7 OFC 4 ke 06v oA 00 S e sa oss z 009 gt E o B0 L Specifications 309 Appendix A Type R filter off VT1508A 09A 001 080 090 ov 0 OE XD Pq A PECENE ETES AS TUO AC t E e a Ik We a erem PATCR NANA e a ox Yurvde 440 42314 61 100 V6OS LEA Es i E ARA RA A A AAA RAT RARAS HAO 4914 8T 140 VROSTLA Appendix A 310 Specifications Type S filter off Ol XO Sag J40 PEI 9X ELIdQ VEOSTLA AAA A J0 19114 8X ET 110 VEOSLLA o mom e e ee e Wm ue e o dm ih aa E a Ae e e mom AJO 1914 21140 VZOSLLA ARA A A pr JO PWA 11 KO VIOSLLA OS I 001 Am mtm UR e s taste PRISA Aa E A AS leat Lt eee a ars A vd M T Fs ar pur dur ranar i anular
81. 20 mA max output static float min output 004 4 mA min output get value from input buffer channel 8 calculate desired output check output greater than limit if so output max limit check output less than limit if so output min limit split output val between two SCP channels to get up to 20 mA max FF following lines input limit output between min and max output and outputs output is split to two current output channels wired in parallel to provide 20 mA 0116 max min output min max output 12 5 1108 2 0117 max min output min max output 12 5 1108 2 The Algorithm Execution Environment This section describes the execution environment that the VT1415A provides for algorithms Here the relationship of an algorithm to the main function that calls it 1s described Chapter 4 Creating and Running Custom Algorithms 113 The Main Function All C language programs consist of one or more functions A C program must have a function called main In the VT1415A the main function is usually generated automatically by the driver when the INIT command is executed The main function executes each time the module is triggered and controls execution of algorithm functions See Figure 4 1 for a partial listing of main How the when the module is INITiated a set of control variables and a function Algorith ms Fit n calling sequen
82. 212 MEMory VME SIZE essseeeeeee eens 212 MEMory VME SIZE ie eru eee betes eb R9 ore eRe abe ys 213 MEMory VME STATe eceso ec eee eee 213 MEMory VME STATe 0 0 cece ee ehh 214 OUT Put 413 265 ba bette mb Up Oe pta di weed 215 OUTPut CURRent AMPLitude 0 0 0 0 0 eee 215 OUTPut CURRent AMPLitude 2 0 eee 216 OUTPut CURRent STATe 0 0 0 0 0 ccc eee eee 217 OUTPut CURRent STATe rener nnne na eee 217 Table of Contents xi OUTPu t POLarity Lu evecethe ertet ie Re Yn 218 OUTP t POLarity os ones tas SERERE EE St 218 OUTPUtSHUNLE eden rh urguet e AE ae RT RR e 218 OUTPut SHUNE vii rettet Rie res RR e ae ets 219 OUTPutTTLTrg SOURce uesssssseeee nee 219 OUTPut TTL Tre SOURCE 6 05 sad e CURRERE e 220 OUTPut TTLTrg lt n gt STATe 2 2 20 0 0 eee 220 OUTPut TTLTrg lt n gt STATe 2 0 0 0 eee ce eee 221 OUTP t TYPE asesora ond cod Sede BEA hoe Eee ROT ba 221 OUTPUUTY PE Lct eo bete dee e edd dade 222 OUTPut VOLTage AMPLitude 2 0 cee eee ee eee 222 OUTPut VOLTage AMPLitude 2 0 0 e eee eee 223 ROUTE PEPERIT 224 ROUTe SEQuence DEFine 1 0 0 0 0 0000 c cee 224 ROUTe SEQuence POINts 2 0 0 cece cece nnn 225 SAMPLE ci Sa eM pue toe eed URRRA TN Obs ewe ERE Ree ERE EIS 226 SAMPIe TIMer ueteri Ae anche ew up eae Wade e 226 SAMPle TIMET iiu cou wend eae eves IRE XA DERE need Sete 64 227 SEN Solos gust eres ee eod re directo
83. 25 Calling user defined functions 120 Capability maximum tare 106 CAUTIONS Loss of process control by algorithm 162 172 273 Safe handling procedures 21 Certification iii Changing an algorithm while it s running 124 Changing gains 106 Changing gains or filters 106 Changing timer interval while scanning 276 CHANnel ALGorithm UPDate CHANnel 177 Channel calibration CAL 278 Channel identifiers communication using 128 Channels defined input 116 output 60 70 116 setting up analog input 60 setting up digital input 70 CHANnels SENSe REFerence CHANnels 248 Channels accessing I O 116 Channels adding settling delay for specific 110 Channels input 116 Channels output 116 Channels special identifiers for 137 Characteristics settling 108 Checking for problems 109 CHECksum DIAG CHECK 195 Clearing event registers 99 Clearing the enable registers 99 Clipping limits 76 Coefficients 89 Command Abbreviated 156 Implied 156 Linking 159 Separator 156 Command Quick Reference 288 290 291 292 293 294 295 Command Reference Common CAL 278 CLS 279 DMC 279 EMC 279 EMC 279 ESE 279 ESE 280 ESR 280 GMC 280 DN 280 LMC 281 412 Index OPC 281 OPC 281 PMC 281 RMC 281 RST 282 SRE 283 SRE 283 STB 283 TRG 283 TST 283 WAI 287 Command Reference SCPI 161 ABORt subsystem 162 ALGorithm EXPLicit STATe 172 173 ALGorithm
84. 26 G6 H57 L57 7 27 G7 H58 L58 6 28 GND H59 L59 5 29 GND H60 L60 4 30 GND H61 L61 3 31 GND H62 L62 2 32 GND H63 L63 1 Figure 2 18 VT1415A Connector Pin Signal List Chapter 2 Field Wiring 51 Notes 52 Field Wiring Chapter 2 Chapter 3 Programming the VT1415A for PID Control About This Chapter The focus in this chapter is to show the VT415A s programming model The programming model is basically a sequence of SCPI commands an application program sends to a VT1415A to configure it to execute defined PID proportional integral derivative algorithms This programming model is virtually the same for the pre defined PID algorithms and user defined custom algorithms This chapter contains e Overview of the VT1415A Loop Controller page 54 Programming Model lsslesses esses page 55 e Executing the Programming Model page 57 Programming Overview Diagram sess page 59 Setting up Analog Input and Output Channels page 60 Configuring Programmable SCP Parameters page 60 Linking Input Channels to EU Conversion page 62 Linking Output Channels to Functions page 69 Setting up Digital Input and Output Channels page 70 Digital Input Channels 0200005 page 70 Digital Output Channels 2 0 05 pa
85. 271 SYS Tem VERSION uod cada a A cs x Re de eR REC RC due a aoe a P E RR UR page 272 154 VT1415A Command Reference Chapter 6 TRIGSer COUNE SIFIP COUN 6 oue dus ewe ox Eve UU Rx AGIR ARR AE Role Xu page 275 TRICGSer COUNE ue iugo mue n m RES ROS a WB eg U ek EE REAR SE ERE demos de d s page 275 TRIGeer IMMediate os o ERE xx ew REE a X 9 eh p Ro o9 ws page 275 TRIGger SOURce BUS EXT HOLD IMM SCP TlMer TTLTrg lt n gt page 276 TRIGger SOURCE 5 xS nee ee a Ye oe ne d Sa eee ae X S RS page 277 TRIGger TIMer PERiod trig interval 2222s page 277 TRIGeerTIMer PER10d cocos kom 9o EO GG Rd Reg 93 X Dor d ee RE Ress page 277 Common Commands uo D MCCC ee a eas ido ea Cate iy es AP ce cee Ore ee ee gee de a Bee CP page 278 CLS aces bebe ee fa eho i eee bbSeh net ake a deed te ee deed edaas page 279 DMC lt name gt lt cmd data gt x dose oe BRA CR AR SUR DA Re RR RR draps page 279 EMC enable ee QoS OER ERE PROG EM Pee Sow 9m Ow REGE edu page 279 EMCES oe ae he xS aid Boe GS Node vo o eth oe ee LR page 279 ESE scorer 446625 4509 Se 403 A x pO RD 9X xg e RS AS VE bh OAS page 279 FESE a a s Gap eGR Bie ee num aie eae ee yo oe ad Wa deny us page 280 ESR La gave Hwa eI o e OMA Gwe DEG eee ba See ORS wee Wu eiue page 280 GMC Ham x deh ee EROR 43e ER e e DOR X ARE Sd x Ae EU C o Re dits page 280 IDN babe ee Sede eek beens Stee ha de POR G a ee ex ep dE deed e x page 280 EMC eu S
86. 355 Resistance temperature measurements 65 Saving time when doing channel calibration 75 Selecting manual range vs SCP gains 63 Setting the interrupt level 19 pene conflict ARM SOUR vs TRIG SOUR 180 Thermocouple reference temperature usage 246 248 TRIGger SOURce vs ARM SOURce 81 82 Warmup before executing TST 330 When algorithm variables are initialized 141 NTRansition STAT OPER NTRansition 264 STAT QUES NTRansition 269 NTRansition STAT OPER NTRansition 265 STAT QUES NTRansition 269 O Octal constant 141 Offset A D 186 278 channel 186 278 Offsets compensating for system 104 Offsets residual sensor 105 Offsets system wiring 104 Operating sequence 120 Operation 74 105 Operation and restrictions 74 Operation status group examples 97 Operation custom EU 102 Operation standard EU 101 Operation VT1415A background 100 Operational overview 54 Operator assignment 137 Operator unary arithmetic 146 Operator unary logical 137 Operators 137 Operators arithmetic 137 Operators comparison 137 Operators logical 137 Operators the arithmetic 146 Operators the comparison 146 Operators the logical 146 Operators unary 137 Option A3F 49 Options Terminal module 49 Order algorithm execution 121 Organization of the CVT 85 OTD restrictions NOTE 107 OTDetect DIAGnostic OTDetect 107 OUTP CURRent AMPLitude 215 OUTP CURRent AMPLitude 216 OUTP SHUNt 218
87. 60 FREQuency INP FILT FREQ 206 Function frequency 70 Function setting input 70 Function static state CONDition 70 72 Function the main 114 Function totalizer 71 Functions and statements intrinsic abs expression 137 interrupt 119 137 max expression l expression2 137 min expressionl expression2 137 writeboth expression cvt_element 137 writecvt expression cvt_element 118 137 writefifo expression 119 137 Functions calling user defined 120 Functions linking output channels to 69 Functions setting output 72 Functions 138 G Gain channel 278 GAIN INPut GAIN 207 GAIN INP GAIN 208 Gains setting SCP 60 GFACtor SENSe STRain GFACtor 250 SENSe STRain GFACtor 250 Global variables 141 accessing 117 defining 117 416 Index Glossary 335 336 337 338 Grounding Noise due to inadequate 355 Group an example using the operation 97 Guard connections 355 H HALF SENS DATA FIFO COUNt HALF 233 SENS DATA FIFO HALF 233 Hexadecimal constant 141 HINTS for quiet measurements 39 Read chapter 3 before chapter 4 111 History mode 77 How to use CAL 74 I Identifier 141 Identifiers 136 IEEE INF 202 IMMediate ALGorithm UPDate 176 ARM IMMediate 181 INIT IMM 204 TRIG IMMediate 275 Impedance input 298 Implementing feed forward control 129 Implementing multivariable control 128 Implementing setpoint profiles 132 Implied Commands 156 IMPORT
88. ALG SCAN RATIO and ALG STATE changes when the specified digital input level changes state When the ALG UPD CHAN command is executed the current state of the digital input specified is saved The update will be performed at the next update phase UPDATE in Figure 6 1 following the channel s change of digital state This command allows multiple VT1415As to be synchronized so that all variable updates can be processed simultaneously Parameters Parameter Parameter Range of Default Name Type Values Units dig chan Algorithm Input channel for VT1533A Iccc Bb none Language channel for VT1534A Iccc specifier string Where ccc normal channel number and b bit number include B Comments The duration of the level change to the designated bit or channel MUST be at least the length of time between scan triggers Variable and algorithm changes can be accepted during the INPUT or UPDATE phases Figure 6 1 when INIT is active All writes to variables and algorithms occur to their buffered elements upon receipt However these changes do not take effect until the ALG UPD CHAN command is processed at the beginning of the UPDATE phase Note that the ALG UPD WINDow command specifies the maximum number of updates to do If no update command is pending when entering the UPDATE phase then this time is dedicated to receiving more changes from the system NOTE As soon as the ALG UPD CHAN command is received the
89. ALG UPDATE command has been sent the VT1415A simply switches to executing ALG3 s new algorithm from space B at the next Update Phase see Figure 4 2 If yet another ALG3 were sent it would be loaded and executed from ALG3 s space A In order to define an algorithm for swapping it is necessary to know how much algorithm memory to allocate for it or any of its replacements This information can be queried from the VT1415A Use the following sequence 1 Define the algorithm without swapping enabled This will cause the VT1415A to allocate only the memory actually required by the algorithm 2 Execute the ALG SIZE alg name gt command to query the amount of memory allocated The minimum amount of memory required for the algorithm is now known 3 Repeat 1 and 2 for each of the algorithms that can be swapped with the original From this the minimum amount of memory required for the largest is known Chapter 4 Creating and Running Custom Algorithms 125 NOTES l Execute RST to erase all algorithms Re define one of the algorithms with swapping enabled and specify swap size at least as large as the value from step 3 above and probably somewhat larger because as alternate algorithms declare different variables space is allocated for total of all variables declared Swap each of the alternate algorithms for the one defined in step 5 ending with the one to run now Remember the swap size parameter is not
90. CUSTom is pre defined as Type E with 0 C reference junction temp and is not re defineable For type THERmistor the lt sub_type gt parameter may be specified in ohms or kohm The CAL command calibrates resistance channels based on Current Source SCP and Sense Amplifier SCP setup at the time of execution If SCP settings are changed those channels are no longer calibrated CAL must be executed again Related Commands SENSE FUNC TEMP RST Condition Reference temperature is 0 C Chapter 6 VT1415A Command Reference 247 SENSe Usage sense the reference temperature on channel 20 using an RTD SENSE REF RTD 92 120 SENSe REFerence CHANnels Parameters Comments Usage SENSe REFerence CHANnels lt ref_channel gt lt ch_list gt causes channel specified by lt ref_channel gt to appear in the scan list just before the channel s specified by cA list This command is used to include the thermocouple reference temperature channel in the scan list before other thermocouple channels are measured Parameter Parameter Range of Default Name Type Values Units ref channel channel list string 100 163 none ch list channel list string 100 163 none e Use SENS FUNC TEMP to configure channels to measure thermocouples Then use SENS REF to configure one or more channels to measure an isothermal reference temperature Now use SENS REF CHAN to group the refe
91. Event register STAT OPER Same as above STATus OPERation NTRansition STATus OPERation NTRansition transition mask sets bits in the Negative Transition Filter NTF register When a bit in the NTF register is set to one the corresponding bit in the Condition register must change from a one to a zero in order to set the corresponding bit in the Event register When a bit in the NTF register is Zero a negative transition of the Condition register bit will not change the Event register bit Parameters Parameter Parameter Range of Default Name Type Values Units transition mask numeric uint16 0 32767 none Comments The transition mask parameter may be sent as decimal hex H octal Q or binary ZB e f both the STAT OPER PTR and STAT OPER NTR registers have a corresponding bit set to one any transition positive or negative will set the corresponding bit in the Event register 264 VT1415A Command Reference Chapter 6 STATus e f neither the STAT OPER PTR or STAT OPER NTR registers have a corresponding bit set to one transitions from the Condition register will have no effect on the Event register e Related Commands STAT OPER NTR STAT OPER PTR e Cleared By STAT PRESet and power on e RST Condition No change Usage STAT OPER NTR 16 When Measuring bit goes false set bit 4 in Status Operation Event register STATus OPERation NTRansition STATus OPERation NT
92. Exceeded Exceeded 1116 Mask chan16 limit test digital If Exceeded interrupt Chapter 4 Creating and Running Custom Algorithms 131 Implementing Setpoint Profiles A setpoint profile is a sequence of set points inputted to a control algorithm A normal setpoint is either static or modified by operator input to some desired value where it will then become static again A setpoint profile is used to cycle a device under test through some operating range and the setpoint remains for some period of time before changing The automotive industry uses setpoint profiles to test their engines and drive trains That is each new setpoint is a simulation of an operator sequence that might normally be encountered A setpoint profile can either be calculated for each interval or pre calculated and placed into an array If calculated the algorithm is given a starting setpoint and an ending setpoint A function based upon time then calculates each new desired setpoint until traversing the range to the end point Some might refer to this technique as setpoint ramping Most setpoint profiles are usually pre calculated by the application program and downloaded into the instrument performing the sequencing In that case an array affords the best alternative for several reasons e Arrays can hold up to 1 024 points e Arrays can be downloaded quickly while the algorithm is running e Time intervals can be tied to trigger events and e
93. Module Current lo lom lpn Dm IPm IDm IPm IDm IPm IDm IPm IDm IDm Dynamic Module Current 1 0 0 02 0 06 0 01 0 01 0 01 0 1 0 01 0 1 0 01 0 15 0 01 Cooling Requirements Average watts slot A Pressure mm H O Air Flow liters s 14 0 08 0 08 Power Available for SCPs 1 0A 24 V 3 5A5V See VXI Catalog or SCP manuals for SCP current Measurement Ranges dc volts VT1501A or VT1502A 62 5 mV to 16 V Full Scale Temperature Thermocouples 200 to 1700 C Thermistors Opt 15 required 80 to 160 C RTD s Opt 15 required 200 to 850 C Resistance VT1505A with VT1501A 512 O to 131 kQ FS Strain 25 000 we or limit of linear range of strain gage Measurement Resolution 16 bits including sign Maximum Update Rate pp a ue running PIDA algorithm Oops z id oor 32 Loops 250 Hz Trigger Timer and 100 ppm 0 01 from 10 C to 70 C Sample Timer Accuracy Specifications 297 External Trigger Input TTL compatible input Negative true edge triggered except first trigger will occur if external trigger input is held low when module is INITiated Minimum pulse width 100 ns Since each trigger starts a complete scan of 2 or more channel readings maximum trigger rate depends on module configuration Maximum Input Voltage With Direct Input Passive Filter or Amplifier SCPs N mode pl d Operating lt 16 V peak Damage level gt 42 V peak Ne ee NOT With VT1513A Divide by 1
94. Now analyze this statement a 3 4 12 Again the translator simplifies the expression by performing the integer divide for 3 4 This results in the integer value 0 being multiplied by 12 which results in the float constant 0 0 being assigned to the variable a at run time This is obviously not what was desired but is exactly what the algorithm instructed These subtle problems can be avoided by specifically including a decimal point in decimal constants where an integer operation is not desired For example if either of the constants in the division above were made a float constant by including a decimal point the translator would have promoted the other constant to a float value and performed a float divide operation resulting in the expected 0 75 12 or the value 8 0 So the statement a 3 4 12 ee 22 will result in the value float 8 0 being assigned to the variable a All VT1415A variables local or global must be declared as static An example static float gain var integer var deriv var three vars declared In C local variables that are not declared as static lose their values once the function completes The value of a local static variable remains unchanged between calls to an algorithm Treating all variables this way allows an algorithm to remember its previous state The static variable is local in scope but otherwise behaves as a global variable Also note that variables may n
95. PIDB and specifies the input and output channels PIDB also takes an alarm channel The general form of the string is PIDx inp channel outp channel alarm channel7 Where x is A or B Note that alarm channel is only supported for PIDB Enclose alg def string within single quotes apostrophe character or double quotes The alg def string gt commands the driver s translator function to download the program code for the selected PID algorithm into the VT1415A s algorithm memory space where is can be executed The source code listings for the available PIDs can be seen in Appendix D To select PID algorithm PIDB and use channel 0 for its input channel 8 for its output and channel 24 bit 0 as the alarm channel execute ALG DEF ALG1 PIDB 1100 0108 0124 B0 NOTES 1 If error messages are received when a PID algorithm is defined the most common causes are 1 Trying to re define an algorithm by the same name or 2 Using a channel identifier that is not defined make sure the first letter in channel specifier is uppercase and that bit identifiers start with the uppercase B 78 Programming the VT1415A for PID Control Chapter 3 2 The channels specified in the PID definition can be any GLOBAL variable identifier defined prior to the algorithm definition Use ALG DEF GLOBALS var declaration source ALG DEF GLOBALS static float pid1_outp pid2_inp ALG DEF ALG1 PIDB
96. Programming the VT1415A for PID Control Chapter 3 Setting the VT1505A Current Source SCP The cutoff frequency selections provided by the SCP can be assigned to any channel individually or in groups Send a separate command for each frequency selection For example To set 10 Hz cutoff for channels 0 4 6 and 10 through 19 send INP FILT FREQ 10 100 104 106 110 119 To set 10 Hz cutoff for channels 0 through 15 and 100 Hz cutoff for channels 16 through 23 send INP FILT FREQ 10 100 115 INP FILT FREQ 100 116 123 or to combine into a single command message INP FILT FREQ 10 100 115 FREQ 100 116 123 By default after RST or at power on the filters are enabled To disable or re enable individual or all channels use the INP FILT ON OFF lt ch_list gt command For example to program all but a few filters on send INP FILT STAT ON 100 163 all channel s filters on same as at RST INP FILT STAT OFF 100 123 146 163 only channels 0 23 46 and 63 OFF The Current Source SCP supplies excitation current for resistance type measurements These include resistance and temperature measurements using resistance temperature sensors The commands to control Current Source SCPs are OUTPut CURRent AMPLitude lt amplitude gt lt ch_list gt and OUTPut CURRent STATe lt enable gt e The lt amplitude gt parameter sets the current output level It is specified in units of amps dc and for the VT1505A SC
97. Register query Return Standard Event Status Register contents SRE mask Service Request Enable Set Service Request Enable register bit mask SRE Service Request Enable query Return current setting of the Service Request Enable register STB Read Status Byte query Return current Status Byte value Macros DMC Define Macro Command Assigns one or a sequence of commands to a macro name cmd data EMC 1 0 Enable Macro Command Enable Disable defined macro commands EMC Enable Macros query Returns for macros enabled 0 for disabled GMC lt name gt Get Macro query Returns command sequence for named macro LMC Learn Macro query Returns comma separated list of defined macro names PMC Purge Macro Commands Purges all macro commands RMC lt name gt Remove Individual Macro Removes named macro command Synchronization OPC Operation Complete Standard Event register s Operation Complete bit will be 1 when all pending device operations have been finished OPC Operation Complete query Places an ASCII 1 in the output queue when all pending operations have finished TRG Trigger Trigger s module when TRIG SOUR is HOLD WAI Wait to Complete 294 VT1415A Command Reference Chapter 6 Command Quick Reference Notes Chapter 6 VT1415A Command Reference 295 Appendix A e Ld e Specifications Power Requirements with no SCPs installed 5 V 12 V 12 V 24 V 24 V 5 2 V IPm Peak
98. SENSe FREQuency APERture gate time gt lt ch list ee page 236 SENSe FREQuency APERture lt channel gt oo page 236 SENSe FUNCtion CONDition g ch list 2 2s page 237 SENSe FUNCtion CUSTom range Q ch list o a aaa page 237 SENSe FUNCtion CUSTom REFerence lt range gt lt ch_lis gt ee page 238 SENSe FUNCtion CUSTom TCouple type range Q ch list ooo ooo page 239 SENSe FUNCtion FREQuency lt ch list ee page 240 SENSe FUNCtion RESistance excite current range ch list page 241 SENSe FUNCtion STRain FBENding crange7 Q ch list ole page 242 SENSe FUNCtion STRain FBPoisson crange7 Q ch list ee page 242 SENSe FUNCtion STRain FPOisson lt range gt lt ch_lis gt len page 242 SENSe FUNCtion STRain HBENding lt range gt lt ch_list gt ee page 242 SENSe FUNCtion STRain HPOisson lt range gt lt ch_lis lens page 242 SENSe FUNCtion STRain QUARter lt range gt lt ch_lis lens page 242 Chapter 6 VT1415A Command Reference 153 SENSe FUNCtion TEMPerature lt sensor_type gt lt sub_type gt lt range gt lt ch_lis gt page 243 SENSe FUNCtion TOTalize Q ch list ee page 245 SENSe FUNCtion VOLTage DC lt range gt lt ch_lis gt
99. STATus e Related Commands STAT OPER PTR STAT OPER NTR e Set to all ones by STAT PRESet and power on e RST Condition No change Usage STAT OPER PTR 16 When Measuring bit goes true set bit 4 in Status Operation Event register STATus OPERation PTRansition STATus OPERation PTRansition returns the value of bits set in the Positive Transition Filter PTF register Comments Returned Value Decimal weighted sum of all set bits The C SCPI type is uint16 e Related Commands STAT OPER PTR e RST Condition No change Usage STAT OPER PTR Enter statement returns current value of bits set in the PTF register STATus PRESet STATus PRESet sets the Operation Status Enable and Questionable Data Enable registers to 0 After executing this command none of the events in the Operation Event or Questionable Event registers will be reported as a summary bit in either the Status Byte Group or Standard Event Status Group STATus PRESet does not clear either of the Event registers Comments Related Commands STB SPOLL STAT OPER ENABLE STAT OPER ENABLE STAT QUES ENABLE STAT QUES ENABLE e RST Condition No change Usage STAT PRESET Clear both of the Enable registers The Questionable Data Group The Questionable Data Group indicates when errors are causing lost or questionable data The bit assignments are 266 VT1415A Command Reference Chapter 6 STATus Bit decvalue hex value Bit Name Descripti
100. Scan List SCP Swapping Terminal Blocks The Digital Signal Processor DSP chip that performs all of the VT1415A s internal hardware control functions as well as performing the EU Conversion process Same as Control Processor Engineering Units Engineering Unit Conversion Converting binary A D readings in units of A D counts into engineering units of voltage resistance temperature strain These are the built in conversions see SENS FUNC The VT1415A also provides access to custom EU conversions see SENS FUNC CUST in command reference and Creating and Loading Custom EU Tables in Chapter 3 The First In First OUT buffer that provides output buffering for data sent from an algorithm to an application program Non volatile semiconductor memory used by the VT1415A to store its control firmware and calibration constants A list of up to 64 channels that is built by the VT1415A Channels referenced in algorithms are placed in the Scan List as the algorithm is defined This list will be scanned each time the module is triggered Signal Conditioning Plug On Small circuit boards that plug onto the VT1415A s main circuit board Available analog input SCPs can provide noise canceling filters signal amplifiers signal attenuators and strain bridge completion Analog output SCPs are available to provide measurement excitation current controlling voltage and controlling current Digital SCPs are available to both
101. See NESE SEPTATE es RUNE POIS eae CMLL A EIS Sree ggi pasen QPZ A A A Ae teh sae tes os eres i M oc z sese OG OO A 090 me OPO 440 Pld POX 61 140 V OSLEA erm me ene gt OO e Be Ve d Hh GN Hm He GA ie a GM Hs RA n A nid dd dm d dm dm dd vm Rom 000 A UU rn 440 393114 1300 VIOSLLA 2 aq UL E MOT Appendix A 324 Specifications Thermistor 10 kQ filter off VT1508A 09A 00 071 00001 0008 00709 00 0t oroz opo o 33a A A APA no z pope AA ODER CE m RUSSE diens pr go A A A MOVANTA OE CHE A A ds 0zz meo ete E e REN ME DO e o ORT 430 12114 61 190 V60SLLA 440 29114 81 WO V8OSLLA ULL MOT Specifications 325 Appendix A 326 Specifications Appendix A Appendix B Error Messages Possible Error Messages 108 109 160 211 212 213 221 222 224 240 253 281 282 310 410 1000 2001 2003 2007 2008 2009 2016 3000 Parameter not allowed Missing parameter Block data error Trigger ignored Arm ignored Init ignored Settings conflict Data out of range Illegal parameter value Hardware error Execute TST Corrupt media Cannot create program
102. TIME return for undefined algorithm 173 Algorithm Language case sensitivity 136 Algorithm Language reserved keywords 136 Algorithm source string terminated with null 124 Algorithm source string terminates with null 167 Algorithm swapping limitations 168 Algorithm Swapping restrictions 126 Algorithm variable declaration and assignment 117 Amplifier SCPs can reduce measurement noise 110 BASIC s vs C s is equal to symbol 145 Bitfield access C vs Algorithm Language 140 Cannot declare channel ID as variable 137 Combining SCPI commands 160 CVT contents after RST 86 231 Decimal constants can be floating or integer 141 418 Index Default RST Engineering Conversion 62 Define user function before algorithm calls 120 Do not CAL TARE thermocouple wiring 188 Do use CAL TARE for copper in TC wiring 104 Do use CAL TARE for copper TC wiring 188 Don t use CAL TARE for thermocouple wiring 104 Flash memory limited lifetime 105 187 Isothermal reference measurements 34 MEM subsystem vs command module model 211 MEM subsystem vs TRIG and INIT sequence 211 MEM system vs TRIG and INIT sequence 200 Memory required by an algorithm 125 moe of updates vs ALG UPD WINDOW 164 Open transducer detect restrictions 107 OUTP CURR AMPL command 62 eee for resistance measurements OUTP VOLT AMPL command 62 PID definition errors and channel specifiers 78 Reference to noise reduction literature
103. That is they are in the VT1415A s driver and the driver can automatically insert channel references into the code as it is loading it Otherwise there is no difference in fact the standard PIDs are written in the same Algorithm Language used to create custom algorithms The source code for PIDA PIDB as well a third algorithm PIDC are supplied with the VT1415A which can be used as the basis for custom PID algorithms Overview of the Algorithm Language As mentioned in the Introduction the VT1415A s Algorithm Language is based on the ANSI C programming language This section will present a quick look at the Algorithm Language The complete language reference is provided in Chapter 5 Arithmetic Operators add subtract multiply divide NOTE Also see Calling User Defined Functions on page 120 Assignment Operator Comparison Functions less than lt less than or equal lt greater than gt greater than or equal gt equal to not equal to Boolean Functions and amp amp or not Variables scalars of type static float and single dimensioned arrays of type static float limited to 1 024 elements Constants 32 bit decimal integer Dddd where D and d are decimal digits but D is 112 Creating and Running Custom Algorithms Chapter 4 Example Language Usage not zero No decimal point or exponent specified 32 bit octal integer Doo where 0 is a leading zero and o
104. V Full Scale with 200 Ohm can use 4 Volt range for better resolution Figure 2 15 Series amp Parallel Component Examples Chapter 2 Field Wiring 47 Terminal Module Wiring Maps Figure 2 16 shows the Terminal Module map for the VT1415A
105. VAL RES CAL STOR ADC e When Accepted Not while INITiated 184 VT1415A Command Reference Chapter 6 Command Sequence CAL CONF RES Connect reference resistor to Calibration Bus OPC or SYST ERR must wait for CAL CONF RES to complete now measure ref resistor with external DMM CAL VAL RES measured value Send measured value to module CAL STORE ADC Store cal constants in non volatile memory used only at end of complete cal sequence CALibration CONFigure VOLTage CALibration CONFigure VOLTage lt range gt lt zero_fs gt connects the on board voltage reference to the Calibration Bus A measurement of the source voltage can be made with an external multimeter connected to the H Cal and L Cal terminals on the Terminal Module or the V H and V L terminals on the Cal Bus connector The range parameter controls the voltage level available when the zero fs parameter is set to FSCale full scale Parameters Parameter Parameter Range of Default Name Type Values Units range numeric float32 See comments volts zero fs discrete string ZERO FSCale none Comments The range parameter must be within 5 of one of the five following values 0 0625 V dc 0 25 V dc 1 V dc 4 V dc 16 V dc range may be specified in millivolts mv e The FSCALE output voltage of the calibration source will be greater than 90 of the nominal value for each range except the 16 V range where the
106. VT1415A s internal calibration resistor The values generated from this calibration are then stored in nonvolatile memory and become the basis for Working Calibrations These procedures each require a sequence of several commands from the CALibration subsystem CAL CONFIG CAL VALUE and CAL STORE ADC Always execute CAL ora CAL TARE operation after A D Calibration 2 Working Calibration This category consists of three levels see Figure 6 3 A D Zero This function quickly compensates for any short term A D converter offset drift This would be called the auto zero function in a conventional voltmeter In the VT1415A where channel scanning speed is of primary importance this function is performed only when the CAL ZERO command is executed Execute CAL ZERO as often as the control setup will allow Channel Calibration This function corrects for offset and gain errors for each module channel The internal current sources are also calibrated This calibration function corrects for thermal offsets and component drift for each channel out to the input side of the Signal Conditioning Plug On SCP AII calibration sources are on board and this function is invoked using either the CAL or CAL SETup command Channel Tare This function CAL TARE corrects for voltage offsets in external system wiring Here the user places a short across transducer wiring and the voltage that the module measures is no
107. VXI Technology Lake Stevens Instrument Division VXI Technology Inc 1924 203 Bickford Snohomish WA 98290 Phone 425 212 2285 Fax 425 212 2289 Technical Support Phone 949 955 1894 Fax 949 955 3041 E mail support vxitech com Visit http www vxitech com for worldwide support sites and service plan information Support xvii Support xviii Chapter 1 Getting Started About This Chapter This chapter will explain hardware configuration before installation in a VXIbus mainframe By attending to each of these configuration items the VT1415A won t have to be removed from its mainframe later Chapter contents include e Configuring the VTI4ISA 2 0 eee eee page 19 e Instrument Drivers 2 0 0 0 cece e page 27 e About Example Programs 0000 c eee netri page 27 e Verifying a Successful Configuration 00 page 27 Configuring the VT1415A There are several aspects to configuring the module before installing it in a VXIbus mainframe They are e Setting the Logical Address Switch oooooooooooo page 20 e Installing Signal Conditioning Plug Ons page 20 e Disabling the Input Protect Feature 0 4 page 25 e Disabling Flash Memory Access o oo ooooooooomooooo page 25 For most applications only the Logical Address switch needs to be changed prior to installation The other settings can be used as delivered
108. VXIplug amp play Drivers and Product Manuals CD file name verif cs The program uses the IDN query command to verify the VT1415A is operational and responding to commands The program also has an error checking function check_error It is important to include an instrument error checking routine in programs particularly the first trial programs so that instant feedback can be provided while learning about the VT1415A After the C SCPI preprocessor is run and the program is compiled and loaded type verif to run the example Chapter 1 Getting Started 27 verif cs 1 5 Prints the Module s identification manufacturer and revision number 2 Prints the Signal Conditioning Plug ons SCPs identification if any at each of the SCP positions v include lt stdio h gt include lt cscpi h gt Defines module s logical address define LADD 208 Declares module as a register device INST DECL el415 E1415A REGISTER Prototypes of functions declared later void rst clr void void id scps void int32 check error char J KCKCKCKCKCKCkC Ck kk Ck Ck ECKE CK CK CK KK aR KK KK KK KK KK KK A KC KC KK KC SK kk Sk kk ke ke ke ke ke ke ke ke e ke x f void main Main function char read id 80 Clear screen and announce program printf 033H 033J n n Installation Verification Program n n printf inn Please Wait Start the registe
109. Xfactor slope if Mfactor lt 32767 amp amp Mfactor gt 32768 only save if M is within limits Adjust EX to match runtime asm EX jj uint16 Xofst Xfactor 33 uinti16 Mfactor OxFFFFE remove leading 1 s B round32f two to the N Xfactor result ii 1 Appendix F Generating User Defined Functions 369 Bhigh jj uint16 B gt gt 16 amp Ox0OOO00FFFF Blow jj uint16 B amp OxOO000FFFF end for Build actual tables for downloading into the E1415 memory for 11 0 ii 128 iit copy 64 sets of coefficents conv_array ii 4 M ii conv_array ii 4 1 EX ii conv_array ii 4 2 Bhigh ii conv_array ii 4 3 Blow ii printf sd d Sd Sd S d n ii M ii EX ii Bhigh ii Blow ii 7 return Main program ARGSUSED Keeps lint happy int main int argc char argv Main program local variable declarations char algorithm Algorithm string arie alg num Algorithm number being loaded char string 333 Holds error information int32 error Holds error number if O Set to 1 if reading algorithm files Check pass parameters if arge lt 2 arge gt 33 Must have 1 to 32 algorithms usage argv 0 exit 1 endif INST STARTUP Initialize the C SCPI routines dif 0 Set to 1 to open in
110. aaa 3 LLLLLLLELLLELLLET ANNAN LOL EE EE E E E EG E ENT a Event Enable latched 1 enable Condition ilter real time STATus QUEStionable NTR and STATus QUEStionable PTR set filters Summary Bit STATUS BYTE GROUP Summary Enable real time 1 enable YO 291607 lt mask_value gt Summary Bit QUE Questionable Data MAV Message Available ESB Standard Event RQS Request Service OPR Operation Status Summary Bit STANDARD EVENT GROUP Event Enable latched 1 enable Operation Complete Request Control Query Error Device Dependent Error Execution Error Command Error YO 1201607 User Request Power On ESR ESE lt mask_value gt ESE Figure 3 12 VT1415A Status System Chapter 3 Programming the VT1415A for PID Control 95 Status Bit Descriptions Questionable Data Group Bit Bit Value Event Name Description 8 256 Lost Calibration At RST or Power on Control Processor has found a checksum error in the Calibration Constants Read error s with SYST ERR command and re calibrate areas that lost constants 9 512 Trigger Too Fast Scan not complete when another trigger event received 10 1024 FIFO Overflowed Attempt to store more than 65 024 values in FIFO 11 2048 Over voltage If the input protection jumper has not been cut th
111. algorithms defined to have more variables that need to be pre set before INIT than will be changed in one update after the algorithms are running INIT can be sent with updates pending The INIT command automatically performs the updates before starting the algorithms ALGOrithm UPDate WINDow ALGOrithm UPDate WINDow returns the number of variable and algorithm updates allowed within the UPDATE window e Returned Value number of updates in the UPDATEwindow The type is int16 Chapter 6 VT1415A Command Reference 179 ARM ARM NOTE With the VT1415A when the TRIG SOURCE is set to TIMer an ARM event must occur to start the timer This can be something as simple as executing the ARM IMMediate command or it could be another event selected by ARM SOURCE The ARM subsystem may only be used when the TRIGger SOURce is TIMer If the TRIGger SOURce is not TIMer and ARM SOURce is set to anything other than IMMediate an Error 221 Settings conflict will be generated The ARM command subsystem provides e An immediate software ARM ARM IMM e Selection of the ARM source ARM SOUR BUS EXT HOLD IMM SCP TTLTRG lt n gt when TRIG SOUR is TIMer Figure 6 2 shows the overall logical model of the Trigger System ARM SOURce source 2 1 gt 2 TRIGger TIMer interval o gt Trigger 8 Time
112. an algorithm they must be defined To be defined an SCP must be installed and an appropriate SOURce or SENSe FUNCtion must explicitly or implicitly in the case of VT1531A amp 32A SCPs be tied to the channels If an algorithm references an input channel identifier that 1s not configured as an input 116 Creating and Running Custom Algorithms Chapter 4 Defining and Accessing Global Variables NOTES Determining First Execution First loop channel or an output channel identifier that is not configured as an output channel the driver will generate an error when the algorithm is defined with ALG DEF Global variables are those declared outside of the main function and any algorithms see Figure 4 1 A global variable can be read or changed by any algorithm To declare global variables use the command ALG DEF GLOBALS source code where source code is Algorithm Language source limited to constructs for declaring variables It must not contain executable statements Examples declare single variable without assignment ALG DEF GLOBALS static float glob scal var declare single variable with assignment ALG DEF GLOBALS static float glob scal var 22 53 declare one scalar variable and one array variable ALG DEF GLOBALS static float glob scal var glob array var 12 Access global variables within an algorithm like any other variable glob scal var P factor 1108
113. and Service Office for service and repair to ensure that safety features are maintained DO NOT service or adjust alone Do not attempt internal service or adjustment unless another person capable of rendering first aid and resuscitation is present DO NOT substitute parts or modify equipment Because of the danger of introducing additional hazards do not install substitute parts or perform any unauthorized modification to the product Return the product to a VXI Technology Sales and Service Office for service and repair to ensure that safety features are maintained Note for European Customers If this symbol appears on your product it indicates that it was manufactured after August 13 2005 This mark is placed in accordance with EN 50419 Marking of electrical and electronic equipment in accordance with Article 11 2 of directive 2002 96 EC WEEE End of life product can be returned to VTI by obtaining an RMA number Fees for recycling will apply if not prohibited by national law mmm SCP cards for use with the VT1415A have this mark placed on their packaging due to the densely populated nature of these cards Declaration of Conformity according to ISO IEC Guide 22 and EN 45014 Manufacturer s Name VXI Technology Inc Manufacturer s Address 2031 Main Street Irvine CA 92614 6509 declares that the product Product Name Algorithmic Closed Loop Controller Model Number VTI415A Product Options All conforms to t
114. are enabled Only sending OPC or STAT OPER QUES ENAB with cscpi overlap ON will enable interrupts In addition the user can enable or disable all interrupts via the SICL calls tintron and introff Creating and Loading Custom EU Conversion Tables Standard EU Operation The VT1415A provides for loading custom EU conversion tables This allows for the on board conversion of transducers not otherwise supported by the VT1415A The EU conversion tables built into the VT1415A are stored in a library in the module s non volatile Flash Memory When a specific channel is linked to a standard EU conversion using the SENSe FUNC command the module copies that table from the library to a segment of RAM allocated to the specified channel When a single EU conversion is specified for multiple channels multiple copies of that conversion table are put in RAM one copy into each channel s Table RAM Segment The conversion table per channel arrangement allows higher speed scanning since the table is already loaded and ready to use when the channel is scanned Chapter 3 Programming the VT1415A for PID Control 101 Custom EU Operation Custom EU conversion tables are loaded directly into a channel s Table RAM Segment using the DIAG CUST LIN and DIAG CUST PIEC commands The DIAG CUST commands can specify multiple channels To link custom conversions to their tables execute the SENSe FUNC CUST lt range gt lt ch_list gt
115. are provided in the VT1415A s Algorithm Language Chapter 5 Algorithm Language Reference 137 Program Flow Control Conditional Constructs Exiting the Algorithm Data Types Functions abs expression return absolute value of expression max expressionl expression2 return largest of the two expressions min expressionl expression2 return smallest of the two expressions Statements interrupt sets VXI interrupt writeboth expression cvt loc write expression result to FIFO and CVT element specified writecvt expression cvt loc write expression result to CVT element specified writefifo expression write expression result to FIFO Program flow control is limited to the conditional execution construct using if and else and return Looping inside an algorithm function is not supported The only loop is provided by repeatedly triggering the VT1415A Each trigger event either external or internal Trigger Timer executes the main function which calls each defined and enabled algorithm function There is no goto statement The VT1415A Algorithm Language provides the if else construct in the following general form if expression statement else statement2 If expression evaluates to non zero statement is executed If expression evaluates to zero statement2 is executed The else clause with its associated statement2 is optional Statement and or statement2 can be compound statement That is statement statement
116. as reference SENS FUNC CUST REF lt range gt lt ch_list gt set up scan list sequence ch 0 in this case Now run the algorithm that uses the custom reference conversion table dump reference temp register to FIFO DIAG CUST REF TEMP read the diagnostic reference temperature value SENS DATA FIFO DIAGnostic IEEE DIAGnostic IEEE lt mode gt enables 1 or disables 0 IEEE 754 NAN Not A Number and INF value outputs This command was created for the Agilent VEE platform Parameters Parameter Parameter Range of Default Name Type Values Units mode boolean uint 16 0 1 volts Chapter 6 VT1415A Command Reference 197 DIAGnostic Comments When mode is set to 1 the module can return INF and NAN values according to the IEEE 754 standard When mode is set to 0 the module returns values as 9 9E37 for INF and 9 91E37 for NAN e Related Commands DIAG IEEE e RST Condition DIAG IEEE 1 Usage Set IEEE mode DIAG IEEE 1 INF values returned in IEEE standard DIAGnostic IEEE DIAGnostic IEEE returns the currently set IEEE mode Comments e The C SCPI type is int16 e Related Commands DIAG IEEE e RST Condition DIAG IEEE 1 DIAGnostic INTerrupt LINe DIAGnostic INTerrupt LINe intr line sets the V XIbus interrupt line the module will use Parameters Parameter Parameter Range of Default Name Type Values Units intr line numeric int16 0 throug
117. be the master for the other VT1415A s in the system They all would be monitoring one of their digital input channels to signal a change in setpoint profiles Chapter 4 Creating and Running Custom Algorithms 133 Notes 134 Creating and Running Custom Algorithms Chapter 4 Chapter 5 Algorithm Language Reference The VT1415A s Algorithm Language is a limited version of the C programming language It is designed to provide the necessary control constructs and algebraic operations to support standard PID as well as custom control algorithms There are no loop constructs multi dimensional arrays or transcendental functions Further an algorithm must be completely contained within a single function subprogram ALGn The algorithm cannot call another user written function subprogram It is important to note that while the VT1415A s Algorithm Language has a limited set of intrinsic arithmetic operators it also provides the capability to call special user defined functions f x An off line program included with the VT1415A converts the functions supplied into piece wise linear interpolated tables and gives them user defined names The VT1415A can extract function values from these tables in under 18 us regardless of the function s original complexity This method provides faster algorithm execution by moving the complex math operations off board See Appendix F Generating User Defined Functions This s
118. before or after INIT The next section in this chapter Executing the Programming Model shows the programming sequence that should be followed when setting up the VT1415A to run algorithms Power On Trigger Idle State 4 x Before INIT Commands Accepted INITiate IMM All commands except TRG TRIGGER and ALG UPD CHAN yes v Waiting for Trig Count After INIT Trigger State Exhausted Commands Accepted TIMer or other All commands except trigger event RST ABORT Most ALG subsystem ARM IMM Input yes FETCH Execute Algs RST or ABORt FORMAT Output SOURce DATA STATus SYSTem TRG amp Trigger IMMediate if TRIG SOUR is HOLD Figure 3 2 Module States 56 Programming the VT1415A for PID Control Chapter 3 Executing the Programming Model This section shows the sequence of programming steps that should be used for the VT1415A Within each step most of the available choices are shown using command sequence examples with further details available in the Command Reference Chapter 6 IMPORTANT It is very important while developing an application to execute the SYSTem ERRor command after each programming command This is the only way to know if there is a programming error SYST ERR returns an error number and description or 0 No Error Power On and RST some ofthe programming operations that follow may already be
119. bit identifier of choice e g O108 B0 5 Now save this algorithm source file as ONOFFPID C Algorithm to Algorithm Communication Communication Using Channel Identifiers Implementing Multivariable Control The ability for one algorithm to have access to values from another can be very important particularly in more complex control situations One of the important features of the VT1415A is that this communication can take place entirely within the algorithms environment The application program is freed from having to retrieve values from one algorithm and then send those values to another algorithm The value of all defined input and output channels can be read by any algorithm Here is an example of inter algorithm channel communication In this example two PID algorithms each control part of a process and due to the process dynamics are interactive This situation can call for what is known as a decoupler The job of the decoupler is to correct for the coupling between these two process controllers Figure 4 3 shows the two PID controllers and how the decoupler algorithm fits into the control loops As mentioned before algorithm output statements don t write to the output SCP channels but are instead buffered in the Output Channel Buffer until 128 Creating and Running Custom Algorithms Chapter 4 the Output Phase occurs This situation allows easy implementation of decouplers because it allows an algorit
120. board reference resistor to the module for A D calibration Parameters Parameter Parameter Range of Default Name Type Value Units ref ohms numeric float32 7 500 5 ohms Comments e The lt ref_ohms gt parameter must be within 5 of the nominal reference resistor value 7 500 Q and may be specified in Q kohm e A four wire measurement of the resistor can be made with an external multimeter connected to the H Cal L Cal H ohm and L ohm terminals on the Terminal Module or the V H V L H and Q L terminals on the Cal Bus connector e Use the CAL CONF RES command to configure the reference resistor for measurement at the Calibration Bus connector 190 VT1415A Command Reference Chapter 6 CALibration When Accepted Not while INITiated Related Commands CAL CONF RES CAL STORE ADC Command Sequence CAL CONF RES now measure ref resistor with external DMM CAL VAL RES measured value Send measured value to module CALibration VALue VOLTage CALibration VALue VOLTage ref volts sends the value of the last measured dc reference source to the module for A D calibration Parameters Parameter Parameter Range of Default Name Type Values Units ref_volts numeric float32 Must be within 10 of range nominal volts Comments e The value sent must be for the currently configured range and output zero or full scale as set by the previous CAL CO
121. channels To configure the lower 8 bit channel of a VT15334 for inverted polarity INP POLARITY INV 108 SCP in SCP position 1 To configure the lower 4 bits of a VT1534A for inverted polarity INP POL INV 132 135 SCP in SCP position 4 Setting Input Function The VT1533A Digital I O SCP and the VT1534A Frequency Totalizer SCP can both input static digital states The VT1534A Frequency Totalizer SCP can also input Frequency measurements and Totalize the occurrence of positive or negative edges Static State CONDition Function To configure digital channels to input static states use the SENSe FUNCtion CONDition lt ch_list gt command Examples To set the lower 8 bit channel of n VT1533A in SCP position 4 to input SENS FUNC COND 132 To set the upper 4 channels bits of a VT1534A in SCP pos 2 to input states SENS FUNC COND 120 123 Frequency Function The frequency function uses two commands For more on this VT1534A capability see the SCP s User s Manual 70 Programming the VT1415A for PID Control Chapter 3 Setting Up Digital Outputs Setting Output Polarity Setting Output Drive Type To set the frequency counting gate time execute SENSe FREQuency APERature lt gate_time gt lt ch_list gt Sets the digital channel function to frequency SENSe FUNCtion FREQuency lt ch_list gt Totalizer Function The totalizer function uses two commands also One sets the channel function and the oth
122. command sequence 90 Example language usage 113 Example programs about 27 Example A quick start PID algorithm 91 Example definite length block data 124 Example indefinite length block data 124 Examples operation status group 97 Examples questionable data group 97 Examples standard event group 98 EXCitation SENSe STRain EXCitation 249 SENSe STRain EXCitation 249 Executing the programming model 57 Execution conditional 146 Exiting the algorithm 138 Expression 143 Expression statement 144 F Faceplate connector pin signal lists 51 FIFO status commands 87 FIFO transfer commands 86 FIFO reading history mode values from the 86 FIFO reading values from the 86 119 FIFO sending data to 118 FIFO time relationship of readings in 119 FIFO writing values to 119 Filters 106 Filters adding circuits to terminal module 47 Filters configuring the transition 96 Fixed width pulses at variable frequency FM 73 Fixing the problem 109 Flash Memory 336 Flash memory access disabling 25 Flash memory limited lifetime 187 FM STATe SOURce FM STATe 255 FM STATe SOURce FM STATe 256 Format Common Command 155 SCPI Command 156 Format specifying the data 79 FORMat DATA 201 FORMat DATA 203 Formats ALG DEFINE s three data 123 FREQuency INPut FILT FREQ 205 SENSe FUNCtion FREQuency 240 Frequency function 70 Frequency setting algorithm execution 90 Frequency setting filter cutoff
123. eese 248 SENSe REFerence TEMPerature 00002 cee 248 SENSe STRain EXCitation eie i a n eee eee 249 xii Table of Contents SENSe STRain EXCitation 2 0 0 0 0 eee ee 249 SENSe STRain GFACtor eens 250 SENSe STRain GFACtor 2 0 0 0 cece eee 250 SENSe STRain POISson 00 0 0 eee ene 251 SENSe STRain POISson 2 0 0 251 SENSe STRain UNSTrained 0 0 00 c cece eee eee 251 SENSe STRain UNSTrained 00 0 ee eee eee 252 SENSe TOTalize RESet MODE 0 00 0 0 cece eee 252 SENSe TOTalize RESet MODE 00 0 0 c eee eee 254 SOURCE c 255 SOURce FM STATe 2 0 0 00 ce IR 255 SOURGe PM STATe vd esee Sahn bees ares oe p le Y CC 256 SOURce FUNCtion SHAPe CONDition 05 256 SOURce FUNCtion SHAPe PULSe oooo oooooooo o o 256 SOURce FUNCtion SHAPe SQUare o ooooooooooom oo 257 SOURce PULM STATEe 2 020 08 I 9 n 257 SOURCE PULMES TAT 6 cena Hace e 257 SOURce PULSe PERi0d esos is ead HY ca EX eras ER 258 SOURce PULSe PERIiod 20 eee eee eee ees 258 SOURce PULSe WIDTh i bk hha BREA ees Rea bee be 259 SOURcE PULSE WIDTH ose rine ai Code oe eee 259 DAT US C CPC rr 260 STATus OPERation CONDition anaana anaana eee 262 STATus OPERation ENABle 00 0 eee eee 263 STATus OPERation ENABle 0 00 eee eee 263 STATus OPERation EVENt 0 0 00 0 0 ee eee 264 STATus
124. either the Process Variable or the ES error exceeds user supplied limits The alarm condition will cause d an interrupt to the host computer set the user specified alarm channel output to one 1 and set a bit in the Status variable to one 1 The interrupt is edge sensitive It will be asserted only on the transition into the alarm state The alarm channel digital i output will persist for the duration of all alarm conditions The ay Status word bits will also persist for the alarm duration No user intervention is required to clear the alarm outputs Ej fF This version provides for limiting or clipping of the Integral Derivative Setpoint Derivative and output to user specified limits The Status Variable indicates when terms are being clipped es Manual control is activated when the user sets the Man state variable RY to a non zero value The output will be held at its last value The f user can change the output by changing the Man out variable User initiated changes in Man out will cause the output to slew to the E Man out value at a rate of Man inc per scan trigger Kf Manual control causes the Setpoint to continually change to match the Process Variable and the Integral term to be constantly updated x to the output value such that a return to automatic control will be bumpless and will use the current Process Variable value as th x
125. f n setpoint INST SEND e1415 alg updNin for i20 i lt 10 i read CVT 10 times ALG1 has elements 10 13 in CVT INST QUERY e1415 data cvt 8010 13 f amp process info 92 Programming the VT1415A for PID Control Chapter 3 printf Process variable f bf bf f n process info 0 process info 1 process info 2 process info 3 PID Algorithm Tuning Tuning control loops is an extensive subject in itself A proper discussion of loop tuning must be undertaken within the context of process and control loop theory With this in mind reading a book that covers the subject well is also recommended Fundamentals Of Process Control Theory by Paul W Murrill Instrument Society of America Research Triangle Park NC 1981 Second Edition 1991 ISBN 1 55617 297 4 The VT1415A Algorithmic Closed Loop Controller provides tuning assistance in the form of the following loop control and monitoring features e Manual control mode e Direct manipulation of variable values in both PIDA and PIDB e PIDB operating values available from CVT e PIDB History Mode puts continuous sequence of operating values into FIFO Using the Status System The VT1415A s Status System allows a single register the Status Byte to be polled quickly to see if any internal condition requires attention Figure 3 11 shows that the three Status Groups Operation Status Questionable Data and the Standard Event Groups and
126. factor PV_old inchan Clip to specified limits if D out gt D max Clip derivative rd if SD out gt SD max Clip Setpoint derivative 344 PID Algorithm Listings Appendix D D out D max Status B2 1 else if D min gt D out D out D min Status B2 1 else Status B2 0 Sum PID amp SD terms outchan Error P factor I out D out SD out Save values for next pass PV_old inchan Setpoint old Setpoint In case we switch to manual on the next pass prepare to hold output at latest value Man_out outchan if Man state Clip output to specified limits if outchan Out max outchan Out max Status B0 1 else if Out min gt outchan outchan Out min Status B0 1 else Status B0 0 Clear alarm output if no alarms if Status B6 Status B5 alarmchan 0 Log appropriate data if History mode Output summary to FIFO amp CVT writefifo ALG _NUM 256 4 writeboth inchan ALG NUM 10 0 writeboth Error ALG NUM 10 1 writeboth outchan ALG NUM 10 2 writeboth Status ALG _NUM 10 3 else Output summary to CVT only writecvt inchan ALG NUM 10 0 writecvt Error ALG NUM 10 41 writecvt outchan ALG NUM 10 2 writecvt Status ALG NUM 10 3 Appendix D PID Algorithm Listings 345 PIDC
127. file s syst err d s n argv alg num error string exit 1 Free the malloc ed memory free algorithm alg_num Next algorithm void printf All d algorithm s loaded without errors n n alg num 1 else Download algorithm with in line code algorithm An Example algorithm uses Custom Functions n This algorithms generates a triangle and n sine wave signal to separate current outputs Nn v n MA D static float inc 1 x 0 gain 2 1 57 n if x 1 57 inc inc Mn if x lt 1 57 inc abs inc n x x inc Mn 0100 x 001 An 0101 gain sin x 001 n v Antes INST SEND e1415 alg def ALG1 B n strlen algorithm 1 algorithm Hendif Preset Algorithm variables Initiate Trigger System start scanning and running algorithms INST SEND e1415 initin This example shows no data retrieval if 1 Set to 1 if using User interactive commands to E1415 Call this function if you want to be able to type SCPI commands and OS their responses NOTE switch to FORM ASC to retrieve ASCII numbers during interactive mode INST SEND e1415 form asc n do interactive Calls cscpi exe in a loop Hendif 408 Example Program Listings Appendix G dif 0 C CSPI way to check for errors INST QUERY e1415
128. file pointer int32 a size Algorithm size int c Character read from input char algorithm Points to algorithm string f fopen file name r xt Ch lt 4 v void fprintf stderr Error can t open algorithm file s An file name exit 1 a_size 0 Count length of algorithm while getc f EOF a sizett rewind f algorithm malloc a_size 1 Storage for algorithm a_size 0 Use as array index while c getc f EOF Read the algorithm algorithm a size c a sizett algorithm a_size 0 Null terminate void fclose f return algorithm Return algorithm string Main program ARGSUSED Keeps lint happy int main int argc char argv Main program local variable declarations char algorithm Algorithm string int alg num Algorithm number being loaded char string 333 Holds error information int32 error Holds error number if 0 Set to 1 if reading algorithm files Appendix G Example Program Listings 381 Check pass parameters if arge lt 2 arge gt 33 Must have 1 to 32 algorithms usage argv 0 exit 1 endif INST STARTUP Initialize the C SCPI routines dif 0 Set to 1 to open interface session If you need to open a VXI device session here s how to do it You need a VXI device se
129. global in scope A user function defined with ALG FUNC DEF is available to all defined algorithms Up to 32 functions can be defined in the VT1415A Call the function using the syntax lt func_name gt lt expression gt Example for user function pre defined as square root with name sqrt 0108 sqrt 1100 channel 8 outputs square root of input channel Os value NOTE A user function must be defined ALG FUNC DEF before any algorithm is defined ALG DEF that references it A C SCPI program that shows the use of a user defined function is supplied on the VXIp ug amp play Drivers and Product Manuals CD tri sine cs See Appendix G for example program listings Operating Sequence This section explains another important factor in an algorithm s execution environment Figure 4 2 shows the same overall sequence of operations seen in Chapter 3 but also includes a block diagram to show which parts of the VT1415A are involved in each phase of the control sequence 120 Creating and Running Custom Algorithms Chapter 4 Overall Sequence A Common Error to Avoid Algorithm Execution Order Here the important things to note about this diagram are e All algorithm referenced input channel values are stored in the Channel Input Buffer Input Phase BEFORE algorithms are executed during the Calculate Phase e The execution of all defined algorithms Calculate Phase is complete BEFORE output values from algorithms stored
130. in Calibration becomes invalid if the SCPs are moved to different SCP locations When power is turned on to the VT1415A after the SCPs are first installed or after an SCP has been moved the module will use approximate values for calibration constants This means that input and output channels will function although the values will not be very accurate relative to the VT1415A s specified capability At this point make sure the module is firmly anchored to the mainframe front panel screws are tight and let it warm up for a full hour After it has warmed up execute CAL The CAL command causes the module to calibrate A D offset and gain and all channel offsets This may take many minutes to complete The actual time it will take the VT1415A to complete CAL depends on the mix of SCPs installed CAL literally performs hundreds of measurements of the internal calibration sources for each channel and must allow seventeen time constants of settling wait each time a filtered channel s calibration source changes value The CAL procedure is internally very sophisticated and results in an extremely well calibrated module When CAL finishes it returns a 0 value to indicate success The generated calibration constants are now in volatile memory as they always are when ready to use If the configuration just calibrated is to be fairly long term execute the CAL STORE ADC command to store these constants in non volatile memory That way the
131. line is solely a comment line if a b c d 1 comment within a code line l This comment is composed of more than one line The comment can be any number of lines long and terminates when the following two characters appear i About the only character combination that is not allowed within a comment is since this will terminate the comment Overall Prog ram The preceding discussion showed the differences between individual Structure Statements in BASIC and C Shown here is the way the VT1415A s Algorithm Language elements are arranged into a program Here is a simple example algorithm that shows most of the elements discussed so far F Example Algorithm to show language elements in the context of a complete custom algorithm Program variables user_flag Set this value with the SCPI command ALG SCALAR user_value Set this value with the SCPI command ALG SCALAR 148 Algorithm Language Reference Chapter 5 Program Function Algorithm returns user flag in CVT element 330 and another value in CVT element 331 each time the algorithm is executed When user flag 0 returns zero in CVT 331 When user flag is positive returns user value 2 in CVT 331 When user flag is negative returns user value 2 in CVT 331 and in FIFO Use the SCPI command ALGorithm SCALar followed by ALGorithm UPDate to set user flag and user value static float user_flag Declaration statements end with st
132. lt channel gt returns the reset mode for the totalizer channel in channel Parameters Parameter Parameter Range of Default Name Type Values Units channel string 100 163 none Comments lt channel gt must specify a single channel e Ifthe channel specified is not on a frequency totalize SCP an error will be generated e Returned Value returns INIT or TRIG The type is string 254 VT1415A Command Reference Chapter 6 SOURce SOURce The SOURce command subsystem allows configuring output SCPs as well as linking channels to output functions Subsystem Syntax SOURce FM STATe 1 0 ON OFF W lt ch_list gt STATe lt channel gt FUNCtion SHAPe CONDition lt ch_list gt PULSe lt ch_list gt SQUare lt ch_list gt PULM STATe 1 0 ON OFF W lt ch_list gt STATe lt channel gt PULSe PERiod lt period gt lt ch_list gt PERiod lt channel gt WIDTh lt pulse_width gt lt ch_list gt WIDTh lt channel gt SOURce FM STATe SOURce FM STATe lt enable gt lt ch_list gt enables the Frequency Modulated mode for a PULSe channel Parameters Parameter Parameter Range of Default Name Type Values Units enable boolean uint16 1 0 ON OFF none ch_list string 100 163 none Comments This command is coupled with the SOURce PULM STATE command If the FM state is ON
133. maximum number of updates to do If no update command is pending when entering the UPDATE phase then this time is dedicated to receiving more changes from the system e As soon as the ALG UPD IMM command is received no further changes are accepted until all updates are complete A query of an algorithm value following an UPDate command will not be executed until the UPDate completes this may be a useful synchronizing method 4 2 3 4 ITPUT 1 UPDATE CALCULATE OUTPUT 1 INPUT INPI table sent variables amp execute all enabled algorithms e output table sent channels from SCP algorithms to SCP channels from channels chanr analog amp digital analog amp Set by ALG OUTPut DELay if any gt Scan Trigger Scan Trigger Figure 6 1 Updating Variables and Algorithms 176 VT1415A Command Reference Chapter 6 ALGorithm e When Accepted Before or after INIT e Related Commands ALG UPDATE WINDOW ALG SCALAR ALG ARRAY ALG STATE and ALG SCAN RATIO ALG DEF with swapping enabled Command Sequence The following example shows three scalars being written with the associated update command following See ALG UPD WINDOW ALG SCAL ALG1 Setpoint 25 ALG SCAL ALG1 P_factor 1 3 ALG SCAL ALG2 P_factor 1 7 ALG UPD ALG SCAL ALG2 Setpoint ALGorithm UPDate CHANnel ALGorithm UPDate CHANnel dig chan This command is used to update variables algorithms
134. module SENSe FUNCtion CUSTom REFerence SENSe FUNCtion CUSTom REFerence lt range gt lt ch_list gt links channels with the custom Engineering Unit Conversion table loaded with the DIAG CUST PIECE command Measurements from a channel linked with SENS FUNC CUST REF will result in a temperature that is sent to the Reference Temperature Register This command is used to measure the temperature of an isothermal reference panel using custom characterized RTDs or thermistors Contact a VXI Technology System Engineer for more information on Custom Engineering Unit Conversion for specific applications Parameters Parameter Parameter Range of Default Name Type Values Units range numeric float32 see comments V de ch_list channel list string 100 163 none Comments See Linking Input Channels to EU Conversion on page 62 for more information 238 VT1415A Command Reference Chapter 6 SENSe e The range parameter The VT1415A has five ranges 0 0625 V dc 0 25 V dc 1 V dc 4 V dc and 16 V dc To select a range simply specify the range value for example 4 selects the 4 V dc range If a value larger than one of the first four ranges is specified the VT1415A selects the next higher range for example 4 1 selects the 16 V dc range Specifying a value larger than 16 generates an error Specifying 0 selects the lowest range 0 0625 V dc Specifying AUTO selects auto range The default
135. new setpoint ay The Status variable indicates when the Manual control mode is active Af 346 PID Algorithm Listings Appendix D Jes EJ At startup in the Manual control mode the output will be held at its current value E E At startup in the Automatic control mode the output will slew from its initial value towards P factor Error at a rate determined E by the Integral control constant I out is initialized to cancel P out E For process monitoring data may be sent to the FIFO and current value table CVT There are three levels of data logging controlled by the History mode variable The location in the CVT is based Kf on n where n is the algorithm number as returned by ALG NUM for example The first value is placed in the 10 n th 32 bit word of the CVT The other values are written in subsequent locations Af e History mode 0 Summary to CVT only In this mode four values Le are output to the CVT pe oy Location Value J PE 0 Input ari 1i Error Je 2 Output RY 3 Status fe History mode 1 Summary to CVT and FIFO In this mode the four sj summary values are written to both the CVT and FIFO A header tag 256 n 4 is sent to the FIFO first T History mode 2 All to FIFO and CVT In this mode nine values are output to both the CVT and FIFO A header tag 256 n 9
136. output is 10 V e When Accepted Not while INITiated e Related Commands CAL VAL VOLT STOR ADC Command Sequence CAL CONF VOLTAGE 0625 ZERO connect voltage reference to Calibration Bus OPC or SYST ERR must wait for CAL CONF VOLT to complete now measure voltage with external DMM CAL VAL VOLT measured value Send measured value to module repeat above sequence for full scale repeat zero and full scale for remaining ranges 0 25 1 4 16 CAL STORE ADC Store cal constants in non volatile memory used only at end of complete cal sequence Chapter 6 VT1415A Command Reference 185 CALibration CALibration SETup CALibration SETup causes the Channel Calibration function to be performed for every module channel with an analog SCP installed input or output The Channel Calibration function calibrates the A D Offset and the Gain Offset for these analog channels This calibration is accomplished using internal calibration references For more information see CAL on page 278 Comments CAL SET performs the same operation as the CAL command except that since it is not a query command it doesn t tie up the C SCPI driver waiting for response data from the instrument If there are multiple VT1415As in a system start a CAL SET operation on each and then execute a CAL SET command to complete the operation on each instrument e Related Commands CAL SETup CAL e When Accepted Not while INITiated Usage CAL SET s
137. position 4 to output a variable frequency square wave SOUR FUNCTION SQUare 134 Example Algorithm Language statement to set output to 20 kHz 0134 2063 For complete VT1534A capabilities see the SCP s User s Manual Chapter 3 Programming the VT1415A for PID Control 73 Performing Channel Calibration Important Operation and Restrictions How to Use CAL What CAL Does The CAL also performed using CAL SETup then CAL SETup is a very important step CAL generates calibration correction constants for all analog input and output channels CAL must be performed in order for the VT1415A to deliver its specified accuracy CAL generates calibration correction constants for each analog input channel for offset and gain at all five A D range settings For programmable input SCPs these calibration constants are only valid for the current configuration gain and filter cut off frequency This means that CAL calibration is no longer valid if channel gain or filter settings INP FILT or INP GAIN are changed but are still valid for changes of channel function or range using SENS FUNC Calibration becomes invalid if the SCPs are moved to different SCP locations For analog output channels both measurement excitation SCPs as well as control output SCPs CAL also generates calibration correction constants These calibration constants are valid only for the specific SCPs in the positions they are currently
138. range no range parameter specified is auto range e f using amplifier SCPs set them first and keep their settings in mind when specifying a range setting For instance if the expected signal voltage is to be approximately 0 1 V dc and the amplifier SCP for that channel has a gain of 8 range must be set no lower than 1 V dc or an input out of range condition will exist e The CAL command calibrates temperature channels based on Sense Amplifier SCP setup at the time of execution If SCP settings are changed those channels are no longer calibrated CAL must be executed again e Related Commands DIAG CUST PIEC SENS FUNC TEMP SENS FUNC CUST TC CAL e RST Condition all custom EU tables erased Usage program must put table constants into array table block DIAG CUST PIEC 1 table_block 108 send characterized reference transducer table for use by channel 8 SENS FUNC CUST REF 25 108 link custom ref temp EU with ch 8 include this channel in a scan list with thermocouple channels REF channel first INITiate then TRIGger module SENSe FUNCtion CUSTom TCouple SENSe FUNCtion CUSTom TCouple lt type gt lt range gt lt ch_list gt links channels with the custom Engineering Unit Conversion table loaded with the DIAG CUST PIECE command The table is assumed to be for a thermocouple and the lt type gt parameter will specify the built in compensation voltage table to be used for reference junction temperature com
139. read cycles While executing CAL STOR once every day would not exceed the lifetime of the Flash Memory for approximately 27 years an application that stored constants many times each day would unnecessarily shorten the Flash Memory s lifetime See Comments below Parameters Parameter Parameter Range of Default Name Type Values Units type discrete string ADC TARE none Comments The Flash Memory Protect jumper JM2201 must be set to the enable position before executing this command see Chapter 1 e Channel offsets are compensated by the CAL TARE command even when not stored in the Flash Memory There is no need to use the CAL STORE TARE command for channels which are re calibrated frequently e When Accepted Not while INITiated e Related Commands CAL VAL RES CAL VAL VOLT e RST Condition Stored calibration constants are unchanged Usage CAL STORE ADC Store cal constants in non volatile memory after A D calibration CAL STORE TARE Store channel offsets in non volatile memory Command Sequence after channel tare Storing A D cal constants perform complete A D calibration then CAL STORE ADC Storing channel tare offset values CAL TARE lt ch_list gt To correct channel offsets CAL STORE TARE Optional depending on necessity of long term storage Chapter 6 VT1415A Command Reference 187 CALibration CALibration TARE CALibration TARE lt ch_list gt measures offset or tare voltage present on the
140. sent with these If an Algorithm too big error is not received then the value for swap size in step 5 was large enough Define any other algorithms in the normal manner Channels referenced by algorithms when they are defined are only placed in the channel list before INIT The channel list cannot be changed after INIT If an algorithm is re defined by swapping after INIT and it references channels not already in the channel list it will not be able to access the newly referenced channels No error message will be generated To make sure all required channels will be included in the channel list define alg name and re define all algorithms that will replace alg name gt by swapping them before INIT is sent This insures that all channels referenced in these algorithms will be available after INIT The driver only calculates overall execution time for algorithms defined before INIT This calculation is used to set the default output delay same as executing ALG OUTP DELAY AUTO If an algorithm is swapped after INIT that takes longer to execute than the original the output delay will behave as if set by ALG OUTP DEL 0 rather than AUTO see ALG OUTP DEL command Use the same procedure from note to make sure the longest algorithm execution time is used to set ALG OUTP DEL AUTO before INIT An example program file named swap cs on the VXIplug amp play Drivers and Product Manuals CD shows how to swap algorithms
141. set to the TRIG SOUR BUS or TRIG SOUR HOLD mode Chapter 6 VT1415A Command Reference 275 TRIGger Comments This command is equivalent to the TRG common command or the IEEE 488 2 GET bus command e Related Commands TRIG SOURCE Usage TRIG IMM Use TRIGGER to start a measurement scan TRIGger SOURce TRIGger SOURce trig source configures the trigger system to respond to the trigger event Parameters Parameter Parameter Range of Default Name Type Values Units trig source discrete string BUS EXT HOLD IMM SCP none TIM TTLTrg lt n gt Comments The following table explains the possible choices Parameter Value Source of Trigger BUS TRIGger IMMediate TRG GET for GPIB EXTernal TRG signal on terminal module HOLD TRIGger IMMediate IMMediate The trigger event is always satisfied SCP SCP Trigger Bus future SCP Breadboard TIMer The internal trigger timer TTLTrg lt n gt The VXIbus TTLTRG lines n 0 through 7 NOTE The ARM system only exists while TRIG SOUR is TIMer When TRIG SOUR is not TIMer SCPI compatibility requires that ARM SOUR be IMM or an Error 221 Settings conflict will be generated e While TRIG SOUR is IMM simply INITiate the trigger system to start a measurement scan e When Accepted Before INIT only e Related Commands ABORt INITiate TRG e RST Condition TRIG SOUR TIMER Usage TRIG SOUR EXT Ha
142. statement The return statement allows terminating algorithm execution before reaching the end by returning control to the main function The return statement can appear anywhere in an algorithm It is not required to include a return statement to end an algorithm The translator treats the end of an algorithm as an implied return The data type for variables is always static float However decimal constant values without a decimal point or exponent character E or e as well as Hex and Octal constants are treated as 32 bit integer values This treatment of constants is consistent with ANSI C To understand what this can mean it is necessary to understand that not all arithmetic statements in an algorithm are actually performed within the VT1415A s DSP chip at algorithm run time Where expressions can be simplified the VT1415A s translator a function of the driver invoked by ALG DEF performs the arithmetic operations before downloading the executable code to the algorithm memory in the VT1415A For example look at the statement a 5 8 138 Algorithm Language Reference Chapter 5 The Static Modifier Data Structures When the VT1415A s translator receives this statement it simplifies it by adding the two integer constants 5 and 8 and storing the sum of these as the float constant 13 At algorithm run time the float constant 13 is assigned to the variable a No surprises so far
143. syst err n d 5 amp error string if error void printf syst err d s n error string exit 1 endif return 0 Normal end of program Appendix G Example Program Listings 409 Notes 410 Example Program Listings Appendix G Index ALG NUM determining an algorithms identity 119 First loop determining first execution 117 FM fixed width pulses at variable frequency 73 FM variable frequency square wave output 73 Important performing channel calibration 74 PWM variable width pulses at fixed frequency 72 CAL how to use 74 RST default settings 57 4 20 mA adding sense circuits for 47 A A common error to avoid 121 A complete thermocouple measurement command sequence 68 A quick start PID algorithm example 91 A very simple first algorithm 126 Abbreviated Commands 156 ABORt subsystem 162 abs expression 138 Access bitfield 140 Accessing I O channels 116 Accessing the VT1415A s resources 115 Accessories Rack Mount Terminal Panel 49 Accuracy 10k ohm Thermistor 324 325 2250 ohm Thermistor 320 321 5k ohm Thermistor 322 323 dc volts 298 E Type Thermocouple 300 301 302 303 E Type Thermocouple extended 304 305 J Type Thermocouple 306 307 K Type Thermocouple 308 R Type Thermocouple 309 310 Reference RTD 317 Reference Thermistor 315 316 RTD 318 319 S Type Thermocouple 311 312 Sample timer 297 T Type Therm
144. the algorithm 112 Layout Terminal Module 35 Lifetime limitation Flash memory 187 Limits Common mode voltage 355 Limits alarm 77 Limits clipping 76 LINe DIAG INT LINe 198 LINe DIAG INT LINe 198 Lines comment 148 Linking channels to EU conversion 62 Linking Commands 159 Linking output channels to functions 69 Linking resistance measurements 63 Linking strain measurements 68 Linking temperature measurements 65 Index 417 Linking voltage measurements 63 Lists Faceplate connector pin signal 51 Loading custom EU tables 103 Loading tables for linear conversions 103 Loading tables for non linear conversions 103 Logical operators 137 Logical AND expression 143 LOW INPut LOW 208 INPut LOW 209 Low noise measurements HINTS 39 Low noise measurements IMPORTANT 34 M Manual control 77 max expressionl expression2 138 Maximum Common mode voltage 298 Input voltage 298 Tare cal offset 298 Update rate 297 Maximum tare capability 106 Measurement accuracy dc volts 298 Ranges 297 Resolution 297 Measurements terminal block considerations for TC 38 Measurements linking resistance 63 Measurements linking strain 68 Measurements linking temperature 65 Measurements linking voltage 63 Measurements reference measurement before thermocouple 67 Measurements thermocouple 66 Measuring the reference temperature 67 MEM VME ADDR 212 MEM VME ADDR 212 MEM VME SIZ
145. the closest binary representation of the test_range such that the new binary value is equal to or greater than the calculated test range Start with the lowest range 1 2 128 and step up until the new binary range is equal or greater than the test range tbl range two to the N 128 JE 2528 tbl range 1 0 tbl range while test range tbl range tbl range 2 range tbl range Xofst 157 exponent bias for DSP calculations side Note Also A A F 0 AECA X a Now divide the full range of the table into 128 segments 129 points scanning first the positive side of the X axis and then the negativ of the X axis that 129 points are calculated in order to generate a line segment for calculating slope note that the entire binary range is built to include the min and max values entered as min input and max input for ii20 ii 264 iit 0 to FS input ii center tbl_range 64 0 float 64 ii result ii custom_function input ii if ii continue This is the first point skip slope jj 644 11 1 generate numbers for prev segment for second and subsequent points t result ii 1 using prev seg base if t 0 0 t 1 0 use abs value magnitude of t compute the exponent of the offset B is 31 bits Appendix F Generating User Defined Functions 367 if t 0 0 don
146. the next error message from the Error Queue Chapter 6 VT1415A Command Reference 271 SYSTem SYSTem VERSion SYSTem VERSion returns the version of SCPI this instrument complies with Comments Returned Value String 1990 The C SCPI type is string Usage SYST VER Returns 1990 272 VT1415A Command Reference Chapter 6 TRIGger TRIGger The TRIGger command subsystem controls the behavior of the trigger system once it is initiated see INITiate command subsystem Figure 6 5 shows the overall Trigger System model The shaded area shows the ARM subsystem portion ARM SOURCce source 2 1 gt s TRIGger TIMer interval o i gt Trigger 8 Timer eo gt gt p gt amp 3 TRIGger SOURce source TIMer BUS SR sese we pa ee ee ee ee eee gt gt y 2 EXTemal 8 3 gt 2 z HOLD 2 Internal amp gt lt Trigger Trigger Signal 9 MMediate 8 gt Enable gt 2 gt g TILTrg lt n gt D 8 e S SCP Trig gt Trigger Counter CAUTION TRIGger COUNt lt count gt Figure 6 5 Logical Trigger Model Algorithms execute at most once per trigger event Should trigger events cease external trigger source stops or are ignored TRIGger COUNt reached algorithms execution will stop In this case control outputs are left at the last value set b
147. then the PULM state is OFF If the PULM state is ON then the FM state is OFF If both the FM and the PULM states are OFF then the PULSe channel is in the single pulse mode e f the channels specified are not on a Frequency Totalize SCP an error will be generated e Use SOURce FUNCtion SHAPe SQUare to set FM pulse train to 50 duty cycle Use SOURce PULSe PERiod to set the period e RST Condition SOUR FM STATE OFF SOUR PULM STATE OFF SENS FUNC COND and INP POL for all digital SCP channels Chapter 6 VT1415A Command Reference 255 SOURce e Related Commands SOUR PULM STATe SOUR PULS POLarity SOUR PULS PERiod SOUR FUNC SHAPe SQUare e The variable frequency control for this channel is provided by the algorithm language When the algorithm executes an assignment statement to this channel the value assigned will be the frequency setting For example 0143 2000 set channel 43 to 2 kHz SOURce FM STATe SOURce FM STATe lt channel gt returns the frequency modulated mode state for a PULSe channel Parameters Parameter Parameter Range of Default Name Type Values Units channel string 100 163 none Comments lt channel gt must specify a single channel e Ifthe channel specified is not on a Frequency Totalize SCP an error will be generated e Returned Value returns 1 ON or 0 OFF The type is uint16 SOURce FUNCtion SHAPe CONDition SOURce FUNCtion SHAPe
148. this returned value is string The revision will vary with the revision of the driver software installed in the system This is the only indication of which version of the driver is installed 280 VT1415A Command Reference Chapter 6 LMC OPC NOTE OPC NOTE PMC RMC name Learn Macros query Returns a quoted string name for each currently defined macro If more than one macro is defined the strings are separated by commas If no macro is defined LMC returns a null string Operation Complete Causes an instrument to set bit 0 Operation Complete Message in the Standard Event Status Register when all pending operations invoked by SCPI commands have been completed By enabling this bit to be reflected in the Status Byte Register ESE 1 command synchronization can be ensured between the instrument and an external computer or between multiple instruments Do not use OPC to determine when the CAL SETUP or CAL TARE commands have completed Instead use their query forms CAL SETUP or CAL TARE Operation Complete Query Causes an instrument to place a 1 into the instrument s output queue when all pending instrument operations invoked by SCPI commands are finished By requiring the computer to read this response before continuing program execution synchronization can be ensured between one or more instruments and the computer The C SCPI type for this returned value is int16 Do not use OPC to determine when t
149. trigger events On each trigger the module will perform one control cycle which includes reading analog and digital input channels Input Phase executing all defined algorithms Calculate Phase and updating output channels Output Phase See the TRIGger subsystem to specify the trigger source and count Subsystem Syntax INITiate INITiate IMMediate IMMediate INITiate IMMediate changes the trigger system from the Idle state to the Wait For Trigger state When triggered one or more depending on TRIGger COUNt trigger cycles occur and the instrument returns to the Trigger Idle state Comments e Usage INIT INIT IMM clears the FIFO and Current Value Table If a trigger event is received before the instrument is Initiated a 211 Trigger ignored error is generated If another trigger event is received before the instrument has completed the current trigger cycle measurement scan the Questionable Data Status bit 9 is set and a 3012 Trigger too fast error is generated Sending INIT while the system is still in the Wait for Trigger state already INITiated will cause an error 213 Init 1gnored Sending the ABORt command send the trigger system to the Trigger Idle state when the current input calculate output cycle is completed If updates are pending they are made prior to beginning the Input phase When Accepted Not while INITiated Related Commands ABORt CONFigure TRIGger RST Condition
150. use the piecewise conversion table Compensating for System Offsets System Wiring Offsets The VT1415A can compensate for offsets in a system s field wiring Apply shorts to channels at the Unit Under Test UUT end of the field wiring and then execute the CAL TARE lt ch_list gt command The instrument will measure the voltage at each channel in lt ch_list gt and save those values in RAM as channel Tare constants Important Note for e CAL TARE cannot be used on field wiring that is made up of Thermocouples thermocouple wire The voltage that a thermocouple wire pair generates cannot be removed by introducing a short anywhere between its junction and its connection to an isothermal panel either the VT1415A s Terminal Module or a remote isothermal reference block Thermal voltage is generated along the entire length of a thermocouple pair where there is any temperature gradient along that length To CAL TARE thermocouple wire this way would introduce an unwanted offset in the voltage temperature relationship for that thermocouple If a thermocouple wire pair is inadvertently CAL TARE d see Resetting CAL TARE on page 105 CAL TARE should be used to compensate wiring offsets copper wire not thermocouple wire between the VT1415A and a remote thermocouple reference block Disconnect the thermocouples and introduce copper shorting wires between each channel s HI and LO then execute CAL TARE for these channels 104 P
151. variable variable variable D factor variable Figure 3 6 The Simple PID Algorithm PIDA PIDA algorithm implements the classic PID controller This implementation was designed to be fast In order to be fast this algorithm provides no clipping limit alarm limits status management or CVT FIFO communication History Modes The algorithm performs the following calculations each time it is executed Chapter 3 Programming the VT1415A for PID Control 75 Error Setpoint inp chan _out out factor Error outp chan P factor Error out D factor Error Error old Error old Error See the program listing for PIDA in Appendix D The Pre Defined Figure 3 6 shows the block diagram of a more advanced algorithm that is PIDB Algorithm favored in process control because of the flexibility allowed by its two differential terms The D differential term is driven by changes in the process input measurement The SD differential term is driven by changes in the setpoint variable value This algorithm can be defined by executing ALG DEFINE ALGn PIDB lt inp_channel gt lt outp_channel gt lt alarm_chan gt SD factor variable clip limits Status B3 SD out variable alarm limits Status B5 P factor cae varigbig variable Man_inc variable Error variable clip limits Status B1 lt outp_chan gt channel fa
152. 0 163 none e The table block parameter is a block of 8 bytes that define 4 16 bit values SCPI requires that table block include the definite length block data header C SCPI adds the header automatically e The table range parameter specifies the range of voltage that the table covers from table range to table range The value specified must be within 5 of one of the nominal values from the table above e The ch list parameter specifies which channels may use this custom EU table e Related Commands SENSe FUNCtion CUSTom e RST Condition All custom EU tables erased Usage program puts table constants into array table block DIAG CUST LIN table block 3 116 123 SENS FUNC CUST LIN 1 1 116 123 INITiate then TRIGger module DIAGnostic CUSTom PIECewise DIAGnostic CUSTom PIECewise lt table_range gt lt table_block gt ch list downloads a custom piece wise Engineering Unit Conversion table in table block to the VT1415A Contact a VXI Technology System Engineer for more information on Custom Engineering Unit Conversion for specific applications Parameters Comments send table to VTI415A for chs 16 23 link custom EU with chs 16 23 Parameter Parameter Range of Default Name Type Values Units table range numeric float32 0 015625 0 03125 0 0625 0 125 volts 0 25 0 5 1 2 4 8 16 32 64 table_block definite length See comments non
153. 0 0000 cece ee eee 83 Starting the PID Algorithm 0 20 2 0 0 00 eee eee eee eee 83 The Operating Sequence i scio bb RERO Pe Y Yu REIR BEd 84 Reading Running Algorithm Values 00 02 cee eee ee ee 85 Reading Algorithm Variables 0 0 0 c eee eee ee 85 Reading Algorithm Values From the CVT 2 004 85 Reading History Mode Values From the FIFO 86 Modifying Running Algorithm Variables 0 000020 ee 89 Updating the Algorithm Variables and Coefficients 89 Enabling and Disabling Algorithms lessen 89 Setting Algorithm Execution Frequency 00 000 90 Example Command Sequence 0 c eee ees 90 A Quick Start PID Algorithm Example 00 0000 c neues 9 PID Algorithm Tuning sseeeseeeee IRI II 93 Using the Status System 0 0 tresser eect eee 93 Enabling Events to be Reported in the Status Byte 96 Reading the Status Byte 0 0 eee eee 98 Clearing the Enable Registers 0 0 0 eee eee eee eee 99 The Status Byte Group s Enable RegisteT oooooooooo 99 Reading Status Groups Directly 0 000 c eee eee ee 99 VT1415A Background Operation 000 eese 100 Updating the Status System and VXIbus Interrupts 100 Creating and Loading Custom EU Conversion Tables 101 Compensating for System Offsets liess 104 Special Co
154. 0 After CAL TARE 100 the module will return a reading of 0 volts with a short applied at the UUT and the system wiring offset will be removed from all measurements of the signal to channel 0 Think of the signal applied to the instrument s channel input as the gross signal value CAL TARE removes the tare portion leaving only the net signal value Because of settling times especially on filtered channels CAL TARE can take a number of minutes to execute The tare calibration constants created during CAL TARE are stored in and are usable from the instrument s RAM To store the Tare constants in non volatile Flash Memory execute the CAL STORE TARE command The VT1415A s Flash Memory has a finite lifetime of approximately 10 000 write cycles unlimited read cycles While executing CAL STOR once every day would not exceed the lifetime of the Flash Memory for approximately 27 years an application that stored constants many times each day would unnecessarily shorten the Flash Memory s lifetime To undo the CAL TARE operation execute CAL TARE RESet then CAL CAL SET If current Tare calibration constants have been stored in Flash Memory execute CAL TARE RESET then CAL STORE TARE Chapter 3 Programming the VT1415A for PID Control 105 Special Here are some things to keep in mind when using CAL TARE Considerations Maximum Tare Capability The tare value that can be compensated for is dependent on the instrument range a
155. 0 0 dO 30384 1T 300 VIOSILA o Seg ARRE WUL MS Specifications 315 Appendix A Reference Thermistor 5 kQ filter off VT1508A 09A o 3 q ee rra AAO 32114 81 1d0 V80STLA 00 08 00 09 00 OF 00 02 m LU uS Eus AAA WUL MS 08 0 09 0 OF O 0c 0 000 2 321 Appendix A 316 Specifications Reference RTD filter off 2 8eg JO 19184 FOX 1 HO YEOSLLA J4O 391p CZ 1300 VZOSTLA LARHELELAZAMEAUACEEAAA Stree een PRIN PERRET 440 2329384 110 VIOSTLA mmm nnnm erem om M on 0s E did 00001 pF podecazcrt HOOT HM ce A nds uni n primer t Ep e Ee 00007 007006 A _ a 00 055 00009 Ec mue 2 00 059 O A P l i i 00 0SL 01 X 9 Pq JAA GLa Specifications 317 Appendix A RTD filter off 01 XO Seq AdO Jod POX c1 100 VEOSTLA eom om MU GL e m hom mE omo om om omo om HA Ma Rae Gia aad c ae J40 DU 8X 1 dO V EOSLLA 410 12184 Z1 dO VZOSLLA Me TT EEE ETRE ETT ET TT nU E A e A Bd 440 194 T140 VIOSILA 007 050 000 ais OOO _ QU OSZ 0000 due OSE A 00 00 Y oost 00 005 M M DO OSS c O1 X o 3q ALA Appendix A 318 Specifications RTD filter off VT1508A 09A 01 XD Jaq O80 09 0 070 oTo 000 esc
156. 00 8 scp id AAA AIR RR RAR RRA RR RR I IA IA A I A IA A ke ke A ke ke ke ko ke koe oe f int32 check error char message Check for module generated errors int16 error char err out 256 Check for any errors INST QUERY el415 SYST ERR amp error err out If error is found print out the error s if error while error printf Error d s in function s n error err out message INST QUERY e1415 SYST ERR amp error err out T return 1 return 0 Chapter 1 Getting Started 29 Notes 30 Getting Started Chapter 1 Chapter 2 Field Wiring About This Chapter This chapter shows how to plan and connect field wiring to the VT1415A s Terminal Module The chapter explains proper connection of analog signals to the VT1415A both two wire voltage type and four wire resistance type measurements Connections for other measurement types e g strain using the Bridge Completion SCPs refer to specific SCP manual in the SCP Manuals section Chapter contents include e Planning Wiring Layout for the VT1415A page 31 e Terminal Module 0 cece eee page 35 e Reference Temperature Sensing with the VTIAISA page 37 e Preferred Measurement Connections 00005 page 40 e Connecting the On Board Thermistor 005 page 42 e Wiring and Attaching the Terminal Mod
157. 00 int32 error char string 256 for void printf SCPI command void fflush stdout repeat until it actually gets something Set to 0 to skip this routine while gets command if command break result 0 0 cscpi exe el415 command strlen command result sizeof result INST QUERY e1415 syst err d s error string while error void printf syst err d Ss In error string INST QUERY e1415 syst err d s amp error string if result 0 void printf result s n result Hendif Print usage information void usage char prog name void fprintf stderr usage s algorithm file n prog name Get an algorithm from a filename static char get_algorithm char file name FILE f Algorithm int32 a size Algorithm int Gi Character char algorithm Points to f fopen file name r af t 1 void fprintf stderr Error file name exit 1 a size 0 while getc f EOF a sizett rewind f algorithm malloc a_size 1 a size 0 while c getc f EOF can t open algorithm file file pointer size read from input algorithm string ET in Count length of algorithm Storage for algorithm Use as array index Read the algorithm 400 Example Program Listings Appen
158. 07 INPut GAIN chan gain gt lt ch list ooo page 207 INPut GAIN lt channel gt ee page 208 INPutLOW lt wvolt_type gt lt ch_lis es page 208 INPutLOW lt channel gt esi a t oe eoa aace araos a a aa a E a ela ss page 209 INPut POLarity NORMal INverted lt ch_lis gt oo page 209 INPut POLatity lt channel gt si ii RR EP ew ee page 210 MEMory VME ADDRess 424 address gt s page 212 MEMory VME ADDRess e caom med ypu eh eh ht nn page 212 MEMory VME SIZE mem Siz sus ra ko op RR RA IR ROT ORA SUR OV UR RE RR page 212 MEMory VME SIZE i43 e Se ed Ree EOS x E PUR V REUS LACER RUE RON EX E Re xe s page 213 MEMory VME STATe1 0 ON OFF esee ns page 213 MEMory VME STATe v aagos ami ebb dee eee bat e OS RO dee Pee Resp ries page 214 152 VT1415A Command Reference Chapter 6 OUTPut CURRent AMPLitude lt amplitude gt lt ch_lis gt 22e page 215 OUTPut CURRent AMPLitude lt channel gt 22s page 216 OUTPut CURRent STATe 1 0 ON OFF Q ch list rns page 217 OUTPut CURRent STATe lt channel gt ooo page 217 OUTPut POLarity NORMal INVerted lt ch_list gt oo page 218 OUTPut POLarity lt channel gt o a 22s page 218 OUTPut SHUNt 1 0 Qch list ae uu eee Lee ee Ra AR Ge ewe ee ae a page 218 OUTPut SHUNt lt channel gt 2 1 ee page 219 OUTPut TTLTrg SOURce ALGorithm FTRigger SCPlugon TRIGger pag
159. 1 to ALG32 Algorithm Block must contain termination Must append a null byte to end of algorithm string within the Block Data Unknown SCP Not Tested May be received if using a breadboard SCP Invalid SCP for this product Analog Scan time to big Too much settling time Count of channels referenced by algorithms combined with use of SENS CHAN SETTLING has attempted to build an analog Scan List greater than 64 channels Can t define new algorithm while running Execute ABORT then define algorithm Need ALG UPD before redefining this algorithm again Already have an algorithm swap pending for this algorithm Algorithm swapping already enabled Can t change size Only send swap size parameter on initial definition Appendix B Error Messages 333 3104 GLOBALS can t be enabled for swapping Don t send swap size parameter for ALG DEF GLOBALS 334 Error Messages Appendix B Appendix C Glossary The following terms have special meaning when related to the VT1415A Algorithm Algorithm Language Application Program Buffer In general an algorithm is a tightly defined procedure that performs a task This manual uses the term to indicate a program executed within the VT1415A that implements a data acquisition and control algorithm The algorithm programming language specific to the VT1415A This programming language is a subset of the ANSI
160. 15A Command Reference 213 MEMory e RST Condition MEM VME STAT OFF Usage MEMORY VME STATE ON enable VME card as reading storage MEM VME STAT 0 Disable VME card as reading storage MEMory VME STATe MEMory VME STATe returned value of 0 indicates that VME reading storage is disabled Returned value of 1 indicates VME memory is enabled Comments This command is only available in systems using an Agilent HP E1405B 06A command module e Returned Value Numeric 1 or 0 C SCPI type uint16 e Related Commands MEMory subsystem and FETCH Usage MEM VME STAT Returns 1 for enabled 0 for disabled 214 VT1415A Command Reference Chapter 6 OUTPut OUTPut The OUTPut subsystem is involved in programming source SCPs as well as controlling the state of VXIbus TTLTRG lines 0 through 7 Subsystem Syntax OUTPut CURRent AMPLitude amplitude ch list AMPLitude lt channel gt STATe 1 0 ON OFF lt ch_list gt STATeP lt channel gt POLarity NORMal INVerted lt ch_list gt POLarity lt channel gt SHUNt 1 0 ON OFF lt ch_list gt SHUNt lt channel gt TTLTrg SOURce TRIGger FTRigger SCPlugon LIMit SOURce TTLTrg lt n gt STATe 1 0 ON OFF STATe TYPE PASSive ACTive lt ch_list gt TYPE lt channel gt VOLTage AMPLitude lt amplitude gt lt ch_list gt AMPLitude lt channel gt OUTPut CURRent AMPLitude NOTE Parameter
161. 22 VT1415A Command Reference Chapter 6 OUTPut OUTPut VOLTage AMPLitude OUTPut VOLTage AMPLitude lt channel gt returns the current setting of excitation voltage for the channel specified by channel If the channel is not on a VT1511A SCP the query will return zero Comments channel must specify a single channel only e Returned Value Numeric one of 0 1 2 5 or 10 C SCPI type is float32 e Related Commands OUTP VOLT AMPL Usage OUTP VOLT AMPL 103 returns current setting of excitation voltage for channel 3 Chapter 6 VT1415A Command Reference 223 ROUTe ROUTe The ROUTe subsystem provides a method to query the overall channel list definition for its sequence of channels Subsystem Syntax ROUTe SEQuence DEFine POINts ROUTe SEQuence DEFine ROUTe SEQuence DEFine lt type gt returns the sequence of channels defined in the scan list Parameters Parameter Parameter Range of Default Name Type Values Units type string AIN AOUT DIN DOUT none Comments The channel list contents and sequence are determined primarily by channel references in the algorithms currently defined The SENS REF CHANNELS and SENS CHAN SETTLING commands also effect the scan list contents e The type parameter selects which channel list will be queried AIN selects the Analog Input channel list this is the Scan List AOUT selects the Analog Output channel list
162. 4 latch Um n H gt Bit 15 1 latch 1 Figure 6 4 General Status Register Organization 260 VT1415A Command Reference Chapter 6 Initializing the Status The following table shows the effect of Power on RST CLS and System STATus PRESet on the status system register settings STATus SCPI SCPI SCPI IEEE 488 2 IEEE 488 2 Transition Enable Event Registers ESE Registers Filters Registers Registers and SRE SESR and STB Power On preset preset clear clear clear RST none none none none none CLS none none clear none clear STAT PRESET preset preset none none none Subsystem Syntax STATus OPERation CONDition ENABle enable mask ENABle EVEN NTRansition transition mask NTRansition PTRansition transition mask PTRansition PRESet QUEStionable CONDition ENABle enable mask ENABle EVENt NTRansition transition mask NTRansition PTRansition transition mask PTRansition The Status system contains four status groups e Operation Status Group e Questionable Data Group e Standard Event Group e Status Byte Group This SCPI STATus subsystem communicates with the first two groups while IEEE 488 2 Common Commands documented later in this chapter communicate with Standard Event and Status Byte Groups Chapter 6 VT1415A Command Reference 261 STATus Weighted Bit Values Register queries are returned using dec
163. 415 Use something like this for GPIB and Agilent E1405 6 Command Module Appendix G Example Program Listings 379 define E1415 ADDR hpib 22 26 The SICL address of your E1415 INST DECL e1415 E1415A MESSAGE E1415 Declare instruments that will be accessed with SICL These declarations can also be moved into local contexts INST vxi VXI interface session 5 X FF Xo F X CACA rap instrument errors If this function is used it will be called every time a C SCPI instrument puts an error in the error queue As written the Function will figure out which instrument generated th rror retrieve the error print a message and exit You may want to modify the way the error is printed or comment out the exit if you want the program to continue Note that this works only on REGISTER based instruments because it was a C SCPI register based feature not a general programming improvement If you re using MESSAGE instruments you ll still have to do SYST ERR If your test program generates errors on purpose you probably don t want this error function If so set the following if 1 to fif 0 This function is most useful when you re trying to get your program running dif 1 Set to 0 to skip trapping errors ARGSUSED Keeps lint happy void cscpi error INST id int err
164. 415A User s manual does not consider the high frequency Ecm problem and is there to limit the shield current and to allow the DUT to float up to some dc common mode voltage subject to the maximum 16 volt input specification limit This conflicts with the often recommended good practice of grounding the shield at the signal source and only at that point to eliminate line frequency ground loops which can be high enough to burn up a shield It is recommended that this practice be followed and if high frequency common mode noise is seen or suspected tie the shield to the VT1415A ground through a 0 1 uF capacitor At high frequencies this drives the shield voltage to 0 volts at the VT1415A input Due to inductive coupling to the signal leads the Ecm voltage on the signal leads is also driven to zero 356 Wiring and Noise Reduction Methods Appendix E VT1586A with Filter Option 001 Normal Mode 110 dB CMR to 10 MHz differential Noise Source thermocouple SCSI cable RC filter agi RC filter Option A3F SCSI to DIN Ke shielded twisted pair cable removable Common Mode jumper jumper configured Noise Source ao Note RC filter is a series 5 11 kOhm resistor with a 220 pF capacitor to GND VT1415A ECM 11 DUT Ground V VT1415A Ground rh Reducing Common Mode Rejection Using Tri Filar Transformers Figure E 2 H
165. 6 8 4 2 1 Event Operation Request Standard Message Questionable not used not used not used Status Service Event Available Status SRE STB TRG TST NOTES Status Register Enable Query Returns the weighted sum of all enabled unmasked events those enabled to assert SRQ in the Status Byte Register The C SCPI type for this returned value is int16 Status Byte Register Query Returns the weighted sum of all set bits in the Status Byte Register Refer to the ESE command earlier in this chapter for a table showing the contents of the Status Byte Register STB does not clear bit 6 Service Request The Message Available bit bit 4 may be cleared as a result of reading the response to STB The C SCPI type for this returned value is int16 Trigger Triggers an instrument when the trigger source is set to bus TRIG SOUR BUS command and the instrument is in the Wait for Trigger state Self Test Causes an instrument to execute extensive internal self tests and returns a response showing the results of the self test 1 During the first 5 minutes after power is applied TST may fail Allow the module to warm up before executing TST Chapter 6 VT1415A Command Reference 283 Common Command Reference Comments NOTE 2 Module must be screwed securely to mainframe 3 The VT1415A C SCPI driver for MS DOS implements two versions of TST The def
166. 6 Attenuator SCP Operating lt 60 V dc lt 42 V peak Maximum Common Mode With Direct Input Passive Filter or Amplifier SCPs Voltage Operating lt 16 V peak Damage level gt 42 V peak With VT1513A Divide by 16 Attenuator SCP Operating lt 60 V dc lt 42 V peak Common Mode Rejection 0 to 60 Hz 105 dB Input Impedance greater than 90 MO differential 1 MO with VT1513A Attenuator On Board Current Source 122 yA 0 02 with 17 volts Compliance Maximum Tare Cal Offset SCP Gain 1 Maximum tare offset depends on A D range and SCP gain A D range 16 4 1 0 25 0 0625 V F Scale Max Offset 3 2213 0 82101 0 23061 0 07581 0 03792 The following specifications reflect the performance of the VT1415A with the VT1501A Direct Input Signal Conditioning Plug On The performance of the VT1415A with other SCPs is found in the Specifications section of that SCP s manual Measurement Accuracy 90 days 20 C 1 C with CAL done after 1 hr warm up and CAL ZERO within 5 min dc volts Note If autoranging is ON for readings lt 3 8 V add 0 02 to linearity specifications for readings gt 3 8 V add 0 05 to linearity specifications A D range Linearity Offset Error Noise Noise VF Scale of reading 3 sigma 3 sigma 0 0625 0 01 5 3 pV 18 yv 8 uV 0 25 0 01 10 3 pV 45 uV 24 uV 1 0 0196 31 uV 110 pV 90 uV 4 0 01 122 yv 450 pV 366 pV 16 0 01 488 uV 1 8 mV 1 5 mV Temperature Coeffi
167. 64 input pointer to user function OUTPUT PARAMETERS i float64 range returned table rang is float64 offset returned table offset uintl6 conv array returned coefficient array 512 values for piecewise F void Build table float64 max input float64 min input float64 custom function float64 input float64 range float64 offset uintl6 conv array uint16M 128 uint16 EX 128 uintl16 Bhigh 128 uint16 Blow 128 int32 B intl6 ii int16 jj int32 Mfactor int32 Xfactor int32 Xofst float64 test range float64 tbl range float64 center float64 temp range 366 Generating User Defi ined Functions Appendix F float6 float6 float6 float6 4 t 4 slope 4 absslope 4 exponent float64 exponent2 float64 input 129 float64 result 129 permits the run time code to send the corrected X values assuming First calculate the mid point of the range of values from the min and max input values The offset is the center of the range of min and max inputs The purpose of the offset is to permit calculating the tables based upon a relative centering about the X axis The offset simply the tables were built symetrically around X 0 center min input max input min input 2 0F offset center temp range max input center test range temp range 0 0 temp range temp range Now calculate
168. 65 266 267 268 270 STATus OPERation CONDition 262 STATus OPERation ENABle 263 STATus OPERation ENABle 263 STATus OPERation EVENt 264 STATus OPERation NTRansition 264 STATus OPERation NTRansition 265 STATus OPERation PTRansition 265 STATus OPERation PTRansition 266 STATus PRESet 266 STATus QUEStionable CONDition 267 STATus QUEStionable ENABle 267 STATus QUEStionable ENABle 268 STATus QUEStionable EVENt 268 STATus QUEStionable NTRansition 269 STATus QUEStionable NTRansition 269 STATus QUEStionable PTRansition 270 STATus QUEStionable PTRansition 270 SYSTem subsystem 271 272 SYSTem CTYPe 271 SYSTem ERRor 271 SYSTem VERSion 272 TRIGger subsystem 273 274 275 276 277 TRIGger COUNt 275 TRIGger COUNt 275 TRIGger IMMediate 275 TRIGger SOURce 276 TRIGger SOURce 277 TRIGger TIMer 277 TRIGger TIMer 277 Command sequences defined 27 Commands FIFO status 87 Commands FIFO transfer 86 Comment lines 148 Comments 145 Common Command Format 155 Common mode noise 356 Common mode rejection 298 Common mode voltage Maximum 298 Common mode voltage limits 355 Communication using channel identifiers 128 Communication using global variables 129 Communication algorithm to algorithm 128 Comparison operators 137 Compensating for system offsets 104 Compensation thermocouple reference temperature 66 Components adding terminal module 47 Compound statement 144 CO
169. A to add channel 15 to the Scan List and order channels so channel 15 will be scanned before channels 16 through 23 SENS REF THER 5000 115 5k thermistor temperature for channel 15 SENS FUNC TC J 116 123 Type J thermocouple temperature for channels 16 through 23 SENS REF CHAN 115 116 123 reference channel scanned before channels 16 23 Supplying a Fixed Reference Temperature The SENse REFerence TEMPerature degrees c command immediately stores the temperature of a controlled temperature reference junction panel in the Reference Temperature Register The value is applied to all subsequent thermocouple channel measurements until another reference temperature value is specified or measured There is no need to use SENS REF CHANNELS To specify the temperature of a controlled temperature reference panel SENS REF TEMP 50 reference temp 50 C Now begin scan to measure thermocouples Linking Strain Strain measurements usually employ a Strain Completion and Excitation Measurements SCP VT1506A 07A 11A To link channels to strain EU conversions send the SENSe FUNCtion STRain cbridge type lt range gt lt ch_list gt e The bridge type parameter is not a parameter but is part of the command syntax The following table relates the command syntax to bridge type See the VT1506A VT1507A and VT1511A SCP User s Manuals for bridge schematics and field wiring information
170. ABILITY AND FITNESS FOR A PARTICULAR PURPOSE Exclusive Remedies THE REMEDIES PROVIDED HEREIN ARE BUYER S SOLE AND EXCLUSIVE REMEDIES VXI TECHNOLOGY SHALL NOT BE LIABLE FOR ANY DIRECT INDIRECT SPECIAL INCIDENTAL or CONSEQUENTIAL DAMAGES WHETHER BASED ON CONTRACT TORT or ANY OTHER LEGAL THEORY Notice The information contained in this document is subject to change without notice VXI TECHNOLOGY MAKES NO WARRANTY OF ANY KIND WITH REGARD TO THIS MATERIAL INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE VXI Technology shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing performance or use of this material This document contains proprietary information which is protected by copyright All rights are reserved No part of this document may be photocopied reproduced or translated to another language without the prior written consent of VXI Technology VXI Technology assumes no responsibility for the use or reliability of its software on equipment that is not furnished by VXI Technology Restricted Rights Legend U S Government Restricted Rights The Software and Documentation have been developed entirely at private expense They are delivered and licensed as commercial computer software as defined in DFARS 252 227 7013 Oct 1988 DFARS 252 211 7015 May 1991 or DFARS 252 227 7014 Jun 1995 as a c
171. ANT Do use CAL TARE for copper TC wiring 104 Don t use CAL TARE for thermocouple wiring 104 Making low noise measurements 34 Resolving programming problems 57 Indefinite length block data example 124 INF IEEE 202 INIT IMM 204 Init declarator 143 Init declarator list 143 Initialization declaration 141 Initializing variables 118 INITiate subsystem 204 INITiating Running algorithms 83 INP FILT FREQ 206 INP FILT LPAS STAT 206 INP FILT LPAS STAT 207 INP GAIN 208 Input channels 116 Input impedance 298 Input protect feature disabling 25 INPut subsystem 205 207 209 210 Input voltage maximum 298 INPut FILT FREQ 205 INPut GAIN 207 INPut LOW 208 INPut LOW 209 INPut POLarity 209 INPut POLarity 210 Inputs setting up digital 70 Instrument drivers 27 Interrupt function 119 Interrupt level setting NOTE 19 interrupt 119 138 Interrupts updating the status system 100 VXI 100 Intrinsic functions and statements abs expression 137 interrupt 137 max expressionl expression2 137 min expressionl expression2 137 writeboth expression cvt element 137 writecvt expression cvt element 118 137 writefifo expression 119 137 Intrinsic Functions and Statements interrupt 119 Intrinsic statement 144 Isothermal reference measurement NOTE 34 K Keywords special VT1415A reserved 136 Keywords standard reserved 136 L Language syntax summary 141 Language overview of
172. ATA 201 FORMat DATA 203 INITiate subsystem 204 INITiate IMMediate 204 INPut subsystem 205 207 209 210 INPut FILTer LPASs FREQuency 206 INPut FILTer LPASs STATe 206 INPut FILTer LPASs STATe 207 INPut GAIN 207 INPut GAIN 208 INPut LOW 208 INPut LOW 209 INPut LPASs FILTer FREQuency 205 INPut POLarity 209 INPut POLarity 210 MEMory subsystem 211 213 214 MEMory VME ADDRess 212 MEMory VME ADDRess 212 MEMory VME SIZE 212 MEMory VME SIZE 213 MEMory VME STATe 213 MEMory VME STATe 214 OUTPut subsystem 215 216 217 219 220 221 223 OUTPut CURRent AMPLitude 215 OUTPut CURRent AMPLitude 216 OUTPut CURRent STATe 217 OUTPut CURRent STATe 217 OUTPut POLarity 218 OUTPut POLarity 218 OUTPut SHUNt 218 OUTPut SHUNt 219 OUTPut TTLTrg SOURce 219 OUTPut TTLTrg SOURce 220 OUTPut TTLTrg lt n gt STATe 220 OUTPut TTLTrg lt n gt STATe 221 OUTPut TYPE 221 OUTPut TYPE 222 OUTPut VOLTage AMPLitude 222 OUTPut VOLTage AMPLitude 223 ROUTe subsystem 224 225 ROUTe SEQuence DEFine 224 ROUTe SEQuence POINts 225 SAMPle subsystem 226 227 SAMPle TIMer 226 SAMPle TIMer 227 SENSE subsystem 228 229 230 232 234 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 SENSe CHANnel SETTling 229 SENSe CHANnel SETTling 229 SENSe DATA COUN HALF 233 SENSe DATA CVTable RESet 231 SENSe DATA CVTable 230 SENSe DATA FIFO ALL 231 SENSe
173. ATio places a variable update request in the Update Queue Do not place more update requests in the Update Queue than are allowed by the current setting of ALG UPD WINDOW or a Too many updates send ALG UPDATE command error message will be generated Parameters Parameter Parameter Range of Default Name Type Values Units alg name string ALGI ALG32 none num trigs numeric int16 1 to 32 767 none 170 VT1415A Command Reference Chapter 6 ALGorithm Comments Specifying a value of 1 the default causes the named algorithm to be executed each time a trigger is received Specifying a value of n will cause the algorithm to be executed once every 7 triggers All enabled algorithms execute on the first trigger after INIT e The algorithm specified by alg name gt may or may not be currently defined The specified setting will be used when the algorithm is defined e Related Commands ALG UPDATE ALG SCAN RATIO e When Accepted Both before and after INIT Also accepted before and after the algorithm referenced is defined e RST Condition ALG SCAN RATIO 1 for all algorithms Usage ALG SCAN RATIO ALG4 16 ALGA executes once every 16 triggers ALGorithm EXPLicit SCAN RATio ALGorithm EXPLicit SCAN RATio lt alg name gt returns the number of triggers that must occur for each execution of lt alg_name gt Comments Since ALG SCAN RATIO is valid for an undefined algorithm ALG
174. Boolean Discrete Channel List Accepts all commonly used decimal representations of numbers including optional signs decimal points and scientific notation 123 123E2 123 1 23E2 123 1 23E 2 1 23000E 01 Special cases include MIN MAX and INFinity A parameter that represents units may also include a units suffix These are Volts V mv 1 0 uv 10 Ohms ohm kohm 10 mohm 10 Seconds s msec 10 usec 10 Hertz hz khz 10 mhz 10 ghz 10 The Comments section within the Command Reference will state whether a numeric parameter can also be specified in hex octal and or binary H7B Q173 B1111011 Represents a single binary condition that is either true or false ON OFF 1 0 Selects from a finite number of values These parameters use mnemonics to represent each valid setting An example is the TRIGger SOURce lt source gt command where lt source gt can be BUS EXT HOLD IMM SCP TIMer or TTLTrg lt n gt The general form of a single channel specification is ccnn where cc represents the card number and nn represents the channel number Chapter 6 VT1415A Command Reference 157 Since the VT1415A has an on board 64 channel multiplexer the card number will be 1 and the channel number can range from 00 to 63 Some example channel specifications channel 0 100 channel 5 105 channel 54 154 The General form of a channel range specification is cenn cenn colon separator th
175. CALibration SETup MODE 194 DIAGnostic CALibration TARE OTDetect MODE 194 DIAGnostic CALibration TARE OTDetect MODE 195 DIAGnostic CHECKSUM cocoa eee ee ea cae See CR 195 DIAGnostic CUSTom LINear 00 0c cee 195 DIAGnostic CUSTom PIECewise 00 0 cece ee eee 196 DIAGnostic CUSTom REFerence TEMPerature 197 DIA Gnostic EEE steer e c e Re e ee 197 DIAGnosticTIBEE cs rose b RR DERE Hess bed amp EVER IP EE 198 DIAGnostic INTerrupt LINe 0 00 0000 ec eee 198 DIAGnostic INTerrupt LINe 20 0 0 0 ee 198 FOR Mats i a an Up ERU d es de aah we adden tos dde eats 201 FORMAI DATA 25 333 xe te REOR RAOUL ENG ates 201 FORMat DATA 0 0 0 0 ccc cc III 203 Illy PE LEE 204 INITiate IMMediate lesse 204 ui Mr 205 INPut FILTer LPASs FREQuency 2 0 20 0 cee eee 205 INPut FILTer LPASs FREQuency 0 0 0 0 cee ee eee 206 INPut FILTer LPASs STATe 2 0 0 0 00 0 0 eee 206 INPut FILTer LPASs STATe 0 0 0 0 0 ccc eee 207 INP t GAIN iio eds desea eda dearer YA 207 INPUt Cr AINT Ss uem be E E eS heben aad wed RATE UN 208 INPut EOW iix cass nis ok RR b eR a bla Led EI ERE e e 208 INPut EOW tras ed ds tun eke eh eee lis 209 INP t POLDAarity s ora TRES Wags e CI Eds 209 INP t POLarity iio dea it 210 MEMO ey ii id A Rs pea E 211 MEMory VME ADDRess sleseeeeee e 212 MEMory VME ADDRess ee eee
176. CE sequence and SeQuEnCe are all acceptable Implied Commands Implied commands are those which appear in square brackets in the command syntax Note that the brackets are not part of the command and are not sent to the instrument Suppose a second level command is sent but the preceding implied command is not sent In this case the instrument assumes the implied command is intended and it responds as if were sent Examine the INITiate subsystem shown below INITiate IMMediate The second level command IMMediate is an implied command To set the instrument s trigger system to INIT IMM send either of the following command statements INIT IMM or INIT 156 VT1415A Command Reference Chapter 6 Variable Command Some commands will have what appears to be a variable syntax As an example Syntax OUTPut TTLTrg lt n gt STATe ON In these commands the lt n gt is replaced by a number No space is left between the command and the number because the number is not a parameter The number is part of the command syntax The purpose of this notation is to save a great deal of space in the Command Reference In the case of TTLTrg lt n gt n can be from 0 through 7 An example command statement OUTPUT TTLTRG2 STATE ON Parameters Parameter Types The following section contains explanations and examples of parameter types that are seen later in this chapter Parameter Types Explanations and Examples Numeric
177. CONDition lt ch_list gt sets the SOURce function to output digital patterns to bits in cA list Parameters Parameter Parameter Range of Default Name Type Values Units ch list string 100 163 none Comments e The VT1533A SCP sources 8 digital bits on the channel specified by this command The VT1534A SCP can source 1 digital bit on each of the the channels specified by this command SOURce FUNCtion SHAPe PULSe SOURce FUNCtion SHAPe PULSe W lt ch_list gt sets the SOURce function to PULSE for the channels in lt ch_list gt Parameters Parameter Parameter Range of Default Name Type Values Units ch list string 100 163 none 256 VT1415A Command Reference Chapter 6 SOURce Comments This PULSe channel function is further defined by the SOURce FM STATe and SOURce PULM STATe commands If the FM state is enabled then the frequency modulated mode is active If the PULM state 1s enabled then the pulse width modulated mode is active If both the FM and the PULM states are disabled then the PULSe channel is in the single pulse mode SOURce FUNCtion SHAPe SQUare SOURce FUNCtion SHAPe SQUare lt ch_list gt sets the SOURce function to output a square wave 50 duty cycle on the channels in lt ch_list gt Parameters Parameter Parameter Range of Default Name Type Values Units ch list string 100 163 none
178. CPI Most programs use one or more functions from the C standard library include lt stdio h gt T O functions Most programs will also use standard 398 Example Program Listings Appendix G y include lt stddef h gt This file is also often useful include lt math h gt Needed for any floating point fn s Other system include files Whenever using system or library calls check the call description to see which include files should be included Xu Instrument control include files finclude cscpi h C SCPI include file Declare any constants that will be useful to the program In particular it is usually best to put instrument addresses in this area to make the code more maintainable define E1415 ADDR vxi 208 The SICL address of your E1415 INST DECL el415 E1415A REGISTER E1415 Use something like this for GPIB and Agilent E1405 6 Command Module define E1415 ADDR hpib 22 26 The SICL address of your E1415 INST DECL e1415 E1415A MESSAGE E1415 Declare instruments that will be accessed with SICL These declarations can also be moved into local contexts INST vxi VXI interface session i SS ACA FF Xo F X Xo Xo F xo ox rap instrument errors If this function is used it will be called every time a C SCPI instrument puts an
179. D Mfactor gt 32768 0 THEN 2260 only save if M is in limits 2270 Ex Jj Xofst Xfactor 2280 Jj 2Mfactor remove leading 1 s 2290 B PROUND 2 Xfactor Result Ii 1 0 2300 Bhigh Jj INT B 65536 0 truncates 2310 B1 B Bhigh Jj 65536 0 2320 IF B1 gt 32767 THEN B1 B1 65536 2330 Blow J3 B1 2340 END IF 2350 Loopend2 NEXT Ii 2360 2370 Copy the calculated table values to the output array Appendix F Generating User Defined Functions 377 2380 2390 4 2400 Store M E and B terms in array 2410 2420 FOR Ii 0 TO 127 2430 copy 128 sets of coefficents 2440 Coef array Ii 4 M Ii 2450 Coef array 1i 4 1 Ex Ii 2460 Coef array 1i 4 2 Bhigh Ii 2470 Coef array 1i 4 3 Blow Ii Ii Ex Ii Bhigh Ii Blow Ii 2480 PRINT Ii M 2490 NEXT Ii 2500 SUBEND 2510 2520 ck ck ck ck ck ck kk KKK ck kk ck ck kk ck ck 0k kk ck ck ck kk ck ck ck ck kk ck ck kk ck ck ck ok ck kc ok kk ck ockock ko ko ko ko ko ko koc 2530 Insert your desired function here 2540 2550 DEF FNMy function REAL In val 2560 RETURN SIN In val 2570 FNEND 378 Generating User Defined Functions Appendix F Appendix G Example Program Listings This appendix includes listings of example programs that are not printed in other parts of the manual The example simp_pid cs is shown here because the listing in Chapter 3 is a shortened version Simp PIANOS cessus
180. DATA FIFO COUNt 232 SENSe DATA FIFO HALF 233 SENSe DATA FIFO MODE 234 SENSe DATA FIFO MODE 235 SENSe DATA FIFO PART 235 SENSe DATA FIFO RESet 236 SENSe FREQuency APERture 236 SENSe FREQuency APERture 236 SENSe FUNC CONDition 237 SENSe FUNCtion CUSTom 237 Index 413 SENSe FUNCtion CUSTom REFerence 238 SENSe FUNCtion CUSTom TCouple 239 SENSe FUNCtion FREQuency 240 SENSe FUNCtion RESistance 241 SENSe FUNCtion STRain FBEN 242 SENSe FUNCtion STRain FBP 242 SENSe FUNCtion STRain FPO 242 SENSe FUNCtion STRain HBEN 242 SENSe FUNCtion STRain QUAR 242 SENSe FUNCtion STRainHPO 242 SENSe FUNCtion TEMPerature 243 SENSe FUNCtion TOTalize 245 SENSe FUNCtion VOLTage 245 SENSe REFerence 246 SENSe REFerence CHANnels 248 SENSe REFerence TEMPerature 248 SENSe STRain EXCitation 249 SENSe STRain EXCitation 249 SENSe STRain GFACtor 250 SENSe STRain GFACtor 250 SENSe STRain POISson 251 SENSe STRain POISson 251 SENSe STRain UNSTrained 251 SENSe STRain UNSTrained 252 SENSe TOTalize RESet MODE 252 SENSe TOTalize RESet MODE 254 SOURce subsystem 255 256 257 258 259 SOURce FM STATe 255 SOURce FM STATe 256 SOURce FUNC SHAPe 257 SOURce FUNC SHAPe CONDition 256 SOURce FUNC SHAPe PULSe 256 SOURce PULM STATe 257 SOURce PULM STATe 257 SOURce PULSe PERiod 258 SOURce PULSe PERiod 258 SOURce PULSe WIDTh 259 SOURce PULSe WIDTh 259 STATus subsystem 260 261 262 264 2
181. DO NOT program outputs when they are executed Instead these statements write to an intermediate Output Channel Buffer which is read and used for output AFTER all algorithms have executed AND the algorithm output delay has expired see Figure 6 1 Also note that not all outputs will occur at the same time but will take approximately 10 us per channel to write e When delay is 0 the Output phase begins immediately after the Calculate phase This provides the fastest possible execution speed while potentially introducing variations in the time between trigger and beginning of the Output phase The variation can be caused by conditional execution constructs in algorithms or other execution time variations e f delay is set to less than the time required for the Input Update Calculate ALG OUTP DELAY will report the time set but the effect will revert to the same that is set by ALG OUTP DELAY 0 Output begins immediately after Calculate e When delay is AUTO the delay is set to the worst case time required to execute phases 1 through 3 This provides the fastest execution speed while maintaining a fixed time between trigger and the OUTPUT phase e To set the time from trigger to the beginning of OUTPUT use the following procedure After defining all algorithms execute ALG OUTP DEL AUTO sets minimum stable delay ALG OUTP DEL returns this minimum delay ALG OUTP DEL lt minimum additional gt additional desired minimum
182. E 212 MEM VME SIZE 213 MEM VME STATe 213 MEM VME STATe 214 Messages error 327 328 329 330 331 332 333 334 min expressionl expression2 138 MODE SENS DATA FIFO MODE 234 SENSe TOTalize RESet MODE 252 Mode history 77 Mode selecting the FIFO 80 MODE SENS DATA FIFO MODE 235 SENSe TOTalize RESet MODE 254 Mode which FIFO 87 Model determining SCPI programming 280 Model executing the programming 57 Model programming 55 Modifier the static 139 Modifying a standard PID algorithm 127 Modifying running algorithm variables 89 Modifying the standard PIDA 128 Modifying the terminal module circuit 47 Module SCPs and Terminal 35 Modules Terminal 35 More on auto ranging 108 Multiplicative expression 142 Multiplicative operator 142 N NaN 202 Next where to go 149 Noise Common mode 356 Normal mode 356 Noise due to inadequate grounding 355 Noise reduction with amplifier SCPs NOTE 110 Noise reduction wiring techniques 354 Noise Rejection 356 Noisy measurements Quieting 34 39 Non Control algorithms 131 Normal mode noise 356 Not a Number 202 NOTES RST effect on custom EU tables 102 TST sets default ASC 7 data format 202 E overvoltage return format from FIFO 232 233 ALG SCAN RATIO vs ALG UPD 170 ALG SIZE return for undefined algorithm 171 ALG STATE effective after ALG UPDATE 89 ALG STATE effective only after ALG UPD 172 ALG
183. E Enter statement returns current value of bits set in the Questionable Enable register STATus QUEStionable EVENt STATus QUEStionable EVENt returns the decimal weighted value of the bits set in the Event register Comments e When using the Questionable Event register to cause SRQ interrupts STAT QUES EVENT must be executed after an SRQ to re enable future interrupts e Returned Value Decimal weighted sum of all set bits The C SCPI type is uint16 e Cleared By CLS power on and by reading the register 268 VT1415A Command Reference Chapter 6 e Related Commands STB SPOLL STAT QUES COND STAT QUES ENABLE STAT QUES ENABLE Usage STAT QUES EVENT Enter statement will return the value of bits set in the Questionable Event register STAT QUES Same as above STATus QUEStionable NTRansition STATus QUEStionable NTRansition transition mask sets bits in the Negative Transition Filter NTF register When a bit in the NTF register is set to one the corresponding bit in the Condition register must change from a one to a Zero in order to set the corresponding bit in the Event register When a bit in the NTF register is zero a negative transition of the Condition register bit will not change the Event register bit Parameters Parameter Parameter Range of Default Name Type Values Units transition mask numeric uint16 0 32767 none Comments rransition mask may be sent as
184. EER EREET Figure 4 1 Source Listing of Function main Accessing the VT1415A s Resources This section describes how an algorithm accesses hardware and software resources provided by the VT1415A The following is a list of these resources e O channels e Global variables defined before an algorithm is defined e The constant ALG NUM which the VT1415A makes available to an algorithm ALG NUM 1 for ALGI 2 for ALG2 etc e User defined functions defined with the ALG FUNC DEF command e The Current Value Table CVT and the data FIFO buffer FIFO to output algorithm data to the application program e VXIbus Interrupts Chapter 4 Creating and Running Custom Algorithms 115 Accessing I O in the Algorithm Language channels are referenced as pre defined variable Channels identifiers The general channel identifier syntax is Iccc for input channels and Occc for output channels where ccc is a channel number from 100 channel 0 through 163 channel 63 Like all VT1415A variables channel identifier variables always contain 32 bit floating point values even when the channel is part of a digital I O SCP If the digital I O SCP has 8 bit channels like the VT1533A the channel s identifiers Occc and Iccc can take on the values 0 through 255 To access individual bit values append Bn to the normal channel syntax where n is the bit number 0 through 7 If the Digital I O SCP has single bit channels like th
185. EXPLicit ARRay 164 ALGorithm EXPLicit ARRay 165 ALGorithm EXPLicit DEFine 165 ALGorithm EXPLicit SCALar 169 ALGorithm EXPLicit SCALar 170 ALGorithm EXPLicit SCAN RATio 171 ALGorithm EXPLicit SIZe 171 ALGorithm EXPLicit TIMe 173 ALGorithm EXPLicit SCAN RATio 170 ALGorithm FUNCtion DEFine 174 ALGorithm OUTPut DELay 175 ALGorithm OUTPut DELay 176 ALGorithm UPDate IMMediate 176 ALGorithm UPDate CHANnel 177 ALGorithm UPDate WINDow 178 ALGorithm UPDate WINDow 179 ARM subsystem 180 181 ARM IMMediate 181 ARM SOURce 181 ARM SOURce 182 CALibration subsystem 183 184 186 187 188 189 190 191 192 CALibration CONFigure RESistance 184 CALibration CONFigure VOLTage 185 CALibration SETup 186 CALibration SETup 186 CALibration STORe 187 CALibration TARE 188 CALibration TARE RESet 189 CALibration TARE 190 CALibration VALue RESistance 190 CALibration V ALue VOL Tage 191 CALibration ZERO 192 lO subsystem 193 194 195 197 198 199 DIAGnostic CALibration SETup MODE 193 DIAGnostic CALibration SETup MODE 194 DIAGnostic CALibration TARe MODE 194 DIAGnostic CALibration TARe MODE 195 DIAGnostic CHECksum 195 DIAGnostic CUSTom LINear 195 DIAGnostic CUSTom PIECewise 196 DIAGnostic CUSTom REFerence TEMPerature 197 DIAGnostic IEEE 197 DIAGnostic IEEE 198 DIAGnostic INTerrupt LINe 198 DIAGnostic INTerrupt LINe 198 FORMat subsystem 201 202 203 FORMat D
186. Executing the Programming Model 0 0 0 eee eee eee 57 Power On and RST Default SettidgS o ooooooomomoo 57 Table of Contents vii Setting Up Analog Input and Output Channels 0 60 Configuring Programmable Analog SCP Parameters 60 Linking Channels to EU Conversion 0 00 00 less 62 Linking Output Channels to Functions 0 02 00 69 Setting Up Digital Input and Output Channels 0 70 Setting Up Digital Inputs 70 Setting Up Digital Outputs llle 71 Performing Channel Calibration Important ooooooooommo 74 Defining Standard PID Algorithms 0 0 cee eee eee eee 75 The Pre Defined PIDA Algorithm 00 00 0000 00 75 The Pre Defined PIDB Algorithm esee 76 Defining a PID with ALG DEFINE 000000020 ee 78 Pre Setting PID Variables and Coefficients 0 0000 79 Pre Setting PID Variables 0 0 eee eee 79 Defining Data Storage wicca sve AA RE E AA 79 Specifying the Data Format 79 Selecting the FIFO Mode i eoe nacie denme enna ea 80 Setting up the Trigger System sucas eros eee eee eee 80 Arm and Trigger Sources 0 2 2 0c eee eee eee 80 Programming the Trigger Timer 2 0 0 0 cee eee ee eee 82 Setting the Trigger Counter 0 0 0 0 eese 83 Outputting Trigger Signals 1 0 00 2 eee eee 83 INITiating Running Algorithms 0
187. F Common Mode Filters One VT1413C customer determined that greater than 100 dB CMR to 10 MHz was required to get good thermocouple TC measurements in his test environment To accomplish this requires the use of tri filar transformers which are an option to the VT1586A Remote Rack Terminal Panel This also provides superior isothermal reference block performance for thermocouple measurements This works by virtue of the inductance in the shield connected winding presenting a significant impedance to high frequency common mode noise and forcing all the noise voltage to be dropped across the winding The common mode noise at the input amplifier side of the winding is forced to 0 volts by virtue of the low impedance connection to the VT1415A ground via the selectable short or parallel combination of 1 KQ and 0 1 uF The short cannot be used in situations where there is a very high common mode voltage dc and or ac that could generate very large shield currents The tight coupling through the transformer windings into the signal Hi and Low leads forces the common mode noise at the input amplifier side of those windings to 0 volts This achieves the 110 dB to 10 MHz desired keeping the high frequency common mode noise out of the amplifier thus preventing the amplifier from rectifying this into an offset error This effectively does the same thing that shielded twisted pair cable does only better It is especially effective if the shield connec
188. FIFO Mode if using History Mode Define Global Variables optional Setup Algorithm s and Preset Algorithm Variables Initiate Trigger System INP OUTP Commands SENSe FUNC Commands INP OUTP SENSe SOURce CAL or CAL SETup Command ARM SOUR TRIG SOUR TRIG COUNt TRIG TIMer Command FORMAT Command SENS DATA FIFO MODE Command ALGorithm DEFine GLOBALS Command ALG DEF ALG ARRay ALG SCALar ALG SCAN RATio ALG UPDate INITiate command rigger events execute algs Retrieve Data Modify Algorithm Variables SENS DATA FIFO SENS CVT ALG SCAL and ALG ARR commands ALG ARRay ALG SCALar ALG STAT ALG SCAN RATio ALG UPD Figure 3 3 Programming Sequence 58 Programming the VT1415A for PID Control Chapter 3 Programming Model Block Diagram VXI Intterupts INPut FILTer INPut GAIN OUTPut CURRent AMPLitude OUTPut CURRent STATe OUTPut SHUNt OUTPut VOLTage AMPlitude INPut POLarity SENSe FREQuency APERture SENSe FUNCtion CONDition SENSe FUNCtion FREQuency SENSe FUNCtion TOTalize SENSe FREQuency SENSe TOTtalize RESet MODE SCP Data Bus OUTPut POLarity OUTPut TYPE SOURce FM STATe SOURce FUNCtion CONDition SOURce FUNCtion PULSe SOURce FUNCtion SQUare SOURce PULM STATe SOURce PULSe PERiod SOURce PULSe WIDTh
189. FUNCtion STRain FBENding FBPoisson FPOisson HBENding HPOisson QUARter Note on Syntax Although the strain function is comprised of six separate SCPI commands the only difference between them is the bridge type they specify to the strain EU conversion algorithm e SENSe FUNCtion STRain lt bridge_type gt lt range gt lt ch_list gt links the strain EU conversion with the channels specified by lt ch_list gt to measure the bridge voltage See Linking Input Channels to EU Conversion on page 62 for more information bridge type is not a parameter but is part of the command syntax The following table relates the command syntax to bridge type See the user s manual for the optional Strain SCP for bridge schematics and field wiring information Command Bridge Type FBENding Full Bending Bridge FBPoisson Full Bending Poisson Bridge FPOisson Full Poisson Bridge HBENding Half Bending Bridge HPOisson Half Poisson Bridge QUARter Quarter Bridge default 242 VT1415A Command Reference Chapter 6 Parameters SENSe Parameter Parameter Range of Default Name Type Values Units range numeric flt32 see comments V dc ch list channel list string 100 163 none Comments e Strain measurements require the use of Bridge Completion Signal Conditioning Plug Ons Bridge Completion SCPs provide the strain measurement bridges and
190. G TIM in Chapter 6 the Command Reference Input over voltage Calibration relays opened if JM2202 not cut to protect module inputs and Questionable Data Status bit 11 set Execute RST to close relays and or reset status bit FIFO overflow Indicates that the FIFO buffer has filled and that one or more readings have been lost Usually caused by algorithm values stored in FIFO faster than FIFO was read Calibration failed Unable to map A24 VXI memory Incorrect range value Range value sent is not supported by instrument Command not yet implemented 0x1 DSP Unrecognized command code 0x2 DSP Parameter out of range 328 Error Messages Appendix B 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 0x4 DSP Flash rom erase failure 0x8 DSP Programming voltage not present 0x10 DSP Invalid SCP gain value Check that SCP is seated or replace SCP Channel numbers are in FIFO 0x20 DSP Invalid CAL constant or checksum CAL required 0x40 DSP Couldn t cal some channels Check that SCP is seated or replace SCP Channel numbers are in FIFO 0x80 DSP Re Zero of ADC failed 0x100 DSP Invalid Tare CAL constant or checksum Perform CAL TARE CAL TARE procedure 0x200 DSP Invalid Factory CAL constant or checksum Perform A D Ca
191. GRD jumper in place Figure 2 6 B D 5 In general the GND GRD jumper can be left in place unless it is necessary to remove to break low frequency below 1 kHz ground loops 6 Use good quality foil or braided shield signal cable 7 Route signal leads as far as possible from the sources of greatest noise 8 In general don t connect Hi or Lo to Guard or Ground at the VT1415A 9 It is best if there is a dc path somewhere in the system from Hi or Lo to Guard Ground 10 The impedance from Hi to Guard Ground should be the same as from Lo to Guard Ground balanced 11 Since each system is different don t be afraid to experiment using the suggestions presented here until an acceptable noise level is found Chapter 2 Field Wiring 39 4 power Device B Sn Hi Under Test pressure A Ph x V b A Guard NE power Remove Jumper to Example for break Ground Loop sl Powered L shield connected to I power Transducers ground at transducer Device Shield Hi Under Test pressure MO ie oe 0 Lo V Guard B E Leave Jumper power in Place transducer floating Shield Y Hi Device i Under Test B C Guard rH Example for o Remove Jumper to Thermocouples J break Ground Loop L shield connected to Shield Hi ground at transducer Device l Under Test Lo D Guard gt Leave Jumper in Place transducer floating Sh
192. I114 pid1_outp 0124 Use global for PIDB output ALG DEF ALG2 PIDB pid2_inp O132 0124 Use global for PIDB input Use ALG SCALAR GLOBALS lt var_name gt lt value gt to assign a value Use ALG SCALAR GLOBALS lt var_name gt to read the value Pre Setting PID Variables and Coefficients Pre Settin To send values to variables in standard PID algorithms use the command g g PID Variables LGorithm EXPLicit SCALar lt alg_name gt lt variable_name gt lt value gt To set PID ALGI s gain to 5 and turn off the I and D term send ALG SCALAR ALG1 P_factor 5 set gain to 5 ALG SCALAR ALG1 l_factor 0 turn off I term ALG SCALAR ALG1 D_factor 0 turn off D term ALG SCALAR ALG1 Setpoint 8 adjust Setpoint to 8 volts ALG UPDATE cause all variables to be updated immediately Defining Data Storage Specifying the The format of the values stored in the FIFO buffer and CVT never changes Data Format They are always stored as IEEE 32 bit Floating point numbers The FORMat lt format gt lt ength gt command merely specifies whether and how the values will be converted as they are transferred from the CVT and FIFO to the host computer e The lt format gt lt length gt parameters can specify PACKED Same as REAL 64 except for the values of IEEE INF IEEE INF and Not a Number NaN See FORMat command in Chapter 5 for details REAL 32 means real 32 bit n
193. IN for overall time Defines a custom conversion function Sets the delay from scan trigger to start of outputs Returns the delay from scan trigger to start of outputs Requests immediate update of algorithm code variable or array Sets dig channel to synch algorithm updates Sets a window for num updates to occur RST default is 20 Returns setting for allowable number variable and algorithm updates Arm if ARM SOUR is BUS or HOLD software ARM Specify the source of Trigger Timer ARM Return current ARM source Prepare to measure on board references with an external multimeter Configure to measure reference resistor Configure to measure reference voltage range at zero or full scale Performs Channel Calibration procedure Returns state of CAL SETup operation returns error codes or 0 for OK Store cal constants to Flash RAM for either A D calibration or those generated by the CAL TARE command 288 VT1415A Command Reference Chapter 6 Command CALibration cont TARE lt ch_list gt RESet TARE VALue RESistance ref ohms VOLTage ref volts ZERO DIAGnostic CALibration SETup MODE 0 1 MODE TARe OTD MODE 0 1 MODE CHECksum COMMand SCPWRITE lt reg_addr gt lt reg_data gt CUSTom LINear lt table_ad_range gt lt table_block gt lt ch_list gt PIECewise lt table ad range gt lt table_block gt U lt ch_list gt REFerence TEMPerature INT
194. KK HK KK RR RR RAR A KK CK KK KK KK KK KK KK RARA KC KK KC KK KC KK kk ek kk ke ke ke ke ke ke ke e e ek PIDC J KCKCKCKCKCKCk kk Ck Ck Ck Kk Kk KC KC KC KC KK KK CK KK KK KK KK KK KK KK KK KK KC KK KK KK KK KC KC A ke ke ke e ke ke ke e ke ek I O Channels Must be defined by the user E inchan Input channel name outchan Output channel name alarmchan Alarm channel name ay pe VE AA A rac Tu J KCKCKCKCkC Ck Ck kk kk Ck kk Ck CK Ck CK Kk CK Kk KK Kk KK Kk KK Ck KC Ck KK Kk KC Sk A Ck kk kk kk e ke ke ke e ke ke ko ke ke ke oe A PID algorithm for E1415A controller module This algorithm is called once per scan trigger by main It performs Proportional Integral and Derivative control E pe a pe e The output is derived from the following equations yes D PID out P out I out D out SD out Tur P out Error P factor EJ I out I out Error I factor Tu D out PV old PV D factor SD out Setpoint Setpoint old SD factor Error Setpoint PV pm d where Setpoint is the desired value of the process variable user supplied PV is the process variable measured on the input channel PID out is the algorithm result sent to the output channel p P factor I factor D factor and SD factor are the PID constants user supplied x rds mU Alarms may be generated when
195. LG UPDATE or ALG UPD CHAN command is received This allows multiple ALG STATE commands to be sent with a synchronized effect 2 ALG STATE places a variable update request in the Update Queue Do not place more update requests in the Update Queue than are allowed by the current setting of ALG UPD WINDOW or a Too many updates send ALG UPDATE command error message will be generated CAUTION When ALG STATE OFF disables an algorithm its control output is left at the last value set by the algorithm Depending on the process this uncontrolled situation can be dangerous Make certain that the process is in a safe state before halting the execution of a controlling algorithm The Agilent HP E1535 Watchdog Timer SCP was specifically developed to automatically signal that an algorithm has stopped controlling a process Use of the Watchdog Timer is recommended for critical processes Parameters Parameter Parameter Range of Default Name Type Values Units alg name string ALGI ALG32 none enable boolean uint16 0 1 ON OFF none Comments The algorithm specified by alg name may or may not be currently defined The setting specified will be used when the algorithm is defined e RST Condition ALG STATE ON e When Accepted Both before and after INIT Also accepted before and after the algorithm referenced is defined e Related Commands ALG UPDATE ALG STATE ALG DEFINE 172 VT1415A Command R
196. Libration TARE RESet Command Sequence CALibration TARE RESet resets the tare calibration constants to zero for all 64 channels Executing CAL TARE RES affects the tare cal constants in RAM only To reset the tare cal constants in Flash Memory execute CAL TARE RES and then execute CAL STORE TARE CAL TARE RESET to reset channel offsets CAL STORE TARE Optional if necessary to reset tare cal constants in Flash Memory Chapter 6 VT1415A Command Reference 189 CALibration CALibration TARE CALibration TARE Returns a value to indicate the success of the last CAL TARE operation CAL TARE returns the value only after the CAL TARE operation 1s complete e Returned Value Value Meaning Further Action 0 Cal OK None 1 Cal Error Query the Error Queue SYST ERR See Error Messages in Appendix B Also run TST 2 No results available Perform CAL TARE before CAL TARE The C SCPI type for this returned value is int16 e Executing CAL TARE sets the Calibrating bit bit 0 in Operation Status Group Executing CAL TARE resets the bit e Related Commands CAL STOR TARE Command Sequence CAL TARE ch list to correct channel offsets CAL TARE to return the success flag from the CAL TARE operation CAL STORE TARE Optional depending on necessity of long term storage CALibration VALue RESistance CALibration VALue RESistance ref ohms sends the just measured value of the on
197. ME memory card to be used as additional reading storage Parameters Parameter Parameter Range of Default Name Type Values Units A24 address numeric valid A24 address none Comments This command is only available in systems using an Agilent HP E1405B 06A command module e The default if MEM VME ADDR not executed is 240000 e lt A24 address gt may be specified in decimal hex H octal Q or binary 8B e Related Commands MEMory subsystem FORMat and FETCH e RST Condition VME memory address starts at 200000 When using an Agilent HP E1405B 06A command module the first VT1415A occupies 200000 23FFFF Usage MEM VME ADDR H400000 Set the address for the VME memory card to be used as reading storage MEMory VME ADDRess MEMory VME ADDRess returns the address specified for the VME memory card used for reading storage Comments e Returned Value numeric e This command is only available in systems using an Agilent HP E1405B 06A command module e Related Commands MEMory subsystem FORMat and FETCH Usage MEM VME ADDR Returns the address of the VME memory card MEMory VME SIZE MEMory VME SIZE mem size Specifies the number of bytes of VME memory to allocate for additional reading storage 212 VT1415A Command Reference Chapter 6 MEMory Parameters Parameter Parameter Range of Default Name Type Values Units mem size numeric to limit of av
198. NDition SENSe FUNC CONDition 237 SOURce FUNC SHAPe 256 STAT OPER CONDition 262 CONDition STAT QUES CONDition 267 Conditional constructs 138 Conditional execution 146 Configuring programmable analog SCP parameters 60 Configuring the enable registers 97 Configuring the transition filters 96 Configuring the VT1415A 19 Conformity declaration VT1413C v Connecting the on board thermistor 42 Connection recommended 39 signals to channels 39 Connections Guard 355 Considerations special 106 Constant decimal 141 Constant hexadecimal 141 Constant octal 141 Constructs conditional 138 Continuous Mode 276 Continuously reading the FIFO FIFO mode BLOCK 87 Control implementing feed forward 129 Control implementing multivariable 128 Control manual 77 Index Control PIDA with digital on off 127 Control program flow 138 Controller describing the VT1415A closed loop 112 Controller overview of the VT1415A algorithmic loop 54 Conversion EU 336 Conversion linking channels to EU 62 Conversions custom EU 69 Conversions custom reference temperature EU 102 Conversions custom thermocouple EU 102 Conversions loading tables for linear 103 Conversions loading tables for non linear 103 COUNt SENS DATA FIFO COUNt 232 Counter setting the trigger 83 Creating and loading custom EU conversion tables 101 Creating conversion tables 103 CTYPe SYST CTYPe 271 Current Value Table
199. NDow 179 Algorithm definition 144 Algorithms disabling 89 enabling 89 Algorithms defining custom 123 Algorithms defining standard PID 75 Index 411 Algorithms INITiating Running 83 Algorithms non control 131 ALL DATA FIFO ALL 231 AMPLitude OUTP CURRent AMPLitude 215 OUTPut CURRent AMPLitude 216 An example using the operation group 97 APERture SENSe FREQuency APERture 236 APERture SENSe FREQuency APERture 236 Arithmetic operators 137 Arm and trigger sources 80 ARM subsystem 180 181 ARM SOURCce 181 ARM SOURce 182 ARRay ALGorithm EXPLicit ARRay 164 ARRay ALGorithm EXPlicit EXPLicit ARRay 165 Assigning values 145 Assignment operator 137 Attaching and removing the terminal module 45 Attaching the terminal module 43 Attaching the VT1415A terminal module 45 Autoranging more on 108 Available Power for SCPs 297 B Bitfield access 140 Bit number 142 BLOCK continuously reading the FIFO FIFO mode 87 Byte enabling events to be reported in the status 96 Byte reading the status 98 C CAL CONF RES 184 CAL CONF VOLT 185 CAL SETup 186 CAL SETup 186 CAL STORe 187 CAL TARE 188 CAL TARE and thermocouples 104 CAL TARE resetting 105 CAL TARE RESet 189 CAL TARE 190 CAL VAL RESistance 190 CAL VAL VOLTage 191 CAL ZERO 192 CALibration subsystem 183 184 186 187 188 189 190 191 192 Calibration channel CAL 278 Calibration control of
200. NF VOLT range ZERO FSCale command Full scale values must be within 10 of 0 0625 0 25 1 4 or 10 the voltage reference provides 10 V dc on the 16 V range The ref volts parameter may be specified in millivolts mv A measurement of the source voltage can be made with an external multimeter connected to the H Cal and L Cal terminals on the Terminal Module or the V H and V L terminals on the Cal Bus connector Use the CAL CONF VOLT command to configure the on board voltage source for measurement at the Calibration Bus connector When Accepted Not while INITiated Related Commands CAL CONF VOLT CAL STORE ADC Command Sequence CAL CONF VOLTAGE 4 FSCALE OPC Wait for operation to complete enter statement now measure voltage with external DMM CAL VAL VOLT measured value Send measured value to module Chapter 6 VT1415A Command Reference 191 CALibration CALibration ZERO CALibration ZERO corrects Analog to Digital converter offset for any drift since the last CAL or CAL ZERO command was executed The offset calibration takes about 5 seconds and should be done as often as the control set up allows Comments The CAL ZERO command only corrects for A D offset drift zero Use the CAL common command to perform on line calibration of channels as well as A D offset CAL performs gain and offset correction of the A D and each channel with an analog SCP installed both input and output e Retu
201. NSe FUNCtion TEMPerature lt type gt lt sub_type gt lt range gt lt ch_list gt links channels to an EU conversion for temperature based on the sensor specified in type and sub type Not for sensing thermocouple reference temperature for that use the SENS REF lt type gt lt sub_type gt lt channel gt command Chapter 6 VT1415A Command Reference 243 SENSe Parameters Parameter Parameter Range of Default Name Type Values Units type discrete string RTD THERmistor TCouple none sub type numeric float32 for RTD use 85 92 none numeric float32 for THER use 2250 5000 10000 ohms discrete string for TC use CUSTom E EEXT none J K N R SI T range numeric float32 see comments V dc ch list channel list string 100 163 none Comments Resistance temperature measurements RTDs and THERmistors require the use of Current Source Signal Conditioning Plug Ons The following table shows the Current Source setting that must be used for the following RTDs and Thermistors Required Current Temperature Sensor Types and Amplitude Subtypes MAX 488 uA for RTD and THER 2250 MIN 30 A for THER 5000 and THER 10000 e The range parameter The VT1415A has five ranges 0 0625V dc 0 25V dc 1 V dc 4 V dc and 16 V dc To select a range simply specify the range value for example 4 selects the 4 V dc range Ifa
202. O VEOSTLA E os dd Ul CLIO VEOSLLA Cr LM 440 19184 G1 Mo VIOSTLA 0323 Appendix A 300 Specifications Type E 200 to 800 C filter off E1508 09 3 deg muni ree ET PEER PETS TTR ET TENET TERRE rA YA n AY AAO 29014 81 140 VROSTLA 00 009 00 00r 00 00 00061 00 00 c O1 X 2 q Specifications 301 Appendix A Type E 0 to 800 C filter off 3 3ag 140 1931 F9X 1 140 VEOSILA A E ERMHETEETENTTENAM EAS AIO Puy 1140 VIOSLLA G0 008 00099 00 00y 00 00 0070 x cx wo we wd Ws UA M P RAL EST i i A Aah yt et ELSE ANTE me anal pacem imm onm Lj f p A a nt tt a en EA t A A E E EEIE SETEN EAA OTOT OG OSS 5 01 XD Pq Appendix A 302 Specifications Type E 0 to 800 C filter off VT1508A 09A ee RARE RERTRTRRREMARATATTATEGAREAREZLUULARRERE ER ch ERA Q0 008 00009 00 00b 00 00Z 000 00 002 3 82g 30 3919 61 140 V60S LEA AFO 2914 81 300 V80SLEA Specifications 303 Appendix A Type EEXtended filter off 01 xo Seq 440 19184 PIX T 1dO VEOSTLA ome m AA CAMS on eso Hex Var Ras C o mers AR dmi oun Ge mo om HE Om EA Hr a ddO 1314 Z1 WO VCOSTLA J40 19184 11 1d0 VIOSLLA op 050 popuo3x A 9d T Appen
203. ODE 2222 page 195 DiIAGnostic CHECKSUM ce e o qb voE E A ew d X a Wee Pe ia page 195 DIAGnostic CUStom LINear table range7 table block ch list page 195 DIAGnostic CUStom PIECewise lt table_range gt lt table_block gt lt ch_list gt page 196 DIAGnostic CUSTom REFerence TEMPerature a page 197 DIAGnostic IEEE OIL suspirar aa a a A dog d page 197 DIA Gnostic JEEE s oko a e SEAR Goa Rd ee ee ad page 198 DIAGnostic INTerrupt LINe lt int_line gt 22e page 198 DIAGnostic INTerrupt LINe 2222s page 198 DIAGnostic OTDetect STATe 1 0 ON OFF Q ch list ee page 200 DIAGnostic OTDetect STATe lt channel gt ee page 200 DIAGnostic QUERy SCPREAD reg addr o page 201 DIAGnostic VERSION uos now noces Y a oR De ee we RO o P Rx y OX A page 201 BETCh 23945 Beck ah or ee Ses es ok dabitur At ea dea ev ae ip EE page 202 FORMat DATA lt format gt lt size gt o page 201 EORMAatE DATA soak a Oe eae ORS a S sow ey ee aw SC ic Fox Sos page 203 INITiate IMMedi te uomo RUE shee ee oY ee eee dade ee Oe Re Sew ee ed page 204 INPut FILTer LPASs FREQuency cutoff freq gt lt ch_list gt ooo ooo page 205 INPut FILTer LPASs FREQuency lt channel gt ooo page 206 INPut FILTer LPASs STATe 1 0 ON OFF lt ch_list gt ooo o page 206 INPut FILTer LPASs STATe lt channel gt ooo page 2
204. OPERation NTRansition 0 0 00 c cee eee 264 STATus OPERation NTRansition 0 0 0 0 0c eee 265 STATus OPERation PTRansition 00000 cece eee 265 STATus OPERation PTRansition 0 0 0000 c eee eee 266 STATus PRES t cc cc08 eed heme v ie aa 266 STATus QUEStionable CONDition 0 00000 esses 267 STATus QUEStionable ENABle 00000 cee eee 267 STATus QUEStionable ENABle 00000 cc eee 268 STATus QUEStionable EVENt 2 0 0 0 0000 c eee 268 STATus QUEStionable NTRansition 00000 eee eee 269 STATus QUEStionable NTRansition 000 eee eee 269 STATus QUEStionable PTRansition 0 0000 c eee eee 270 STATus QUEStionable PTRansition 0 000 e eens 270 SYSTEM aora Maes SI a beds dados weed 271 SYS LemCTY Pe errar ERG EU Ses VER UbSE TS E E 271 SXSTem BRRoOI sesion Kee cba bee Rede Y eere 271 SYSTem VBRSIORDT eese xe ENDE Mees 272 TRIG fii uisa cire ean ea tee dod alae des eER ai kee ea 273 TRIG COUN sesiones sr er E REED E 275 TRIG COUNT e add tee bie REI EL DRE RR EE T 275 TRIGger IMMediate cceann a a IRR 215 TRIGser SOURCE ise eee c aaa Peace ds 276 Table of Contents xiii TRiGger SOURCE enim narra da edd ess 277 TRIGger TIMer PERiod 0 0 0 tep eremura 277 TRIGger TIMer PERiod 1 0 2 0 nenni e eee 277 Common Command Reference lees 278 C ATI rad cm aaa anal CIE eie E EE PSI 278 PSUS cS 279 DMC lt nam
205. OURce PULSe POLarity OUTPut TYPE Chapter 6 VT1415A Command Reference 221 e RST Condition OUTP TYPE ACTIVE for TTL compatibility Usage OUTP TYPE PASS 140 143 make channels 40 to 43 passive pull up OUTPut TYPE OUTPut TYPE channel returns the output drive characteristic for a digital channel Parameters Parameter Parameter Range of Default Name Type Values Units channel string 100 163 none Comments channel must specify a single channel e Ifthe channel specified is not on a digital SCP an error will be generated e Returned Value returns PASS or ACT The type is string e RST Condition returns ACT OUTPut VOLTage AMPLitude OUTPut VOLTage AMPLitude lt amplitude gt lt ch_list gt sets the excitation voltage on programmable Strain Bridge Completion SCPs pointed to by ch list the VT1511A for example This command is not used to set output voltage on SCPs like the VT1531A Voltage Output SCP Parameters Parameter Parameter Range of Default Name Type Values Units amplitude numeric float32 MIN 0 1 2 5 10 MAX none ch_list channel list string 100 163 none Comments e To turn off excitation voltage when using external voltage source program lt amplitude gt to 0 e Related Commands OUTP VOLT AMPL e RST Condition MIN 0 Usage OUTP VOLT AMPL 5 116 119 set excitation voltage for channels 16 through 19 2
206. OUTP SHUNt 219 OUTP TTLT lt n gt STATe 220 OUTP TTLT lt n gt STATe 221 Output channels 116 OUTPut subsystem 215 216 217 219 220 221 223 OUTPut CURRent STATe 217 OUTPut CURRent STATe 217 OUTPut POLarity 218 OUTPut POLarity 218 OUTPut TTLTrg SOURce 219 OUTPut TTLTrg SOURce 220 OUTPut TYPE 221 OUTPut TYPE 222 OUTPut VOLTage AMPLitude 222 OUTPut VOLTage AMPLitude 223 Outputs setting up digital 71 Outputting trigger signals 83 OVER reading the latest FIFO values FIFO mode 88 Overall program structure 148 Overloads unexpected channel 106 Overview of the algorithm language 112 Overview of the VT1415A algorithmic loop controller 54 Overview operational 54 P Parameter data and returned value types 160 Parameters configuring programmable analog SCP 60 PART SENS DATA FIFO PART 235 Performing channel calibration Important 74 PERiod SOURce PULSe PERiod 258 PERiod SOURce PULSe PERiod 258 PID algorithm tuning 93 Index 419 PIDA with digital on off control 127 PIDA modifying the standard 128 Planning grouping channels to signal conditioning 31 planning wiring layout 31 sense vs output SCPs 33 thermocouple wiring 34 Points ROUT SEQ POINts 225 POISson SENSe STRain POISson 251 SENSe STRain POISson 251 POLarity INPut POLarity 209 OUTPut POLarity 218 Polarity setting input 70 Polarity setting output 71 POLarity INPut POLarity 210 OUTPut POLarit
207. Output Process control drive value PIDB amp C xx3 Status Bit values indicate Clips Alarms limited PIDB amp C xx4 Setpoint Setpoint value PIDC only xx5 Setpoint D Value of Differential term from setpoint PIDC only xx6 P Value of Proportional term PIDC only xx7 I Value of Integral term PIDC only xx8 D Value of Differential term PIDC only xx9 reserved for future use e Elements 0 through 9 are not accessible e Custom written algorithms can use CVT elements 330 511 The user defines how a custom algorithm will use this area e The format of values returned is set using the FORMat DATA command e Returned Value ASCII values are returned in the form 1 234567E 123 For example 13 325 volts would be 1 3325000E 001 Each value is followed by a comma A line feed LF and End Or Identify EOI follow the last value The C SCPI data type is a string array 230 VT1415A Command Reference Chapter 6 REAL 32 REAL 64 and PACK 64 values are returned in the IEEE 488 2 1987 Definite Length Arbitrary Block Data format This data return format is explained in Arbitrary Block Program Data on page 158 of this chapter For REAL 32 each value is 4 bytes in length the C SCPI data type is a float32 array For REAL 64 and PACK 64 each value is 8 bytes in length the C SCPI data type is a float64 array NOTE After RST Power on each element in the CVT contains the IEEE 754 value Not a number NaN Elements specif
208. P TIMER lt interval gt X chan repeats from SENS CHAN SETT When Accepted Not while INITiated Related Commands SENSE CHAN SETTLING SAMP TIMER RST Condition Sample Timer for all Channel Lists set to 1 0E 5 seconds Usage SAMPLE TIMER 50E 6 Pace measurements at 50 us intervals 226 VT1415A Command Reference Chapter 6 SAMPle SAMPlIe TIMer SAMPIe TIMer returns the sample timer interval Comments Returned Value Numeric The C SCPI type is float32 e Related Commands SAMP TIMER e RST Condition Sample Timer set to 1 0E 5 seconds Usage SAMPLE TIMER Check the interval between channel measurements Chapter 6 VT1415A Command Reference 227 SENSe SENSe Subsystem Syntax SENSe CHANnel SETTling lt settle_time gt lt ch_list gt SETTling lt channel gt A CVTable W lt element_list gt RESet FIFO ALL COUNP HALF HALF MODE BLOCK OVERwrite MODE PART n values RESet FREQuency APERture gate time gt lt ch_list gt FREQuency APERture channel FUNCtion CONDition lt ch_list gt CUSTom lt range gt lt ch_list gt REFerence lt range gt lt ch_list gt TC lt type gt lt range gt lt ch_list gt FREQuency W lt ch_list gt RESistance lt excite_current gt lt range gt lt ch_list gt STRain FBENding lt range gt lt ch_list gt FBPoisson lt range gt lt ch_list gt FPOisson lt range gt
209. P can take on the values 30e 6 or MIN and 488e 6 or MAX Select 488 wA for measuring resistances of less than 8 000 Q Select 30 wA for resistances of 8 000 Q and above e The lt ch_list gt parameter specifies the Current Source SCP channels that will be set To set channels 0 through 9 to output 30 wA and channels 10 through 19 to output 488 LA OUTP CURR 30e 6 100 109 OUTP CURR 488e 6 110 119 separate command per output level or to combine into a single command message OUTP CURR 30e 6 100 109 CURR 488e 6 110 119 Chapter 3 Programming the VT1415A for PID Control 61 NOTE Setting the VT1511A Strain Bridge SCP Excitation Voltage NOTE Linking Channels to EU Conversion NOTE The OUTPut CURRent AMPLitude command is only for programming excitation current used in resistance measurement configurations It 1s does not program output DAC SCPs like the VT1532A The VT1511A Strain Bridge Completion SCP has a programmable bridge excitation voltage source The command to control the excitation supply is OUTPut VOLTage AMPLitude lt amplitude gt lt ch_list gt e The lt amplitude gt parameter can specify 0 1 2 5 or 10 volts for the VT1511A s excitation voltage e The lt ch_list gt parameter specifies the SCP and bridge channel excitation supply that will be programmed There are four excitation supplies in each VT1511A To set the excitation supplies for channels 0 through 3 to output 2 vo
210. P channels as inputs this is the RST condition for all digital I O channels Parameters Parameter Parameter Range of Default Name Type Values Units ch list string 100 163 none Comments e The VT1533A SCP senses 8 digital bits on each channel specified by this command The VT1534A SCP senses 1 digital bit on each channel specified by this command e Ifthe channels specified are not on a digital SCP an error will be generated e Use the INPut POLarity command to set input logical sense e Related Commands INPut POLarity e RST Condition SENS FUNC COND and INP POL NORM for all digital SCP channels Usage To set second 8 bits of VT1533A at SCP position 4 and upper 4 bits of VT1534A at SCP position 5 to digital inputs send SENS FUNC COND 133 144 147 SENSe FUNCtion CUSTom SENSe FUNCtion CUSTom lt range gt lt ch_list gt links channels with the custom Engineering Unit Conversion table loaded with the DIAG CUST LINEAR or DIAG CUST PIECE commands Contact a VXI Technology System Engineer for more information on Custom Engineering Unit Conversion for specific applications Parameters Parameter Parameter Range of Default Name Type Values Units range numeric float32 see first comment V dc ch list channel list string 100 163 none Chapter 6 VT1415A Command Reference 237 SENSe Comments range parameter The VT1415A has five
211. Programming the VT1415A for PID Control 99 VT1415A Background Operation The VT1415A inherently runs its algorithms and calibrations in the background mode with no interaction required from the driver All resources needed to run the measurements are controlled by the on board Control Processor DSP The driver is required to setup the type of measurement to be run modify algorithm variables and to unload data from the card after it appears in the CVT or FIFO Once the INIT IMM command is given the VT1415A is initiated and all functions of the trigger system and algorithm execution are controlled by its on board control processor The driver returns to waiting for user commands No interrupts are required for the VT1415A to complete its measurement While the module is running algorithms the driver can be queried for its status and data can be read from the FIFO and CVT The ABORT command may be given to force continuous execution to complete Any changes to the measurement setup will not be allowed until the TRIG COUNT is reached or an ABORT command is given Of course any commands or queries can be given to other instruments while the VT1415A is running algorithms Updating the Status System and VXIbus Interrupts The driver needs to update the status system s information whenever the status of the VT1415A changes This update is always done when the status system is accessed or when CALibrate INITiate or ABORt commands are execu
212. Put POLarity OUTPut POLarity e RST Condition OUTP POL NORM for all digital channels Usage OUTP POL INV 144 OUTPut POLarity OUTPut POLarity lt channel gt returns the polarity on the digital output channel in lt channel gt invert output logic sense on channel 44 Parameters Parameter Parameter Range of Default Name Type Values Units channel string 100 163 none Comments e channel must specify a single channel e Returned Value returns one of NORM or INV The type is string OUTPut SHUNt OUTPut SHUNt lt enable gt lt ch_list gt adds shunt resistance to one leg of bridge on Strain Bridge Completion SCPs This can be used for diagnostic purposes and characterization of bridge response Parameters Parameter Parameter Range of Default Name Type Values Units enable boolean uint16 0 1 ON OFF none ch list channel list string 100 163 none Chapter 6 218 VT1415A Command Reference OUTPut Comments e If cA list specifies a non strain SCP a 3007 Invalid signal conditioning plug on error is generated e When Accepted Not while INITiated e Related Commands SENSe FUNCtion STRain SENSe STRain e RST Condition OUTP SHUNT 0 on all Strain SCP channels Usage OUTP SHUNT 1 116 119 add shunt resistance at channels 16 through 19 OUTPut SHUNt OUTPut SHUNt lt channel gt returns the status of the shunt re
213. Ransition returns the value of bits set in the Negative Transition Filter NTF register Comments Returned Value Decimal weighted sum of all set bits The C SCPI type is uint16 e Related Commands STAT OPER NTR e RST Condition No change Usage STAT OPER NTR Enter statement returns current value of bits set in the NTF register STATus OPERation PTRansition STATus OPERation PTRansition lt transition_mask gt sets bits in the Positive Transition Filter PTF register When a bit in the PTF register is set to one the corresponding bit in the Condition register must change from a zero to a one in order to set the corresponding bit in the Event register When a bit in the PTF register is zero a positive transition of the Condition register bit will not change the Event register bit Parameters Parameter Parameter Range of Default Name Type Values Units transition mask numeric uint16 0 32767 none Comments rransition mask may be sent as decimal hex H octal HQ or binary 8B e f both the STAT OPER PTR and STAT OPER NTR registers have a corresponding bit set to one any transition positive or negative will set the corresponding bit in the Event register e f neither the STAT OPER PTR or STAT OPER NTR registers have a corresponding bit set to one transitions from the Condition register will have no effect on the Event register Chapter 6 VT1415A Command Reference 265
214. Result of E1415 self test test result 1 Make sure it gets assigned INST QUERY e1415 TST n Sd amp test result if test_result void fprintf stderr E1415A failed self test n exit 1 Hendif Setup SCP functions INST SEND e1415 sens func volt 116 n Analog in volts INST SEND e1415 sour func cond 141 n Digital output dif 0 Set to 1 to do calibration Perform Calibrate if necessary int cal result Result of E1415 self test cal result 1 Make sure it gets assigned INST QUERY e1415 CAL n Sd amp cal result if cal_result void fprintf stderr E1415A failed calibrationin void fprintf stderr Check FIFO for channel errors n exit 1 Hendif Configure Trigger Subsystem and Data Format INST SEND e1415 trig sour timer trig timer 001 n INST SEND e1415 samp timer 10e 6 n default S INST SEND e1415 form real 32 n Download Globals INST SEND e1415 alg def globals static float x Nn Download Custom Function The 7 Ed Appendix F Generating User Defined Functions 371 float64 maxInput set to maximum expected input float64 minInput set to minimum expected input float64 tableOffset offset used in building table uintl6 coef array 512 512 elements flo
215. SCAN RATIO will return the current ratio setting for alg name even if it is not currently defined e Returned Value numeric to 32 768 The type is int16 ALGorithm EXPLicit SlZe ALGorithm EXPLicit SIZe lt alg_name gt returns the number of words of memory allocated for algorithm lt alg name gt Parameters Parameter Parameter Range of Default Name Type Values Units alg name string ALGI ALG32 none Comments e Since the returned value is the memory allocated to the algorithm it will only equal the actual size of the algorithm if it was defined by ALG DEF without its lt swap_size gt parameter If enabled for swapping if swap size included at original definition the returned value will be equal to swap size7 2 NOTE If alg name gt specifies an undefined algorithm ALG SIZ returns 0 This can be used to determine whether algorithm a g name gt is defined Chapter 6 VT1415A Command Reference 171 ALGorithm e Returned Value numeric value up to the maximum available algorithm memory this approximately 46k words The type is int32 e RST Condition returned value is 0 ALGorithm EXPLicit STATe ALGorithm EXPLicit STATe lt alg_name gt lt enable gt specifies that algorithm alg name gt when defined should be executed ON or not executed OFF during run time NOTES 1 The command ALG STATE alg name gt ON OFF does not take effect until an A
216. SCPI register based feature not a general programming improvement If you re using MESSAGE instruments you ll still have to do SYST ERR If your test program generates errors on purpose you probably don t want this error function If so set the following if 1 to fif 0 This function is most useful when you re trying to get your program running dif 1 Set to 0 to skip trapping errors ARGSUSED Keeps lint happy void cscpi error INST id int err AC CA A Xo F Xo Xo F char errorbuf 255 Holds instrument error message char idbuf 255 Holds instrument response to IDN cscpi exe id IDN n 6 idbuf 255 cscpi exe id SYST ERR n 10 errorbuf 255 void fprintf stderr Instrument error s from s n errorbuf idbuf Hendif The following routine allows you to type SCPI commands and see the results If you don t call this from your program set the following if 1 to aif Qt Hif 1 Set to 0 to skip this routine void do interactive void char command 5000 char result 5000 int32 error char string 256 for void printf SCPI command void fflush stdout repeat until it actually gets something while gets command if command break result 0 0 cscpi exe el415 command strlen command result sizeof result INST QUERY e1415 syst err d s error stri
217. SSNSN fe N Extraction Levers VT1415A Module Figure 2 11 Wiring and Connecting the VT1415A Terminal Module Cont 44 Field Wiring Chapter 2 Attaching Removing the VT1415A Terminal Module Figure 2 12 shows how to attach the terminal module to the VT1415A and Figure 2 13 shows how to remove it Extend the extraction levers on the Terminal Module Install Mylar Thermal Barrier on Terminal Module connectors Extraction Lever w NN OOOO 4 Y o CH o REIA ES Cw ANY RR NN Use a small screwdriver to pry and release the two extraction levers Align the Terminal Module connectors to the VT1415A A module connectors Apply gentle pressure to attach the Terminal Module to the VT1415A Module al Extraction Levers N q t ARAS E 4 Push in the extraction levers to lock the Terminal Module onto the VT1415A Module Figure 2 12 Attaching the VT1415A Terminal Module Chapter 2 Field Wiring 45 Release the two extraction levers and push both levers out simultaneously Extraction Lever PS Use a small screwdriver to pry and release the NO A two extraction levers S 2 Free and remove the Terminal Module from the A D Module Extraction Le
218. STATe 221 OUTP TTLTrg lt n gt STATe 220 Tuning PID algorithm 93 TYPe OUTPut TYPE 221 Type setting output drive 71 TYPe OUTPut TYPE 222 Types data 138 U nary arithmetic operator 146 nary logical operator 137 nary operators 137 nary expression 142 nary operator 142 nexpected channel offsets or overloads 106 JNSTrained SENSe STRain UNSTrained 251 SENSe STRain UNSTrained 252 pdate rate maximum 297 pdating the algorithm variables 89 pdating the algorithm variables and coefficients 89 pdating the status system and VXI interrupts 100 sage example language 113 sing the status system 93 Ciel Cnc eni em em Cae UG OG GG V Value types parameter data 160 returned 160 Values assigning 145 Values reading running algorithm 85 Variable Command Syntax 157 Variable frequency square wave output FM 73 Variable width pulse per trigger 72 Variable width pulses at fixed frequency PWM 72 Variable status 77 Variables communication using global 129 Variables declaring 145 Variables global 141 Variables initializing 118 Variables modifying running algorithm 89 Variables reading algorithm 85 Verifying a successful configuration 27 VERsion SYST VERSion 272 Voids Warranty Cutting Input Protect Jumper 25 Voltage CAL VALue VOLTage 191 VOLTage CAL CONF VOLT 185 SENS FUNC VOL Tage 245 Voltage setting the VT1511A strain bridge SCP excitation 62 VOLTage AMPLitude
219. Se PERiod lt period gt lt ch_list gt ooo page 258 SOURce PULSe PERiod lt channel gt sosca 22s page 258 SOURce PULSe WIDth lt width gt lt ch_list gt 22s page 259 SOURce PULSe WIDth lt channel gt 22s page 259 STATus OPERation CONDition lt o ee occ llle rs page 262 STATus OPERation ENABle enable mask 22s page 263 STATus OPERation ENABle scos o ee 5245s oso REVISE ee page 263 STATus OPERation BEVENt e e us yo Roy REE EO X V Ree ae de Bos s page 264 STATus OPERation NTRansition transition mask ee page 264 STATus OPERation NTRansition gt lt e es ee page 265 STATus OPERation PTRansition transition mask gt oo page 265 STATus OPERation PTRansition e e a E a e O rs page 266 SLATus PRESet 23 3o oko e Gee ROS belo GS FCRC GE A e a E dise d p page 266 STATus QUEStionable CONDition 2 lll rs page 267 STATus QUEStionable ENABle enable mask o page 267 STATus QUEStionable ENABle ee page 268 STATus QUEStionable EVENt 2 0 0 ee page 268 STATus QUEStionable NTRansition transition mask oonan eA page 269 STATus QUEStionable NTRansition 2 222 lll ee page 269 STATus QUEStionable PTRansition transition mask oo page 270 STATus QUEStionable PTRansition lll ee page 270 SYSTem CTYPe lt channel gt s e a aoaea a e a e e rs page 271 SYSLEM ERROL 4 4 4 je ae Sa ee Pe e E GR RON ae EUR a LS Pe ae ee ye page
220. T T LGT 2 0 take log base 2 ELSE Exponent 100 0 END IF compute slope in bits each tabl ntry represents 512 bits Slope Result Ii Result Ii 1 512 0 don t take the log of a negative slope Absslope ABS Slope compute the exponent of the slope M is 16 bits IF Absslope lt gt 0 THEN Exponent2 15 0 LGT Absslope LGT 2 0 ELSE Exponent2 100 0 END IF Choose the smallest exponent maximize resolution IF Exponent2 Exponent THEN Exponent Exponent2 Xfactor INT Exponent convert to integer IF T lt gt 0 THEN Ltemp PROUND LGT T LGT 2 0 0 IF Xfactor Ltemp gt 30 THEN Xfactor 30 Ltemp END IF Mfactor PROUND 2 Xfactor Slope 0 IF Mfactor 32768 0 THEN There is an endpoint problem Re compute if on endpoint Xfactor Xfactor 1 Mfactor PROUND 2 Xfactor Slope 0 END IF IF Mfactor lt 32767 0 AND Mfactor gt 32768 0 THEN only save if M is in limits Ex Jj Xofst Xfactor 376 Generating User Defined Functions Appendix F 1760 M Jj Mfactor remove leading 1 s 1770 B PROUND 2 Xfactor Result Ii 1 0 1780 Bhigh Jj INT B 65536 0 truncates 1790 B1 B Bhigh Jj 65536 0 1800 IF B1 gt 32767 THEN B1 B1 65536 1810 Blow Jj Bl 1820 END IF 1830 Loopendl NEXT Ii 1840 FOR Ii 0 TO 64 STEP 1 1850 Input Ii Center Tbl range 64 0 Ii 1860 Result Ii FNMy function Input Ii 1870 IF Ii 0 THEN GOTO Loo
221. T PRESet 266 STAT QUES CONDition 267 STAT QUES ENABle 267 STAT QUES ENABle 268 STAT QUES EVEMNt 268 STAT QUES NTRansition 269 STAT QUES NTRansition 269 STAT QUES PTRansition 270 STAT QUES PTRansition 270 STATe ALGorithm EXPLicit 172 INP FILT LPAS STATe 206 INP FILT LPAS STATe 207 MEM VME STATe 213 MEM VME STATe 214 OUTPut CURRent STATe 217 OUTPut CURRent STATe 217 SOURce PULM STATe 257 STATe ALGorithm EXPlicit 173 SOURce PULM STATe 257 Statement algorithm language writecvt 118 writefifo 119 Statement 144 Statement list 144 Statements and functions intrinsic abs expression 137 interrupt 119 137 max expressionl expression2 137 min expressionl expression2 137 writeboth expression cvt element 137 writecvt expression cvt element 118 137 writefifo expression 119 137 Statements 138 Static discharge safe handling CAUTION 21 Static state CONDition function 70 72 STATus subsystem 260 261 262 264 265 266 267 268 270 Status variable 77 422 Index Storage defining data 79 STORe CAL STORe 187 STRain SENS FUNC STRain 242 Structure overall program 148 Structures data 139 Sub subsystem 193 194 195 197 198 199 200 201 202 203 211 213 214 Subsystem ABORT 162 ARM 180 181 CALibration 183 184 186 187 188 189 190 191 DIAGnostic 193 194 195 197 198 199 200 FORMat 201 202 203 INITiate 204 INPu
222. T1415A for each channel specified e The table block parameter is a block of 1 024 bytes that define 512 16 bit values SCPI requires that table block include the definite length block data header C SCPI adds the header automatically e The table range parameter specifies the range of input voltage that the table covers from table range to table range The value specified must be within 5 of 0 015625 0 03125 0 0625 0 125 0 25 0 5 1 2 4 8 16 32 64 e The cA list parameter specifies which channels will have this custom EU table loaded Chapter 3 Programming the VT1415A for PID Control 103 Usage Example The program puts table constants into array table block DIAG CUST PIEC table_block 1 124 131 send table for chs 24 31 to VTI415A SENS FUNC CUST PIEC 1 1 124 131 link custom EU with chs 24 31 and set the 1 V A D range INITiate then TRIGger module Summary The following points describe the capabilities of custom EU conversion e A given channel has only one active EU conversion table assigned to it Changing tables requires loading it with a DIAG CUST command e The limit on the number of different custom EU tables that can be loaded in a VT1415A is the same as the number of channels e Custom tables can provide the same level of accuracy as the built in tables In fact the built in resistance function uses a linear conversion table and the built in temperature functions
223. T1533A Digital I O SCP and VT1534A Frequency Totalizer SCP can output static digital states The VT1534A Frequency Totalizer SCP can also output single pulses per trigger continuous pluses that are width modulated PWM and continuous pulses that are frequency modulated FM Static State CONDition Function To configure digital channels to output static states use the SOURce FUNCtion CONDition lt ch_list gt command Examples To set the upper 8 bit channel of a VT1533A in SCP position 4 to output SOUR FUNC COND 133 To set the lower 4 channels bits of a VT1534A in SCP pos 2 to output states SOUR FUNC COND 116 119 To configure digital channels to output static states Variable Width Pulse Per Trigger This function sets up one or more VT1534A channels to output a single pulse per trigger per algorithm execution The width of the pulse from these channels is controlled by Algorithm Language statements Use the command SOURce FUNCtion SHAPe PULSe lt ch_list gt Example command sequence To set VT1534A channel 2 at SCP position 4 to output a pulse per trigger SOUR FUNC PULSE 134 Example algorithm statement to control pulse width to 1 ms 0134 0 001 Variable Width Pulses at Fixed Frequency PWM This function sets up one or more VT1534A channels to output a train of pulses A companion command sets the period for the complete pulse T edge to T edge This of course fixes the frequency of the pulse train
224. TARE can compensate for is dependent on the range chosen and SCP gain setting The following table lists these values Maximum CAL TARE Offsets A D range Offset V Offset V Offset V Offset V V F Scale Gain x1 Gain x8 Gain x16 Gain x64 16 3 2213 0 40104 0 20009 0 04970 4 0 82101 0 10101 0 05007 0 01220 1 0 23061 0 02721 0 01317 0 00297 0 25 0 07581 0 00786 0 00349 0 00055 0 0625 0 03792 0 00312 0 00112 n a Channel offsets are compensated by the CAL TARE command even when not stored in the Flash Memory There is no need to use the CAL STORE TARE command for channels which are re calibrated frequently The VT1415A s Flash Memory has a finite lifetime of approximately ten thousand write cycles unlimited read cycles While executing CAL STOR once every day would not exceed the lifetime of the Flash Memory for approximately 27 years an application that stored constants many times each day would unnecessarily shorten the Flash Memory s lifetime See Comments below Executing CAL TARE sets the Calibrating bit bit 0 in Operation Status Group Executing CAL TARE resets the bit When Accepted Not while INITiated Related Commands CAL TARE CAL STOR TARE RST Condition Channel offsets are not affected by RST Command Sequence CALTARE c list To correct channel offsets CAL TARE To return the success flag from the CAL TARE operation CAL STORE TARE Optional depending on necessity of long term storage CA
225. TS ON ON Ja BOARD 8 LI BOARD B o REM n REM REMote Place both J1 jumpers here to route current source to terminals HTI and LTI Connect these terminals to remote thermistor or RTD Sense with any sense channel M ON o BOARI O a E a dH 004 014 024 035 r044 r054 r064 072 567 r574 584 594 0604 r614 0624 7634 O J MN HLGHLGHLGHLGHLGHLGHLGHLG IG LHGLHGLHGLHGLHGLHGLHGLH D ji vt HLGHLGHLGHLGHLGHLGHLGHLG ls LHGLHGLHGLHGLHGLHGLHGLH a Los Cos Caod C113 C126 134 Cad C184 bags L49 0592 512 L52 537 542055 q 5 e o or ER o o EY I II N D p A a O 164 1174 183 1194 r20 3 1214 229 23 407 r413 4270437 044714571467 p474 O ON HLGHLGHLGHLGHLGHLGHLGHLG IG LHGLHGLHGLHGLHGLHGLHGLH V HLGHLGHLGHLGHLGHLGHLGHLG Ib LHGLHGLHGLHGLHGLHGLHGLH Y a faatasi 26 Jlar 2841291307 Lar E32 Laa Esa Las Laos sr tae tae 0 2 a Im
226. TTLTrg lt n gt The VXIbus TTLTRG lines n 0 through 7 e See note about ARM subsystem on page 180 e When TRIG SOURCE is TIMER an ARM event is required only to trigger the first scan After that the timer continues to run and the module goes to the Waiting For Trigger state ready for the next Timer trigger An ABORT command will return the module to the Trigger Idle state after the current scan is completed See TRIG SOURce for more detail While ARM SOUR is IMM simply INITiate the trigger system to start a measurement scan Chapter 6 VT1415A Command Reference 181 e When Accepted Before INIT only e Related Commands ARM IMM ARM SOURCE INIT IMM TRIG SOUR e RST Condition ARM SOUR IMM Usage ARM SOUR BUS Arm with ARM command ARM SOUR TTLTRG3 Arm with VXIbus TTLTRG3 line ARM SOURce ARM SOURce returns the current arm source configuration See the ARM SOUR command for more response data information e Returned Value Discrete one of BUS HOLD IMM SCP or TTLTO through TTLT7 The C SCPI type is string Usage ARM SOUR An enter statement return arm source configuration 182 VT1415A Command Reference Chapter 6 CALibration CALibration The Calibration subsystem provides for two major categories of calibration 1 A D Calibration In these procedures an external multimeter is used to calibrate the A D gain on all 5 of its ranges The multimeter also determines the value of the
227. The width of the pulses from these channels is controlled by Algorithm Language statements 72 Programming the VT1415A for PID Control Chapter 3 Use the command SOURce FUNCtion SHAPe PULSe lt ch_list gt Example command sequence To enable pulse width modulation for VT 1534 s first channel at SCP position 4 SOUR PULM STATE ON 132 To set pulse period to 0 5 ms which sets the signal frequency 2 kHz SOUR PULSE PERIOD 0 5e 3 132 To set function of VT1534A s first channel in SCP position 4 to PULSE SOUR FUNCTION PULSE 132 Example algorithm statement to control pulse width to 0 1 ms 20 duty cycle 0132 0 1e 3 Fixed Width Pulses at Variable Frequency FM This function sets up one or more VT1534A channels to output a train of pulses A companion command sets the width T edge to Y edge of the pulses The frequency of the pulse train from these channels is controlled by Algorithm Language statements Use the command SOURce FUNCtion SHAPe PULSe lt ch_list gt Example command sequence To enable FM for VT1534A s second channel at SCP position 4 SOUR FM STATE ON 133 To set pulse width to 0 3333 ms SOUR PULSE WIDTH 0 3333e 3 133 To set function of VT1534A s second channel in SCP position 4 to PULSE SOUR FUNCTION PULSE 133 Example algorithm statement to control frequency to 1000 Hz 0133 1000 Variable Frequency Square Wave Output FM To set function of VT1534A s third channel in SCP
228. Trigger 2 a a 3 Timer hi m T o En se TRIGger SOURce CAL PI FTR TiMer SCPlugon Sger CALibration SETup BUS SETup e TRIGger LIMit EXTernal Soa e Oo o HOLD PL Trigger IPSE Cal EU Enable rg Source IMMediate 33 Selector OUTPut TRIGger SOURce as Fa Titirg lt n gt 8 lines E CALibration CONFiguration RESistance SCP Trigger Y VOLTage TILTrg Output VALue RESistance y Trigger Counter Selector OUTPut TTLTrg lt n gt VOLTage Cal Resistor STORe TRIGger COUNt TILTRG7 TILTRGO ZERO Cal Zero VXlbus TTLTRGn 8 lines l TRG OUT on HP E1313 Term Module 59 Programming the VT1415A for PID Control Chapter 3 Setting Up Analog Input and Output Channels This section covers configuring input and output channels to provide the measurement values and output characteristics that algorithms need to operate Configuring This step applies only to programmable Signal Conditioning Plug Ons such Prog rammable asthe VT1503A Programmable Amplifier Filter SCP the VT1505A Current Source SCP the VT1510A Sample and Hold SCP and the Analog SCP VTI511A Transient Strain SCP Refer to the individual SCP s user s Parameters manual to determine the gain filter cutoff frequency or excitation amplitude selections that it may provide Setting SCP Gains An important concept to understand about input amplifier SCPs is that given a fixed input value at a channel changes in channel gain do not change the value an algor
229. VT1415A Algorithmic Closed Loop Controller AAA User s Manual APPLICABILITY This manual edition is intended for use with the following instrument drivers e Downloaded driver revision A 01 02 or later for Agilent HP Command Modules e C SCPI driver revision D 01 02 or later Call your local VXI Technology Sales Office for information on other drivers E AA G Technology Copyright VXI Technology Inc 2005 P N 82 0074 000 Rev February 23 2011 Printed in U S A Certification VXI Technology Inc certifies that this product met its published specifications at the time of shipment from the factory VXI Technology further certifies that its calibration measurements are traceable to the United States National Institute of Standards and Technology formerly National Bureau of Standards to the extent allowed by that organization s calibration facility and to the calibration facilities of other International Standards Organization members Warranty This VXI Technology product is warranted against defects in materials and workmanship for a period of three years from date of shipment Duration and conditions of warranty for this product may be superseded when the product is integrated into becomes a part of other VXI Technology products During the warranty period VXI Technology will at its option either repair or replace products which prove to be defective For warranty service or repair this product must
230. VT1415A begins to closely monitor the state of the update channel and can not execute other commands until the update channel changes state to complete the update Chapter 6 VT1415A Command Reference 177 ALGorithm Note that an update command issued after the start of the UPDATE phase will be buffered but not executed until the beginning of the next INPUT phase At that time the current stored state of the specified digital channel is saved and used as the basis for comparison for state change If at the beginning of the scan trigger the digital input state had changed then at the beginning of the UPDATE phase the update command would detect a change from the previous scan trigger and the update process would begin When Accepted Before and After INIT Command Sequence The following example shows three scalars being written with the associated update command following When the ALG UPD CHAN command is received it will read the current state of channel 108 bit 0 At the beginning of the UPDATE phase a check will be made to determine if the stored state of channel 108 bit 0 is different from the current state If so the update of all three scalars take effect next Phase 2 INIT ALG SCAL ALG1 Setpoint 25 ALG SCAL ALG1 P_factor 1 3 ALG SCAL ALG2 P_factor 1 7 ALG UPD CHAN 1108 B0 update on state change at bit zero of 8 bit channel 8 ALGorithm UPDate WINDow ALGorithm UPDate WINDow num upda
231. Value Numeric value either 0 off or pass through or 1 on The C SCPI type is int16 e channel must specify a single channel only Usage INPUT FILTER LPASS STATE 115 Enter statement returns either 0 or 1 INP FILT 0115 Same as above INPut GAIN INPut GAIN lt gain gt lt ch_list gt sets the channel gain on programmable amplifier Signal Conditioning Plug Ons Parameters Parameter Parameter Range of Default Name Type Values Units gain numeric float32 see comment none discrete string MIN MAX ch_list channel list string 100 163 none Comments A programmable amplifier SCP has a choice of several discrete gain settings The gain set will be the one closest to the value specified by gain Refer to the SCP manual for specific information on the SCP being programmed Sending MAX will program the highest gain available with the SCP installed Sending MIN will program the lowest gain e Sending a value for lt gain gt that is greater than the highest or less than the lowest setting allowable for the SCP will generate a 222 Data out of range error Chapter 6 VT1415A Command Reference 207 e When Accepted Not while INITiated e Related Commands INP GAIN e RST Condition gain set to MIN Usage INP GAIN 8 100 119 Set gain of 8 for first 20 channels INPUT GAIN 64 155 Set gain of 64 for channel 55 INPut GAIN INPut GAIN lt channel gt r
232. WIDTh SOURce PULSe WIDTh lt pulse_width gt lt ch_list gt sets the fixed pulse width value on the frequency modulated pulse channels in lt ch_list gt Parameters Parameter Parameter Range of Default Name Type Values Units pulse width numeric float32 7 87E 6 to 7 8125E 3 seconds 238 4E 9 resolution ch list string 100 163 none Comments e If the channels specified are not on a Frequency Totalize SCP an error will be generated e RST Condition SOUR FM STATE OFF and SOUR PULM STATE OFF e Related Commands SOUR PULM STATE SOUR PULS POLarity e The variable frequency control for this channel is provided by the algorithm language When the algorithm executes an assignment statement to this channel the value assigned will be the frequency setting For example 0143 2000 set channel 43 to 2 kHz Usage SOUR PULS WIDTH 2 50E 3 143 set fixed pulse width of 2 5 ms on channel 43 SOURce PULSe WIDTh SOURce PULSe WIDTh lt ch_list gt returns the fixed pulse width value on a frequency modulated pulse channel Parameters Parameter Parameter Range of Default Name Type Values Units channel string 100 163 none Comments e channel must specify a single channel e f the channels specified are not on a Frequency Totalize SCP an error will be generated e Returned Value returns the numeric pulse width The type is float32 Chapt
233. When using the VT1586A Rack Mount Terminal Panel as the isothermal reference add 0 2 C to the thermocouple accuracy specs to account for temperature gradients across the VT1586A The VT1586A should be mounted in the bottom part of the rack below and away from other heat sources for best performance The temperature graphs are found on the following pages e Thermocouple Type E 200 to 800 C 2 00 300 301 e Thermocouple Type E 0 to 800 C 0 ee eee esses 302 303 e Thermocouple Type EEXtended 0 00 e eee eee 304 305 e Thermocouple TypeJ 1 0 0 0 0 eee eee eee 306 307 e Thermocouple Type K 0 0 0 ce eens 308 e Thermocouple Type R 20 ccc eee eee 309 310 e Thermocouple Type S 0 0 cece EA 311 264 e Thermocouple Type T 2 0 00 eects 313 314 e Reference Thermistor 5k o o oooooooooooo 315 316 Reference RTD T00 O uan es para ida 317 RTD 100 iiie RR dido MER E ER 318 319 e Thermistor 2250 0 coo ves mente eive atre em Eden 320 321 D hermistot 3 kOe eos prices 322 323 e Thermistor 10 kOe eee eee 324 325 Appendix A Specifications 299 Type E 200 to 800 C filter off 00008 Q0 009 00 00P 00 007 000 00 007 9 Seq 000 O T E DOT mi a 00 on E ft o0 i4 00 S m 009 comu buses A ae eo ias oye dove ZEEN E eee AO PW POX E LIDO VEOSTLA T LLL dd PU 8X ELI
234. a VXI interrupt NOTE In C SCPI the C SCPI overlap mode must be on for VXIbus interrupts to occur e Related Commands STB SPOLL STAT OPER COND STAT OPER EVENT STAT OPER ENABLE e Cleared By STAT PRESet and power on e RST Condition No change Usage STAT OPER ENABLE 1 Set bit 0 in the Operation Enable register STATus OPERation ENABle STATus OPERation ENABle returns the value of bits set in the Operation Enable register Comments Returned Value Decimal weighted sum of all set bits The C SCPI type is uint16 Chapter 6 VT1415A Command Reference 263 STATus e Related Commands STB SPOLL STAT OPER COND STAT OPER EVENT STAT OPER ENABLE e RST Condition No change Usage STAT OPER ENABLE Enter statement returns current value of bits set in the Operation Enable register STATus OPERation EVENt STATus OPERation EVENt returns the decimal weighted value of the bits set in the Event register Comments e When using the Operation Event register to cause SRQ interrupts STAT OPER EVENT must be executed after an SRQ to re enable future interrupts e Returned Value Decimal weighted sum of all set bits The C SCPI type is uint16 e Related Commands STB SPOLL STAT OPER COND STAT OPER ENABLE STAT OPER ENABLE e Cleared By CLS power on and by reading the register e RST Condition No change Usage STAT OPER EVENT Enter statement will return the value of bits set in the Operation
235. a ee alta Orr te er eer E rt eA da AJO 491114 81 140 WROSTLA E aL 0L xo 89q Specifications 319 Appendix A Thermistor 2250 Q filter off Q0 0DI 00 08 00 09 oror 000 000 2 89q QT OCT as orc FE A TS Ama TA HA AAO AA G1 AGO VIOSLEA WUL cscc Appendix A 320 Specifications Thermistor 2250 Q filter off VT1508A 09A 2 ded wen MIU tee eee oat eee ee ee ee ee AAO 2914 81 140 VROSLLA 00 001 00 08 00 09 00 0p E A AN AOS A Ort A NX NUN A A og i M oet ov T WE A Las OT LL 080 0970 7 O A OT 0 N ENS ps 000 UrDU L cscc 9321 Specifications 321 Appendix A Thermistor 5 KQ filter off 9323 AJO ASMA 21 140 VZOSLIA 440 IMA TADO VIOSTLA 00 08 00 09 d opor 00 07 000 pentane ie pe OF T Oe I WUL MS Appendix A 322 Specifications Thermistor 5 kQ filter off VT1508A 09A 031 rr A 410 33114 81 140 V8OSTLA 00 08 0009 00 0r 00 0Z 0000 Sat ort 08 TF GLUE MS OY ae DPT e PIES o Ry TS 08 Qr 090 cesses QUA CO 000 9 Seq Specifications 323 Appendix A Thermistor 10 kQ filter off opogi 00 001 00 08 0009 00 0 00 OZ 000 3 Seq uU CAE
236. a totalizer SENSe FUNCtion VOLTage DC SENSe FUNCtion VOLTage DC lt range gt lt ch_list gt links the specified channels to return dc voltage Chapter 6 VT1415A Command Reference 245 SENSe Parameters Comments Parameter Parameter Range of Default Name Type Values Units range numeric float32 see comments V dc ch list channel list string 100 163 none The lt range gt parameter The VT1415A has five ranges 0 0625 V dc 0 25 V de 1 V dc 4 V dc and 16 V dc To select a range simply specify the range value for example 4 selects the 4 V dc range Ifa value larger than one of the first four ranges is specified the VT1415A selects the next higher range for example 4 1 selects the 16 V dc range Specifying a value larger than 16 causes an error Specifying 0 selects the lowest range 0 0625 V dc Specifying AUTO selects auto range The default range no range parameter specified is auto range If using amplifier SCPs set them first and keep their settings in mind when specifying a range setting For instance if the expected signal voltage is to be approximately 0 1 V dc and the amplifier SCP for that channel has a gain of 8 range must be set no lower than 1 V dc or an input out of range condition will exist The CAL command calibrates channels based on Sense Amplifier SCP setup at the time of execution If SCP settings are changed those channels a
237. ach command in this chapter Data Types Description int16 Signed 16 bit integer number int32 Signed 32 bit integer number uint16 Unsigned 16 bit integer number uint32 Unsigned 32 bit integer number float32 32 bit floating point number float64 64 bit floating point number string String of characters null terminated 160 VT1415A Command Reference Chapter 6 SCPI Command Reference The following section describes the SCPI commands for the VT1415A Commands are listed alphabetically by subsystem and also within each subsystem A command guide is printed in the top margin of each page The guide indicates the current subsystem on that page Chapter 6 VT1415A Command Reference 161 ABORt The ABORt subsystem is a part of the VT1415A s trigger system ABORt resets the trigger system from its Wait For Trigger state to its Trigger Idle state Subsystem Syntax ABORt CAUTION ABORt stops execution of a running algorithm The control output is left at the last value set by the algorithm Depending on the process this uncontrolled situation can be dangerous Make certain that the process is in a safe state before halting the execution of a controlling algorithm Comments ABORt does not affect any other settings of the trigger system When the INITiate command is sent the trigger system will respond just as it did before the ABORt c
238. ach n trigger events can simply access the next element in the array e Real time calculations of setpoint profiles by the algorithm itself complicates the algorithm e The application program has better control over time spacing and the complexity and range of the data For example successive points in the array could be the same value just to keep the setpoint at that position for extra time periods The following is an example program that sequences data from an array to an Analog Output There are some unique features illustrated here that can be used e The application program can download new profiles while the application program is running The algorithm will continue to sequence through the array until it reaches the end of the array At this time it will set its index back to 0 and toggle a Digital Output bit to create an update channel condition on a Digital Input Then at the next trigger event the new array values will take effect before the algorithm executes As long as the new array is download into memory before the index reaches 1 023 the switch to the new array elements will take place If the array is downloaded AFTER the index reaches 1 023 the same setpoint profile will be executed until index reaches 1 023 again e The application program can monitor the index value with ALG SCAL alg1 index so it can keep track of where the profile sequence is currently running The interval can also be made shorter or longer b
239. ad algorithm with in line code algorithm An Example algorithm uses Custom Function n This algorithms builds a haversine Wn Nn An 372 Generating User Defined Functions Appendix F v static float radians 0 y n y sin radians n Y HUS INST SEND e1415 alg def ALG1 B n strlen algorithm 1 algorithm endif v Preset Algorithm variables Initiate Trigger System start scanning and running algorithms INST SEND e1415 init n Print out results float32 pi 3 14159654 float32 radians float32 y Note that alg scal won t execute until alg upd is done for radians pi 2 0 radians lt pi 2 0 radians pi 10 0 INST SEND e1415 alg scal algl radians f Nn radians INST SEND e1415 alg updin INST QUERY e1415 alg scal algl y n SE amp y printf C sin f Sf E1415A sin f f n radians float32 sin float64 radians radians y if 1 Set to 1 if using User interactive commands to E1415 Call this function if you want to be able to type SCPI commands and xs their responses NOTE switch to FORM ASC to retrieve ASCIT numbers during interactive mode E INST SEND e1415 form asc n do interactive Calls cscpi exe in a loop endif dif 0 C CSPI way to check for errors INST QUERY
240. ailable VME memory none Comments This command is only available in systems using an Agilent HP E1405B 06A command module e mem size may be specified in decimal hex H octal Q or binary B e mem size should be a multiple of four 4 to accommodate 32 bit readings e Related Commands MEMory subsystem FORMAT and FETCH e RST Condition MEM VME SIZE 0 Usage MEM VME SIZE 32768 Allocate 32 kilobytes kB of VME memory to reading storage 8 192 readings MEMory VME SIZE MEMory VME SIZE returns the amount in bytes of VME memory allocated to reading storage Comments This command is only available in systems using an Agilent HP E1405B or E1406A command module e Returned Value Numeric e Related Commands MEMory subsystem and FETCH Usage MEM VME SIZE Returns the number of bytes allocated to reading storage MEMory VME STATe MEMory VME STATe enable enables or disables use of the VME memory card as additional reading storage Parameters Parameter Parameter Range of Default Name Type Values Units enable boolean uint16 1 0 ON OFF none Comments This command is only available in systems using an Agilent HP E1405B 06A command module e When the VME memory card is enabled the INIT command does not terminate until data acquisition stops or VME memory is full e Related Commands Memory subsystem and FETCH Chapter 6 VT14
241. alf full and Measurement complete interrupts could come repetitively at rates that would cause the operating system to be swamped processing interrupts These conditions are dependent upon the user s overall system design therefore the driver allows the user to decide which if any interrupts will be enabled The way the user controls which interrupts will be enabled is via the OPC STATUS OPER QUES ENABLE and STAT PRESET commands Each of the interrupting conditions listed above has a corresponding bit in the QUES or OPER registers If that bit is enabled via the STATus OPER QUES ENABle command to be a part of the group summary bit it will also enable the VT14154A interrupt for that condition If that bit is not enabled the corresponding interrupt will be disabled Sending STAT PRESET will disable all the interrupts from the VT1415A Sending the OPC command will enable the measurement complete interrupt Once this interrupt 1s received and the OPC condition sent to the status system this interrupt will be disabled if it was not previously enabled via the STATUS OPER QUES ENABLE command The above description is always true for a downloaded driver In the C SCPI driver however the interrupts will only be enabled if cscpi overlap mode is ON when the enable command is given If cscpi overlap is OFF the user is indicating they do not want interrupts to be enabled Any subsequent changes to cscpi overlap will not change which interrupts
242. algorithm source code Appendix B Error Messages 331 3084 Error 1 Number too big for a 32 bit float Error 2 Number too big for a 32 bit integer Error 3 8 or 9 not allowed in an octal number Error 4 Syntax error Error 5 Expecting Error 6 Expecting Error 7 Expecting an expression Error 8 Out of driver memory Error 9 Expecting a bit number Bn or Bnn Error 10 Expecting Error 11 Expecting an identifier Error 12 Arrays can t be initialized Error 13 Expecting static Error 14 Expecting float Error 15 Expecting Error 16 Expecting 5 Error 17 Expecting Error 18 Expecting Error 19 Expecting Error 20 Expecting a statement Error 21 Expecting 1f Error 22 Can t write to input channels Error 23 Expecting a constant expression Error 24 Expecting an integer constant expression Error 25 Reference to an undefined variable Error 26 Array name used in a scalar context Error 27 Scalar name used in an array context Error 28 Variable name used in a custom function context Error 29 Reference to an undefined custom function Error 30 Can t have executable code in GLOBALS definition Error 31 CVT address range is 10 511 Error 32 Numbered al
243. ame gt Here 1s an example of defining an algorithm for swapping define ALG3 so it can be swapped with an algorithm as large as 1000 words ALG DEF ALG3 1000 241698 698char alg source The number of characters bytes in an algorithm s source code parameter is not well related to the amount of memory space the algorithm requires Remember this parameter contains the algorithm s source code not the executable code it will be translated into by the ALG DEF command The algorithm s source might contain extensive comments none of which will be in the executable algorithm code after it 1s translated The example algorithm definition above will be used for this discussion When a value for swap size is specified at algorithm definition the VT1415A allocates two identical algorithm spaces for ALG3 each the size specified by swap size in this example 1000 words This is called a double buffer They will be arbitrarily called space A and space B The algorithm is loaded into ALG3 s space A at first definition Later while algorithms are running replace ALG3 by again executing ALG DEF ALG3 242435 2435char alg source Notice that swap size is not must not be included this time This ALG DEF works like an Update Request The VT1415A translates and downloads the new algorithm into ALG3 s space B while the old ALG3 is still running from space A When the new algorithm has been completely loaded into space B and an
244. ame hierarchical level and part of the same command branch as the keyword preceding the semicolon The colon immediately following the semicolon tells the SCPI parser to reset the expected hierarchical level to Root Linking a complete SCPI Command with other keywords from the same branch and level Separate the first complete SCPI command from next partial command with the semicolon only For example take the following portion of the SENSE subsystem command tree the FUNCtion branch SENSe FUNCtion RESistance lt range gt lt ch_list gt TEMPerature lt sensor gt lt range gt lt ch_list gt VOLTage DC lt range gt lt ch_list gt Rather than sending a complete SCPI command to set each function send FUNC RES 10000 100 107 TEMP RTD 92 108 115 VOLT 116 123 This sets the first eight channels to measure resistance the next eight channels to measure temperature and the next eight channels to measure voltage Chapter 6 VT1415A Command Reference 159 NOTE The command keywords following the semicolon must be from the same command branch and level as the complete command preceding the semicolon or a 113 Undefined header error will be generated C SCPI Data The following table shows the allowable type and sizes of the C SCPI parameter Types data sent to the module and query data returned by the module The parameter and returned value type is necessary for programming and is documented in e
245. amp error string if error void printf syst err d s n error string exit 1 Start from a known instrument INST CLEAR e1415 Selected device clear INST SEND e1415 VERS TS ChSAN i 7 E Setup SCP functions INST SEND e1415 sens func volt 116 n Analog in volts INST SEND e1415 sour func cond 8141 Nn Digital output Configure Trigger Subsystem and Data Format INST SEND e1415 trig sour timer trig timer 001 n INST SEND e1415 samp timer 10e 6 n default INST SEND e1415 form real 321n Download algorithm with in line code INST SEND el415 alg def algl PIDB I116 0100 0141 B0 n Preset Algorithm variables INST SEND el415 alg scal algl Setpoint f n 3 0 INST SEND e1415 alg scal algl P factor f n 0 0001 INST SEND el415 alg scal algl I factor f n 0 00025 INST SEND e1415 alg upd n Initiate Trigger System start scanning and running algorithms E a g INST SEND e1415 initNn Alter run time variables and Retrieve Data while 1 float32 setpoint 0 process info 4 int m type in 100 to exit printf Enter desired setpoint scanf f amp setpoint if setpoint 100 00 break INST SEND el415 alg scal algl Setpoint
246. ance of the current source is in the gigaohm region Even though this is a higher level measurement than the previous example the settling time can be even longer due to the slower discharge of the stray capacitances The simple answer here is to always use an SCP that presents a low impedance buffered output to the VT1415A s Range Amp and A D The VT1503A 08A 09A 10A 12A and 14A through 17A SCPs all provide this capability 108 Programming the VT1415A for PID Control Chapter 3 Checking for Problems Fixing the Problem Use Amplifier SCPs The method used to quickly determine if any of the channels in a system need more settling time is to simply apply some settling time to every channel Use this procedure 1 First run the system to make a record of its current measurement performance 2 Then use the SAMPle TIMer command to add a significant settling delay to every measurement in the scan list Take care that the sample time multiplied by the number of channels in the scan list doesn t exceed the time between triggers 3 Now run the system and look primarily for low level channel measurements like thermocouples with dc values that change somewhat If channels are found that respond to this increase in sample period it may also be noticed that these channels return slightly quieter measurements as well The extra sample period reduces or removes the affected channels coupling to the value of the channel measured just before
247. ases but the changes don t take place until an ALG UPDATE command is received and the update phase begins If no ALG UPDATE command is pending the update phase is simply used to accept variable and algorithm changes from the application program using ALG SCAL ALG ARR ALG DEF Data acquired by external specialized measurement instruments can be sent to the algorithms at this time CALCULATE all INPUT and UPDATE values have been made available to the algorithm variables and each enabled algorithm is executed The results to be output from algorithms are stored in the Output Channel Buffer OUTPUT each Output Channel Buffer value stored during CALCULATE is sent to its assigned SCP channel The start of the OUTPUT phase relative to the Scan Trigger can be set with the SCPI command ALG OUTP DELay 84 Programming the VT1415A for PID Control Chapter 3 Reading Running Algorithm Values Reading Algorithm Variables Reading Algorithm Values From the CVT Organization of the CVT The PIDB algorithm stores its most important working values into the Current Value Table CVT each time it executes Further by changing the variable named History mode from 0 to 1 PIDB will also send these value to the FIFO buffer In addition any PID algorithm variable can be read directly from the running algorithm Use this method to read a variable that isn t available from the CVT or FIFO To directly read algorithm variables
248. at by installing analog input SCPs in positions 0 through 3 and digital I O SCPs in positions 4 through 7 these types of signals are separated by the width of the VT1415A module The signals are further isolated because they remain separated on the connector module as well Note that in Figure E 1 even though only six of the eight SCP positions are filled the SCPs present are not installed contiguously but are arranged to provide this digital analog separation If it is necessary to mix analog input and digital I O SCPs on the same side the following suggestions will help provide quieter analog measurements e Use analog input SCPs that provide filtering on the mixed side e Route only high level analog signals to the mixed side CP Pos 0 CP Pos 1 CP Pos 2 SCP Pos 3 P i i CP Pos 7 CP Pos 6 CP Pos 5 SCP Pos 4 E E P Figure E 1 Separating Analog and Digital Signals Appendix E Wiring and Noise Reduction Methods 353 Recommended Wiring and Noise Reduction Techniques Unshielded signal wiring is very common in Data Acquisition applications While this worked well for low speed integrating A D measurements and or for measuring high level signals it does not work for high speed sampling A Ds particularly when measuring low level signals like thermocouples or strain gage bridge output
249. at64 tableRange Range on which table was built maxInput 2 minlInput 2 Build table maxInput minInput my function amp tableRange amp tableOffset coef array Download the table range and the table array to the card Piecewise requires 128 sets of table values INST SEND el415 ALGorithm FUNCtion DEFine sin f f 1024b tableRange tableOffset coef array Download algorithms if O Set to 1 if algorithms passed in as files Get an algorithm s from the passed filename s We assign sequential algorithm numbers to each successive file name ALG1 ALG2 etc when you execute this program as progname langl lang2 lang3 m ay alg num 1 Starting algorithm number while argc gt alg num algorithm get algorithm argv alg num Read the algorithm Define the algorithm char alg 6 Temporary algorithm name void sprintf alg ALG d alg num INST SEND e1415 alg def S B n alg strlen algorithm 1 algorithm Check for algorithm errors INST QUERY e1415 syst err n d S amp error string if error A void printf While loading file s syst err d s Nn argv alg num error string exit 1 Free the malloc ed memory free algorithm alg_num Next algorithm void printf All d algorithm s loaded without errorsinin alg num 1 else Downlo
250. atic float user_value writecvt user_flag 330 Always write user flag in CVT statement ends with if user_flag if statement note no brace opens compound statement if user_flag gt 0 writecvt user_value 2 331 one line if statement writecvt ends with else else immediately follows complete if statement construct open compound statement for else clause writecvt user_value 2 331 each simple statement ends in even within compound writefifo user_value these two statements could combine with writeboth close compound statement for else clause close compound statement for first if else writecvt 0 331 else clause goes with first if statement Note single line else Where To Go Next ifone has already read Chapter 3 Programming the VT1415A for PIDs read Chapter 4 Creating and Running Custom Algorithms It is very important to read Chapter 3 first since almost all of the programming steps for PIDs apply to programming the VT1415A to run custom algorithms Chapter 5 Algorithm Language Reference 149 Notes 150 Algorithm Language Reference Chapter 5 Chapter 6 VT1415A Command Reference Using This Chapter This chapter describes the Standard Commands for Programmable Instruments SCPI command set and the IEEE 488 2 Common Commands for the VT1415A e Overall Command Index o o page 151 e Comma
251. ation CONDition ENABle enable mask ENABle EVENt NTRansition transition mask NTRansition PTRansition transition mask PTRansition PRESet QUEStionable CONDition ENABle enable mask ENABle EVENt NTRansition transition mask NTRansition PTRansition transition mask PTRansition SYSTem CTYPe lt channel gt ERRor SCPI Command Quick Reference Description Returns the Poisson Ratio set for lt channel gt Specifies the Unstrained Voltage by channel to the strain EU conversion Returns the Unstrained Voltage set for channel Configure digital channels to output frequency modulated signal Returns state of channels for FM output Configures channels to output static digital levels Configures channels to output digital pulse s Configures channels to output 50 50 duty cycle digital pulse train Configure digital channels to output pulse width modulated signal Returns state of channels for PW modulated output Sets pulse period for PW modulated signals Returns pulse period for PW modulated signals Sets pulse width for FM modulated signals Returns pulse width setting for FM modulated signals Operation Status Group Bit assignments 0 Calibrating 4 Measuring 8 Scan Complete 10 FIFO Half Full 11 algorithm interrupt Returns state of Operation Status signals Bits set to 1 enable status events to be summarized into Status Byte Returns the decimal weighted
252. ault version is an abbreviated self test that executes only the Digital Tests By loading an additional object file the full self test can be executed as described below See the documentation that comes with the VT1415A C SCPI driver for MS DOS e Returned Value Value Meaning Further Action 0 TST OK None 1 TST Error Query the Error Queue SYST ERR for error 3052 See explanation below e IF error 3052 Self test failed Test info in FIFO is returned A FIFO value of 1 through 99 or gt 300 is a failed test number A value of 100 through 163 is a channel number for the failed test A value of 200 through 204 is an A D range number for the failed test where 200 0 0625 201 20 25 V 202 1 V 203 4 V and 204 16 V ranges For example DATA FIFO returns the values 72 and 108 This indicates that test number 72 failed on channel 8 Test numbers 20 30 37 72 74 76 and 80 93 may indicate a problem with a Signal Conditioning Plug On For tests 20 and 30 37 remove all SCPs and see if TST passes If so replace SCPs one at a time until the one causing the problem is found For tests 72 74 76 and 80 93 try to re seat the SCP that the channel number s points to or move the SCP and see if the failure s follow the SCP If the problems move with the SCP replace the SCP These are the only tests where the user should troubleshoot a problem Other tests which fail should be referred to q
253. be returned to a service facility designated by VXI Technology Buyer shall prepay shipping charges to VXI Technology and VXI Technology shall pay shipping charges to return the product to Buyer However Buyer shall pay all shipping charges duties and taxes for products returned to VXI Technology from another country VXI Technology warrants that its software and firmware designated by VXI Technology for use with a product will execute its programming instructions when properly installed on that product VXI Technology does not warrant that the operation of the product or software or firmware will be uninterrupted or error free Limitation Of Warranty The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by Buyer Buyer supplied products or interfacing unauthorized modification or misuse operation outside of the environmental specifications for the product or improper site preparation or maintenance The design and implementation of any circuit on this product is the sole responsibility of the Buyer VXI Technology does not warrant the Buyer s circuitry or malfunctions of VXI Technology products that result from the Buyer s circuitry In addition VXI Technology does not warrant any damage that occurs as a result of the Buyer s circuit or any defects that result from Buyer supplied products NO OTHER WARRANTY IS EXPRESSED OR IMPLIED VXI TECHNOLOGY SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANT
254. bration CAL can take several minutes Configure the Trigger System ARM SOURCE IMMEDIATE RST default TRIGGER COUNT INF RST default TRIGGER TIMER 010 RST default TRIGGER SOURCE TIMER RST default specify data format FORMAT ASC 7 RST default select FIFO mode SENSE DATA FIFO MODE BLOCK may read FIFO while running Define PID algorithm ALG DEFINE ALG1 PIDB I100 0124 0132 B0 Pre set PID coefficients ALG SCAL ALG1 P_factor 5 ALG SCAL ALG1 l_factor 0 ALG SCAL ALG1 D factor 90 Programming the VT1415A for PID Control Chapter 3 initiate trigger system start algorithm INITIATE retrieve PID data SENSE DATA CVT lt element_list gt A Quick Start PID A Igorithm Example This example uses the PIDB algorithm to control a simulated process provided by a capacitor two resistors and a diode The object is to control the voltage level in the capacitor The example program is written in C SCPI To save space the program shown here does not include any error trapping The source file for this example does implement error trapping The source file is named simp_pid cs and can be found in the VXIplug amp play Drivers and Product Manuals CD See Appendix G for program listings C SCPI Example x This program ex E Standard includ include lt stdlib h include lt stdio h gt include lt stddef h include math h Instrument cont i
255. c eee ee 172 ALGorithm EXPLicit STATe 5 losses 173 ALGorithm EXPLicit TIMe 0 0 ccc eee 173 ALGorithm FUNCtion DEFine 00 eran eee eee 174 ALGorithm OUTPut DELay 0 0 00 cee ee 175 ALGorithm OUTPut DELay 2 0 0 0 0 ccc o 176 ALGorithm UPDate IMMediate 20 00 0 e ee ee eee 176 ALGorithm UPDate CHANnel 20 00 cece ee eee ee 177 ALGorithm UPDate WINDow 00 0 cece eee ee ene 178 ALGOrithm UPDate WINDow 00000 cece eee eee 179 ARM weg acess ERE Pues COR ane Sead Me EEG Oop kee ets 180 ARM IMMediate 0 00000 ees 181 ARMG SOURCGe 21e rb ee eee bee ER Ree EE 181 ARNESOURGe cesa Rep TERRE E ERI tee e ghee TS 182 CALibration oia ote s haw Baw RAE SC eee te E AUR 183 CALibration CONFigure RESistance 0oocoocococcoconco o 184 CALibration CONFigure VOLTage 0 00 eee eee 185 CALibration SETup 0 0 186 CALibration SETup 0 0c eee cece eens 186 x Table of Contents CALibration TARE 1 0 0 0 ccc teens 188 CALibration TARE RESet seos 20 0000 ec een ee 189 CALibration TARE ios e er ER ER Yd 190 CALibration VALue RESIStance 2 0 0 0 00 0 cee eee 190 CALibration VALue VOLTage 2 0 0 0 cece eens 191 CALibration ZERO is zoo Saw enh eele nls weed ER n 192 DEAGROSLUG eis ocean Saud Sena elaine RT baa E ER Se eni os 193 DIAGnostic CALibration SETup MODE 193 DIAGnostic
256. can only output voltage while the VT1532A can only output current The only way to control the output amplitude of these SCPs is through the VT1415A s Algorithm Language Chapter 3 Programming the VT1415A for PID Control 69 Setting Up Digital Input and Output Channels Setting Up Digital Digital inputs can be configured for polarity and depending on the SCP Inputs model a selection of input functions as well The following discussion will explain which functions are available with a particular Digital I O SCP model Setting a digital channel s input function is what defines it as an input channel Setting Input Polarity To specify the input polarity logical sense for digital channels use the command INPut POLarity lt mode gt lt ch_list gt This capability is available on all digital SCP models This setting is valid even while the specified channel in not an input channel If and when the channel is configured for input an input FUNCtion command the setting will be in effect e The lt mode gt parameter can be either NORMal or INVerted When set to NORM an input channel with 3 V applied will return a logical 1 When set to INV a channel with 3 V applied will return a logic 0 e The ch list parameter specifies the channels to configure The VT1533A has 2 channels of 8 bits each All 8 bits in a channel take on the configuration specified for the channel The VT1534A has 8 I O bits that are individually configured as
257. ce is created for all algorithms defined The value of variable State n is set with the ALGorithm STATe command and determines whether the algorithm will be called The value of Ratio n is set with the ALGorithm SCAN RATio command and determines how often the algorithm will be called relative to trigger events Since the function calling interface to an algorithm is fixed in the main function the header of an algorithm function is also pre defined This means that unlike standard C language programming an algorithm program a function need not must not include the function declaration header opening brace and closing brace Only the body of the function is supplied the VT1415A s driver supplies the rest Think of the program space in the VT1415A in the form of a source file with any global variables first then the main function followed by as many algorithms as are defined Of course what is really contained in the VT1415A s algorithm memory are executable codes that have been translated from the downloaded source code While not an exact representation of the algorithm execution environment Figure 4 1 shows the relationship between a normal C program and two VT1415 algorithms 114 Creating and Running Custom Algorithms Chapter 4 GLOBALS you define with ALG DEF GLOBALS go here Global variables area O 9 global variable First loop equals 1 unt
258. ch all of the VT1415A s channels can be commanded to disconnect from the system e Sets the trigger system as follows TRIGGER SOURCE TIMER TRIGGER TIMER 10E 3 TRIGGER COUNT 0 infinite ARM SOURCE IMMEDIATE e SAMPLE TIMER 10E 6 e Aborts all pending operations returns to Trigger Idle state e Disables the OPC and OPC modes e MEMORY VME ADDRESS 240000 MEMORY VME STATE OFF MEMORY VME SIZE 0 e Sets STAT QUES COND bit 13 RST does not affect e Calibration data e The output queue e The Service Request Enable SRE register e The Event Status Enable ESE register 282 VT1415A Command Reference Chapter 6 SRE mask Service Request Enable When a service request event occurs it sets a corresponding bit in the Status Byte Register this happens whether or not the event has been enabled unmasked by SRE The SRE command allows events to be identified which will assert a GPIB service request SRQ When an event is enabled by SRE and that event occurs it sets a bit in the Status Byte Register and issues an SRQ to the computer sets the GPIB SRQ line true An event is enabled by specifying its decimal weight for lt mask gt To enable more than one event specify the sum of the decimal weights Refer to The Status Byte Register for a table showing the contents of the Status Byte Register The C SCPI type for lt mask gt is int16 Bit 7 6 5 4 3 2 1 0 Weighted Value 128 64 32 1
259. cients Gain 10ppm C Offset 0 40 C 0 14 pV C 40 55 C 0 8 pV 0 38 uV P C N 98 Specifications Appendix A Temperature Accuracy The following pages have temperature accuracy graphs that include instrument and firmware linearization errors The linearization algorithm used is based on the IPTS 68 78 standard transducer curves Add the custom transducer s accuracy to determine total measurement error The thermocouple graphs on the following pages include only the errors due to measuring the voltage output of the thermocouple as well as the algorithm errors due to converting the thermocouple voltage to temperature To this error must be added the error due to measuring the reference junction temperature with an RTD or a 5k thermistor See the graphs for the RTD or the 5k thermistor to determine this additional error Also the errors due to gradients across the isothermal reference must be added If an external isothermal reference panel is used consult the manufacturer s specifications If VXI Technology termination blocks are used as the isothermal reference see the notes below NOTE 1 When using the Terminal Module as the isothermal reference add 0 6 C to the thermocouple accuracy specs to account for temperature gradients across the Terminal Module The ambient temperature of the air surrounding the Terminal Module must be within 2 C of the temperature of the inlet cooling air to the VXI mainframe 2
260. ck Panel Accessories Mount Terminal Panel to the VT1415A Option A3F In both cases four cables are required if all 64 channels are needed These cables do not come with the VT1415A Option A3F and must be ordered separately Chapter 2 Field Wiring 49 Standard Cable This cable VT1588A is a 16 channel twisted pair cable with an outer shield This cable is suitable for relatively short cable runs Custom Length Cable This cable 1s available in custom lengths It is a 16 channel twisted pair cable with each twisted pair individually shielded to provide better quality shielding for longer cable runs Contact a VXI Technology Sales Representative for more information HF Common Mode Filters Optional High Frequency HF Common Mode Filters are on the VT1586A Rack Mount Terminal Panel s input channels VT1586A 001 RF Filters They filter out ac common mode signals present in the cable that connects between the terminal panel and the device under test The filters are useful for filtering out small common mode signals below 5 V To order these filters order P N 73 0027 001 Final Assy VT1586A 001 Rf Filters Large Common Mode Signals 50 Field Wiring Chapter 2 Faceplate Connector Pin Signal Lists Figure 2 18 shows the Faceplate Connector Pin Signal List for the
261. connected to the transducer at the source In this case the best performance will most likely be achieved by leaving the GND GRD jumper in place 4 In general the GND GRD jumper can be left in place unless it is necessary to break low frequency below 1 kHz ground loops 354 Wiring and Noise Reduction Methods Appendix E VT1415A Guard The vr1415A guard connection provides a 10 KQ current limiting resistor Connections between the guard terminals G and VT1415A chassis ground for each 8 channel SCP bank This is a safety device for the case where the Device Under Test DUT isn t actually floating the shield is connected to the DUT and also connected to the VT1415A guard terminal G The 10 kQ resistor limits the ground loop current which has been known to burn out shields This also provides 20 kQ isolation between shields between SCP banks which helps isolate the noise source Common Mode Be very careful not to exceed the maximum common mode voltage Voltage Limits referenced to the card chassis ground of 16 volts 60 volts with the VT1513A Attenuator SCP There is an exception to this when high frequency 1 kHz 20 kHz common mode noise is present see VT1415A Noise Rejection below Also if the DUT is not grounded then the shield should be connected to the VT1415A chassis ground When to Make Itis not always possible to state positively the best shield connection for all Shield Connections 4S S Shield performa
262. ctor variable process variable Setpoint variable clip limits Status B2 clip limits Man state variable variable Status B4 alarm limits Status B6 variable lt inp_chan gt channel Figure 3 6 The Advanced Algorithm PIDB Clipping Limits The PIDB algorithm provides clipping limits for its I D SD terms and the value sent to lt outp_chan gt Values for these terms are not allowed to range outside of the set limits The variables that control clipping are I term limits I maxand I min D term limits D maxand D min SD term limits SD maxand SD min lt outp_chan gt limits Out maxand Out min 76 Programming the VT1415A for PID Control Chapter 3 Alarm Limits The PIDB algorithm provides Alarm Limits for the process variable PV and the Error term variable Error If these limits are reached the algorithm sets the value of alarm chan true and generates a VXIbus interrupt The variables that control alarm limits are Process Variable from inp chan PV maxand PV min Error term alarm limits Error maxand Error min The max and min limits for clipping and alarms are set to 9 9E 37 and 9 9E 37 respectively when the algorithm is defined This effectively turns the limits off until the values are changed with the ALG SCALAR and ALG UPDATE commands as described in Pre setting PID Variables and Coefficients later in this section Manual Control The PIDB alg
263. d PV D factor SD out Setpoint Setpoint old SD factor Error Setpoint PV pm d where Setpoint is the desired value of the process variable user supplied PV is the process variable measured on the input channel PID out is the algorithm result sent to the output channel p P factor I factor D factor and SD factor are the PID constants E user supplied Ae is T Alarms may be generated when either the Process Variable or the E error exceeds user supplied limits The alarm condition will cause an interrupt to the host computer set the user specified alarm channel output to one 1 and set a bit in the Status variable to one 1 The interrupt is edge sensitive It will be asserted only on the transition into the alarm state The alarm channel digital i output will persist for the duration of all alarm conditions The ay Status word bits will also persist for the alarm duration No user intervention is required to clear the alarm outputs Ej fF This version provides for limiting or clipping of the Integral Derivative Setpoint Derivative and output to user specified limits The Status Variable indicates when terms are being clipped es Manual control is activated when the user sets the Man state variable RY to a non zero value The output will be held at its last value The f user can change the output by chan
264. d max of the offset is to permit calculating the tables The offset simply code to send the corrected X values assuming tables were built symetrically around X 0 min input center max input center temp range 0 0 temp range max input min input 2 0F ffset temp range Now calculate the closest binary representation of the test range such the new binary value is equal to or greater than the calculated Start with the lowest range 1 2 128 and step up until the new binary range is equal or greater than the test range el tbl range two to the N 128 JE 228 wy 402 Example Program Listings Appendix G tbl range 1 0 tbl range while test range tbl range tbl_range 2 range tbl range Xofst 157 exponent bias for DSP calculations Now divide the full range of the table into 128 segments 129 points scanning first the positive side of the X axis and then the negativ side of the X axis Note that 129 points are calculated in order to generate a line segment for calculating slope Also note that the entire binary range is built to include the min and max values entered as min input and max input for ii20 ii 264 iit 0 to FS input ii center tbl_range 64 0 float 64 ii result ii custom function input ii if ii 0 continue This is the first point skip slo
265. decimal hex H octal HQ or binary 4B e If both the STAT QUES PTR and STAT QUES NTR registers have a corresponding bit set to one any transition positive or negative will set the corresponding bit in the Event register e f neither the STAT QUES PTR or STAT QUES NTR registers have a corresponding bit set to one transitions from the Condition register will have no effect on the Event register e Related Commands STAT QUES NTR STAT QUES PTR e Cleared By STAT PRESet and power on e RST Condition No change Usage STAT QUES NTR 1024 When FIFO Overflowed bit goes false set bit 10 in Status Questionable Event register STATus QUEStionable NTRansition STATus QUEStionable NTRansition returns the value of bits set in the Negative Transition Filter NTF register Comments Returned Value Decimal weighted sum of all set bits The C SCPI type is uint16 e Related Commands STAT QUES NTR e RST Condition No change Chapter 6 VT1415A Command Reference 269 STATus Usage STAT QUES NTR Enter statement returns current value of bits set in the NTF register STATus QUEStionable PTRansition STATus QUEStionable PTRansition transition mask sets bits in the Positive Transition Filter PTF register When a bit in the PTF register is set to one the corresponding bit in the Condition register must change from a zero to a one in order to set the corresponding bit in the Event register When a bit in the PTF regis
266. ded that the jumper be left in this position so that all of the calibration commands can function Changing the jumper to the protect position prevents the following from being executed e The SCPI calibration command CAL STORE ADC TARE e The register based calibration commands STORECAL and STORETAR e Any application that installs firmware updates or makes any other modification to Flash Memory through the A24 window With the jumper in the PROG position one or more VT1415As can be completely calibrated without removing them from the application system A VT1415A calibrated in its working environment will in general be better calibrated than if it were calibrated separate from its application system The multimeter used during the periodic calibration cycle should be considered the calibration transfer standard Provide Calibration Organization control unauthorized access to its calibration constants See the VT1415A VT1419A Service Manual for complete information on VTI1415A periodic calibration If access to the VT1415A s calibration constants must be limited place JM2201 in the protected position and cover the shield retaining screws with calibration stickers See following illustration for location of JM2201 Chapter 1 Getting Started 25 Accessing and Locating JM2201 and JM2202 VT1415A En Flash Memory Protect Jumper Default PROG g recommended X
267. dition No change Usage STATUS QUESTIONABLE CONDITION Enter statement will return value from condition register STATus QUEStionable ENABle STATus QUEStionable ENABle lt enable_mask gt sets bits in the Enable register that will enable corresponding bits from the Event register to set the Questionable summary bit Chapter 6 VT1415A Command Reference 267 STATus Parameters Parameter Parameter Range of Default Name Type Values Units enable mask numeric uint16 0 32767 none Comments enable mask may be sent as decimal hex H octal Q or binary 4B e VXI Interrupts When bits 9 10 or 11 are enabled and C SCPI overlap mode is on or if using non compiled SCPI VXI card interrupts will be enabled When the event corresponding to bit 9 10 or 11 occurs the card will generate a VXI interrupt e Related Commands STB SPOLL STAT QUES COND STAT QUES EVENT STAT QUES ENABLE e Cleared By STAT PRESet and power on e RST Condition No change Usage STAT QUES ENABLE 128 Set bit 7 in the Questionable Enable register STATus QUEStionable ENABle STATus QUEStionable ENABle returns the value of bits set in the Questionable Enable register Comments Returned Value Decimal weighted sum of all set bits The C SCPI type is uint16 e Related Commands STB SPOLL STAT QUES COND STAT QUES EVENT STAT QUES ENABLE e RST Condition No change Usage STAT QUES ENABL
268. dix A 304 Specifications Type EEXtended filter off VT1508A 09A 0i XD Seq dH 0011 a 0071 440 yl 61 140 V6OSLLA a XD QQE maremas ee ee drthec4ruausute RRA Rm AAO 39114 81 100 VSOSLLA NOCT EET o Seg popuojx3 q ody Specifications 305 Appendix A Type J filter off o Seg AdO 19N1J POX 1 MO VEOSLLA mcm cmm Sao te mes em unm A eu cR mas m A m dep m rem omm om 440 BRI 8X E1140 VEOSLLA J40 19184 21 100 VZOSTLA marrano O AI 440 1184 11340 VIOSLLA 00008 00009 00 00t 0000 000 00 007 A at er a R R ee oe PN i i a mE HTTP M EN ifi ori oo u H occ AAA aerate pee M ann H Orc Appendix A 306 Specifications Type J filter off VT1508A 09A 9 3q AAA Ar AA 430 39114 81 180 V80SLLA 00008 00 009 00 00b 00 00Z Specifications 307 Appendix A Type K filter off 001 oso 00 0 01 xo deg pss T al MAAAR hne deme Tam NT mede nte ex aua dba e E et TDS bbb dd esac EMIS aft AAA ME wey AMARA ee PLI deem Mtem a ur t b ah rera manat ear ij ag SH 007 1 Oo OU t AA OS E AdQ PUE pox E1140 VEOSLLA lod O BAR ELO WEDSLLA AA SO iecit H 00v T AAO
269. dix G algorithm a size c a sizett i algorithm a_size 0 Null terminate void fclose f return algorithm Return algorithm string J BK kk RAR RR CK IIA I IA I IEA IA I A Ck A A A kk kk e ke e ke e ke e ke e NAME static float64 two to the N TASK Calculates 2 n static float64 two to the N int32 n compute 2 n float64 r 1 int32 i for i 0 i lt n i pk 2s return r J BK kkk RR RR RR RR AI IE I A I KC Ck KC Ck KC A A A kk e ke e ke e ke e e e NAME static int32 round32f TASK Rounds a 32 bit floating point number static int32 round32f float64 number add or subtract 0 5 to round based on sign of number float64 half number gt 0 0 0 5 0 5 return int32 number half BK kkk RAR RR A III I IA I A A IA I A IA A ek kk e ke e ke ke ke e ke e NAME static float64 my function TASK User supplied function for calculating desired results of f x HAVERSINE float64 my function float64 input float64 returnValue returnValue sin input return returnValue J BK kk kA RARA RR RRA A I IEA I A A IA I A IA A ek kk e ke e ke e ke e e e NAME void Build table TASK Generates tables of mx b values used for Custom Functions in the E1415A Generate the three coefficients for the CUSTOM FUNCTION algorithm a The exponent value b T
270. ds these locations with EU conversion tables copied from its non volatile FLASH Memory For Custom EU conversions these table values must be loaded using either of two SCPI commands Loading Tables for Linear Conversions The DIAGnostic CUSTom LlNear table range table block lt ch_list gt command downloads a custom linear Engineering Unit Conversion table to the VT1415A for each channel specified e The table block parameter is a block of 8 bytes that define 4 16 bit values SCPI requires that table block include the definite length block data header C SCPI adds the header automatically e The table range parameter specifies the range of input voltage that the table covers from table range to table range The value specified must be within 5 of 0 015625 0 03125 0 0625 0 125 0 25 0 5 1 2 4 8 16 32 64 e The lt ch_list gt parameter specifies which channels will have this custom EU table loaded Usage Example The program puts table constants into array lt table_block gt DIAG CUST PIEC table_block 1 132 163 send table for channels 32 63 to VT1415A SENS FUNC CUST PIEC 1 1 132 163 link custom EU with channels 32 63 and set the 1 V A D range INITiate then TRIGger module Loading Tables for Non Linear Conversions The DIAGnostic CUSTom PlECewise table range table block lt ch_list gt command downloads a custom piecewise Engineering Unit Conversion table to the V
271. duce copper shorting wires between each channel s HI and LO then execute CAL TARE for these channels Parameters Parameter Parameter Range of Default Name Type Values Units ch list channel list string 100 163 none Comments CAL TARE also performs the equivalent of a CAL operation This operation uses the Tare constants to set a DAC which will remove each channel offset as seen by the module s A D converter As an example assume that the system wiring to channel 0 generates a 0 1 volt offset with 0 volts a short applied at the Unit Under Test UUT Before CAL TARE the module would return a reading of 0 1 volts for channel 0 After CAL TARE 100 the module will return a reading of 0 volts with a short applied at the UUT and the system wiring offset will be removed from all measurements of the signal to channel 0 e Set Amplifier Filter SCP gain before CAL TARE For best accuracy choose the gain that will be used during measurements If the range or gain setup later is changed later be sure to perform another CAL 188 VT1415A Command Reference Chapter 6 CALibration If Open TransducerDetect OTD is enabled when CAL TARE is executed the module will disable OTD wait 1 minute to allow channels to settle perform the calibration and then re enable OTD If a program turns off OTD before executing CAL TARE it should also wait 1 minute for settling The maximum voltage that CAL
272. e Comments This command is used to specify to the VT1415A the temperature of a controlled temperature thermocouple reference junction e When Accepted Not while INITiated e Related Commands FUNC TEMP TC e RST Condition Reference temperature is 0 C Usage SENSE REF TEMP 40 subsequent thermocouple conversion will assume compensation junction at 40 C SENSe STRain EXCitation SENSe STRain EXCitation lt excite_v gt lt ch_list gt specifies the excitation voltage value to be used to convert strain bridge readings for the channels specified by lt ch_list gt This command does not control the output voltage of any source Parameters Parameter Parameter Range of Default Name Type Values Units excite v numeric flt32 0 01 99 volts ch list channel list string 100 163 none Comments c list must specify the channel used to sense the bridge voltage not the channel position on a Bridge Completion SCP e Related Commands SENSE STRAIN SENSE FUNC STRAIN e RST Condition 3 9V Usage STRAIN EXC 4 100 107 set excitation voltage for channels 0 through 7 SENSe STRain EXCitation SENSe STRain EXCitation lt channel gt returns the excitation voltage value currently set for the sense channel specified by lt channel gt Parameters Parameter Parameter Range of Default Name Type Values Units channel channel list strin
273. e ESR command This will return bit values for events which have occurred in this group After reading this status register is cleared Note that bits 2 through 5 in this group indicate error conditions If any of these bits are set error messages will be found in the Error Queue Use the SYST ERR command to read these Bit 7 OPR Read the Operation Status Group s Event Register bit value 128 using the STAT OPER EVENT command This will return bit values for events which have occurred in this group After reading the Event Register is cleared 98 Programming the VT1415A for PID Control Chapter 3 Clearing the Enable Registers The Status Byte Group s Enable Register Reading Status Groups Directly Reading Event Registers Clearing Event Registers Reading Condition Registers To clear the Enable Registers execute STAT PRESET for Operation Status and Questionable Data Groups ESE 0 for the Standard Event Group SRE 0 for the Status Byte Group The Enable Register for the Status Byte Group has a special purpose Notice in Figure 3 12 how the Status Byte Summary bit wraps back around to the Status Byte The summary bit sets the RQS request service bit in the Status Byte Using this Summary bit and those from the other status groups the Status Byte can be polled and the RQS bit checked to determine if there are any status conditions which need attention In this way the RQS bit is like the GPIB s SRQ S
274. e Reading History Mode Values from the FIFO on page 86 Writing values to the FIFO and CVT The writeboth expression cvt element statement sends the value of expression both to the FIFO and to a cvt element Reading these values is done the same way as mentioned for writefifo and writecvt The algorithm language provides the function interrupt to force a VXIbus interrupt When interrupt is executed in an algorithm a V XIbus interrupt line selected by the the SCPI command DIAG INTR LINe is asserted The following example algorithm code tests an input channel value and sets an interrupt if it is higher or lower than set limits static float upper limit 1 2 lower limit 0 2 if 1124 gt upper limit 1124 lower limit interrupt When an algorithm is defined with the ALG DEF ALGn command the VT1415A s driver makes available to the algorithm the constant ALG NUM ALG NUM has the value n from ALGn For instance if an algorithm is defined with a g name gt equal to ALG3 then ALG NUM within that algorithm would have the value 3 What can be done with this value The standard PID algorithm PIDB uses ALG NUM to determine which CVT elements it should use to store values Here s a short example of the code used writecvt inp channel ALG NUM 10 0 writecvt Error ALG NUM 10 1 writecvt outp channel ALG NUM 10 2 writecvt Status ALG NUM 10
275. e block data ch_list channel list string 100 163 none e The lt table_block gt parameter is a block of 1 024 bytes that define 512 16 bit values SCPI requires that lt table_block gt include the definite length block data header C SCPI adds the header automatically 196 VT1415A Command Reference Chapter 6 DIAGnostic e The table range parameter specifies the range of voltage that the table covers from table range to table range e The ch list parameter specifies which channels may use this custom EU table e Related Commands SENSe FUNCtion CUSTom e RST Condition All custom EU tables erased Usage program puts table constants into array table block DIAG CUST PIEC table_block 124 131 Send table for chs 24 31 to VT1415A SENS FUNC CUST PIEC 1 1 124 131 Link custom EU with chs 24 31 INITiate then TRIGger module DIAGnostic CUSTom REFerence TEMPerature DIAGnostic CUSTom REFerence TEMPerature extracts the current Reference Temperature Register Contents converts it to 32 bit floating point format and sends it to the FIFO This command is used to verify that the reference temperature is as expected after measuring it using a custom reference temperature EU conversion table Usage The program must have EU table values stored in table block download the new reference EU table DIAG CUST PIECEWISE table range table block g ch list designate channel
276. e defined to convert signal values from standard sensors to values more closely related to the process variables being measured For instance voltage from a pressure sensor can be converted to PSI The input data appear to the control algorithm as program constants They are constants only in that the algorithmic program cannot change their values These values are updated each time a trigger causes the input channels to be scanned After all input channels are scanned each of the defined and enabled control algorithms are executed Process Control Out Control output to the process is determined by the executing algorithms In general the algorithm assigns a value to one of 64 special output channel identifiers If the algorithm executes the statement 0107 control out var the value of the variable control out var is placed in the Output Channel Buffer entry for channel 7 After all active algorithms have been executed the buffer values one for each assigned channel are sent to the output Signal Conditioning Plug Ons SCP at those channel positions The characteristic of the actual output quantity is determined by the type of output SCP that is installed at the specified channel For instance if a VT1532A Current Output SCP were installed at the specified channel the parameter value could range from 0 01 to 0 01 amps 10 mA A Voltage Output SCP at the channel would allow a parameter value of 16 to 16 volts Programming Mod
277. e lt stdlib h gt Most programs use one or more functions from the C standard library my include lt stdio h gt Most programs will also use standard T O functions include lt stddef h gt This file is also often useful include lt math h gt Needed for any floating point fn s Other system include files Appendix G Example Program Listings 391 Whenever using system or library calls check the call description to see which include files should be included Au Instrument control include files include lt cscpi h gt C SCPI include file Declare any constants that will be useful to the program In particular it is usually best to put instrument addresses in this area to make the code more maintainable define E1415 ADDR vxi 208 The SICL address of your E1415 INST DECL el415 E1415A REGISTER E1415 Use something like this for GPIB and Agilent E1405 6 Command Module define E1415 ADDR hpib 22 26 The SICL address of your E1415 INST DECL e1415 E1415A MESSAGE E1415 Declare instruments that will be accessed with SICL These declarations can also be moved into local contexts INST vxi VXI interface session n rap instrument errors If this function is used it will be called every time a C SCPI instrument puts an error in the error queue As written
278. e 219 OUTPut TPLTre SOURCE 2 4 sw m kom a a da E EU page 220 OUTPut TTLTrg lt n gt STATe 1 0JONJOFE ees page 220 QUTPUE TIL Item LESA TEE 24d kie e a d e Tek eiat eb e page 221 OUTPut TYPE PASSive ACTive lt ch_lis gt eee page 221 OUTPut TYPE lt channel gt rh page 222 OUTPut VOLTage AMPLitude lt amplitude gt lt ch_list gt ooo page 222 OUTPut VOLTage AMPLitude lt channel gt e page 223 ROUTe SEQuence DEFine AIN AOUT DIN DOUT ooo oo o page 224 ROUTe SEQuence POINts AIN AOUT DIN DOUT ls page 225 SAMPIe TIMet InteFval regiae raea dea Qoae Voy e Nos E SO a page 226 SAMPIe TIMeE sit aa mom ERR dae RAE ed doe en o devi qiu dee OR e page 227 SENSe CHANnel SETTling lt settle_time gt lt ch_lis gt lll page 229 SENSe CHANnel SETTling lt channel gt o page 229 SENSe DATA CVTable D lt element list oo o page 230 SENSe DATA CVTable RESet ee page 231 SENSe DATA FIFO ALL 42e RR hr page 231 SENSe DATA FIFO COUNT oa dac sedete eee hm hh mrs page 232 SENSe DATA FIFO COUNT HALF o page 233 SENSe DATA FIFO HALE os e ed Seb a TOR SV oed Ee dod page 233 SENSe DATA FIFO MODE BLOCk OVERwrite aoaaa e page 234 SENSe DATA FIFO MODE 4 lee eee hh hrs page 235 SENSe DATA FIFO PART n readings ss page 235 SENS IDATASBEIEO RESet s re a rere a wer as RR E e rre Ro e ug page 236
279. e Block Data may be either Definite Length or Indefinite Length depending on the data query command executed These data return formats are explained in Arbitrary Block Program Data on page 158 of this chapter For REAL 32 readings are 4 bytes in length C SCPI type is float32 array For REAL 64 and PACK 64 readings are 8 bytes in length C SCPI type is float64 array ASCii is the default format ASCII readings are returned in the form 1 234567E 123 For example 13 325 volts would be 1 3325000E 001 Each reading is followed by a comma A line feed LF and End Or Identify EOI follow the last reading C SCPI type is string array Chapter 6 VT1415A Command Reference 201 FORMat NOTE TST leaves the instrument in its power on reset state This means that the ASC 7 data format is set even if something else was set before executing TST If the FIFO must be read for test information set the format after TST and before reading the FIFO e Related Commands SENSe DATA FIFO SENSe DATA CV Table MEMory subsystem and FETCh Also see how DIAG IEEE can modify REAL 32 returned values e RST Condition ASCII 7 e After RST Power on each channel location in the CVT contains the IEEE 754 value Not a number NaN Channel readings which are a positive over voltage return IEEE INF and a negative over voltage return IEEE INF The NaN INF and INF values for each format are shown in the followin
280. e CAL SETup e Returned Value Value Meaning Further Action 0 Cal OK None 1 Cal Error Query the Error Queue SYST ERR See Error Messages in Appendix B The C SCPI type for this returned value is int16 e When Accepted Not while INITiated e Related Commands CALibration SETup CALibration SETup CALibration STORe ADC e CAL STOR ADC stores the calibration constants for CAL and CAL SETup into non volatile memory e Executing this command does not alter the module s programmed state function range etc It does however clear STAT QUES COND register bit 13 If Open Transducer Detect OTD is enabled when CAL is executed the module will disable OTD wait 1 minute to allow channels to settle perform the calibration and then re enable OTD If a program turns off OTD before executing CAL it should also wait 1 minute for settling 278 VT1415A Command Reference Chapter 6 CLS Common Command Reference Clear Status Command The CLS command clears all status event registers Standard Event Status Event Register Standard Operation Status Event Register Questionable Data Event Register and the instrument s error queue This clears the corresponding summary bits bits 3 5 and 7 in the Status Byte Register CLS does not affect the enable bits in any of the status register groups The SCPI command STATus PRESet does clear the Operation Status Enable and Questionable Data Enab
281. e CVT elements by executing the SCPI command SENSe DATA CVT lt element_list gt where lt element_list gt specifies one or more individual elements and or a range of contiguous elements The following example command will help to explain the element list syntax DATA CVT 10 20 30 33 40 43 330 Return elements 10 20 30 33 40 43 and element 330 118 Creating and Running Custom Algorithms Chapter 4 Setting a VXlbus Interrupt Determining an Algorithm s Identity ALG NUM Individual element numbers are isolated by commas A contiguous range of elements is specified by starting element gt colon lt ending element Writing values to the FIFO The FIFO as the name implies is a First In First Out buffer It can buffer up to 65 024 values This capabihty allows an algorithm to send a continuous stream of data values related in time by their position in the buffer It can be thought of as an electronic strip chart recorder Each value is sent to the FIFO by executing the Algorithm Language intrinsic statement writefifo lt expression gt The following in an example algorithm statement writecvt O124 send output channel 24 s value to the FIFO Since the actual algorithm execution rate can be determined see Programming the Trigger Timer on page 82 the time relationship of readings in the FIFO is very deterministic Reading values from the FIFO For a discussion on reading values from the FIFO se
282. e VT1534A its channel identifiers can only take on the values 0 and 1 Examples 0100 1 assign value to output chan 0 on VT1534A Inp_val 1108 from 8 bit channel on VT1533A Inp_val will be 0 to 255 Bit 4 1109 B4 assign VT1533A chan 9 bit 4 to variable Bit_4 Output Channels Output channels can appear on either or both sides of an assignment operator They can appear anywhere other variables can appear Examples 0100 12 5 send value to output channel buffer element 0 0108 B4 O108 B4 compliment value found in output channel buffer element 8 bit 4 each time algorithm is executed writecvt O116 350 send value of output channel 16 to CVT element 350 Input Channels Input channel identifiers can only appear on the right side of assignment operators It doesn t make sense to output values to an input channel Other than that they can appear anywhere other variables can appear Examples dig bit value 1108 B0 retrieve value from Input Channel Buffer element 8 bit 0 inp value 1124 retrieve value from Input Channel Buffer element 24 0156 4 1124 retrieve value from Input Channel Buffer element 24 multiply by 4 and send result to Output Channel Buffer element 56 writefifo 1124 send value of input channel 24 to FIFO buffer Defined Input and An algorithm references channels It can reference input or output Output Channels channels but in order for these channels to be available to
283. e algorithm for alg name is again changed it will be executed from spacel and so on Note that swap size must be large enough to contain the original executable code derived from source code and any subsequent replacement for it or an error 3085 Algorithm too big will be generated If swap size is not included the VT1415A will allocate just enough memory for algorithm lt alg_name gt Since there is no swapping buffer allocated this algorithm cannot be changed until a RST command is sent to clear all algorithms See When Accepted and Usage e The source code parameter contents can be When alg name gt is ALG through ALG32 PIDA lt inp_channel gt lt outp_channel gt or PIDB inp channel outp channel alarm channel channel parameters can specify actual input and output channels or they can specify global variables This can be useful for inter algorithm communication Any global variable name used in this manner must have already been defined before this algorithm ALG DEF ALG3 PIDB 1100 0124 0132 B2 Algorithm Language source code representing a custom algorithm ALG DEF ALG5 if First loop 0116 0 0116 0116 0 01 When lt alg_name gt is GLOBALS Algorithm Language variable declarations A variable name must not be the same as an already define user function ALG DEF GLOBALS static float my_glob_scalar my glob array 24 The Algori
284. e clear plastic cover must be on the Terminal Module 2 The thin white mylar thermal barrier must be inserted over the Terminal Module connector VT1415A only This prevents airflow from the VT1415A A D Module into the Terminal Module The Terminal Module must also be in a fairly stable temperature environment and it is best to minimize the temperature gradient between the VT1415A module and the Terminal Module The VXI mainframe cooling fan filters must be clean and there should be as much clear space in front of the fan intakes as possible Recirculating warm air inside a closed rack cabinet can cause a problem if the Terminal Module is suspended into ambient air that is significantly warmer or cooler If the mainframe recess is mounted in a rack with both front and rear doors closing both doors helps keep the entire VT1415A at a uniform temperature If there is no front door try opening the back door VXI Technology recommends that the cooling fan switch on the back of the of an Agilent HP E1401 Mainframe be in the High position The normal variable speed cooling fan control can make the internal VT1415A module temperature cycle up and down which affects the amplifiers with these microvolt level signals 38 Field Wiring Chapter 2 Preferred Measurement Connections For any A D Module to scan channels at high speeds it must use a very short sample period lt 10 us for the VT1415A If significant norma
285. e clip limits static float SD min 9 9e 37 static float History mode 0 Activates fifo data logging ad Other Variables static float I out Integral term x static float P_out Proportional term x static float D out Derivative term Static float Error Error term static float PV old Last process variable static float Setpoint old Last setpoint for derivative say static float SD out Setpoint derivative term static float Status 0 Algorithm status word ef pe B0 PID out at clip limit nd Bl I out at clip limit pA B2 D out at clip limit E B3 SD out at clip limit B4 in Manual control mode ur B5 Error out of limits B6 PV out of limits f others unused Ei X PID algorithm code E Test for Process Variable out of limits if inchan gt PV max PV min gt inchan PV alarm test if Status B6 Status B6 1 alarmchan 1 interrupt else Status B6 0 Do this when in the Manual control mode if Man state On the first trigger after INIT only if First_loop Man out outchan Maintain output at manual smooth start On subsequent triggers slew output towards Man out else if Man out gt outchan abs Man inc outchan outchan abs Man inc else if outchan gt Man out abs Man inc outchan outchan abs Man inc else outc
286. e currently set mode for controlling Open Transducer Detect current while performing CAL TARE operation Comments e Returns a 0 when OTD current will be turned off during CAL TARE Returns 1 when OTD current will be left on during CAL TARE operation The C SCPI type is int16 e Related Commands DIAG CAL TARE MOD DIAG OTD CAL TARE e RST Condition DIAG CAL TARE MODE 0 DIAGnostic CHECksum DIAGnostic CHECksum performs a checksum operation on Flash Memory A returned value of 1 indicates that Flash memory contents are correct A returned value of 0 indicates that the Flash Memory is corrupted or has been erased Comments Returned Value Returns 1 or 0 The C SCPI type is int16 Usage DIAG CHEC Checksum Flash Memory return 1 for OK 0 for corrupted DIAGnostic CUSTom LlNear DIAGnostic CUSTom LINear lt table_range gt lt table_block gt lt ch_list gt downloads a custom linear Engineering Unit Conversion table in table block to the VT1415A Contact a VXI Technology System Engineer for more information on Custom Engineering Unit Conversion for specific applications Chapter 6 VT1415A Command Reference 195 Parameters Comments Parameter Parameter Range of Default Name Type Values Units table range numeric float32 0 015625 0 03125 0 0625 0 125 volts 0 25 0 5 1 2 41 8 16 32 64 table block definite length See comments none block data ch list channel list string 10
287. e elements 20 29 ALG3 can use elements 30 39 etc through ALG32 which can use elements 320 329 Each of these 10 element areas are called a segment Note that PIDA does not record its operating values and PIDB records four values For PIDB the values stored in each segment are Element Variable Description xx0 Sense Process value monitored xxl Error Setpoint value minus Sense value xx2 Output Process control drive value xx3 Status Sum of bit values for Clips Alarms exceeded xx4 not used xx5 not used Xx6 not used xx7 not used xx8 not used xx9 not used Chapter 3 Programming the VT1415A for PID Control 85 The CVT has a total size of 512 elements Elements 10 through 511 are available to algorithms Elements 0 through 9 are reserved for internal use NOTE After RST Power on each element in the CVT contains the IEEE 754 value Not a Number NaN Channel values which are a positive over voltage return IEEE INF and negative over voltage return IEEE INF Refer to the FORMat command in on page 201 for the NaN INF and INF values for each data format The command used to return values from CVT elements is the SENSe DATA CVT g element list The element list parameter has the same form as a cA list parameter The format of returned data is dependent on the current setting from the FORMat command To access the latest values from PIDB algorithms ALGI SENS DATA CVT 10 13 returns Sense Error Output and Sta
288. e format of values returned is set using the FORMat DATA command Returned Value ASCII values are returned in the form 1 234567E 123 For example 13 325 volts would be 1 3325000E 001 Each value is followed by a comma A line feed LF and End Or Identify EOD follow the last value The C SCPI data type is a string array REAL 32 REAL 64 and PACK 64 values are returned in the IEEE 488 2 1987 Indefinite Length Arbitrary Block Data format This data return format is explained in Arbitrary Block Program Data on page 158 of this chapter For REAL 32 each value is 4 bytes in length the C SCPI data type is a float32 array For REAL 64 and PACK 64 each value is 8 bytes in length the C SCPI data type is a float64 array NOTE Algorithm values which are a positive over voltage return IEEE INF and a negative over voltage return IEEE INF see table on page 202 for actual values for each data format Related Commands SENSE DATA FIFO HALF RST Condition FIFO is empty Usage DATA FIFO return all FIFO values until measurements complete and FIFO empty Command Sequence setup scan lists and trigger SENSE DATA FIFO ALL now execute read statement read statement does not complete until triggered measurements are complete and FIFO is empty SENSe DATA FIFO COUNt SENSe DATA FIFO COUNt returns the number of values currently in the FIFO buffer Comments e DATA FIFO COUNT is used to determine the number of valu
289. e gt lt cmd_data gt 0 06 cece ee 279 Qi os 35 arse rae A A ORT 279 MEIC idad tuse tuse eS diei bom Ces 279 ESE lt Mas coii va th debere e ber i 279 TESE TEM 280 ds dM EET aoa acu ese dana ancl 280 OMO SHaIe s es ente Scis Se eats d ee Paap CA ce RR UR as 280 DAA II E E E 280 EMO a e tees ae aca E E ar Sec A A 281 ul EE TC PCI T II 281 OPE CPC 281 PMC CMT 281 RMC lt name gt luae a PEE SE EXEC 281 TRIS ctun bes anes tete E end marine a pM EE 282 ESRE MASK ea e NO ture Re pec E Ica oe o 283 ESKE puerta aaa Duo 283 STB aid e ade o dd det 283 O E UE ieu kd 283 ETS MT da de 283 UU IPTE 287 Command Quick Reference 00 ccc eee nen 288 CHAPTER A Specifications 0 0 cece cece eee eee eee eee 297 CHAPTER B Error Messages 0 cece ccc c nnn 327 CHAPTER C Glossary oo oie issese sete te css sost rr Rr oie ew des 335 CHAPTER D PID Algorithm Listings 0c cee eeee 339 PIDA ca ad fu un ana 339 PIDD PC e iO A OA OE aa 341 PO EN 346 CHAPTER E Wiring and Noise Reduction Methods 353 Separating Digital and Analog SCP SignalS oo ooooooo 353 Recommended Wiring and Noise Reduction Techniques 354 Wiring Checklist eese e p neo e E aaa ale 354 VT1415A Guard Connections llle 355 Common Mode Voltage Limits 00 00 00 ce eee eee 355 When to Make Shield Connections 0000000 e ee 355 Noise Due t
290. e information void usage char prog_name void fprintf stderr usage s algorithm file n prog name Get an algorithm from a filename static char get algorithm char file name FILE and Algorithm file pointer int32 a size Algorithm size int c Character read from input char algorithm Points to algorithm string f fopen file name r xt Ch lt 4 v void fprintf stderr Error can t open algorithm file s An file name exit 1 a_size 0 Count length of algorithm while getc f EOF a sizett rewind f algorithm malloc a_size 1 Storage for algorithm a_size 0 Use as array index while c getc f EOF Read the algorithm algorithm a size c a sizett algorithm a_size 0 Null terminate void fclose f return algorithm Return algorithm string Main program ARGSUSED Keeps lint happy int main int argc char argv Main program local variable declarations char algorithm Algorithm string int alg num Algorithm number being loaded char string 333 Holds error information int32 error Holds error number dif 1 Set to 1 if reading algorithm files Appendix G Example Program Listings 387 Check pass parameters if arge lt 2 arge gt 33 Must have 1 to 32 algorithm
291. e input relays have been Detected on Input opened and RST is required to reset the module Over voltage will also generate an error 12 4096 VME Memory The number of values taken exceeds VME memory space Overflow 13 8192 Setup Changed Channel Calibration in doubt because SCP setup may have changed since last CAL or CAL SETup command RST always sets this bit Operation Status Group Bit Bit Value Event Name Description 0 1 Calibrating Set by CAL TARE and CAL SETup Cleared by CAL TARE and CAL SETup Set while CAL executing then cleared 4 16 Measuring Set when instrument INITiated Cleared when instrument returns to Trigger Idle State 8 256 Scan Complete Set when each pass through a Scan List is completed 9 512 SCP Trigger Reserved for future SCPs 10 1024 FIFO Half Full FIFO contains at least 32 768 values 11 2048 Algorithm Interrupt The interrupt function was called in an executing algorithm Standard Event Group Bit Bit Value Event Name Description 0 1 Operation Complete OPC command executed and instrument has completed all pending operations 1 2 Request Control Not used by VT1415A 2 4 Query Error Attempting to read empty output queue or output data lost 3 8 Device Dependent Error A device dependent error occurred See Appendix B 4 16 Execution Error Parameter out of range or instrument cannot execute a proper command because it would conflict with another instrument setting 5 32 Command Error Unrecognized command or improp
292. e same and are used the same way as those in BASIC However there are differences and they can cause programming errors until they are recognized The arithmetic operators available to the VT1415A are the same as those equivalents in BASIC addition subtraction multiplication division Again same as BASIC unary minus Examples a b c unary plus a c b Here there are some differences Notes BASIC is equal to Different hard to remember lt gt or is not equal to Different but obvious gt is greater than gt Same lt is less than gt Same gt is greater than or equalto gt Same lt is less than or equal to lt Same A common C programming error for BASIC programmers is to inadvertently use the assignment operator instead of the comparison operator in an if statement Fortunately the VT1415A will flag this as a Syntax Error when the algorithm is loaded There are three operators They are very different from those in BASIC BASIC Examples Cc Examples AND IFA BANDB C amp amp if a b amp amp b c OR IF A B OR A C I if a b a c NOT IF NOT B if b The VT1415A Algorithm Language provides the if else construct for conditional execution The following figure compares the elements of the C if else construct with the BASIC if then else end if construct The general form of the if else const
293. e second channel must be greater than the first Example channels 0 through 15 100 115 By using commas to separate them individual and range specifications can be combined into a single channel list 0 5 6 through 32 and 45 100 105 106 132 145 Note that a channel list is always contained within and The Command Reference always shows the and punctuation Q ch list Arbitrary Block This parameter or data type is used to transfer a block of data in Program and the form of bytes The block of data bytes 1s preceded by a Response Data preamble which indicates either 1 the number of data bytes which follow definite length or 2 that the following data block will be terminated upon receipt of a New Line message and for GPIB operation with the EOI signal true indefinite l length The syntax for this parameter is Definite Length lt non zero digit gt lt digit s gt lt data byte s gt Where the value of lt non zero digit gt is 1 9 and represents the number of lt digit s gt The value of lt digit s gt taken as a decimal integer indicates the number of lt data byte s gt in the block Example of sending or receiving 1024 data bytes 4 1024 lt byte gt lt byte1 gt lt byte2 gt lt byte3 gt lt byte4 gt lt byte1021 gt lt byte1022 gt lt byte1023 gt lt byte1024 gt OR Indefinite Length 0 lt data byte s gt lt NL END gt Examples of sending or receiving 4 data bytes
294. ead these values the algorithms must be stopped use ABORT This forms a record of the algorithm s latest performance In the OVERwrite mode the FIFO cannot be read while it is accepting readings from algorithms Algorithm execution must be stopped before the application program reads the FIFO Here is an example command sequence that can be used to read values from the FIFO after algorithms are stopped ABORT sent SENS DATA FIFO COUNT query count of values in FIFO input n_values here if n_values if any values SENS DATA FIFO PART n_values Format of values set by FORMat input read_data here get remaining values from FIFO end of if 88 Programming the VT1415A for PID Control Chapter 3 Modifying Running Algorithm Variables Updating the The values sent with the ALG SCALAR command are kept in the Update Algorithm Variables Queue until an ALGorithm UPDate command is received and Coefficients ALG UPD cause changes to take place Updates are performed during phase 2 see Figure 3 8 on page 84 of the algorithm execution cycle The UPDate WINDow num updates command can be used to specify how many updates will need to be performed during phase 2 UPDATE phase and assigns a constant window of time to accomplish all of the updates that will be made The default value for num updates is 20 Fewer updates shorter window means slightly faster loop execution times Each update takes approximately 1 4 us To set the Update Wind
295. eally in the C language as the VT1415A s Algorithm Language is based on C See Chapter 5 for a description of the Algorithm Language The contents of this chapter are e Describing the VTI415A 0 eee esee page 112 e What is a Custom Algorithm 0 000000 ce eee page 112 e Overview of the Algorithm Language page 112 e The Algorithm Execution Environment page 113 e Accessing the VT1415A s Resources o o ooooooooo page 115 Accessing I O Channels 0 0000 eee eee eee page 116 Defining and Accessing Global Variables page 117 Determining First Execution page 117 Initializing Variables 0 0 0 0 cece page 118 Sending Data to the CVT and FIFO page 118 Setting a VXIbus Interrupt 0 20 0 eee eee page 119 Determining an Algorithms ID ALG NUM page 119 Calling User Defined Functions 0000 page 120 e Operating Sequence cece eee eee page 120 e Defining Custom Algorithms ALG DEF page 123 e A Very Simple First Algorithm 0205 page 126 e Modifying a Standard PID Algorithm page 127 e Algorithm to Algorithm Communication page 128 Communication Using Channel Identifiers page 128 Communication Using Global Variables page 129 e Non Control Algorithms
296. eclaration initialization statements The string must not contain any executable source code Language Syntax Summary NOTE This section documents the VT1415A s Algorithm Language elements Identifier TEE first character is A Z a z or _ optionally followed by characters A Z a z 0 9 or Only the first 31 characters are significant For example a abc al al2 a 12 now is the time gainl Decimal Constant first character is 0 9 or decimal point Remaining characters if present are 0 9 a one only a single E or e optional or 0 9 For example 0 32 2 123 123 456 1 23456e 2 12 34E3 Decimal constants without a decimal point character are treated by the translator as 32 bit integer values See Data Types on page 138 Hexadecimal Constant first characters are 0x or 0X Remaining characters are 0 9 and A F 6e 5 or a f No allowed Octal Constant first character is 0 Remaining characters are 0 7 If e or E is found the number is assumed to be a Decimal Constant as above Chapter 5 Algorithm Language Reference 141 Primary Expression constant expression scalar identifier scalar identifier bitnumber array identifier expression abs expression max expression expression min expression expression Bit Number Bn where n 0 9 Bnn where nn 10 15 Unary Expression primary expression unary operator
297. ection assumes that the user already programs in some language If the user is a C language programmer the reference section here as well as Chapter 4 Customizing Algorithms is all that will likely be needed to create an algorithm If unfamiliar with the C programming language study the Program Structure and Syntax section before attempting to to write custom algorithms e Language reference 0 cece eee eee page 135 Standard Reserved Keywords 0 000 nanana page 136 Special VT1415A Reserved Keywords page 136 Identifiers 25 ebbe sos aa Deda Ode URGES qoe page 136 Special Identifiers for Channels 0 0000 page 137 Operators ees opaco ee PE OD RH e RT DP Ras page 137 Intrinsic Functions and Statements 0 page 137 Program Flow Control 0 0000 c cee eee page 138 Data Types vestes oat gates wee diea A de o Rede page 138 Data Str clutes ui xS IER ERO ET page 139 Bitfield Access llle page 140 e Language Syntax Summary 0 0 0 e eee page 141 e Program Structure and Syntax 0 0 0 0 cee ee eee page 145 Language Reference This section provides a summary of reserved keywords operators data types constructs intrinsic functions and statements Chapter 5 Algorithm Language Reference 135 Standard Reserved Keywords NOTE Special VT1415A Reserved Keywords Identifiers NOTE The list of reser
298. ecvt expression constant expression writeboth expression constant expression exit expression Expression Statement scalar identifier expression scalar identifier bit number expression array identifier integer constant expression expression intrinsic statement Selection Statement if expression statement if expression statement else statement Compound Statement statement list t NOTE Variable declaration not allowed in compound statement Statement expression statement compound statement selection statement Statement List statement statement list statement Algorithm Definition declarations statement list statement list 144 Algorithm Language Reference Chapter 5 Program Structure and Syntax Declaring Variables Assigning Values NOTE In this section the portion of the C programming language that is directly applicable to the VT1415A s Algorithm Language will be discussed To do this C Algorithm Language elements will be compared with equivalent BASIC language elements In BASIC the DIM statement is typically used to name variables and allocate space in memory for them In the Algorithm Language the variable type and a list of variables is specified BASIC C DIM a var array 3 static float a var array 3 Here three variables are declared Two simple variables a and var and a single dimensioned array array Comme
299. eference Chapter 6 ALGorithm Usage ALG STATE ALG2 0FF disable ALG2 ALGorithm EXPLicit STATe ALGorithm EXPLicit STATe lt alg name gt returns the state enabled or disabled of algorithm lt alg name gt Parameters Parameter Parameter Range of Default Name Type Values Units alg name string ALGI ALG32 none Comments Since ALG STATE is valid for an undefined algorithm ALG STATE will return the current state for alg name gt even if it is not currently defined e Returned Value Numeric 0 or 1 Type is uint16 e RST Condition ALG STATE 1 ALGorithm EXPLicit TIMe ALGorithm EXPLicit TIMe alg name gt computes and returns a worst case execution time estimate in seconds Parameters Parameter Parameter Range of Default Name Type Values Units alg name string ALGI ALG32 or MAIN none Comments When alg name is ALGI through ALG32 ALG TIME returns only the time required to execute the algorithm s code e When alg name is MAIN ALG TIME returns the worst case execution time for an entire measurement amp control cycle sum of MAIN all enabled algorithms analog and digital inputs and control outputs e f triggered more rapidly than the value returned by ALG TIM MAIN the VT1415A will generate a Trigger too fast error NOTE If alg name specifies an undefined algorithm ALG TIM returns 0 Thi
300. el The SCPI command set is used to configure start stop and communicate with the VT1415A The module can be in one of two states the idle state or the running state The INITiate IMMediate command moves the module from the idle state to the running state These two states will be called before INIT and after INIT See Figure 3 2 for the following discussion Before INIT the module is in the Trigger Idle State and its DSP chip the on board control processor is ready to accept virtually any of its SCPI or Common commands At this point send it commands that configure SCPs link input channels to EU conversions configure digital input and output channels configure the trigger system and define control algorithms Chapter 3 Programming the VT1415A for PID Control 55 After INIT and with trigger events occurring the DSP is busy measuring input channels executing algorithm code sending internal algorithm values to the CVT and updating control outputs To insulate the DSP from commands that would interrupt its algorithm execution the VT1415A s driver disallows execution of most SCPI commands after INIT The driver does allow certain commands that make sense while the module is running algorithms These are the commands that read and update algorithm variables retrieve CVT and FIFO data and return Status System values The Command Reference Section Chapter 6 specifies whether a command is accepted
301. ement Parameters Parameter Parameter Range of Default Name Type Values Units channel channel list string 100 163 none Comments Returned Value Numeric value of unstrained voltage The C SCPI type is f1t32 e lt channel gt must specify a single channel only e Related Commands STRAIN UNST Usage STRAIN UNST 9107 query unstrained voltage for channel 7 enter statement here returns the unstrained voltage set by STR UNST SENSe TOTalize RESet MODE SENSe TOTalize RESet MODE lt select gt lt ch_list gt sets the mode for resetting totalizer channels in lt ch_list gt 252 VT1415A Command Reference Chapter 6 Parameters SENSe Parameter Parameter Range of Default Name Type Values Units select discrete string INIT TRIGger seconds ch list string 100 163 none Comments e Usage SENS TOT RESET MODE TRIG 134 In the INIT mode the total is reset only when the INITiate command is executed In the TRIGger mode the total is reset every time a new scan is triggered If the channels specified are not on a Frequency Totalize SCP an error will be generated Related Commands SENS FUNC TOT INPUT POLARITY RST Condition SENS TOT RESET MODE INIT totalizer at channel 34 resets at each trigger event Chapter 6 VT1415A Command Reference 253 SENSe SENSe TOTalize RESet MODE SENSe TOTalize RESet MODE
302. ency Ecm is very effectively rejected by a good differential instrumentation amplifier and it can be averaged out when measured through the Direct Input SCP VT1501A However high frequency Ecm is rectified and generates an offset with the amplifier and filter SCPs such as VT1502A VT1503A VT1508A and VT1509A This is since these SCPs have buffer amplifiers on board and is a characteristic of amplifiers The best way to deal with this is to prevent the noise from getting into the amplifier Most common mode noise is about 60 Hz so the differential amplifier rejection is very good The amplifier Common Mode Noise characteristics are 120 dB flat to 300 Hz then 20 dB octave rolloff The VT1415A amplifiers are selected for low gain error offset temperature drift and low power These characteristics are generally incompatible with good high frequency CMR performance More expensive high performance amplifiers can solve this problem but since they aren t required for many systems VXI Technology elected to handle this with the High Frequency Common Mode Filter option to the VT1586A Remote Rack Panel VT1586A 001 RF Filter discussed below Shielded twisted pair lead wire generally does a good job of keeping high frequency common mode noise out of the amplifier provided the shield is connected to the VT1415A chassis ground through a very low impedance Not via the guard terminal The VT1415A guard terminal connection shown in the VT1
303. ent Value Table specified by cA list Resets all entries in the Current Value Table to IEEE Not a number 290 VT1415A Command Reference Chapter 6 Command Quick Reference Command EALL COUNt HALF HALF MODE BLOCK OVERwrite MODE PART lt n_readings gt RESet FREQuency APERture lt gate_time gt lt ch_list gt APERture lt channel gt FUNCtion CONDition lt ch_list gt CUSTom lt range gt lt ch_list gt REFerence lt range gt lt ch_list gt TC lt type gt lt range gt O lt ch_list gt FREQuency lt ch_list gt RESistance lt excite_current gt lt range gt lt ch_list gt STRain FBENding lt range gt lt ch_list gt FBPoisson lt range gt lt ch_list gt FPOisson lt range gt lt ch_list gt HBENding lt range gt lt ch_list gt HPOisson lt range gt lt ch_list gt QUARter lt range gt lt ch_list gt SCPI Command Quick Reference RTD TCouple CUST E EEXT J K N S T THERmistor TEMPerature lt sensor_type gt lt sub_type gt lt range gt lt ch_list gt TOTalize lt ch_list gt VOLTage DC lt range gt lt ch_list gt RTD 85 92 THERmistor 5000 REFerence lt sensor_type gt lt sub_type gt lt range gt lt ch_list gt CHANnels lt ref channel gt lt ch_list gt TEMPerature lt degrees_c gt STRain EXCitat
304. equency Sending MIN for the cutoff freq selects the SCP s lowest cutoff frequency To disable filtering the pass through mode execute the INP FILT STATE OFF command Sending a value greater than the SCP s highest cutoff frequency or less than the SCP s lowest cutoff frequency generates a 222 Data out of range error When Accepted Not while INITiated Related Commands INP FILT FREQ INP FILT STAT ON OFF RST Condition set to MIN Chapter 6 VT1415A Command Reference 205 Usage INP FILT FREQ 100 100 119 Set cutoff frequency of 100 Hz for first 20 channels INPUT FILTER FREQ 2 155 Set cutoff frequency of 2 Hz for channel 55 INPut FILTer LPASs FREQuency INPut FILTer LPASs FREQuency lt channel gt returns the cutoff frequency currently set for lt channel gt Non programmable SCP channels may be queried to determine their fixed cutoff frequency If the channel is not on an input SCP the query will return zero Parameters Parameter Parameter Range of Default Name Type Values Units channel channel list string 100 163 none Comments channel must specify a single channel only e This command is for programmable filter SCPs only e Returned Value Numeric value of Hz as set by the INP FILT FREQ command The C SCPI type is float32 e When Accepted Not while INITiated e Related Commands INP FILT LPAS FREQ INP FILT STATE e RST Condition MIN
305. er capabilities Module s serial number is earlier than 3313A00530 Multiple attempts to erase Flash Memory failed Multiple attempts to program Flash Memory failed Programming voltage jumper not set properly See Disabling Flash Memory Access in Chapter 1 JM2201 Identification of Flash ROM incorrect Checksum error on Flash Memory WARNING Old Opt 16 or Opt 17 card can damage SCP modules must use VT1506A 07A Too many entries in CVT list Invalid entry in CVT list Can only be 10 to 511 Too many updates in queue Must send UPDATE command To allow more updates per ALG UPD increase ALG UPD WINDOW Invalid Algorithm name Can only be ALG1 through ALG32 or GLOBALS or MAIN Algorithm is undefined In ALG SCAL ALG SCAL ALG ARR or ALG ARR Algorithm already defined Trying to repeat ALG DEF with same alg name gt and is not enabled to swap or trying to define GLOBALS again since last RST Variable is undefined Algorithm exists but has no local variable by that name Invalid Variable name Must be valid C identifier see Chapter 5 Global symbol variable or custom function already defined Trying to define a global variable with same name as a user defined function or vice versa User functions are also global Algorithmic error queue full ALG DEF has generated too many errors from the
306. er 6 VT1415A Command Reference 259 STATus STATus The STATus subsystem communicates with the SCPI defined Operation and Questionable Data status register sets Each is comprised of a Condition register a set of Positive and Negative Transition Filter registers an Event register and an Enable register Condition registers allow the current real time states of their status signal inputs signal states are not latched to be viewed The Positive and Negative Transition Filter registers allow the polarity of change from the Condition registers to be controlled that will set Event register bits Event registers contain latched representations of signal transition events from their Condition register Querying an Event register reads and then clears its contents making it ready to record further event transitions from its Condition register Enable registers are used to select which signals from an Event register will be logically OR ed together to form a summary bit in the Status Byte Summary register Setting a bit to one in an Enable register enables the corresponding bit from its Event register NOTE For a complete discussion see Using the Status System on page 93 Condition P N Transition Even Enable 7 HAA gt BitO 5 latch 1 T Logical gt Bit 1 m latch OR Summary Bit 1 Status Byte NS ANA o 71 E y Bit 1
307. er parameter count or type 6 64 User Request Not used by VT1415A i 128 Power On Power has been applied to the instrument Enabling Events to be Reported in the Status Byte Configuring the Transition Filters There are two sets of registers that individual status conditions must pass through before that condition can be recorded in a group s Event Register These are the Transition Filter Registers and the Enable registers They provide selectivity in recording and reporting module status conditions Figure 3 12 shows that the Condition Register outputs are routed to the input of the Negative Transition and Positive Transition Filter Registers For space reasons they are shown together but are controlled by individual SCPI commands Here is the truth table for the Transition Filter Registers 96 Programming the VT1415A for PID Control Chapter 3 Configuring the Enable Registers Condition Reg Bit PTRansition Reg Bit NTRansition Reg Bit Event Reg Input 021 0 0 0 190 0 021 1 10 1 021 0 190 0 1 1 0 0 0 1 1 021 1 1 0 1 0 0 1 1 1290 The Power on default condition is All Positive Transition Filter Register bits set to one and all Negative Transition Filter Register bits set to 0 This applies to both the Operation and Questionable Data Groups An Example Using the Operation Group Suppose it is necessary to have the module report via the Status S
308. er sets the condition that will reset the totalizer count to zero For more on this VT1534A capability see the SCP s User s Manual To set the VT1534A s totalize reset mode SENSe TOTalize RESet MODE INIT TRIG lt ch_list gt To configure VT1534A channels to the totalizer function SENSe FUNCtion TOTalize lt ch_list gt Digital outputs can be configured for polarity output drive type and depending on the SCP model a selection of output functions as well The following discussion will explain which functions are available with a particular Digital I O SCP model Setting a digital channel s output function is what defines it as an output channel To specify the output polarity logical sense for digital channels use the command OUTPut POLarity lt mode gt lt ch_list gt This capability is available on all digital SCP models This setting is valid even while the specified channel in not an output channel If and when the channel is configured for output an output FUNCtion command the setting will be in effect e The lt mode gt parameter can be either NORMal or INVerted When set to NORM an output channel set to logic 0 will output a TTL compatible low When set to INV an output channel set to logic 0 will output a TTL compatible high e The lt ch_list gt parameter specifies the channels to configure The VT1533A has 2 channels of 8 bits each All 8 bits in a channel take on the configuration specified for
309. er than 1 V dc or an input out of range condition will exist The sub type EEXTended applies to E type thermocouples at 800 C and above The CAL command calibrates temperature channels based on Sense Amplifier SCP setup at the time of execution If SCP settings are changed those channels are no longer calibrated CAL must be executed again Related Commands DIAG CUST PIEC CAL SENS REF and SENS REF TEMP RST Condition all custom EU tables erased Usage program must put table constants into array table block DIAG CUST PIEC 1 table_block 100 107 send characterized thermocouple table for use by channels 0 7 SENS FUNC CUST TC N 25 100 107 link custom thermocouple EU with chs 0 7 use reference temperature compensation for N type wire SENSE REF RTD 92 120 designate a channel to measure the reference junction temperature include these channels in a scan list REF channel first INITiate then TRIGger module SENSe FUNCtion FREQuency SENSe FUNCtion FREQuency lt ch_list gt sets the SENSe function to frequency for channels in cA list Also configures the channels specified as digital inputs Parameters Parameter Parameter Range of Default Name Type Values Units ch list string 100 163 none Comments e If the channels specified are on an SCP that doesn t support this function an error will be generated See the SCP s User s Manual for its capabilities
310. erates Modifying the Standard PIDA A PID is to control a bath temperature at 140 C With the Setpoint at 140 and the process variable PV reading 130 the value sent to the output is a positive value which drives the digital output to 1 heater on When the process value reading reaches 140 the error term would equal zero so the value sent to the digital output would be 0 heater off Fine so far but as the bath temperature coasts even minutely above the setpoint a small negative value will be sent to the digital output which represents a boolean true value At this point the output will again be 1 heater on and the bath temperature will continue go up rather than down This process is now out of control This behavior is easy to fix Simply modify the standard PIDA algorithm source code supplied with the VT14154A in the file PIDA C and then define it as a custom algorithm Use the following steps 1 Load the source file for the standard PIDA algorithm into a text editor 2 Find the line of code near the end of PIDA that reads outchan Error P factor out D factor Error Error old and insert this line below it if outchan lt 0 outchan 0 all value not positive are now zero 3 Going back to the beginning of the file change all occurrences of inchan to the input channel specifier of choice e g 1100 4 As in step 3 change all occurrences of outchan to the digital output channel
311. eriod value on a pulse width modulated pulse channel This sets the frequency 1 period of the pulse width modulated pulse train Parameters Parameter Parameter Range of Default Name Type Values Units period numeric float32 25E 6 to 7 8125E 3 seconds resolution 0 238 us ch list string 100 163 none Comments If the channels specified are not on a Frequency Totalize SCP an error will be generated e RST Condition SOUR FM STATE OFF and SOUR PULM STATE OFF e Related Commands SOUR PULM STATE SOUR PULS POLarity e The variable pulse width control for this channel is provided by the algorithm language When the algorithm executes an assignment statement to this channel the value assigned will be the pulse width setting For example 0140 0025 set channel 43 pulse width to 2 5 ms Usage SOUR PULS PER 005 140 set PWM pulse train to 200 Hz on channel 40 SOURce PULSe PERiod SOURce PULSe PERiod lt channel gt returns the fixed pulse period value on the pulse width modulated pulse channel in channel Parameters Parameter Parameter Range of Default Name Type Values Units channel string 100 163 none Comments e If the channels specified are not on a Frequency Totalize SCP an error will be generated 258 VT1415A Command Reference Chapter 6 SOURce e Returned Value numeric period The type is float32 SOURce PULSe
312. error in the error queue As written the Function will figure out which instrument generated the error retrieve the error print a message and exit You may want to modify the way the error is printed or comment out the exit if you want the program to continue Note that this works only on REGISTER based instruments because it was a C SCPI register based feature not a general programming improvement If you re using MESSAGE instruments you ll still have to do SYST ERR If your test program generates errors on purpose you probably don t want this error function If so set the following if 1 to fif 0 This function is most useful when you re trying to get your program running dif 1 Set to 0 to skip trapping errors ARGSUSED Keeps lint happy void cscpi error INST id int err char errorbuf 255 Holds instrument error message char idbuf 255 Holds instrument response to IDN cscpi_exe id IDN n 6 idbuf 255 cscpi exe id SYST ERR n 10 errorbuf 255 void fprintf stderr Instrument error s from s n errorbuf idbuf Hendif The following routine allows you to type SCPI commands and see the results If you don t call this from your program set the following if 1 to dif 0 Appendix G Example Program Listings 399 Sif 1 void do interactive void char command 5000 char result 50
313. errupt LINe lt intr_line gt INTerrupt LINe OTDetect STATe ON OFF lt ch_list gt OTDetect STATe lt channel gt QUERy SCPREAD lt reg_addr gt VERSion FETCh FORMat DATA lt format gt lt size gt ASCii 7 PACKed 64 REAL 32 REAL 64 DATA INITiate IMMediate INPut FILTer LPASs FREQuenoy lt cutoff_freq gt lt ch_list gt FREQuency lt channel gt SCPI Command Quick Reference Description Calibrate out system field wiring offsets Resets cal constants from CAL TARE back to zero for all channels Returns state of CAL TARE operation returns error codes or 0 for OK Send to instrument the value of just measured reference resistor Send to instrument the value of just measured voltage reference Correct A D for short term offset drift returns error codes or 0 for OK Set analog DAC output SCP calibration mode Return current setting of DAC calibration mode Set mode to control OTD current during tare calibration Return current setting of OTD control during tare calibration Perform checksum on Flash RAM and return a 1 for OK a 0 for corrupted or deleted memory contents Writes values to SCP registers Loads linear custom EU table Loads piecewise custom EU table Puts the contents of the Reference Temperature Register into the FIFO Sets the VXIbus interrupt line the module will use Returns the V XIbus interrupt line the module is using
314. ervice Request line The difference is that while executing a GPIB serial poll SPOLL releases the SRQ line executing the STB command does not clear the RQS bit in the Status Byte The Event Register must be read of the group whose summary bit is causing the RQS Status groups can be directly polled for instrument status rather than via polling the Status Byte for summary information The Questionable Data Operation Status and Standard Event Groups all have Event Registers These Registers log the occurrence of even temporary status conditions When read these registers return the sum of the decimal values for the condition bits set then are cleared to make them ready to log further events The commands to read these Event Registers are STAT QUES EVENT Questionable Data Group Event Register STAT OPER EVENT Operation Status Group Event Register ESR Standard Event Group Event Register To clear the Event Registers without reading them execute CLS clears all group s Event Registers The Questionable Data and Operation Status Groups each have a Condition Register The Condition Register reflects the group s status condition in real time These registers are not latched so transient events may be missed when the register is read The commands to read these registers are STAT QUES COND Questionable Data Group Condition Register STAT OPER COND Operation Status Group Condition Register Chapter 3
315. es then return to Trig Idle State The VT1415A can output trigger signals on any of the VXIbus TTLTRG lines Use the OUTPut TTLTrg lt n gt STATe ON OFF command to select one of the TTLTRG lines and then choose the source that will drive the TTLTRG line with the command OUTPut TTLTrg SOURce command For details see OUTP TTLTRG commands starting on page 219 To output a signal on the TTLTRGI line each time the Trigger Timer cycles execute the commands TRIG SOUR TIMER select trig timer as trig source OUTP TTLTRG1 ON select and enable TTLTRGI line OUTP TTLTRG SOUR TRIG each trigger output on TTLTRGI INITiating Running Algorithms Starting the PID Algorithm When the INITiate IMMediate command is sent the VT1415A builds the input Scan List from the input channels referenced when the algorithm was defined with the ALG DEF command above The module also enters the Waiting For Trigger state In this state all that 1s required to run the algorithm is a trigger event for each pass through the input calculate output cycle To initiate the module send the command INIT module to Waiting for Trigger State When an INIT command is executed the driver checks several interrelated settings programmed in the previous steps If there are conflicts in these settings an error message is placed in the Error Queue read with the SYST ERR command Some examples e If TRIG SOUR is not TIMer then ARM SOUR must be IMMediate e The time it w
316. es to acquire with the DATA FIFO PART command Returned Value Numeric 0 through 65 024 The C SCPI type is int32 Related Commands DATA FIFO PART RST Condition FIFO empty Usage DATA FIFO COUNT Check the number of values in the FIFO buffer 232 VT1415A Command Reference Chapter 6 SENSe DATA FIFO COUNt HALF SENSe DATA FIFO COUNt HALF returns a 1 if the FIFO is at least half full contains at least 32 768 values or 0 if FIFO is less than half full Comments DATA FIFO COUNT HALF is used as a fast method to poll the FIFO for the half full condition e Returned Value Numeric 1 or 0 The C SCPI type is int16 e Related Commands DATA FIFO HALF e RST Condition FIFO empty Command Sequence DATA FIFO COUNT HALF poll FIFO for half full status DATA FIFO HALF returns 32 768 values SENSe DATA FIFO HALF SENSe DATA FIFO HALF returns 32 768 values if the FIFO buffer is at least half full This command provides a fast means of acquiring blocks of values from the buffer Comments e For acquiring data from continuous algorithm executions an application needs to execute a DATA FIFO HALF command and a read statement often enough to keep up with the rate that values are being sent to the FIFO e Use the DATA FIFO ALL command to acquire the values remaining in the FIFO buffer after the ABORT command has stopped execution e The format of values returned is set using the FORMat DATA command e Ret
317. et using the FORMat DATA command e Returned Value ASCII values are returned in the form 1 234567E 123 For example 13 325 volts would be 1 3325000E 001 Each value is followed by a comma A line feed LF and End Or Identify EOI follow the last value The C SCPI data type is a string array REAL 32 REAL 64 and PACK 64 values are returned in the IEEE 488 2 1987 Definite Length Arbitrary Block Data format This data return format is explained in Arbitrary Block Program Data on page 158 of this chapter For REAL 32 each value is 4 bytes in length the C SCPI data type is a float32 array For REAL 64 and PACK 64 each value is 8 bytes in length the C SCPI data type is a float64 array NOTE Algorithm values which are a positive over voltage return IEEE INF and a negative over voltage return IEEE INF see table on page 202 for actual values for each data format e Related Commands DATA FIFO COUNT e RST Condition FIFO buffer empty Usage DATA FIFO PART 256 return 256 values from FIFO Chapter 6 VT1415A Command Reference 235 SENSe SENSe DATA FIFO RESet SENSe DATA FIFO RESet clears the FIFO of values The FIFO counter is reset to 0 Comments When Accepted Not while INITiated e Related Commands SENSE DATA FIFO e RST Condition SENSE DATA FIFO RESET Usage SENSE DATA FIFO RESET Clear the FIFO SENSe FREQuency APERture SENSe FREQuency APERture lt gate_time gt lt ch_list g
318. eturns the gain currently set for lt channel gt If the channel is not on an input SCP the query will return zero Parameters Parameter Parameter Range of Default Name Type Values Units channel channel list string 100 163 none Comments channel must specify a single channel only e f the channel specified does not have a programmable amplifier INP GAIN will return the nominal as designed gain for that channel e Returned Value Numeric value as set by the INP GAIN command The C SCPI type is float32 e When Accepted Not while INITiated e Related Commands INP GAIN e RST Condition gain set to 1 Usage INPUT GAIN 9105 Check gain on channel 5 INP GAIN 100 Check gain on channel 0 INPut LOW INPut LOW lt wvolt_type gt lt ch_list gt controls the connection of input LO at a Strain Bridge SCP channel specified by lt ch_list gt LO can be connected to the Wagner Voltage ground or left floating Parameters Parameter Parameter Range of Default Name Type Values Units wvolt type discrete string FLOat WVOLtage none ch list channel list string 100 163 none 208 VT1415A Command Reference Chapter 6 INPut e Related Commands INP LOW Comments e RST Condition INP LOW FLOAT all Option 21 channels Usage INP LOW WVOL 100 103 116 119 connect LO of channels 0 th
319. ew code to run No error Error RST ALG DEF ALG3 200 if 0108 lt 15 0 0108 0108 0 1 else 0108 15 0 INIT starts algorithm ALG DEF ALG3 200 if 0108 lt 12 0 0108 0108 0 2 else 0108 12 0 Algorithm swapping already enabled Can t change size Because swap size included at re definition 1 Channels referenced by algorithms when they are defined are only placed in the channel list before INIT The list cannot be changed after INIT If an algorithm is re defined by swapping after INIT and it references channels not already in the channel list it will not be able to access the newly referenced channels No error message will be generated To make sure all required channels will be 168 VT1415A Command Reference Chapter 6 ALGorithm included in the channel list define lt alg_name gt and re define all algorithms that will replace a g name by swapping them before sending INIT This insures that all channels referenced in these algorithms will be available after INIT If an algorithm is re defined by swapping after INIT and it declares an existing variable the declaration initialization statement e g static float my var 3 5 will not change the current value of that variable The driver only calculates overall execution time for algorithms defined before INIT This calculation is used to set the default output delay same as executing ALG OUTP DELAY AUTO If an algorithm is s
320. ew he ee eee wee a Wee Eee ee OEE cA XR Rs Qoae Ewe ee page 281 FOPO ione Ow Pea wes Eur Se Pee ews Cee See eee OHSS EE SEE page 281 ODC Ls E a OE eee oo RE a e dU ke Bo eS page 281 12 22 5 iaa aa ee page 281 RMG SHIT e uei et oo dg de puo e GP ais qoos page 281 Ql PPP dd a UN hy a da eed GM uence Traction a da Saeco page 282 MORE wa Wig ee ea a A A hes page 283 TORE arde de a Ga Sco St he Ma Be Gn ts BU oS he a ee ds page 283 SUB sew ke dele ASS He ORR EES SE A a as page 283 MAG m gc ch Fy he eevee ai fer eee oe Genes py ete hey ac egy ee eh gs os Ges ee a ue es oe Ge page 283 ESTI krae Sse at oe oh ee A ee eo Ne eee ee le ee ee ee ei page 283 UMWELT page 287 Command Fundamentals Commands are separated into two types IEEE 488 2 Common Commands and SCPI Commands The SCPI command set for the VT1415A is 1990 compatible Common The IEEE 488 2 standard defines the Common commands that perform functions Command like reset self test status byte query etc Common commands are four or five F t characters in length always begin with the asterisk character and may include orma one or more parameters The command keyword is separated from the first parameter by a space character Some examples of Common commands are RST ESR 32 STB Chapter 6 VT1415A Command Reference 155 SCPI The SCPI commands perform functions like configuring channels setting up the Command trigger system and querying instrument states or retriev
321. ew values are discarded e OVERwrite mode is used record the latest 65 024 values The module must be halted ABORT sent before attempting to read the FIFO In OVERwrite Mode if the FIFO becomes full and measurements are still being made new values overwrite the oldest values e n both modes Error 3021 FIFO Overflow is generated to indicate that measurements have been lost e When Accepted Not while INITiated e Related Commands SENSE DATA FIFO MODE SENSE DATA FIFO ALL SENSE DATA FIFO HALF SENSE DATA FIFO PART SENSE DATA FIFO COUNT e RST Condition SENSE DATA FIFO MODE BLOCk Usage SENSE DATA FIFO MODE OVERWRITE Set FIFO to overwrite mode DATA FIFO MODE BLOCK Set FIFO to block mode 234 VT1415A Command Reference Chapter 6 SENSe DATA FIFO MODE SENSe DATA FIFO MODE returns the currently set FIFO mode Comments Returned Value String value either BLOCK or OVERWRITE The C SCPI type is string e Related Commands SENSE DATA FIFO MODE Usage DATA FIFO MODE Enter statement returns either BLOCK or OVERWRITE SENSe DATA FIFO PART SENSe DATA FIFO PART n values returns n values from the FIFO buffer Parameters Parameter Parameter Range of Default Name Type Values Units n values numeric int32 1 2 147 483 647 none Comments Use the DATA FIFO COUNT command to determine the number of values in the FIFO buffer e The format of values returned is s
322. f the statement following the else clause Figure 5 2 shows examples of these forms BASIC Syntax 4 Examples gt C Syntax IF A 0 THEN C ABS A IF A 0 THEN C B A END IF IF A lt gt B AND A lt gt C THEN A A B B B 1 C20 END IF IF A 5 OR B 5 THEN C ABS C C 2 C ELSE C A B END IF if a lt 0 c abs a if a 0 c b a if a b amp amp a c a a b b b I c 0 if 5 b 5 c abs c c 2 cC else c a b Figure 5 2 Examples of C and BASIC if Statements Chapter 5 Algorithm Language Reference 147 Note that in C else is part of the closest previous if statement So the example if x ify z 1 else z 2 executes like not like if x if x if y if Cy 1 z l z l else Z 2 else Z 2 Comment Lines Probably the most important element of programming is the comment In older BASIC interpreters the comment line began with REM and ended at the end of line character s probably carriage return then linefeed Later BASICs allowed comments to also begin with various shorthand characters such as or In all cases a comment ended when the end of line is encountered In C and the Algorithm Language comments begin with the the two characters and continue until the two characters are encountered Examples this
323. fiers Use if word var BO word var B3 if either bit 0 or bit 3 true word var B15 1 set bit 15 i NOTES 1 A bitfield structure does not have to be declared in order to use it In the Algorithm Language the bitfield structure is assumed to be applicable to any simple variable including channel identifiers 2 Unlike C the Algorithm Language allows for both bit access and whole access to the same variable Example static float my word var my word var 255 set bits 0 through 7 my word var B3 0 clear bit 3 140 Algorithm Language Reference Chapter 5 Declaration Initialization NOTE Global Variables Only simple variables not array members may be initialized in the declaration statement static float my var 2 The initialization of the variable only occurs when the algorithm is first defined with the ALG DEF command The first time the algorithm is executed module INITed and triggered the value will be as initialized But when the module is stopped ABORT command and then re INITiated the variable will not be re initialized but will contain the value last assigned during program execution In order to initialize variables each time the module is re INITialized see Determining First Execution on page 117 To declare global variables execute the SCPI command ALG DEF GLOBALS lt program_string gt The program string can contain simple variable and array variable d
324. g table Format IEEE Term Value Meaning ASCIii INF 9 9E37 Positive Overload INF 9 9E37 Negative Overload NaN 9 91E37 No Reading REAL 32 INF 7F800000 Positive Overload INF FF800000 Negative Overload NaN TFFFFFFF 6 No Reading REAL 64 INF FF000 00 Positive Overload INF FFF000 00 Negative Overload NaN 7FFF FF No Reading PACKed 64 INF 47D2 9EAD 3677 AF6F Positive Overload 9 0E37 19 INF C7D2 9EAD 3677 AF6F Negative Overload 9 0E37 0 NaN 47D2 A37D CED4 6143 No Reading 9 91E37 0 Usage FORMAT REAL FORM REAL 64 FORMAT ASCII 7 Set format to IEEE 32 bit Floating Point Set format to IEEE 64 bit Floating Point Set format to 7 bit ASCII 202 VT1415A Command Reference Chapter 6 FORMat FORMat DATA FORMat DATA returns the currently set response data format for readings Comments Returned Value Returns REAL 32 REAL 64 PACK 64 ASC 7 The C SCPI type is string int16 e Related Commands FORMAT e RST Condition ASCII 7 Usage FORMAT Returns REAL 32 REAL 64 PACK 64 ASC 7 Chapter 6 VT1415A Command Reference 203 INITiate INITiate The INITiate command subsystem moves the VT1415A from the Trigger Idle state to the Waiting For Trigger state When initiated the instrument is ready to receive one IMMediate or more depending on TRIG COUNT
325. g 100 163 none Chapter 6 VT1415A Command Reference 249 SENSe Comments Usage SENSe STRain Parameters Comments Usage SENSe STRain Parameters Comments Usage e Returned Value Numeric value of excitation voltage The C SCPI type is f1t32 e lt channel gt must specify a single channel only e Related Commands STRAIN EXCitation STRAIN EXC 107 query excitation voltage for channel 7 enter statement here returns the excitation voltage set by STR EXC GFACtor SENSe STRain GFACtor lt gage_factor gt lt ch_list gt specifies the gage factor to be used to convert strain bridge readings for the channels specified by lt ch_list gt Parameter Parameter Range of Default Name Type Values Units gage_factor numeric f1t32 1 5 none ch_list channel list string 100 163 none e lt ch_list gt must specify the channel used to sense the bridge voltage not the channel position on a Bridge Completion SCP e Related Commands SENSE STRAIN GFAC SENSE FUNC STRAIN e RST Condition Gage factor is 2 STRAIN GFAC 3 100 107 set gage factor for channels 0 through 7 GFACtor SENSe STRain GFACtor lt channel gt returns the gage factor currently set for the sense channel specified by channel Parameter Parameter Range of Default Name Type Values Units channel channel list string 100 163 none e Re
326. g 100 163 none Comments channel must specify a single channel e Ifthe channel specified is on an SCP that doesn t support this function an error will be generated See the SCP s User s Manual to determine its capabilities e Returned Value returns NORM or INV The type is string 210 VT1415A Command Reference Chapter 6 MEMory The MEMory subsystem allows using VME memory as an additional reading storage buffer Subsystem Syntax MEMory VME ADDRess lt A24 address gt ADDRess SIZE lt mem_size gt SIZE STATe 1 0 ON OFF STATe NOTE This subsystem is only available in systems using an Agilent HP E1405B 06A command module Use Sequence RST MEM VME ADDR H300000 MEM VME SIZE H100000 1 MB or 262 144 readings MEM VME STAT ON ii set up VTI415A for scanning TRIG SOUR IMM let unit trigger on INIT INIT OPC program execution remains here until VME memory is full or the VT1415A has stopped taking readings FORM REAL 64 affects only the return of data FETCH return data from VME memory NOTE When using the MEM subsystem the module must be triggered before executing the INIT command as shown above unless an external trigger EXT trigger is being used When using EXT trigger the trigger can occur at any time Chapter 6 VT1415A Command Reference 211 MEMory VME ADDRess MEMory VME ADDRess A24 address sets the A24 address of the V
327. g an algorithms identity ALG NUM 119 Determining first execution First loop 117 Determining model SCPI programming 280 DIAG CHECK 195 DIAG CUST REF TEMP 197 DIAG INT LINe 198 DIAG INT LINe 198 DIAGnostic DIAGnostic CALibration SETup MODE 193 DIAGnostic CALibration SETup MODe 194 DIAGnostic CALibration TARe MODE 194 DIAGnostic CALibration TARe MODE 195 DIAGnostic CUSTom LINear 195 DIAGnostic CUSTom PIECewise 196 DIAGnostic IEEE 197 DIAGnostic IEEE 198 DIAGnostic CALibration SETup MODE 194 DIAGnostic CALibration SETup MODE 193 DIAGnostic CA Libration TARe MODE 194 DIAGnostic CALibration TARe MODE 195 DIAGnostic CUSTom LINear 195 DIAGnostic CUSTom PIECewise 196 DIAGnostic IEEE 197 DIAGnostic IEEE 198 DIAGnostic OTDetect 107 Directly reading status groups 99 Disabling flash memory access optional 25 Disabling the input protect feature optional 25 Does what CAL 74 Drivers 27 DSP 336 Index 415 E ENABle STAT OPER ENABle 263 STAT QUES ENABle 267 ENABle STAT OPER ENABle 263 STAT QUES ENABle 268 Enabling and disabling algorithms 89 Enabling events to be reported in the status byte 96 Environment the algorithm execution 113 Equality expression 143 Equality operator 143 Error Messages 327 328 329 330 331 332 333 334 Self Test 329 ERRor SYST ERRor 271 EU 336 EU Conversion 336 EVENt STAT OPER EVENt 264 STAT QUES EVENt 268 Example
328. g point calculation a complex waveform such as sine x could take more than 100 us to get the desired result A faster solution is desirable and available The VT1415A provides a solution to approximating such complex waveforms by using a piece wise linearization of virtually any complex waveform The technique is simple The DOS disc supplied with the VTI415A contains both a C and Rocky Mountain BASIC program which calculates 128 Mx B segments over a specified range of values for the desired function The user supplies the function the program generates the segments in a table The resulting table can be downloaded into the VT1415A s RAM with the ALG FUNC DEF command where any desired name of the function i e sin x tan x etc can be selected Up to 32 functions can be created for use in algorithms At runtime where the function is passed an x value the time to calculate the Mx B function is approximately 17 us The VT14154 actually uses this technique to convert volts to temperature strain etc The accuracy of the approximation is really based upon how well the range is selected over which the table is built For thermocouple temperature conversion the VT1415A fixes the range to the lowest A D range 64 millivolts so that small microvolt measurements yield the proper resolution of the actual temperature for a non linear transducer In addition the VT1415A permits Custom Engineering Unit conversions to be created for cu
329. ge 71 Performing Channel Calibration Important page 74 Defining PID algorithms 2 000005 page 75 The VT1415A s Standard PID algorithms page 75 Pre setting PID variables and coefficients page 79 Defining Data Storage 00 0 0 cece eee eee page 79 Specifying the Data Format page 79 Selecting the FIFO Mode 0 0005 page 80 Setting up the Trigger System 005 page 80 Arm and Trigger Sources 00 000 e eee page 80 Programming the Trigger Timer page 82 INITiating Running Algorithms page 83 The Operating Sequence 0 0 0 0 nterra page 84 Reading Running Algorithm Values page 85 Reading History Mode Values From the FIFO page 86 Reading Algorithm Values From the CVT page 85 Reading Algorithm Variables o page 85 Modifying Algorithm Variables o page 89 Updating Algorithm Variables page 89 Enabling Disabling Algorithms page 89 Setting Algorithm Execution Frequency page 90 A Quick Start PID Algorithm Example page 91 Algorithm Tuning 00 00 cece cece r pinn Ta page 93 Using the Status System 2 2 eee eee page 93 VT1415A Background Operation 00005 page 100 Updating the Status System and VXI Interrupts
330. gin Data Retrieval STAT OPER COND bit 4 Measuring Yes Algorithms Stopped Enough Values In FIFO Execute Bulk Transfer command DATA FIFO COUNT gt DATA FIFO PART n values gt Execute Final Transfer command Exit Data Retrieval Figure 3 9 Controlling Reading Count Chapter 3 Programming the VT1415A for PID Control 87 An example command sequence for Figure 3 9 is provided below It assumes that the FIFO mode was set to BLOCK and that at least one algorithm is sending values to the FIFO a PIDB with History mode set to 1 following loop reads number of values in FIFO while algorithms executing loop while measuring bit is true see STAT OPER COND bit 4 SENS DATA FIFO COUNT query for count of values in FIFO input n_values here if n_values gt 16384 Set the minimum block size to transfer SENS DATA FIFO PART n values ask for n values input read data here Format depends on FORMat cmd end if end while loop following checks for values remaining in FIFO after measuring false SENS DATA FIFO COUNT query for values still in FIFO input n_values here if n_values if any values SENS DATA FIFO PART n values input read data here get remaining values from FIFO end if Reading the Latest FIFO Values FIFO mode OVER In this mode the FIFO always contains the latest values up to the FIFO s capacity of 65 024 values from running algorithms In order to r
331. ging the Man out variable User initiated changes in Man out will cause the output to slew to the E Man out value at a rate of Man inc per scan trigger Kf Manual control causes the Setpoint to continually change to match the Process Variable and the Integral term to be constantly updated ay to the output value such that a return to automatic control will be bumpless and will use the current Process Variable value as th ai new setpoint ay The Status variable indicates when the Manual control mode is active Af Appendix D PID Algorithm Listings 341 ee EJ At startup in the Manual control mode the output will slew to Man out at a rate of Man inc per scan trigger E f E At startup in the Automatic control mode the output will abruptly idi change to P factor Error Je T For process monitoring data may be sent to the FIFO and current Ef value table CVT There are two levels of data logging controlled s i by the History mode variable The location in the CVT is based ay on n where n is the algorithm number as returned by ALG NUM for example The first value is placed in the 10 n th 32 bit word of the CVT The other values are written in subsequent locations pe E History mode 0 Summary to CVT only In this mode four values are output to the CVT as EJ Location Value ey
332. gorithms can only be called from MAIN Error 33 Reference to an undefined algorithm Error 34 Attempt to redefine an existing symbol var or fn Error 35 Array size is 1 1024 Error 36 Expecting a default PID parameter Error 37 Too many FIFO or CVT writes per scan trigger Error 38 Statement is too complex Error 39 Unterminated comment 3085 Algorithm too big Algorithm exceeded 46k words 23k 1f enabled to swap or exceeded size specified in swap _size gt 332 Error Messages Appendix B 3086 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3099 3100 3101 3102 3103 Not enough memory to compile Algorithm The algorithm s constructs are using too much translator memory Need more memory in the Agilent HP E1406 Try breaking the algorithm into smaller algorithms Too many functions Limit is 32 user defined functions Bad Algorithm array index Must be from 0 to declared size 1 Algorithm Compiler Internal Error Call VXI Technology with details of operation Illegal while not initiated Send INIT before this command No updates in queue legal Variable Type Sent ALG SCAL with identifier of array ALG ARR with scalar identifier ALG UPD CHAN with identifier that is not a channel etc Invalid Array Size Must be 1 to 1024 Invalid Algorithm Number Must be ALG
333. gram In particular it is usually best to put instrument addresses in this area to make the code more maintainable define E1415 ADDR vxi 208 The SICL address of your E1415 INST DECL el415 E1415A REGISTER E1415 Use something like this for GPIB and Agilent E1405 6 Command Module Appendix G Example Program Listings 385 define E1415 ADDR hpib 22 26 The SICL address of your E1415 INST DECL e1415 E1415A MESSAGE E1415 Declare instruments that will be accessed with SICL These declarations can also be moved into local contexts INST vxi VXI interface session 5 X FF Xo F X CACA rap instrument errors If this function is used it will be called every time a C SCPI instrument puts an error in the error queue As written the Function will figure out which instrument generated th rror retrieve the error print a message and exit You may want to modify the way the error is printed or comment out the exit if you want the program to continue Note that this works only on REGISTER based instruments because it was a C SCPI register based feature not a general programming improvement If you re using MESSAGE instruments you ll still have to do SYST ERR If your test program generates errors on purpose you probably don t want this error function If so set
334. grouping channels to signal conditioning 31 sense vs output SCPs 33 SCP Power Available 297 SCP setting the HP E1505 current source 61 SCPI commands DIAGnostic OTDetect 107 SCPI Commands 151 Format 156 SCPs and Terminal Module 35 Selecting the FIFO mode 80 Selecting the trigger source 81 Selecting trigger timer arm source 82 Selection statement 144 Self test and C SCPI for MS DOS R 284 how to read results 284 Self Test error messages 329 Sending Data to the CVT and FIFO 118 SENS DATA CVT RESet 231 SENS DATA FIFO COUNt HALF 233 SENS DATA FIFO COUNt 232 SENS DATA FIFO HALF 233 SENS DATA FIFO MODE 234 SENS DATA FIFO MODE 235 SENS DATA FIFO PART 235 SENS DATA FIFO RESet 236 SENS FUNC CUST REF 238 SENS FUNC CUST TC 239 SENS FUNC RESistance 241 SENS FUNC STRain 242 SENS FUNC TEMPerature 243 SENS FUNC VOL Tage 245 SENS REF TEMPerature 248 SENS REFerence 246 SENSe subsystem 228 229 230 232 234 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 SENSe CHANnel SETTling 229 SENSe CHANnel SETTling 229 SENSe DATA CVTable 230 SENSe FREQuency APERture 236 SENSe FREQuency APERture 236 SENSe FUNC CONDition 237 SENSe FUNC CUSTom 237 SENSe FUNCtion FREQuency 240 SENSe FUNCtion TOTalize 245 SENSe REFerence CHANnels 248 SENSe STRain EXCitation 249 SENSe STRain EXCitation 249 SENSe STRain GFACtor 250 SENSe STRain GFACto
335. h 7 none Comments e Related Commands DIAG INT LINE e Power on and RST Condition DIAG INT LINE 1 Usage DIAG INT LINE 5 Module will interrupt on VXIbus interrupt line 5 DIAGnostic INTerrupt LINe e PACKed 64 returns the same values as REAL 64 except for Not a Number NaN IEEE INF and IEEE INF The NaN IEEE INF and IEEE INF values returned by PACKed 64 are in a form compatible with HP Workstation BASIC and HP BASIC UX Refer to the FORMat command for the actual values for NaN INF and INF e ASCii is the default format 198 VT1415A Command Reference Chapter 6 DIAGnostic ASCII readings are returned in the form 1 234567E 123 For example 13 325 volts would be 1 3325000E 001 Each reading is followed by a comma A line feed LF and End Or Identify EOI follow the last reading Related Commands MEMory Subsystem FORMat DATA RST Condition MEMORY VME ADDRESS 240000 MEMORY VME STATE OFF MEMORY VME SIZE 0 Chapter 6 VT1415A Command Reference 199 DIAGnostic Use Sequence MEM VME ADDR H300000 MEM VME SIZE H100000 1 megabyte MB or 262 144 readings MEM VME STAT ON set up VTI415A for scanning TRIG SOUR IMM Let unit trigger on INIT INIT Program execution remains here until VME memory is full or the VTI415A has stopped taking readings FORM REAL 64 Affects only the return of data FETCH NOTE When using the MEM subsystem the module mu
336. han Man out 348 PID Algorithm Listings Appendix D Set manual mode bit in status word Statu No err Statu s B4 1 or alarms s B5 0 while in Manual mode In case we exit manual mode on the next trigger Set up for bumpless transfer I out Setpo PV ol Setpo outchan int d inchan int old inchan inchan Do PID calculations when not in Manual mode else if Man state Status B4 0 First find the Process Variable error This calculation has gain of minus one 1 Error Setpoint inchan Test for error out of limits if Error gt Error max Error min gt Error if Status B5 Status B5 1 alarmchan 1 interrupt else Status B5 0 On the first trigger after INIT initialize the I and D terms if First_loop For no abrupt output change at startup make the I term cancel the P term I out outchan Error I factor P factor Zero the derivative terms PV old inchan Setpoint old Setpoint On subsequent triggers continue integrating else not First trigger I out Error I factor I out Clip the Integral term to specified limits it I out gt I max I out I max Status Bl 1 else if I min gt I out I out I min Status Bl 1 else Status Bl 0 Calculate the Setpoin
337. he slope or M value A Ax X X Appendix G Example Program Listings 401 void Build table float64 max input uint16 uint16 uint16 uinti int32 int16 int16 int32 int32 int32 floa floa floa floa floa floa floa floa floa floa floa Firs inpu inpu the AC A A F FN M center o temp range test range that test range t64 t64 t64 t64 t64 t64 t64 t64 t64 t64 t64 based upon a relative centering about the X axis permits the run tim C The intercept or B value INPUT PARAMETERS float64 max input maximum input expected float64 min input minimum input expected float64 custom function float64 input pointer to user function OUTPUT PARAMETERS A float64 range returned table rang iS float64 offset returned table offset uintl6 conv array returned coeficient array 512 values for piecewise F float64 min input float64 custom function float64 input float64 range float64 offset uintl16 conv_array M 128 EX 128 Bhigh 128 Blow 128 B ii jj Mfactor Xfactor Xofst test range tbl range center temp range t slope absslope exponent exponent2 input 129 result 129 t calculate the mid point of t values Th ts The purpos the range of values from the min and max offset is the center of the range of min an
338. he Analog Input list selects the Analog Output list selects the Digital Input list selects the Digital Output list e Returned Value Numeric The C SCPI type is int16 e RST Condition The Analog Input list returns 8 the others return 0 Usage ROUT SEQ POINTS AIN query for analog input channel count Chapter 6 VT1415A Command Reference 225 SAMPle SAMPle The SAMPle subsystem provides commands to set and query the interval between channel measurements pacing Subsystem Syntax SAMPle SAMPle TIMer TIMer interval TIMer SAMPle TIMer interval sets the time interval between channel measurements It is used to provide additional channel settling time See Settling Characteristics discussion on page 108 Parameters Parameter Parameter Range of Default Name Type Values Units interval numeric float32 1 0E 5 to 16 3825E 3 seconds string MIN MAX Comments e The minimum lt interval gt is 10 us The resolution for lt interval gt is 2 5 us If the Sample Timer interval multiplied by the number of channels in the specified Scan List is longer than the Trigger Timer interval at run time a Trigger too fast error will be generated the SAMP TIMER interval can change the effect of the SENS CHAN SETTLING command ALG CHAN SETT specifies the number of times a channel measurement should be repeated The total settling time per channel then is SAM
339. he CAL SETUP or CAL TARE commands have completed Instead use their query forms CAL SETUP or CAL TARE Purge Macros Command Purges all currently defined macros Remove individual Macro Command Removes the named macro command Chapter 6 VT1415A Command Reference 281 Common Command Reference RST WARNING Reset Command Resets the VT1415A as follows e Frases all algorithms e All elements in the Input Channel Buffer 1100 1163 set to zero e All elements in the Output Channel Buffer 0100 0163 set to zero e Defines all Analog Input channels to measure voltage e Configures all Digital I O channels as inputs e Resets VT1531A and VT1532A Analog Output SCP channels to zero e When Accepted Not while INITiated Note the change in character of output channels when RST is received Digital outputs change to inputs appearing now is 1 kW to 3 V a TTL one and analog control outputs change to zero current or voltage Keep these changes in mind when applying the VT1415A to a system or engineering a system for operation with the VT1415A Also note that each analog output channels disconnects for 5 6 milliseconds to discharge to zero at each RST It isn t difficult to have the VT1415A signal a system when RST is executed A solution that can provide signals for several types of failures as well as signaling when RST is executed is the Agilent HP E1535 Watchdog Timer SCP The Watchdog SCP even has an input through whi
340. he following Product Specifications Safety IEC 1010 1 1990 Incl Amend 1 1992 EN61010 1 1993 CSA C22 2 1010 1 1992 UL 3111 EMC CISPR 11 1990 EN55011 1991 Group 1 Class A IEC 801 2 1991 EN50082 1 1992 4kV CD 8kV AD IEC 801 3 1984 EN50082 1 1992 3V m IEC 801 4 1988 EN50082 1 1992 1kV Power Line 0 5kV Signal Lines Supplementary Information The product herewith complies with the requirements of the Low Voltage Directive 73 23 EEC and the EMC Directive 89 336 EEC inclusive 93 68 EEC and carries the CE marking accordingly Tested in a typical configuration in an HP C Size VXI mainframe July 30 2004 teve Mauga QA Manager vi Table of Contents lucu MMC 111 Safety Symbols 2545 er iras ra a pas iv Note for European Customers ssela sertap 0000 cece i E ees iv Support RESOUTCES eee cete tee PLC I eror EE O T UR xvii Chapter 1 Getting Started 00 0 ccc ccc ce cece cece ee ee ees 19 About This Chapters osic 244 aes cate a eed Sees eda wea MAG wed weds 19 Configuring the VTI415A 20 2 eee nee 19 Setting the Logical Address Switch 0 000000 e eee 20 Installing SEPS seg sheen ee eee ac doe ates 21 Disabling the Input Protect Feature Optional 25 Disabling Flash Memory Access Optional ooo o o o oo 25 Instrument Drivers oes arre per Ee ER ER 27 About Example Programs 000 0 c a E ees 27 Verifying a Successful Configuration
341. he standard PID algorithms can provide excellent general closed loop process control there will be times when a process has specialized requirements that are not addressed by the default form of the VT1415A s PID algorithms This section shows how to copy and modify a standard PID algorithm Both of the VT1415A s standard PID algorithms PIDA and PIDB are also available as source files supplied with the VT1415A Also included is a source file for a PIDC algorithm PIDC has more features than PIDB but is not pre defined in the VT1415A s driver like PIDA and PIDB It is only available as a source file The VT1415A s PID algorithms are written to supply control outputs through analog output SCPs While it would not be an error to specify a digital channel as the PID control output the PID algorithm as written would not operate the digital channel as desired The value written to a digital output bit 1s evaluated as if it were a boolean value That is if the value represents a boolean true the digital output is set to a binary 1 If the value represents a boolean false the digital output is set to a binary 0 The VT1415A s Algorithm Language like C specifies that a value of 0 is a boolean false 0 any other value is considered true 1 With that in mind the operation of a standard PIDA will be analyzed with a digital output as its control output Chapter 4 Creating and Running Custom Algorithms 127 How the Standard PIDA Op
342. hm following the two PIDs to inspect their output values and make adjustments to them before they are sent to output channels The decoupler algorithm s Decoupl_factor1 and Decouple factor2 variables assumes a simple interaction are local and can be independently set using ALG SCALAR decoupler algorithm must follow the coupled algorithms in execution sequence static float Decouple factor1 Decouple_factor2 0124 0124 Decouple factor2 0125 0125 0125 Decouple_factor1 0124 0124 0124 Decoupl factor1 Setpoint E ALG3 E C PID Controller ALG1 De coupler D 0125 Decoupl factor2 0125 gt Setpoint EN O PID Controller ALG2 i Process Interaction Figure 4 3 Algorithm Communication with Channels Communication A more traditional method of inter algorithm communication uses global g g Using Global variables Global variables are defined using the ALG DEF command in the form Variables ALG DEF GLOBALS variable declaration statements Example of global declaration ALG DEF GLOBALS static float cold setpoint Implementing Feed Forward In this example two algorithms mix hot and cold water supplies in a ratio Control that results in a tank being filled to a desired temperature The temperature of the make up supplies is assumed to be constant Figure 4 4 shows the process diagram To set up the algorithms for this example 1 Define the global variab
343. iate 8 P Enable zi g gt 9 TTLTrg lt n gt D p a SCP Trig E Trigger Counter gt TRIGger COUNt lt count gt Selecting the Trigger Source Figure 3 7 Logical Arm and Trigger Model In order to start an algorithm execution cycle a trigger event must occur The source of this event is selected with the TRIGger SOURce lt source gt command The following table explains the possible choices for lt source gt Parameter Value Source of Trigger after INITiate command BUS TRIGger IMMediate TRG GET for GPIB EXTernal TRG signal input on terminal module HOLD TRIGger IMMediate IMMediate The trigger signal is always true scan starts when an INITiate command is received SCP SCP Trigger Bus future SCP Breadboard TIMer The internal trigger interval timer must set Arm Source TTLTrg lt n gt The VXlbus TTLTRG lines n 0 through 7 NOTES 1 When TRIGger SOURce is not TlMer ARM SOURce must be set to IMMediate the RST condition If not the INIT command will generate an error 221 Settings conflict 2 When TRIGger SOURce is TlMer the trigger timer interval TRIG TIM lt interval gt must allow enough time to scan all channels execute all algorithms and update all outputs or a 3012 Trigger Too Fast error will be generated during the algorithm cycle See the TRIG TIM command on page 277 for details To set the trigger source to the interna
344. id fprintf stderr Failed to open the E1415 at address s n E1415 ADDR void fprintf stderr C SCPI open error was d n cscpi open error void fprintf stderr SICL error was d s n igeterrno igeterrstr igeterrno exit 1 Check for startup errors INST QUERY e1415 syst err n d S amp error string if error void printf syst err d s n error string exit 1 Usually you ll want to start from a known instrument state The following provides this l 394 Example Program Listings Appendix G INST CLEAR e1415 Selected device clear INST SEND e1415 RST CLSWMn if O Set to 1 to do self test Does the E1415 pass self test int test_result Result of E1415 self test test_result 1 Make sure it gets assigned INST QUERY e1415 TST n Sd amp test result if test_result void fprintf stderr E1415A failed self testin exit 1 endif Setup SCP functions INST_SEND e1415 sens func volt 116 n Analog in volts Ef INST SEND e1415 sour func cond 141 n Digital output dif 0 Set to 1 to do calibration Perform Calibrate if necessary int cal result Result of E1415 self test cal result 1 Make sure it gets assigned INST QUERY e1415 CAL n Sd amp cal res
345. identifiers appear as variable identifiers within the algorithm and have a fixed reserved syntax The identifiers 1100 to 1163 specify input channel numbers The I must be uppercase They may only appear on the right side of an assignment operator The identifiers O100 to O163 specify output channel numbers The O must be uppercase They can appear on either or both sides of the assignment operator Trying to declare a variable with a channel identifier will generate an error The VT1415A s Algorithm Language supports the following operators assignment example c 1 2345 addition examples c a b subtraction c a b multiplication c a b division c a b unary minus c a b unary plus c a tb is equal to examples a is not equal to al b lt is less than a lt b gt is greater than a gt b lt is less than or equal to a lt b gt is greater than or equal to a gt b or examples a b a c amp amp and a b amp amp a c not example lb The result of a comparison operation is a boolean value It is still a type float but its value is either 0 zero if false or 1 one if true Any variable can be tested with the if statement A value of zero tests false if any other value it tests true For example if my var is other than 0 increment count var if my var count var count var 1 The following functions and statements
346. ied in the DATA CVT command that have not been written to be an algorithm will return the value 9 91E37 e RST Condition All elements of CVT contains IEEE 754 Not a Number Usage SENS DATA CVT 10 13 Return all variables from Std PIDB ALG1 DATA CVT 30 38 Return all nine variables from PIDC ALG3 DATA CVT 10 13 Return only element 0 Sense and element 3 Status from PID ALGI DATA CVT 330 337 350 360 Return custom algorithm values from elements 330 337 350 and 360 SENSe DATA CVTable RESet SENSe DATA CV Table RESet sets all 64 Current Value Table entries to the IEEE 754 Not a number Comments The value of NaN is 9 910000E 037 ASCII e Executing DATA CVT RES while the module is INITiated will generate an error 3000 Illegal while initiated e When Accepted Not while INITiated e Related Commands SENSE DATA CVT e RST Condition SENSE DATA CVT RESET Usage SENSE DATA CVT RESET Clear the Current Value Table SENSe DATA FIFO ALL SENSe DATA FIFO ALL returns all values remaining in the FIFO buffer until all measurements are complete or until the number of values returned exceeds FIFO buffer size 65 024 Comments DATA FIFO may be used to acquire all values even while they are being made into a single large buffer or can be used after one or more DATA FIFO HALF commands to return the remaining values from the FIFO Chapter 6 VT1415A Command Reference 231 SENSe Th
347. ield Hi A Lo Example for E Guard Jumper may be left in Resistive Transducers is at VT1415A GND Potential Es place since Current Lo Current Hi Current Lo o Figure 2 6 Preferred Signal Connections 40 Field Wiring Chapter 2 Terminal Module External Connections 1 ko G0 o GND to GRD Jumper o removable For each Zr SCP Position FT gt 1 ko G7o VVV 2 o4yuF GND to GRD Jumper 10 ka ji removable i Figure 2 7 GRD GND Circuitry on Terminal Module Removing Guard to Ground on Channel 00 N
348. il all algorithms called First loop declared by static float First loop global value set to 1 at each INIT VT1415Avs driver RR Oda function main eii The VT1415 driver Begin main function creates main at INIT time This example shows a main created built by VT1415A s driver after 2 algorithms have been defined main declaration of variables local to main static float State 1 Ratio 1 Count 1 created if alg1 defined static float State_2 Ratio_2 Count_2 created if alg2 defined this section created if ALG1 is defined Count 1 Count 1 1 Count 1 used for ALG SCAN RATIO E if Count 1 lt 0 test for ratio met 20 means execute Count 1 Ratio 1 Count 1 ALG SCAN RATIO setting J if State_1 alg1 if ALG STATE ALG1 ON call alg1 End main function __ s this section created if ALG2 is defined Count 2 Count 2 1 Count 2 used for ALG SCAN RATIO Begin algorithm shells it Count 2 0 test for ratio met lt 0 means built by VT1415A s driver or n Count 2 Ratio 2 Count 2 ALG SCAN RATIO setting El if State 2 alg2 if ALG STATE ALG2 ON call alg2 Your algorithms go here First_loop 0 reset First_loop after last alg has been called f Settee EEE and function main FRERER REA ekeeke de AR
349. ilable to all defined algorithms Values for lt range gt offset and func data are generated by a program supplied with the VT1415A It is provided in C SCPI and Agilent BASIC forms See Appendix F Generating User Defined Functions for full information The range and lt offset gt parameters define the allowable input values to the function domain If values input to the function are equal to or outside of lt range gt lt offset gt the function may return INF in IEEE 754 format For example range 8 8 to 8 offset 12 The allowable input values must be greater than 4 and less than 20 The func data parameter is a 512 element array of type uint16 The algorithm syntax for calling is function name expression for example 0116 squareroot 2 Input val Functions must be defined before defining algorithms that reference them When Accepted Before INIT only Usage ALG FUNC DEF F1 8 12 block data send range offset and table values for function F1 174 VT1415A Command Reference Chapter 6 ALGorithm ALGorithm OUTPut DELay ALGorithm OUTPut DELay delay sets the delay from Scan Trigger to start of output phase Parameters Parameter Parameter Range of Default Name Type Values Units delay numeric float32 0 0 081 AUTO 2 5 us resolution seconds Comments The algorithm output statements e g O115 Out val
350. ill be easiest to understand what is being done if the waveforms stay near the X 0 point since most of the measurement results will have 1e 6 16 values for volts One final note Truncation errors may be seen in the fourth digit of the results This is because only 15 bits of the input value is sent to the function This occurs because the same technique used for Custom EU conversion is used here and the method assumes input values are from the 16 bit A D 15 bits sign bit This 1s evident in Table F 1 where the first and last entries return 40 9999 rather than 1 For most applications this accuracy should be more than adequate 362 Generating User Defined Functions Appendix F Program Listings C Version Header C SCPI Example program for the E1415A Algorithmic Closed Loop Controller sine fn cs S Z This is a general purpose example of using Custom Functions to generate a haversine function This is a template for building E1415A C programs that may use C SCPI or SICL to control instruments gt Standard include files include lt stdlib h gt Most programs use one or more functions from the C standard library bald include lt stdio h gt Most programs will also use standard I O functions include lt stddef h gt This file is also often useful include lt math h gt Needed for any floating point fn s Other s
351. imal weighted bit values Enable registers can be set using decimal hex octal or binary The following table can be used to help set Enable registers using decimal and decode register queries Status System Decimal Weighted Bit Values bit 15 14 13 12 11 10 9 8 7 6 5 4 321 0 value always 0 16 384 8 192 4 096 2 048 1 024 512 256 128 64 32 16 8 4 2 1 The Operation Status Group The Operation Status Group indicates the current operating state of the VT1415A The bit assignments are Bit decvalue hex value Bit Name Description 0 1 00011 Calibrating Set by CAL TARE and CAL SETup Cleared by CAL TARE and CAL SETup Set while CAL executes and reset when CAL completes Set by CAL CONFIG VOLT or CAL CONFIG RES cleared by CAL VAL VOLT or CAL VAL RES EA Not used 4 16 0010 Measuring Set when instrument INITiated Cleared when Instrument returns to Trigger Idle State 5 7 Not used 8 256 0100 6 Scan Complete Set when each pass through a Scan List completed may not indicate all measurements have been taken when TRIG COUNT gt 1 9 512 0200 SCP Trigger An SCP has sourced a trigger event future VT1415A SCPs 10 1024 0400 FIFO Half Full The FIFO contains at least 32 768 readings 11 2048 0800 6 Algorithm Interrupted The interrupt function was called in an algorithm 12 15 Not used
352. in the Channel Output Buffer are used to update the output channel hardware during the Output Phase In other words algorithms don t actually read inputs at the time they reference input channels and they don t send values to outputs at the time they reference output channels Algorithms read channel values from an input buffer and write and can read output values to from an output buffer Here are example algorithm statements to describe operation inp val 1108 inp val is assigned a value from input buffer element 8 0116 22 3 output buffer element 16 assigned the value 22 3 0125 0124 output buffer 24 is read and assigned to output buffer 25 Since the buffered input algorithm execution buffered output sequence is probably unfamiliar to many a programming mistake associated with it is easy to make A common error is shown below and it is hoped that seeing this error will prevent its occurrence 0124 B0 1 digital output bit on VT1533A in SCP position 3 0124 B0 0 Traditionally the first of these two statements is expected to set output channel 24 bit 0 to a digital 1 then after the time it takes to execute the second statement the bit would return to a digital 0 Because both of these statements are executed BEFORE any values are sent to the output hardware only the last statement has any effect Even if these two statements were in separate algorithms the last one executed would dete
353. ine Example The following is an example of creating a haversine function a sine wave over the range of 7 to 7 The resulting function represents a fairly accurate approximation of this non linear waveform when the range is limited as indicated Since the tables must be built upon binary boundaries i e 0 125 0 25 0 5 1 2 4 etc and since 7 2 is a number greater than 1 but less than 2 the next binary interval to include this range will be 2 Another requirement for building the table is that the waveform range MUST be centered around 0 1 e symmetrical about the X axis Ifthe desired function is not defined on one side or the other of the Y axis then the table is right or left shifted by the offset from X 0 and the table values are calculated correctly but the table is built as though it were centered about the X axis For the most part the last couple of sentences can be ignored if they do not make sense The only reason its brought up here is that accuracy may suffer the farther away the waveform gets from the X 0 point unless it is understood what resolution is available and how much non linearity is present in the waveform This will be discussed later in the Limitations section Figure F 1 shows the haversine function as stated above This type of waveform is typical of the kind of acceleration and deceleration one wants when moving an object from one point to another The desired beginning point would be the location at
354. ing data A subsystem Format command structure is a hierarchical structure that usually consists of a top level or root command one or more lower level commands and their parameters The following example shows part of a typical subsystem MEMory VME ADDRess 424 address gt ADDRess SIZE lt mem_size gt SIZE MEMory is the root command VME is the second level command and ADDRess and SIZE are third level commands Command Separator A colon always separates one command from the next lower level command as shown below ROUTE SEQUENCE DEFINE Colons separate the root command from the second level command ROUTE SEQUENCE and the second level from the third level SEQUENCE DEFINE If parameters are present the first is separated from the command by a space character Additional parameters are separated from each other by commas Abbreviated The command syntax shows most commands as a mixture of upper and lowercase Commands letters The uppercase letters indicate the abbreviated spelling for the command For shorter program lines send the abbreviated form For better program readability send the entire command The instrument will accept either the abbreviated form or the entire command For example if the command syntax shows SEQuence then SEQ and SEQUENCE are both acceptable forms Other forms of SEQuence such as SEQUEN or SEQU will generate an error Upper or lowercase letters may be used Therefore SEQUEN
355. ing for the Trigger Timer If programmed to a shorter time the module will generate a Trigger too fast error How is the minimum time determined After all algorithms are defined send the ALG TIME command with its alg name gt parameter set to MAIN This causes the VT1415A s driver to analyze the time required for all four phases of the execution cycle Input Update Calculate and Output The value returned from ALG TIME MAIN is the minimum allowable Trigger Timer interval With this information execute the command TRIGger TIMer interval and set interval to a time that is equal to or greater than the minimum See Starting the PID Algorithm in a later section in this chapter for more on phases of the execution cycle 82 Programming the VT1415A for PID Control Chapter 3 Setting the Trigger Counter Outputting Trigger Signals The Trigger Counter controls how many trigger events will be allowed to start an input calculate output cycle When the number of trigger events set with the TRIGger COUNt command is reached the module returns to the Trigger Idle State needs to be INITiated again The default Trigger Count is 0 which is the same as INF can be triggered an unlimited number of times This setting will be used most often because it allows un interrupted execution of control algorithms To set the trigger count to 50 perhaps to help debug an algorithm TRIG COUNT 50 execute algorithms 50 tim
356. int to prevent ground loops See Preferred Measurement Connections later in this section and Wiring and Noise Reduction Methods in Appendix E 34 Field Wiring Chapter 2 Terminal Modules The SCPs and Terminal Module Terminal Module Layout The VT1415A is comprised of an A D module and a spring clamp type Terminal Module The terminals utilize a spring clamp terminal for connecting solid or stranded wire Connection is made with a simple push of a three pronged insertion tool P N 8710 2127 which is shipped with the VT1415A If the spring clamp terminal module is not desired an interface to a rack mount terminal panel Option A3F is available see page 49 The Terminal Module provides the following e Terminal connections to field wiring e Strain relief for the wiring bundle e Reference junction temperature sensing for thermocouple measurements e Ground to Guard connections for each channel The same Terminal is used for all field wiring regardless of which Signal Conditioning Plug On SCP is used Each SCP includes a set of labels to map that SCP s channels to the Terminal Module s terminal blocks See step 4 in Installing Signal Conditioning Plug Ons in Chapter 1 page 24 for VT1415A Terminal Modules Figure 2 3 shows a Terminal Module for the VT1415A Chapter 2 Field Wiring 35
357. ion float64 maxInput set to maximum expected input float64 minInput set to minimum expected input float64 tableOffset offset used in building table uintl6 coef array 512 512 elements float64 tableRange Range on which table was built maxInput 2 minInput 2 Build table maxInput minInput my function amp tableRange amp tableOffset coef array Download the table range and the table array to the card Piecewise requires 128 sets of table values E INST SEND el415 ALGorithm FUNCtion DEFine sin f f 1024b tableRange tableOffset coef array Download algorithms if O Set to 1 if algorithms passed in as files Get an algorithm s from the passed filename s We assign sequential algorithm numbers to each successive file name ALG1 ALG2 etc when you execute this program as progname langl lang2 lang3 nd Appendix G Example Program Listings 407 J alg num 1 Starting algorithm number while argc gt alg num algorithm get algorithm argv alg num Read the algorithm Define the algorithm char alg 6 Temporary algorithm name void sprintf alg ALG d alg num INST SEND e1415 alg def S B n alg strlen algorithm 1 algorithm Check for algorithm errors INST QUERY e1415 syst err n d 5 amp error string if error void printf While loading
358. ion No algorithms or variables are defined Chapter 6 VT1415A Command Reference 169 ALGorithm Usage ALG SCAL ALG1 my var 1 2345 ALG SCAL ALG1 another 5 4321 ALG SCAL ALG3 my global var 1 001 ALG UPD ALGorithm EXPLicit SCALar 1 2345 to variable my var in ALGI 5 4321 to variable another also in ALGI 1 001 to global variable update variables from update queue ALGorithm EXPLicit SCALar alg name cvar name returns the value of the scalar variable var name in algorithm lt alg_name gt Parameters Parameter Parameter Range of Default Name Type Values Units alg name string ALGI ALG32 none var name string Valid C variable name none Comments An error is generated if alg name or var name is not defined e Returned Value numeric value The type is float32 ALGorithm EXPLicit SCAN RATio ALGorithm EXPLicit SCAN RATio lt alg_name gt lt num_trigs gt specifies the number of scan triggers that must occur for each execution of algorithm alg name This allows the specified algorithm to be executed less often than other algorithms This can be useful for algorithm tuning NOTES 1 The command ALG SCAN RATio alg name num trigs does not take effect until an ALG UPDATE or ALG UPD CHAN command is received This allows multiple ALG SCAN RATIO commands to be sent with their effect synchronized with ALG UPDATE 2 ALG SCAN R
359. ion lt excite_v gt lt ch_list gt STRain EXCitation lt excite_v gt lt ch_list gt EXCitation lt channel gt GFACtor lt gage_factor gt lt ch_list gt GFACtor lt channel gt POISson lt poisson_ratio gt lt ch_list gt Description Fetch all readings until instrument returns to trigger idle state Returns the number of measurements in the FIFO buffer Returns if at least 32 768 readings are in FIFO else returns 0 Fetch 32 768 readings half the FIFO when available Set FIFO mode Return the currently set FIFO mode Fetch n_readings from FIFO reading buffer when available Reset the FIFO counter to 0 Sets the gate time for frequency counting Returns the gate time set for frequency counting Equate a function and range with groups of channels Sets function to sense digital state Links channels to custom EU conversion table loaded by DIAG CUST LIN or DIAG CUST PIEC commands Links channels to custom reference temperature EU conversion table loaded by DIAG CUST PIEC commands Links channels to custom temperature EU conversion table loaded by DIAG CUST PIEC and performs ref temp compensation for lt type gt Configure channels to measure frequency Configure channels to sense resistance measurements Links measurement channels as having read bridge voltage from Full BENding Full Bending Poisson Full POisson Half BENding Half Poisson QUARter 85 92 thermocouples 2250 5000 10000 Configure cha
360. irst TRigger is used to generate a single TTL TRG output when repeated triggers are being used to make multiple executions of the enabled algorithms The TTLTRG line will go low asserted at the first trigger event and stay low through subsequent triggers until the trigger count as set by TRIG COUNT is exhausted At this point the TTL TRG line will return to its high state de asserted This feature can be used to signal when the VT1415A has started running its control algorithms e Related Commands OUTP TTLT lt n gt STATE OUTP TTLT SOUR TRIG SOUR TRIG COUNT e RST Condition OUTP TTLT SOUR TRIG Usage OUTP TTLT SOUR TRIG toggle TTLTRG line every time module is triggered use to trigger other VT1415As OUTPut TTLTrg SOURce OUTPut TTLTrg SOURce returns the current setting for the TTL TRG line source Comments Returned Value Discrete one of TRIG FTR or SCP C SCPI type is string e Related Commands OUTP TTLT SOUR Usage OUTP TTLT SOUR enter statement will return on of FTR SCP or TRIG OUTPut TTLTrg n STATe OUTPut TTLTrg lt n gt STATe ttltrg cntrI specifies which VXIbus TTLTRG line is enabled to source a trigger signal when the module is triggered TTLTrg lt n gt can specify line 0 through 7 For example TTLTRGA or TTLT4 for VXIbus TTLTRG line 4 220 VT1415A Command Reference Chapter 6 OUTPut Parameters Parameter Parameter Range of Default Name Type Values Units ttltrg cntrl boo
361. is an octal digit No decimal point or exponent specified 32 bit hexadecimal integer OXhhh or Oxhhh where h is a hex digit 32 bit floating point ddd ddd ddd dddetdd dddEtdd ddd dddedd or ddd dddEdd where d is a decimal digit Flow Control conditional construct if else Intrinsic Functions Return minimum min lt expr1 gt lt expr2 gt Return maximum max lt expr1 gt lt expr2 gt User defined function lt user_name gt lt expr gt Write value to CVT element writecvt lt expr gt lt expr gt Write value to FIFO buffer writefifo lt expr gt Write value to both CVT and FIFO writeboth lt expr gt lt expr gt Here are examples of some Algorithm Language elements assembled to show them used in context Later sections will explain any unfamiliar elements seen here Example 1 get input from channel 8 calculate output check limits output to ch 16 amp 17 static float output_max 020 20 mA max output static float output min 004 4 mA min output static float input val output val intermediate I O vars input val_ 1108 output val 12 5 input val if output val gt output max output val output max else if output val lt output min output val output min 0116 output val 2 0117 output val 2 Example 2 same function as example 1 above but shows a different approach static float max output 020
362. it 4 If some improvement is seen increase the sample period again and perform another test When the sample period is increased and no improvement is seen the maximum settling delay that any single channel requires has been found 5 If the quality of the measurements does not respond to this increase in sample period then inadequate settling time is not likely to be causing measurement problems If the system scans fast enough with the increased sample period the problem is solved The system is only running as fast as the slowest channel allows but if it s fast enough that s OK If on the other hand getting quality readings has slowed the scan rate too much there are two other methods that can either separately or in combination have the system making good measurements as fast as possible Amplifier SCPs can remove the need to increase settling delays How Each gain factor of 4 provided by the SCP amplifier allows the Range Amplifier to be set one range higher and still provide the same measurement resolution Amplifier SCPs for the VT1415A are available with gains of 0 5 8 16 64 and 512 Now return to the earlier example of a difficult measurement where one channel is measuring 15 5 volts on the 16 volt range and the next a thermocouple on the 0 0625 range If the thermocouple channel is amplified through an SCP with a gain of 16 the Range Amplifier can be set to the 1 volt range On this range the A D resolution drops
363. ithm will receive from that channel The DSP chip Digital Signal Processor keeps track of SCP gain and Range Amplifier settings and calculates a value that reflects the signal level at the input terminal The only time this in not true is when the SCP gain chosen would cause the output of the SCP amplifier to be too great for the selected A D range An example with SCP gain set to 64 an input signal greater than 0 25 volts would cause an overrange reading even with the A D set to its 16 volt range The gain command for SCPs with programmable amplifiers is INPut GAIN lt gain gt lt ch_list gt to select SCP channel gain The gain selections provided by the SCP can be assigned to any channel individually or in groups Send a separate command for each gain selection An example for the VT1503A programmable Amp amp Filter SCP To set the SCP gain to 8 for channels 0 4 6 and 10 through 19 send INP GAIN 8 100 104 106 110 119 To set the SCP gain to 16 for channels 0 through 15 and to 64 for channels 16 through 23 send INP GAIN 16 100 115 INP GAIN 64 116 123 or to combine into a single command message INP GAIN 16 100 115 GAIN 64 116 123 Setting Filter The commands for programmable filters are Cutoff Frequency o cri Teri PASs FREQuency cutoff freq gt lt ch_list gt to select cutoff frequency INPut FILTer LPASs STATe ON OFF lt ch_list gt to enable or disable input filtering 60
364. l Trigger Timer the default TRIG SOUR TIMER now select ARM SOUR Chapter 3 Programming the VT1415A for PID Control To set the trigger source to the External Trigger input connection TRIG SOUR EXT an external trigger signal To set the trigger source to a VXIbus TTLTRG line TRIG SOUR TTLTRG1 the TTLTRGI trigger line Selecting Trigger Figure 3 7 shows that when the TRIG SOUR is TIMer the other trigger Timer Arm Source sources become Arm sources that control when the timer will start The command to select the arm source is ARM SOURce source e The source parameter choices are explained in the following table Parameter Value Source of Arm after INITiate command BUS ARN IMMediate EXTernal TRG signal input on terminal module HOLD ARN IMMediate IMMediate The arm signal is always true scan starts when an INITiate command is received SCP SCP Trigger Bus future SCP Breadboard TTLTrg lt n gt The VXlbus TTLTRG lines n 0 through 7 NOTE When TRIGger SOURce is not TIMer ARM SOURce must be set to IMMediate the RST condition If not the INIT command will generate an error 221 Settings conflict To set the external trigger signal as the arm source ARM SOUR EXT trigger input on connector module Prog ramming the When the VTI415A is triggered it begins its algorithm execution cycle Trigger Timer The time it takes to complete a cycle is the minimum interval sett
365. l mode noise is presented to its inputs that noise will be part of the measurement To make quiet accurate measurements in electrically noisy environments use properly connected shielded wiring between the A D and the device under test Figure 2 6 shows recommended connections for powered transducers thermocouples and resistance transducers See Appendix E for more information on Wiring Techniques IMPORTANT HINTS 1 Try to install Analog SCPs relative to Digital I O as shown in Separating Digital and Analog Signals in Appendix E 2 Use individually shielded twisted pair wiring for each channel 3 Connect the shield of each wiring pair to the corresponding Guard G terminal on the Terminal Module see Figure 2 7 for schematic of Guard to Ground circuitry on the Terminal Module 4 The Terminal Module is shipped with the Ground to Guard GND GRD shorting jumper installed for each channel These may be left installed or removed see Figure 2 8 to remove the jumper dependent on the following conditions a Grounded Transducer with shield connected to ground at the transducer Low frequency ground loops dc and or 50 60 Hz can result if the shield is also grounded at the Terminal Module end To prevent this remove the GND GRD jumper for that channel Figure 2 6 A C b Floating Transducer with shield connected to the transducer at the source In this case the best performance will most likely be achieved by leaving the GND
366. l mode on the next trigger Set up for bumpless transfer I out outchan Setpoint inchan PV_old inchan Setpoint old inchan Do PID calculations when not in Manual mode else if Man state Status B4 0 First find the Process Variable error This calculation has gain of minus one 1 Error Setpoint inchan Test for error out of limits if Error gt Error max Error min gt Error PID Algorithm Listings 343 if Status B5 Status B5 alarmchan interrupt 1 1 else Status B5 0 On the first trigger after INIT initialize the I and D terms if First loop Zero the I term and start integrating I out Error I factor Zero the derivative terms PV old inchan Setpoint old Setpoint On subsequent triggers continue integrating else not First trigger I out Error I factor I out Clip the Integral term to specified limits if I out gt I max I out I max Status Bl 1 else if I min gt I out I out I min Status Bl 1 else Status Bl 0 Calculate the Setpoint Derivative term SD out SD factor Setpoint Setpoint old Clip to specified limits SD_out SD max Status B3 1 else if SD min gt SD out SD_out SD min Status B3 1 else Status B3 0 Calculate the Error Derivative term D out D
367. l procedure 0x400 DSP DAC adjustment went to limit Execute TST 0x800 DSP Status Do CAL 0x1000 DSP over voltage on input 0x2000 DSP reserved error condition 0x4000 DSP ADC hardware failure 0x8000 DSP reserved error condition Calibration or Test in Process Calibration not in Process ZERO must be sent before FSCale Perform A D Cal sequence as shown in Command Reference under CAL CONF VOLT Memory size must be multiple of 4 From MEM VME SIZE Each VT1415A reading requires 4 bytes Self test failed Test info in FIFO Use SENS DATA FIFO ALL to retrieve data from FIFO NOTE TST always sets the FIFO data FORMat to ASCII 7 Read FIFO data into string variables Appendix B Error Messages 329 NOTE Meaning of TST FIFO data by Value FIIFO Value Definition 1 99 ID number of failed test see following table for possible corrective actions 100 163 channel number s associated with test ch 0 63 164 special channel used for A D tests only 200 A D range 0 0625 V associated with failed test 201 A D range 0 25 V associated with failed test 202 A D range 1 V associated with failed test 203 A D range 4 V associated with failed test 204 A D range 16 V associated with failed test Possible Corrective Action by Failed Test ID Number Test ID Corrective Actions 1 19 21 29 VXI Technology Service
368. le co d setpoint ALG DEF GLOBALS static float cold setpoint 2 Define the following algorithm language code as ALGI the ratio station algorithm Chapter 4 Creating and Running Custom Algorithms 129 static float hot flow cold hot ratio static float cold temp 55 hot temp 180 product temp 120 hot flow 1108 FF get flow rate of cold supply FF following line calculates cold to hot ratio from supply and product temps cold hot ratio hot temp product temp cold temp product temp cold setpoint hot flow cold hot ratio output flow setpoint for ALG2 GLOBAL cold setpoint ALG2 Flow Controller 120 Product 1109 55 Cold Supply flow transmitter ALG1 Ratio Station 180 Hot Supply Figure 4 4 Inter algorithm Communication with Globals 3 Modify a PIDA algorithm so its setpoint variable is the global variable cold_setpoint its input channel is 1109 and its output channel is O116 and Define as ALG2 the cold supply flow controller FF Modified PIDA Algorithm comments stripped out setpoint from global inchan 1109 outchan 0116 the setpoint is not declared so it will be global static float P factor 1 static float factor 0 static float D factor 0 static float out static float Error static float Error old F following line includes global setpoint var and hard coded input chan Error Cold setpoint 1109 if First loop
369. le registers CLS disables the Operation Complete function OPC command and the Operation Complete Query function OPC command DMC name cmd data EMC EMC ESE lt mask gt Define Macro Command Assigns one or a sequence of commands to a named macro The command sequence may be composed of SCPI and or Common commands lt name gt may be the same as a SCPI command but may not be the same as a Common command When a SCPI named macro is executed the macro rather than the SCPI command is executed To regain the function of the SCPI command execute EMC 0 command cmd data is sent as arbitrary block program data see page 158 Enable Macro Command When enable is non zero macros are enabled When enable is zero macros are disabled Enable Macro query Returns either 1 macros are enabled or 0 macros are disabled Standard Event Status Enable Register Command Enables one or more events in the Standard Event Status Register to be reported in bit 5 the Standard Event Status Summary Bit of the Status Byte Register An event is enabled by specifying its decimal weight for lt mask gt To enable more than one event bit specify the sum of the decimal weights The C SCPI type for mask is int16 Bit 7 6 5 4 3 2 1 0 Weighted Value 128 64 32 16 8 4 2 1 Event Power On User Command Execution Device Query Request Operation Request Error Er
370. lean uint16 1 0 ON OFF none Comments Only one VXIbus TTLTRG line can be enabled simultaneously e When Accepted Not while INITiated e Related Commands ABORT INIT TRIG e RST Condition OUTPut TTLTrg lt 0 through 7 gt OFF Usage OUTP TTLT2 ON Enable TTLTRG2 line to source a trigger OUTPUT TTLTRG7 STATE ON Enable TTLTRG7 line to source a trigger OUTPut TTLTrg lt n gt STATe OUTPut TTLTrg lt n gt STATe returns the current state for TTLTRG line lt n gt Comments Returned Value Returns 1 or 0 The C SCPI type is int16 e Related Commands OUTP TTLT lt n gt Usage OUTP TTLT2 See if TTLTRG2 line is enabled returns 1 or 0 OUTPUT TTLTRG7 STATE See if TTLTRG7 line is enabled OUTPut TYPE OUTPut TYPE lt select gt lt ch_list gt sets the output drive characteristic for digital SCP channels Parameters Parameter Parameter Range of Default Name Type Values Units select discrete string PASSive ACTive seconds ch list string 100 163 none Comments e If the channels specified are on an SCP that doesn t support this function an error will be generated See the SCP s User s Manual to determine its capabilities e PASSive configures the digital channel bit to be passive resistor pull up allowing one to wire or more than one output together e ACTive configures the digital channel bit to both source and sink current Related Commands S
371. lexer SCP SCP SCP SCP Figure 2 1 Channel Numbers at SCP Positions Ch 00 Ch 07 lt Ch 08 Ch 15 Ch 16 Ch 23 Ch 24 Ch 31 Ch 32 Ch 39 Ch 40 Ch 47 Ch 48 Ch 55 Ch 56 Ch 63 Terminal Module 32 Field Wiring Chapter 2 Sense SCPs and Some SCPs provide input signal conditioning sense SCPs such as filters Outp ut SCPs and amplifiers while others provide stimulus to the measurement circuit output SCPs such as current sources and strain bridge completion In general channels at output SCP positions are not used for external signal sensing but are paired with channels of a sense SCP Two points to remember about mixing output and sense SCPs 1 Paired SCPs an output and a sense SCP may reside in separate VT1415As SCP outputs are adjusted by CAL to be within a specific limit The Engineering Unit EU conversion used for a sense channel will assume the calibrated value for the output channel 2 Output SCPs while providing stimulus to the measurement circuit reduce the number of external sense channels available to the VT1415A Figure 2 2 illustrates an example of pairing output SCP channels with sense SCP channels in this example four wire resistance measurements
372. lts OUTP VOLT AMPL 2 100 103 The OUTPut VOLTage AMPLitude command is only for programming excitation voltage used measurement configurations It is does not program output DAC SCPs like the VT1531A This step links each of the module s channels to a specific measurement type For analog input channels this tells the on board control processor which EU conversion to apply to the value read on any channel The processor is creating a list of conversion types vs channel numbers The commands for linking EU conversion to channels are SENSe FUNCtion RESistance lt excite_current gt lt range gt lt ch_list gt for resistance measurements SENSe FUNCtion STRain lt excite_current gt lt range gt lt ch_list gt for strain bridge measurements SENSe FUNCtion TEMPerature lt type gt lt sub_type gt lt range gt lt ch_list gt for temperature measurements with thermocouples thermistors or RTDs SENSe FUNCtion VOLTage lt range gt lt ch_list gt for voltage measurements SENSe FUNCtion CUSTom lt range gt lt ch_list gt for custom EU conversions At Power on and after RST the default EU Conversion is autorange voltage for all 64 channels 62 Programming the VT1415A for PID Control Chapter 3 Linking Voltage To link channels to the voltage conversion send the Measurements SENSe FUNCtion VOLTage lt range gt lt ch_list gt command e The cA list parameter specifie
373. ment 10 n 1 Output lt outp_chan gt value to CVT element 10 n 2 Status word bits 0 through 6 Status to CVT element 10 n 3 Where n is the number of the algorithm from ALGn So ALGI places values into CVT elements 10 through 13 ALG2 places values in CVT elements 20 through 23 ALG32 places values into CVT elements 320 through 323 Chapter 3 Programming the VT1415A for PID Control 77 When History mode is set to 1 the operating values are sent to the CVT as above and they are sent to the FIFO buffer as well The algorithm writes a header entry first The header value is n 256 4 where n is the algorithm number from ALGn and the number 4 indicates the number of FIFO entries that follow for this algorithm This identifies which PIDB algorithm the 5 element FIFO entry is from See the program listing for PIDB in Appendix D Defining a PID with Select the PID algorithm that will be used PIDA or PIDB Determine ALG DEFINE Which channels to specify for the PID input PID output and optionally the digital channel to use as an alarm channel Execute the command ALGorithm EXPLicit DEFine lt alg name alg def string gt e ale name gt is ALG for the first defined algorithm ALG2 for the second etc up to the maximum of ALG32 The ALG is not case sensitive That is ALGI algl aLgl are all equivalent e lt alg def string contains a string that selects the PID algorithm PIDA or
374. mes the module can be triggered before it returns to the Trigger Idle State The default count is 0 same as INF so accepts continuous triggers See Figure 6 6 Parameters Parameter Parameter Range of Default Name Type Values Units trig count numeric uint16 0 to 65535 INF none string Comments When frig count gt is set to 0 or INF the trigger counter is disabled Once INITiated the module will return to the Waiting For Trigger State after each trigger event The ABORT preferred and RST commands will return the module to the Trigger Idle State ABORT is preferred since RST also returns other module configurations to their default settings e The default count is 0 e Related Commands TRIG COUNT e RST Condition TRIG COUNT 0 Usage TRIG COUNT 10 Set the module to make 10 passes all enabled algorithms TRIG COUNT 0 Set the module to accept unlimited triggers the default TRIGger COUNt TRIGger COUNt returns the currently set trigger count Comments e If TRIG COUNT returns 0 the trigger counter is disabled and the module will accept an unlimited number of trigger events e Returned Value Numeric 0 through 65 535 The C SCPI type is int32 e Related Commands TRIG COUNT e RST Condition TRIG COUNT returns 0 Usage TRIG COUNT Query for trigger count setting enter statement Returns the TRIG COUNT setting TRIGger IMMediate TRIGger IMMediate causes one trigger when the module is
375. module can restore calibration constants for this configuration in case of a power failure After power returns and after the module warms up these constants will be relatively accurate 74 Programming the VT1415A for PID Control Chapter 3 When to Re Execute CAL e When the channel gain and or filter cut off frequency is changed on programmable SCPs using INPut GAIN or INPut FILTer e When SCPs are reconfigured to different locations This is true even if the SCP is replaced with an identical SCP model because the calibration constants are specific to each SCP channel s individual performance e When the ambient temperature within the mainframe changes significantly Temperature changes affect accuracy much more than long term component drift See temperature coefficients in Appendix A Specifications NOTE To save time when performing channel calibration on multiple VT1415As in the same mainframe use the CAL SETup and CAL SETup commands see Chapter 6 for details Defining Standard PID Algorithms The VT1415A provides two different pre defined PID algorithms that are widely used in process control The Pre Defined Figure 3 5 shows the block diagram of the PID algorithm that is defined PIDA Algorithm when ALG DEFINE is executed ALGn PIDA lt inp_channel gt lt outp_channel gt y lt inp_chan gt channel Setpoint lt outp_chan gt variable channel P_factor variable Error factor Lou
376. nc if First loop sync 0 if sync 1 writecvt M x B 10 J writecvt M x B I ys writecvt M x B 2 12 writecvt 2 M x B 13 sync 2 Results from running this program with the following syntax progname mxplusb Array contents 5 678000 5 678000 2 839000 11 35 Array contents 6 912000 6 912000 3 456000 13 82 Array contents 8 146000 8 146000 4 073000 16 29 Array contents 9 379999 9 379999 4 690000 18 75 Array contents 10 613999 10 613999 5 307000 21 Array contents 11 848000 11 848000 5 924000 23 Array contents 13 082000 13 082000 6 541000 26 Array contents 14 315999 14 315999 7 158000 28 Array contents 15 549999 15 549999 7 775000 31 Array contents 16 783998 16 783998 8 391999 33 endif tri_sine cs SHeader C SCPI Example program for the E1415A Algorithmic tri sine cs x This example shows how to use Custom Functions in the both a triangle and sine wave to a current output This is a template for building E1415A C programs or SICL to control instruments Standard include files include lt stdlib h gt Normal end of program Example algorithm that calculates 4 Mx B values upon M and B terms set by application 6000 3999 2000 9998 227999 695999 164000 631998 099998 567997 Closed Loop Controller E1415A by generating DAC that may use C S
377. nce depends on the noise coupling mechanism which is very difficult to determine The above recommendations are usually the best wiring method but if feasible experiment with shield connections to determine which provides the best performance for an installation and environment NOTE For a thorough rigorous discussion of measurement noise shielding and filtering see Noise Reduction Techniques in Electronic Systems by Henry W Ott of Bell Laboratories published by Wiley amp Sons ISBN 0 471 85068 3 Noise Due to Inadequate Card Grounding If either or both of the VT1415A and Agilent HP E1482 MXI Extender Modules are not securely screwed into the VXIbus Mainframe noise can be generated Make sure that both screws top and bottom are screwed in tight If not it is possible that CVT data could be more noisy than FIFO data because the CVT is located in A24 space the FIFO in A16 space more lines moving could cause noisier readings Appendix E Wiring and Noise Reduction Methods 355 VT1415A Noise Rejection Normal Mode Noise Enm Common Mode Noise Ecm Keeping Common Mode Noise out of the Amplifier See Figure E 2 for the following discussion This noise 1s actually present at the signal source and is a differential noise Hi to Lo It is what is filtered out by the buffered filters on the VT1502A VT1503A VT1508A and VT1509A SCPs This noise is common to both the Hi and Lo differential signal inputs Low frequ
378. nclude cscpi h Declare constan define E1415 ADDR INST DECL e1415 Y Main program void main Chn 0 HI Chn 8 HI Chn0LO PIDA Algorithm Chn LO VT1501A 9 VT1532A Direct Input Current SCP Output SCP e R2 10kQ C1 100uF Load Eom CR1 R1 2kQ KI Current Limit Figure 3 10 Quick Start Example PID program for the E1415A Algorithmic Closed Loop Controller file name simp pid cs ample shows the use of the intrinsic function PIDB e files gt gt rol include files C SCPI include file ts vxi 208 The C SCPI address of your E1415 E1415A REGISTER E1415 Chapter 3 Programming the VT1415A for PID Control 91 Main program local variable declarations char algorithm Algorithm string int alg num Algorithm number being loaded char string 333 Holds error information int32 error Holds error number INST STARTUP Initialize the C SCPI routines Open the E1415 device session with error checking INST OPEN e1415 E1415 ADDR Open the E1415 if el415 Did it open void fprintf stderr Failed to open the E1415 at address s n E1415 ADDR void fprintf stderr C SCPI open error was d n cscpi open error exit 1 Check for startup errors INST QUERY e1415 syst err n d S
379. nd Fundamentals o o page 155 e SCPI Command Reference soi eni aiae dae d o e page 161 e Common Command Reference o o page 278 e Command Quick Reference o o o page 288 Overall Command Index SCPI Commands ABORT sas 444g oo GHA Gla e TT page 162 ALGorithm EXPLicit ARRay lt alg_name gt lt array_name gt lt block_data gt ls page 164 ALGorithm EXPLicit ARRay alg name gt lt array_name gt oo page 165 ALGorithm EXPLicit DEFine lt alg name gt lt swap_enable gt lt size gt lt source_code gt page 165 ALGorithm EXPLicit SCALar lt alg_name gt lt var_name gt lt value gt ooo page 169 ALGorithm EXPLicit SCALar lt alg_name gt lt var_name gt oo page 170 ALGorithm EXPLicit SCAN RATio lt alg name cvalue 222 page 170 ALGorithm EXPLicit SCAN RATio alg name gt 2e page 171 ALGorithm EXPLicit SIZe alg name sacia a etae wa a e a e a a e e page 171 ALGorithm EXPLicit STATe alg name2 1 0 ON JOFF a page 172 ALGorithm EXPLicit STATe alg name 2s page 173 ALGorithm EXPLicit TIMe alg name gt rs page 173 ALGorithm FUNCtion DEFine lt func_name gt lt range gt lt offset gt lt func_data gt cles page 174 ALGorithm OUTPut DELay delay AUTO 2s page 175 ALGorithm OUTPut DELay 2 rs page 176 ALGorithm UPDate IMMediate ska mro ee RRR eee Ew
380. nd SCP channel gain settings The following table lists these limits Maximum CAL TARE Offsets A D range Offset V Offset V Offset V Offset V V F Scale Gain x1 Gain x8 Gain x16 Gain x64 16 3 2213 0 40104 0 20009 0 04970 4 0 82101 0 10101 0 05007 0 01220 1 0 23061 0 02721 0 01317 0 00297 0 25 0 07581 0 00786 0 00349 0 00055 0 0625 0 03792 0 00312 0 00112 N A Changing Gains or Filters To change a channels SCP setup after a CAL TARE operation a CAL operation must be performed to generate new DAC constants and reset the range floor for the stored Tare value The tare capability of the range gain setup must also be considered that is going to be used For instance if the actual offset present is 0 6 volts and was Tared for a 4 volt range Gain x1 setup moving to a 1 volt range Gain x1 setup will return Overload values for that channel since the 1 volt range is below the range floor as set by CAL TARE See table on page 202 for more on values returned for Overload readings Unexpected Channel This can occur when the VT1415A s Flash Memory contains CAL TARE Offsets or Overloads offset constants that are no longer appropriate for its current application Execute CAL TARE RESET then CAL to reset the tare constants in RAM Measure the affected channels again If the problems go away the tare constants in Flash memory can now be reset by executing CAL STORE TARE Detecting Open Transducers Most of the VT1415A s anal
381. nel holds value even when input value changed Sample and Hold channel held value test for droop rate ANALOG OUTPUT AND DIGITAL I O TESTS 301 302 303 304 305 306 307 308 313 315 316 317 318 331 332 333 334 335 336 337 341 342 343 344 345 346 347 348 349 350 351 352 353 Current and Voltage Output SCPs Current and Voltage Output SCPs Current Output SCP Current Output SCP Current Output SCP Current Output SCP Current Output SCP Current Output SCP Voltage Output SCP Voltage Output SCP Voltage Output SCP Voltage Output SCP Voltage Output SCP Digital I O SCP Digital I O SCP Digital I O SCP Digital I O SCP Digital I O SCP Digital I O SCP Digital I O SCP Freq PWM FM SCP Freq PWM FM SCP Freq PWM FM SCP Freq PWM FM SCP Freq PWM FM SCP Freq PWM FM SCP Freq PWM FM SCP Freq PWM FM SCP Freq PWM FM SCP Watchdog SCP Watchdog SCP Watchdog SCP Watchdog SCP digital DAC control DAC noise offset gain shift offset linearity linearity turn over offset offset linearity linearity turn over internal digital interface user input user input user output user output output current output current internal data0 register internal datal register internal parameter register on board processor self test on board processor self test user inputs user outputs outputs ACTive PASSive output interrupts enable disable timer relay dri
382. nels 39 Signals outputting trigger 83 SIZE MEM VME SIZE 212 Size determining an algorithm s 125 SIZe ALGorithm EXPLicit SIZe 171 SIZE MEM VME SIZE 213 SOURce ARM SOURce 181 ARM SOURce 182 OUTPut TTL Trg SOURce 219 TRIG SOURce 276 SOURce subsystem 255 256 257 258 259 Source selecting the trigger 81 Source selecting trigger timer arm 82 SOURce FM STATe 255 SOURce FM STATe 256 SOURce FUNC SHAPe 257 SOURce FUNC SHAPe CONDition 256 SOURce FUNC SHAPe PULSe 256 SOURce PULM STATe 257 SOURce PULM STATe 257 SOURce PULSe PERiod 258 SOURce PULSe PERiod 258 SOURce PULSe WIDTh 259 SOURce PULSe WIDTh 259 SOURce TRIG SOURce 277 Sources arm 80 trigger 80 Special considerations 106 Special identifiers for channels 137 Special VT1415A reserved keywords 136 Specifications 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 Specifying the data format 79 SQUare SOURce FUNC SHAPe 257 Standard Commands for Programmable Instruments SCPI 161 Standard EU operation 101 Standard event group examples 98 Standard reserved keywords 136 Starting the PID algorithm 83 STAT OPER CONDition 262 STAT OPER ENABle 263 STAT OPER ENABle 263 STAT OPER EVENt 264 STAT OPER NTRansition 264 STAT OPER NTRansition 265 STAT OPER PTRansition 265 STAT OPER PTRansition 266 STA
383. ng while error void printf syst err d s n error string INST QUERY e1415 syst err d s amp error string if result 0 void printf result s n result Hendif Print usage information void usage char prog_name 364 Generating User Defined Functions Appendix F void fprintf stderr usage s algorithm file n prog name Get an algorithm from a filename static char get_algorithm char file name FILE SES Algorithm file pointer int32 a_size Algorithm size int cy Character read from input char algorithm Points to algorithm string f fopen file name r iE dto Ed A v void fprintf stderr Error can t open algorithm file s n file name exit 1 a_size 0 Count length of algorithm while getc f EOF a sizett rewind f algorithm malloc a_size 1 Storage for algorithm a_size 0 Use as array index while c getc f EOF Read the algorithm algorithm a size c a sizett algorithm a size 0 Null terminate void fclose f return algorithm Return algorithm string 1 BOKCKCKCKCKCKCkCKCk RR Rk A KK RARA A KK KC KK E KC KK KC KK KK KK KC KK ek eK KG kkk NAME static float64 two to the N TASK Calculates 2 n A static float64 two to the N int32 n
384. ng the VT1415A 45 Removing the VT1415A 45 Wiring and attaching the 43 Terminal Module Layout 35 Terminal module options 49 Terminal module wiring maps 48 Terminal modules 35 The algorithm execution environment 113 The arithmetic operators 146 The comparison operators 146 The logical operators 146 The main function 114 The operating sequence 84 The operations symbols 146 The pre defined PIDA algorithm 75 The pre defined PIDB algorithm 76 The static modifier 139 The status byte group s enable register 99 Thermistor Connecting the on board 42 Thermistor and RTD measurements 65 Thermocouple measurements 66 Thermocouple reference temperature compensation 66 Thermocouples and CAL TARE 104 Time relationship of readings in FIFO 119 TIMe ALGorithm EXPLicit 173 Timer SAMP TIMer 226 SAMP TIMer 227 TIMer TRIG COUNt 275 TRIG TIMer 277 Timer programming the trigger 82 TIMer TRIG TIMer 277 TOTalize SENSe FUNCtion TOTalize 245 Totalizer function 71 Index 423 Transducers detecting open 106 TRIG COUNt 275 TRIG COUNt 275 TRIG IMMediate 275 TRIG SOURce 276 TRIG SOURce 277 TRIG TIMer 277 TRIG TIMer 277 TRIGger subsystem 273 274 275 276 277 trigger system ABORt subsystem 162 ARM subsystem 180 181 INITiate subsystem 204 TRIGger subsystem 273 274 275 276 277 Trigger variable width pulse per 72 TTLTrg SOURce OUTPut TTLTrg SOURce 220 TTLTrg lt n gt OUTP TTLT lt n gt
385. ng the VT1415A for PID Control 63 Two Wire Measurement Four Wire Measurement not recommended 150 Ohm 5 Current Source SCP Current Source SCP HI Field Wiring HI Field Wiring e MN t AAA E 150 Ohm 596 E z R O 2 Lo LO Q 3 AAA ANN Because of the 150 Ohm resistor in series with each of the current source outputs Two Wire resistance and temperature measurements will have a 300 Ohm offset Any Sense SCP HI The current source HI terminal is the negative voltage node The current source LO terminal is the positive voltage node LO Sense Channel Figure 3 4 Resistance Measurement Sensing The lt excite_current gt parameter is used only to tell the EU conversion what the Current Source SCP channel is now set to excite current is specified in amps dc and the choices for the VT1505A SCP are 30e 6 or MIN and 488e 6 or MAX Select 488 uA for measuring resistances of less than 8 000 Q Select 30 yA for resistances of 8 000 Q and above e The optional range parameter can be used to choose a fixed A D range When not specified defaulted the module uses auto range e The cA list parameter specifies which channel s to link to the resistance EU conversion These channels will sense the voltage across the unknown resistance Each can be a Current Source SCP channel a two wire resistance measurement or a sense channel separate from the Current S
386. ngs Appendix G char result 5000 int32 error char string 256 for void printf SCPI command void fflush stdout repeat until it actually gets something while gets command if command break result 0 0 cscpi exe el415 command strlen command result sizeof result INST QUERY e1415 syst err while error d s amp error string void printf syst err d s NMn error string INST QUERY el415 syst err d s amp error string if result 0 void printf result s n result Hendif Print usage information void usage char prog_name void fprintf stderr usage s algorithm file n prog name Get an algorithm from a filename static char get_algorithm char file name FILE E int32 a size int C char algorithm f fopen file name r bt tfe qd v void fprintf stderr file name exit 1 a size 0 while getc f EOF a sizett rewind f algorithm malloc a_size 1 a size 0 while c getc f EOF algorithm a size c a sizett algorithm a_size 0 void fclose f Errori Algorithm file pointer Algorithm size Character read from input Points to algorithm string can t open algorithm file s n Count length of algorithm
387. nnels for temperature measurement types above excitation current comes from Current Output SCP Configure channels to count digital state transitions Configure channels for de voltage measurement RTDs thermistors Configure channel for reference temperature measurements above Groups reference temperature channel with TC measurement channels Specifies the temperature of a controlled temperature reference junction Specifies the Excitation Voltage by channel to the strain EU conversion Specifies the Excitation Voltage by channel to the strain EU conversion Returns the Excitation Voltage set for lt channel gt Specifies the Gage Factor by channel to the strain EU conversion Returns the Gage Factor set for lt channel gt Specifies the Poisson Ratio by channel to the strain EU conversion Chapter 6 VT1415A Command Reference 291 Command Quick Reference Command SENSe STRAin continued POISson lt channel gt UNSTrained lt unstrained_v gt lt ch_list gt UNSTrained lt channel gt SOURce FM STATe 1 0 ON OFF lt ch_list gt STATe lt channel gt FUNCtion SHAPe CONDition lt ch_list gt PULSe lt ch_list gt SQUare lt ch_list gt PULM STATe 1 0 ON OFF ch list SSTATe lt channel gt PERiod lt period gt lt ch_list gt PERiod lt channel gt WIDTh lt width gt lt ch_list gt WIDTH lt channel gt STATus OPER
388. nsiderations eose marese seanina ENEE ETE ees 106 Detecting Open Transducers 1 0 0 0 ccc eects 106 viii Table of Contents More On Auto Ranging sssseeeeee n 108 Settling Characteristics 2 2 0 0 ccc eee tenes 108 Backeround iii pena VERRE Xx x ae teas 108 Checking for Problems 00 0 cece cece eee eens 109 Fixing the Problem escis coso corn RR E Ere R ot 109 Chapter 4 Creating and Running Custom Algorithms 111 About This Chapter llle 111 Describing the VT1415A Closed Loop Controller 112 What is a Custom Algorithm 0 0 2 0 0 cece eee eee 112 Overview of the Algorithm Language 0 00 c eee eee 112 Example Language Usage 0 2 0 0 0 0 cee eee eee 113 The Algorithm Execution Environment 0200 eee 113 The Main Function 0 0 0 cee cece eee eee nes 114 How the Algorithms FitIn 0 0 0 0 c eee eee eee 114 Accessing the VT1415A s Resources 0 2 0 00 00 cece eee eee 115 Accessing I O Channels 0 000 c ccc eee cnet eee 116 Defining and Accessing Global Variables 117 Determining First Execution First lo0p o o ooo o 117 Initializing Variables 118 Sending Data to the CVT and FIFO 2 2 0205 118 Setting a VXIbus Interrupt 0 0 0 0 119 Determining an Algorithm s Identity ALG_NUM 119 Calling User Defined Functions
389. ntf stderr E1415A failed self testin exit 1 382 Example Program Listings Appendix G fendif Tif Setup SCP functions INST SEND e1415 sens func volt 116 n Analog in volts INST SEND e1415 sour func cond 8141 Nn Digital output 0 fendif Tif INST Sl INST SEND e1415 samp timer 10e 6in default INST Si 0 Set to 1 to do calibration Perform Calibrate if necessary int cal result Result of E1415 self test cal result 1 Make sure it gets assigned INST QUERY e1415 CAL n Sd amp cal result if cal result void fprintf stderr E1415A failed calibration Nn void fprintf stderr Check FIFO for channel errors Nn exit 1 Configure Trigger Subsystem and Data Format END e1415 trig sour timer trig timer 001 n END el415 form real 321n Download Globals INST SEND el415 alg def globals static float x Nn Download algorithms Set to 1 if algorithms passed in as files Get an algorithm s from the passed filename s We assign sequential algorithm numbers to each successive file name ALG1 ALG2 etc when you execute this program as lt progname gt langl lang2 lang3 e EJ alg_num 1 Starting algorithm number while argc gt alg num algorithm get algorithm argv alg n
390. nts e Note that the C language statement must be terminated with the semicolon Although all variables in the Algorithm Language are of type float they must be explicitly declared as such All variables in an algorithm are static This means that each time an algorithm is executed the variables remember their values from the previous execution The static modifier must appear in the declaration e Array variables must have a single dimension The array dimension specifies the number of elements The lower bound is always zero 0 in the Algorithm Language Therefore the variable My_array from above has three elements My_array 0 through My_array 2 BASIC and C are the same here Both languages use the symbol to assign a value to a simple variable or an element of an array The value can come from a constant another variable or an expression Examples a 12 345 a My var a My array 2 a My array 1 6 2 My var In BASIC the assignment symbol is also used as the comparison operator is equal to For example IF a b THEN As is discussed later in this chapter C uses a different symbol for this comparison Chapter 5 Algorithm Language Reference 145 The Operations Symbols The Arithmetic Operators Unary Arithmetic Operator The Comparison Operators The Logical Operators Conditional Execution Many of the operation symbols are th
391. num_samples gt lt ch_list gt command to add extra settling time for just these problem channels What SENS CHAN SETTLING does is instructs the VT1415A to replace single instances of a channel in the Scan List with multiple repeat instances of the channel specified in lt ch_list gt The number of repeats is set by lt num_samples gt Example Normal Scan List 100 101 102 103 104 Scan List after SENS CHAN SETT 3 100 103 100 100 100 101 102 103 103 103 104 When the algorithms are run channels 0 and 3 will be sampled three times and the final value from each will be sent to the Channel Input Buffer This provides extra settling time while channels 1 2 and 4 are measured in a single sample period and their values also sent to the Channel Input Buffer 110 Programming the VT1415A for PID Control Chapter 3 Chapter 4 Creating and Running Custom Algorithms Learning Hint This chapter builds upon the VT1415A Programming Model information presented in Chapter 3 That information is common to PIDs and to custom algorithms Read that section before continuing on to this one About This Chapter This chapter describes how to write custom algorithms that apply the VT1415A s measurement calculation and control resources It describes these resources and how they can be accessed with the VT1415A s Algorithm Language This manual assumes that the user has some programming experience already id
392. o Inadequate Card Grounding 0000 355 xiv Table of Contents VT1415A Noise Rejection lssseseeese eee 356 Normal Mode Noise Enm 00 000 cece cee een eee 356 Common Mode Noise Ecm 0 0 00 cece eee nee 356 Keeping Common Mode Noise out of the Amplifier 356 Reducing Common Mode Rejection Using Tri Filar Transformers 357 CHAPTER F Generating User Defined Functions 359 Introduction 4o eee prm td E deen EAS 359 Haversine Example croiss esenee bias ER Hostage eres Pa ERR 360 Limitations 3464 A m 362 Program Listings 22s nase sees veh la CU PS gs 363 CHAPTER G Example Program ListingsS o oo oo oo oo o 379 SIMP PIC CS ciues Wack wb veo ri HE eed ede UEM Weed HAY dH 379 PIG A Do TIL 385 SWap O8 esa cip wie ehh bones EI ees eb REIR EP GOS eee ds 391 iti SINE CS eae eade exu re SUR Y epe eO REAR decease 398 CHAPTER Ide 6X Ee EET IERI ae aeaty 411 Table of Contents xv xvi Table of Contents Support Resources Support resources for this product are available on the Internet and at VXI Technology customer support centers VXI Technology World Headquarters VXI Technology Inc 2031 Main Street Irvine CA 92614 6509 Phone 949 955 1894 Fax 949 955 3041 VXI Technology Cleveland Instrument Division VXI Technology Inc 7525 Granger Road Unit 7 Valley View OH 44125 Phone 216 447 8950 Fax 216 447 8951
393. o conversion fastest REAL same as above REAL 64 means real 64 bit values converted ASCu 7 means 7 bit ASCII values converted ASCI same as above the RST condition To specify that values are to remain in IEEE 32 bit Floating Point format for fastest transfer rate FORMAT REAL 32 Chapter 3 Programming the VT1415A for PID Control 79 To specify that values are to be converted to 7 bit ASCII and returned as a 15 character per value comma separated list FORMAT ASC 7 The RST TST and power on default format Or FORM ASC same operation as above Selecting the The VT1415A s FIFO can operate in two modes One mode is for reading FIFO Mode FIFO values while algorithms are executing the other mode is for reading FIFO values after algorithms have been halted ABORT sent e BLOCking The BLOCking mode is the default and is used to read the FIFO while algorithms are executing The application program must read FIFO values often enough to keep it from overflowing see Continuously Reading the FIFO on page 87 The FIFO stops accepting values when it becomes full 65 024 values Values sent by algorithms after the FIFO is full are discarded The first value to exceed 65 024 sets the STAT QUES COND bit 10 FIFO Overflowed and an error message is put in the Error Queue read with SYS ERR command e Overwrite When the FIFO fills the oldest values in the FIFO are overwritten by the newest values Only the latest 65 024
394. ocouple 313 314 Temperature 299 Adding settling delay for specific channels 110 Adding terminal module components 47 Additive expression 142 Additive operator 142 ADDRess MEM VME ADDR 212 ADDRess MEM VME ADDR 212 Alarm limits 77 ALG DEFINE in the programming sequence 123 ALG DEFINE defining a PID with 78 ALG DEFINE s three data formats 123 ALGorithm EXPLicit STATe 172 173 ALGorithm EXPLicit ARRay 164 ALGorithm EXPLicit ARRay 165 ALGorithm EXPLicit DEFine 165 ALGorithm EXPLicit SCALar 169 ALGorithm EXPLicit SCALar 170 ALGorithm EXPLicit SCAN RATIo 170 ALGorithm EXPLicit SCAN RATio 171 ALGorithm EXPLicit SIZe 171 ALGorithm EXPLicit TIMe 173 Algorithm execution order 121 Algorithm Language reference 135 Algorithm language statement writecvt 118 writefifo 119 Algorithm to algorithm communication 128 Algorithm A very simple first 126 Algorithm data acquisition 131 Algorithm exiting the 138 Algorithm modifying a standard PID 127 Algorithm process monitoring 131 Algorithm running the 127 Algorithm starting the PID 83 Algorithm the pre defined PIDA 75 Algorithm the pre defined PIDB 76 Algorithm What is a custom 112 Algorithm writing the 127 ALGorithm FUNCtion DEFine 174 ALGorithm OUTPut DELay 175 ALGorithm OUTPut DELay 176 ALGorithm UPDate IMMediate 176 ALGorithm UPDate CHANnel 177 ALGorithm UPDate WINDow 178 ALGorithm UPDate WI
395. ode sets whether Open Transducer Detect current will be turned off or left on the default mode during the CAL TARE operation Parameters Parameter Parameter Range of Default Name Type Values Units mode boolean uint 16 0 1 volts Comments When mode is set to 0 the RST Default channels are tare calibrated with their OTD current off When lt mode gt is 1 channels that have their OTD current on DIAGnostic OTDetect ON lt ch_list gt are tare calibrated with their OTD current left on e By default RST the CALibration TARE command will calibrate all channels with the OTD circuitry disabled This is done for two reasons first most users do not leave OTD enabled while taking readings and second the CALibration TARE operation takes much longer with OTD enabled 194 VT1415A Command Reference Chapter 6 DIAGnostic However for users who intend to take readings with OTD enabled setting DIAG CAL TARE OTD MODE to 1 will force the CAL TARE command to perform calibration with OTD enabled on channels so specified by the user with the DIAG OTD command e Related Commands CAL CAL SET DIAG CAL SET MODE e RST Condition DIAG CAL TARE MODE 0 Usage configure OTD on during CAL TARE DIAG CAL TARE MODE 1 Set mode for OTD to stay on CAL TARE Start channel tare cal DIAGnostic CALibration TARE OTDetect MODE DIAGnostic CALibration TARE OTDetect MODE returns th
396. og input SCPs provide a method to detect open transducers When Open Transducer Detect OTD is enabled the SCP injects a small current into the HIGH and LOW input of each channel The polarity of the current pulls the HIGH inputs toward 17 volts and the LOW inputs towards 17 volts If a transducer is open measuring that channel will return an over voltage reading OTD is available on a per SCP basis All eight channels of an SCP are enabled or disabled together See Figure 3 13 for a simplified schematic diagram of the OTD circuit 106 Programming the VT1415A for PID Control Chapter 3 ut l Signal Conditioning Plug on l Multiplexer l l l l l l n i gt o 7 o High l l l l l l l l l l l l l l l l l I l l l l l I l I l l l l l l l l l l l l l l l l l l l I l gt gt o Low Figure 3 13 Simplified Open Transducer Detect Circuit NOTES 1 When OTD is enabled the inputs have up to 0 2 uA injected into them If this current will adversely affect the measurement but checking for open transducers is still desired enable OTD run the algorithms check analog input variables for measurement values that indicate an open transducer then disable OTD and run the algorithms without it The VT1415A s accuracy specifications apply only when OTD is off 2 When a channel s SCP filtering is enabled allow 15 seconds after turning on OTD for the filters capacitors to charge before checking for
397. ommand was sent e Related Commands INITiate IMMediate TRIGger e RST Condition TRIG SOUR HOLD Usage ABORT If INITed goes to Trigger Idle state If running algorithms stops and goes to Trigger Idle state 162 VT1415A Command Reference Chapter 6 ALGorithm The ALGorithm command subsystem provides e Definition of standard and custom control loop algorithms e Communication with algorithm array and scalar variables e Controls to enable or disable individual loop algorithms e Control of ratio of number of scan triggers per algorithm execution e Control of loop algorithm execution speed e Easy definition of algorithm data conversion functions Subsystem Syntax ALGorithm EXPLicit ARRay lt alg_name gt lt array_name gt lt block_data gt ARRay lt alg_name gt lt array_name gt DEFine alg name gt lt swap_size gt lt program_block gt SCALar alg name gt lt var_name gt lt value gt SCALar alg name var name SCAN RATio alg name value7 SCAN RATio alg name gt SIZe alg name gt STATe alg name gt ON OFF STATeP alg name gt TIMe alg name gt FUNCtion DEFine lt func_name gt lt range gt lt offset gt lt block_data gt OUTPut DELay lt usec gt AUTO OUTPut DELay UPDate IMMediate CHANnel channel item WINDow num updates WINDow Chapter 6 VT1415A Command Reference 163 ALGorithm EXPLicit ARRay NOTE Parameters Comments
398. ommercial item as defined in FAR 2 101 a or as Restricted computer software as defined in FAR 52 227 19 Jun 1987 or any equivalent agency regulation or contract clause whichever is applicable You have only those rights provided for such Software and Documentation by the applicable FAR or DFARS clause or the VXI Technology standard software agreement for the product involved Safety Symbols Instruction manual symbol affixed to product Indicates that the user must refer Ny to the manual for specific WARNING or CAUTION information to avoid personal injury or damage to the product oe Direct current dc Alternating current ac Indicates hazardous voltages Indicates the field wiring terminal that l must be connected to earth ground before operating the equipment protects against Calls attention to a procedure practice or electrical shock in case of fault WARNING TF that could cause bodily injury or eath Calls attention to a procedure practice or or Frame or chassis ground CAUTION condition that could possibly cause damage terminal typically connects to the to equipment or permanent loss of data equipment s metal frame Warnings The following general safety precautions must be observed during all phases of operation service and repair of this product Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design man
399. on g amp amp 3 Tt E o e U amp static float input_val val_out input_val 1102 pid algorithm O116 val out Figure 3 1 Simplified Functional Block Diagram Algorithmic The VT1415A is an algorithmic process loop controller It can provide as many as 32 single input single output control loops in a single VXIbus module The term algorithmic indicates that the VT1415A is a digital loop controller An internal Digital Signal Processor DSP executes program code that implements a control algorithm The algorithm is defined for a control loop by selecting one of the VT1415A s two standard PID algorithms or by downloading a custom algorithm created in the VT1415A s Algorithm Programming Language a C like language Once defined the control loop algorithm becomes a subprogram function that 1s executed each time the module receives a trigger signal and after all input signal channels have been scanned 54 Programming the VT1415A for PID Control Chapter 3 Process Data ln The VT1415A provides advanced data acquisition capability which includes on board signal conditioning and Engineering Unit EU conversion Signal conditioning creates accurate signal values from a wide range of process sensors The EU conversion means that signal values measured at process sensors will be returned in standard engineering units such as volts ohms degrees Celsius or microstrain Further custom EU conversions can b
400. on 0 7 Not used 8 256 0100 6 Calibration Lost At RST or Power on Control Processor has found a checksum error in the Calibration Constants Read error s with SYST ERR and re calibrate area s that lost constants 9 512 0200 Trigger Too Fast Scan not complete when another trigger event received 10 1024 0400 FIFO Overflowed Attempt to store more than 65 024 readings in FIFO 11 2048 0800 Over voltage If the input protection jumper has not been cut the Detected on Input input relays have been opened and RST is required to reset the module Over voltage will also generate an error 12 4096 1000 VME Memory The number of readings taken exceeds VME memory Overflow space 13 8192 20006 Setup Changed Channel Calibration in doubt because SCP setup may have changed since last CAL or CAL SETup command RST always sets this bit 14 15 Not used STATus QUEStionable CONDition STATus QUEStionable CONDition returns the decimal weighted value of the bits set in the Condition register Comments The Condition register reflects the real time state of the status signals The signals are not latched therefore past events are not retained in this register see STAT QUES EVENT e Returned Value Decimal weighted sum of all set bits The C SCPI type is uint16 e Related Commands CAL VALUE RESISTANCE CAL VALUE VOLTAGE STAT QUES EVENT STAT QUES ENABLE STAT QUES ENABLE e RST Con
401. open transducers To enable or disable Open Transducer Detection use the DIAGnostic OTDetect enable lt ch_list gt command e The enable parameter can specify ON or OFF e An SCP is addressed when the lt ch_list gt parameter specifies a channel number contained on the SCP The first channel on each SCP is 0 8 16 24 32 40 48 and 56 To enable Open Transducer Detection on all channels on SCPs 1 and 3 DIAG OTD ON 100 116 0 is on SCP 1 and 16 is on SCP3 To disable Open Transducer Detection on all channels on SCPs 1 and 3 DIAG OTD OFF 100 116 Chapter 3 Programming the VT1415A for PID Control 107 More On Auto Ranging There are rare circumstances where an input signal can be difficult for the VT1419A to auto range correctly The module completes the range selection based on the input signal about 6 us before the actual measurement is made on that channel If during that period the signal becomes greater than the selected range can handle the module will return an overflow reading INFinity The only solution to this problem is to use manual range on channels that display this behavior Settling Characteristics Background Some sequences of input signals as determined by their order of appearance in a scan list can be a challenge to measure accurately This section is intended to help determine if a system presents any of these problems and how best to eliminate them or reduce their effect
402. or FNMy function 1 1 w w PRINT String Co Hs Co al Select the Domain values for the function Co o Min input 2 Max input 2 Ww J Co oo 110 kc ck Ck ck Ck Ck ck Ck ck Ck Sk Ck kk Ck ck ck Ck ck Ck ck kk ck ck ck Ck ck kk ck ck ck ck ck kk ck kk kk kk ck kk ko Sk kv Sk k kv ko ko kockok 120 INTEGER Coef array 0 511 Error 130 REAL Hpibintfc Cmdmodule E1413 ladd E1413addr 140 INTEGER Lin piecewise Ilin 0 3 Ipiec 0 514 150 REAL Min input Max input 160 DIM String 333 170 ASSIGN Err TO 1 180 190 KKK KKK ck ck KKK KKK KKK KKK KKK KKK KKK KKK KKK KKK KKK KK KKK KK KKK KK KKK KKK ko kv kv ko ko ko ko kx 200 The following three lines should be customized for each installation 210 Hpibintfc 7 Hpib interface number for E1415 220 Cmdmodule 9 Hpib address for command module for E1415 230 E1415 ladd 208 Logical address for E1415 card 240 Ck ck ck ck ck Ck KKK KKK KKK KKK KK KK KKK KKK KK KKK KKK KKK KKK KKK KKK ck kk ck kk kk kv Kk ko ko kx ko ko ko AA 250 ON TIMEOUT Hpibintfc 12 GOTO End 260 El415addr Hpibintfc 10000 Cmdmodule 100 E1415 ladd 8 270 ASSIGN QGE1415 TO E1415addr 280 ASSIGN GBus TO Hpibintfc FORMAT OFF 290 300 OUTPUT QE1415 RST CLS 310 OUTPUT QE1415 IDN 320 ENTER E1415 String 0 0 0 0 i 39 CALL Build table Max input Min input Table range
403. orithm provides for manual control with bumpless transfer between manual and automatic control The variables that control the manual mode are Auto Manual control Man state 0 automatic default 1 manual Manual output control Man out defaults to current auto value Manual control slew rate Man inc defaults to 9 99E 37 fast change Use the ALG SCALAR and ALG UPDATE commands to change the manual control variables before or after the algorithm is running Status Variable The PIDB algorithm uses 7 bits in a status variable Status to record the state of clipping and alarm limits and the automatic manual mode When a limit 1s reached or the manual mode is set the algorithm sets a status bit to Je Output lt outp_chan gt at clipping limit Status BO I term I out at clipping limit Status B1 D term D_ out reached at limit Status B2 SD term SD_ out at clipping limit Status B3 Control mode Man state is manual Status B4 Error term Error out of limits Status B5 Process Variable lt inp_chan gt out of limits Status B6 History Mode The PIDB algorithm provides two modes of reporting the values of its operating variables A variable History mode controls the two modes The default history mode History mode 0 places the following algorithm values into elements of the Current Value Table the CVT Process Variable inp chan value to CVT element 10 n 0 Error Term variable Error value to CVT ele
404. ot be declared within a compound statement The VT1415A Algorithm Language allows the following data structures e Simple variables of type float Declaration static float simp_var any_var Use simp_var 123 456 any_var 23 45 Another_var 1 23e 6 Storage Each simple variable requires four 16 bit words of memory Chapter 5 Algorithm Language Reference 139 e Single dimensioned arrays of type float with a maximum of 1 024 elements Declaration static float array var 3 Use array var 0 array var 1 array var 2 array var 3 Storage Arrays are double buffered This means that when an array is declared twice the space required for the array is allocated plus one more word as a buffer pointer The memory required is words of memory 8 num elements 1 This double buffered arrangement allows the ALG ARRAY command to download all elements of the array into the B buffer while an algorithm is accessing values from the A buffer Then an ALG UPDATE command will cause the buffer pointer word to point to the newly loaded buffer between algorithm executions Bitfield Access The VT1415A implements bitfield syntax that allows individual bit values to be manipulated within a variable This syntax is similar to what would be done in C but doesn t require a structure declaration Bitfield syntax is supported only for the lower 16 bits bits 0 15 of simple scalar variables and channel identi
405. oth writeboth writeboth writeboth writeboth writeboth writeboth ALG NUM 256 9 inchan ALG NUM 10 0 Error ALG NUM 10 1 outchan ALG NUM 10 2 Status ALG NUM 10 43 Setpoint ALG NUM 10 P out ALG NUM 10 5 M I out ALG NUM 10 6 D out ALG NUM 10 7 SD out ALG NUM 10 8 History mode Output summary to FIFO amp CVT writefifo writeboth writeboth writeboth writeboth else ALG_NUM 256 4 inchan ALG NUM 10 0 Error ALG NUM 10 1 outchan ALG NUM 10 42 Status ALG NUM 10 3 Output summary to CVT only writecvt writecvt writecvt writecvt inchan ALG NUM 10 0 Error ALG NUM 10 1 outchan ALG NUM 10 2 Status ALG _NUM 10 3 Appendix D PID Algorithm Listings 351 352 PID Algorithm Listings Appendix D Appendix E Wiring and Noise Reduction Methods Separating Digital and Analog SCP Signals Analog Input Digital 1 O AA rA Signals with very fast rise time can cause interference with nearby signal paths This is called cross talk Digital signals present this fast rise time situation Digital I O signal lines that are very close to analog input signal lines can inject noise into them Cross talk can be minimized by maximizing the distance between analog input and digital I O signal lines Figure E 1 shows th
406. ould take to execute all algorithms is longer than the TRIG TIMER interval currently set Once the module is INITiated it can accept triggers from any source specified in TRIG SOUR Chapter 3 Programming the VT1415A for PID Control 83 TRIG SOUR TIMER RST default ARM SOUR IMM RST default INIT INIT starts Timer triggers or TRIG SOUR TIMER ARM SOUR HOLD INIT ARM INIT readies module ARM starts Timer triggers and the algorithms start to execute The Operating The VT1415 has four major operating phases Figure 3 8 shows these Seq uence _ Phases A trigger event starts the sequence UT ut table to SCP nels 1 2 3 4 1 INPUT UPDATE CALCULATE OUTPUT INP from SCP variables amp execute all enabled algorithms output table from channels algorithms eee sent to SCP chan analog amp channels anal digital digi Set by ALG OUTPut DELay if any gt Trigger Event Trigger Event 1 Figure 3 8 Sequence of Loop Operations INPUT the state of all digital inputs are captured and each analog input channel that is linked to an algorithm variable is scanned UPDATE The update phase is a window of time made large enough to process all variables and algorithm changes made after INIT Its width is specified by ALG UPDATE WINDOW This window is the only time variables and algorithms can be changed Variable and algorithm changes can actually be accepted during other ph
407. ource SCP channel a four wire resistance measurement See Figure 3 4 for diagrams of these measurement connections To set channels 0 through 15 to measure resistances greater than 8 000 Q and set channels 16 20 and 24 through 31 to measure resistances less than 8k in this case paired to current source SCP channels 32 through 57 OUTP CURR AMPL 306 6 132 147 set 16 channels to output 30 uA for 8 kQ or greater resistances SENS FUNC RES 30e 6 100 115 link channels 0 through 15 to resistance EU conversion 8 kQ or greater OUTP CURR AMPL 488e 6 148 149 150 157 set 10 channels to output 488 uA for less than 8 kQ resistances SENS FUNC RES 4886 6 116 120 124 132 link channels 16 20 and 24 through 32 to resistance EU conversion less than 8 kQ 64 Programming the VT1415A for PID Control Chapter 3 Linking Temperature To link channels to temperature EU conversion send the Measurements SENSe FUNCtion TEMPerature type sub type lt range gt lt ch_list gt command e The cA list parameter specifies which channel s to link to the temperature EU conversion e The type parameter specifies RTD THERmistor or TC for ThermoCouple e The optional range parameter can be used to choose a fixed A D range When not specified defaulted the module uses auto range RTD and Thermistor Measurements Temperature measurements using resistance type sensors involve all the same considerations as
408. ow to allow 10 updates in phase 2 ALG UPD WIND 10 allows slightly faster execution than default of 20 updates A way to synchronize variable updates with an external event is to send the ALGorithm UPDate CHANnel lt dig_chan bit gt command e The dig chan bit parameter specifies the digital channel bit that controls execution of the update operation When the ALG UPD CHAN command is received the module checks the current state of the digital bit When the bit next changes state pending updates are made in the next UPDATE Phase ALG UPD CHAN 1133 B0 perform updates when bit zero of VT1533A at channel 133 changes state Enabling and Analgorithm is enabled by default when it is defined However the Disabling ALG STATe lt alg name gt ON OFF command is provided to enable or disable algorithms When an individual algorithm is enabled it will execute Algorithms when the module is triggered When disabled the algorithm will not execute NOTE The command ALG STATE alg name gt ON OFF does not take effect until an ALG UPDATE command is received This allows multiple ALG STATE commands to be sent with their their effects synchronized To enable ALG1 and ALG2and disable ALG3 and ALG4 ALG STATE ALG1 ON enable algorithm ALGI ALG STATE ALG2 ON enable algorithm ALG2 ALG STATE ALG3 OFF disable algorithm ALG3 ALG STATE ALG4 OFF disable algorithm ALG4 ALG UPDATE changes take effect at next
409. page 176 ALGorithm UPDate CHANnel lt channel gt ooo page 177 ALGorithm UPDate WINDow num updates 22s page 178 ALGorithm UPDate WINDow lll ls as page 179 ARM IMMediate lt s 55s 2 65 4456244056 GREE UXOR CE DEERE S BS ACE S S ESS page 181 ARM SOURce BUS EXT HOLD IMM SCP TTLTrgzn 2e page 181 ARM SOURCE X per 2 he te ee ROUX sueco OES ee ae PES ed ee WO SIEHE 4 X a SR page 182 CALibration CONFigure RESistance 2 22222 sel es page 184 CALibration CONFigure VOLTage range ls page 185 CALibration SETup 5 5 so a ia YoRboexo 3 x x 7303 4 OEE ox S X GG do Y Ea page 186 Chapter 6 VT1415A Command Reference 151 CALibration SETup 3 46444 65544 os kao kv SR E IG Pop ee XO RO eR ee Ew page 186 CALibration STORe ADC TARE ee aag gaa a page 187 CALibration TARE lt ch_list gt ss page 188 CALibration DARE RES et us a ee ae ee Re Fox ee ok Ba CK E a ode x ni page 189 CALibration TARE ovas a tetea PRESE eee wR EE Rs ck dex pw page 190 CALibration VALue RESistance ref ohms oo page 190 CALibration VALue VOLTage ref volts o rs page 191 CALibration ZERO ais a Roe Rose oy Sue o RU ae Eo UR SS ed m EU S page 192 DIAGnostic CALibration SETup MODE 0 1 22s page 193 DIAGnostic CALibration SETup MODE o page 194 DIAGnostic CALibration TARE OTDetect MODE 0 1 o page 194 DIAGnostic CALibration TARE OTDetect M
410. pe jj 64 ii 1 generate numbers for prev segment for second and subsequent points t result ii 1 using prev seg base if t 0 0 t 1 0 use abs value magnitude of t compute the exponent of the offset B is 31 bits if t 0 0 don t take log of zero exponent 31 0 1og10 t 10g10 2 0 take log base 2 else exponent 100 0 compute slope in bits each tabl ntry represents 512 bits slope result ii result ii 1 512 0 don t take the log of a negative slope absslope slope 0 slope slope compute the exponent of the slope M is 16 bits if absslope 0 exponent2 15 0 10g10 absslope 10g10 2 0 else exponent2 100 0 Choose the smallest exponent maximize resolution if exponent2 lt exponent xponent exponent2 Appendix G Example Program Listings 403 Xfactor int32 exponent if t 0 int32 ltemp round32f log10 t 1og10 2 0 if Xfactor ltemp gt 30 Xfactor 30 ltemp Mfactor round32f two to the N Xfactor slope if Mfactor 32768 There is an endpoint problem Re compute if on endpoint Xfactor Mfactor round32f two to the N Xfactor slope if Mfactor lt 32767 amp amp Mfactor gt 32768 only save if M is within limits Adjust EX to match runtime asm
411. pecifying a range setting For instance if the expected signal voltage is to be approximately 0 1 V dc and the amplifier SCP for that channel has a gain of 8 range must be set no lower than 1 V dc or an input out of range condition will exist Resistance measurements require the use of Current Source Signal Conditioning Plug Ons The excite current parameter excitation current does not control the current applied to the channel to be measured The excite current parameter only passes the setting of the SCP supplying current to channel to be measured The current must have already been set using the OUTPUT CURRENT AMPL command The choices for excite current are 30E 6 or MIN and 488E 6 or MAX excite current may be specified in milliamps ma and microamps ua Chapter 6 VT1415A Command Reference 241 SENSe e The CAL command calibrates resistance channels based on Current Source SCP and Sense Amplifier SCP setup at the time of execution If SCP settings are changed those channels are no longer calibrated CAL must be executed again e See Linking Input Channels to EU Conversion on page 62 for more information e When Accepted Not while INITiated e Related Commands OUTP CURR CAL e RST Condition SENSE FUNC VOLT 100 163 Usage FUNC RES 30ua 100 105 107 Set channels 0 5 and 7 to convert voltage to resistance assuming current source set to 30 yA use auto range default SENSe
412. pend2 This is the first point 1880 1890 for second and subsequent points 1900 Jj Ii 1 generate numbers for prev segment 1910 T ABS Result Ii 1 using abs value of prev seg bas 1920 1930 compute the exponent of the offset B is 31 bits 1940 IF T lt gt 0 THEN don t take log of zero 1950 Exponent 31 0 LGT T LGT 2 0 take log base 2 1960 ELSE 1970 Exponent 100 0 1980 END IF 1990 2000 compute slope in bits each table entry represents 512 bits 2010 Slope Result Ii Result Ii 1 512 0 2020 2030 don t take the log of a negative slope 2040 Absslope ABS Slope 2050 2060 compute the exponent of the slope M is 16 bits 2070 IF Absslope lt gt 0 THEN 2080 Exponent2 15 0 LGT Absslope LGT 2 0 2090 ELSE 2100 Exponent2 100 0 2110 END IF 2120 Choose the smallest exponent maximize resolution 2130 IF Exponent2 lt Exponent THEN Exponent Exponent2 2140 Xfactor INT Exponent convert to integer 2150 IF T lt gt 0 THEN 2160 Ltemp PROUND LGT T LGT 2 0 0 2170 IF Xfactor Ltemp gt 30 THEN Xfactor 30 Ltemp 2180 END IF 2190 factor PROUND 2 Xfactor Slope 0 2200 IF Mfactor 32768 0 THEN 2210 There is an endpoint problem Re compute if on endpoint 2220 Xfactor Xfactor 1 2230 factor PROUND 2 Xfactor Slope 0 2240 END IF 2250 IF Mfactor lt 32767 0 AN
413. pensation SENS FUNC CUST TC allows an EU table to be used that is custom matched to thermocouple wire characterized Contact a VXI Technology System Engineer for more information on Custom Engineering Unit Conversion for specific applications Parameters Parameter Parameter Range of Default Name Type Values Units type discrete string E EEXT J K N R S T none range numeric float32 see comments V de ch_list channel list string 100 163 none Comments See Linking Input Channels to EU Conversion on page 62 for more information Chapter 6 VT1415A Command Reference 239 SENSe The range parameter The VT1415A has five ranges 0 0625 V dc 0 25 V dc 1 V dc 4 V dc and 16 V dc To select a range simply specify the range value for example 4 selects the 4 V dc range Ifa value larger than one of the first four ranges is specified the VT1415A selects the next higher range for example 4 1 selects the 16 V dc range Specifying a value larger than 16 generates an error Specifying 0 selects the lowest range 0 0625 V dc Specifying AUTO selects auto range The default range no range parameter specified is auto range If using amplifier SCPs set them first and keep their settings in mind when specifying a range setting For instance if the expected signal voltage is to be approximately 0 1 V dc and the amplifier SCP for that channel has a gain of 8 range must be set no low
414. pers eee geet wera eas a da page 379 e file alg6s LER CIR tet ee pe dete keds e SD page 385 9 SWAP CS cose qw REV ONT EE Ox PER REN Re ae RUE page 391 rl SIDeicS isses Sat as Oo erbe Meme eee PT HER RE eR page 398 simp pid cs SHeader C SCPI Example program for the E1415A Algorithmic Closed Loop Controller simp pid cs This program example shows the use of the intrinsic function PIDB nq This is a template for building E1415A C programs that may use C SCPI or SICL to control instruments Xo Ro Xo Ro F FH Standard include files include lt stdlib h gt Most programs use one or more functions from the C standard library E include lt stdio h gt Most programs will also use standard I O functions include lt stddef h gt This file is also often useful include lt math h gt Needed for any floating point fn s Other system include files Whenever using system or library calls check the call description to see which include files should be included mu Instrument control include files include lt cscpi h gt C SCPI include file Declare any constants that will be useful to the program In particular it is usually best to put instrument addresses in this area to make the code more maintainable define E1415 ADDR vxi 208 The SICL address of your E1415 INST DECL el415 E1415A REGISTER E1
415. ppendix E CAUTION Use approved Static Discharge Safe handling procedures anytime the covers are removed from the VT1415A or are handling SCPs 1 Installing SCPs Removing the Cover VT1415A NUN 7A ANNNNNNNNNNNNNNN Remove the SCP Retaining Screws o lift front and slide out tabs Remove 2 screws 10 Torx Chapter 1 Getting Started 21 2 Installing SCPs VT1415A CAUTION Use approved Static Discharge handling procedures when handling the VT1415A Scanning A D Module and the SCPs m AQAA A N AQAA Tighten the SCP D Retaining Screws Align the SCP Connectors with the Module Connectors and then Push in 22 Getting Started Chapter 1 3 Installing SCPs Reinstalling the Cover VT1415A Line up the 3 Tabs with the 3 Slots then lower cover onto the Module L S A OOOO E Tighten 2 Screws Chapter 1 Getting Started 23 4 Installing SCPs Labeling VT1415A SMA OSOS ANO Terminal Module Connect to A D Module Later Peel off Label from Card and Stick on Connec
416. ptat Sai sess athe She tne IR AU drop er eR RP ea aed 137 Intrinsic Functions and Statements 0000 eee eee 137 Program Flow Control 0 cc cece eee 138 Data TL VPS cese Sopa UR REAL eo d e Ute il esas 138 Data Structures sk ace DET ER e ede Y es 139 Bitfield AGCeSS oea eae ad aed ae tia 140 Language Syntax Summary 0 0 cece eens 141 Program Structure and Syntax 1 2 eee eee eee 145 Declaring Variables 0 00 eect eens 145 Assigning Values zione evaded ities oe aka RR is 145 The Operations Symbols 000 0 eee eee eee eee 146 Conditional Execution 00 cette eee 146 Commenti Mes ura need Gag Woes bye tones ayes cars Gan a 148 Overall Program Structure 148 Where To Go Next cessus em acces ERR Ce Eee ege tede 149 Chapter 6 VT1415A Command Reference eeeee 151 ABOR tico csi WR bested bend p dee cd E TET 162 ALGorthm 2 404d a bear ghd epa herd eh ses ba ea seeded 163 ALGorithm EXPLicit ARRay 0 0c eee eee eee 164 ALGorithm EXPLicit ARRay 0 0 cece eee eee 165 ALGorithm EXPLicit DEFine llle 165 ALGorithm EXPLicit SCALar 5 0 0 0c cece eee 169 ALGorithm EXPLicit SCALar 2 0 0 0 cece eee 170 ALGorithm EXPLicit SCAN RATIO 00 0 0 e eee 170 ALGorithm EXPLicit SCAN RATIO 0 00 0 ce eee 171 ALGorithm EXPLicit SIZe 2 0 ene 171 ALGorithm EXPLicit ESTATe 0 0 00 cc
417. query for error messages types of Signal Conditioning Plug Ons SCPs and the SCPI version currently implemented Subsystem Syntax SYSTem CTYPe lt channel gt ERRor VERSion SYSTem CTYPe SYSTem CTYPe lt channel gt returns the identification of the Signal Conditioning Plug On installed at the specified channel Parameters Parameter Parameter Range of Default Name Type Values Units channel channel list string 100 163 none Comments The channel parameter must specify a single channel only e Returned Value An example of the response string format is Agilent E1415 Option option number and description SCP 0 0 The C SCPI type is string For specific response string refer to the appropriate SCP manual If channel specifies a position where no SCP is installed the module returns the response string 0 No SCP at this Address 0 0 Usage SYST CTYPE 100 return SCP type install at channel 0 SYSTem ERRor SYSTem ERRor returns the latest error entered into the Error Queue Comments SYST ERR returns one error message from the Error Queue returned error is removed from queue To return all errors in the queue repeatedly execute SYST ERR until the error message string 0 No error e Returned Value Errors are returned in the form lt error number gt lt error message string e RST Condition Error Queue is empty Usage SYST ERR returns
418. r p gt amp 3 TRIGger SOURce source TiMer B S oloke pa Es kani aaae NE Eutr Muir E bM gt d gt od 2 EXTernal ES 3 e gt 2 z HOLD 2 Internal E e gt Trigger Trigger Signal 9 MMediate 3 P Enable pe 2 gt g TTLTrg lt n gt o P cn E SCP Trig Trigger Counter d TRIGger COUNt count Figure 6 2 Logical Trigger Model 180 VT1415A Command Reference Chapter 6 ARM Subsystem Syntax ARM IMMediate SOURce BUS EXTernal HOLD IMMediate SCP TTLTrg lt n gt SOURce ARM IMMediate ARM IMMediate arms the trigger system when the module is set to the ARM SOUR BUS or ARM SOUR HOLD mode Comments Related Commands ARM SOURCE TRIG SOUR e RST Condition ARM SOUR IMM Usage ARM IMM After INIT system is ready for trigger event ARM Same as above IMM is optional ARM SOURce ARM SOURce lt arm_source gt configures the ARM system to respond to the specified source Parameters Parameter Parameter Range of Default Name Type Values Units arm_source discrete string BUS EXT HOLD IMM SCP none TTLTrg lt n gt Comments The following table explains the possible choices Parameter Value Source of Arm BUS ARM IMMediate EXTernal TRG signal on terminal module HOLD ARM IMMediate IMMediate The arm signal is always true continuous arming SCP SCP Trigger Bus future SCP Breadboard
419. r 250 SENSe STRain POISson 251 SENSe STRain POISson 251 SENSe STRain UNSTrained 251 SENSe STRain UNSTrained 252 SENSe TOTalize RESet MODE 252 SENSe TOTalize RESet MODE 254 Sensing Reference temperature with the VT1415A 37 Sensing 4 20 mA 47 Separator command 156 Sequence A complete thermocouple measurement command 68 Sequence ALG DEFINE in the programming 123 Sequence example command 90 Sequence operating 120 Sequence the operating 84 Setting algorithm execution frequency 90 Setting filter cutoff frequency 60 Setting input function 70 Setting input polarity 70 Setting output drive type 71 Setting output functions 72 Setting output polarity 71 Setting SCP gains 60 Setting the HP E1505 current source SCP 61 Setting the logical address switch 20 Setting the trigger counter 83 the VT1511A strain bridge SCP excitation voltage Setting up analog input and output channels 60 Setting up digital input and output channels 70 Setting up digital inputs 70 Setting up digital outputs 71 Setting up the trigger system 80 Settings conflict Index 421 ARM SOUR vs TRIG SOUR 180 276 SETTling SENSe CHANnel SETTling 229 Settling characteristics 108 SETTling SENSe CHANnel SETTling 229 SETup CAL SETup 186 CAL SETup 186 Shield Connections When to make 355 Shielded wiring IMPORTANT 34 SHUNt OUTP SHUNt 218 OUTPut SHUNt 219 Signal connection to chan
420. r based operating system for the module INST_STARTUP Enable communications to the module check if successful INST OPEN e1415 vxi LADD if 1e1415 printf INST OPEN failed ladd s Failure code is d n LADD cscpi open error exit 1 Read and print the module s identification INST QUERY e1415 idn read id printf AnWMnInstrument ID s n n read id rst clr Function resets the module id scps Function checks for installed SCPs exit 0 J KCKCKCKCKCKCk kk Ck Ck kk ECKE CK KK KK KK A A KK KK KK KK A KK KC KK KC KK KK KK kk kk kk ke ke ke ke ke ke ke koe koe x f void rst clr Reset the A D module to its power on state 28 Getting Started Chapter 1 intl6 opc wait Reset the module and wait until it resets INST QUERY e1415 RST OPC W amp opc wait Check for module generated errors exit if errors read if check error rst clr exit 1 J KCKCKCKCKCKCk kCkCkCk kk kA AIA IIA IA IA II IAA I A I A A A ek A e ke ke ke ke ke ke koe e ke x A void id scps Check ID of all installed SCPs intl6 scp addr char scp id 100 Get SCP identifications of all SCPs printf NnSCP Identifications n n for scp addr 100 scp addr lt 156 scp addr 8 INST QUERY e1415 SYST CTYP d ss scp addr scp id printf ID for SCP d is s n scp addr 1
421. ranges 0 0625 V dc 0 25 V dc 1 V dc 4 V dc and 16 V dc To select a range simply specify the range value for example 4 selects the 4 V dc range If a value larger than one of the first four ranges is specified the VT1415A selects the next higher range for example 4 1 selects the 16 V dc range Specifying a value larger than 16 causes an error 222 Data out of range Specifying 0 selects the lowest range 0 0625 V dc Specifying AUTO selects auto range The default range no range parameter specified is auto range e Ifusing amplifier SCPs set them first and keep their settings in mind when specifying a range setting For instance if the expected signal voltage is to be approximately 0 1 V dc and the amplifier SCP for that channel has a gain of 8 range must be set no lower than 1 V dc or an input out of range condition will exist e Ifan A D reading is greater than the table range specified with DIAG CUSTOM PIEC an overrange condition will occur e fno custom table has been loaded for the channels specified with SENS FUNC CUST an error will be generated when an INIT command is given e When Accepted Not while INITiated e Related Commands DIAG CUST e RST Condition all custom EU tables erased Usage program must put table constants into array table block DIAG CUST LIN 1 table_block 116 123 send table to VTI415A for chs 16 23 SENS FUNC CUST 1 116 123 link custom EU with chs 16 23 INITiate then TRIGger
422. rce buffer sizeof source buffer close file handle source buffer byte count 0 null to terminate source buffer string sprintf header string od byte count 1 note byte_count 1for null byte sprintf header string Yod d strlen header string byte count viPrintf e1415 ALG DEF ALG4 s s c n header string source buffer null See the section Running the Algorithm later in this chapter for more on loading algorithms from files Changing a The VTI415A has a feature that allows a specified algorithm to be swapped Running Algorithm with another even while it is executing This 1s useful 1f for instance it 1s necessary to alter the function of an algorithm that is currently controlling a process and it is undesirable to have this process uncontrolled In this case when original algorithm is defined enable it to be swapped Defining an Algorithm for The ALG DEF command has an optional parameter that is used to enable Swapping algorithm swapping The command s general form is ALG DEF lt alg_name gt lt swap_size gt lt source_code gt 124 Creating and Running Custom Algorithms Chapter 4 NOTE How Does it Work Determining an Algorithm s Size Note the parameter swap size7 It specifies the amount of memory that will be allocated to algorithm a g name gt Make sure to allocate enough space for the largest algorithm expected to be defined for alg n
423. rdware trigger input at Connector Module 276 VT1415A Command Reference Chapter 6 TRIGger TRIGger SOURce TRIGger SOURce returns the current trigger source configuration e Returned Value Discrete one of BUS EXT HOLD IMM SCP TIM or TTLTO through TTLT7 The C SCPI type is string See the TRIG SOUR command for more response data information Usage TRIG SOUR ask VT1415A to return trigger source configuration TRIGger TIMer PERiod TRIGger TIMer PERiod trig interval sets the interval between scan triggers Used with the TRIG SOUR TIMER trigger mode Parameters Parameter Parameter Range of Default Name Type Values Units trig interval numeric float32 100E 6 to 6 5536 seconds string MIN MAX Comments e In order for the TRIG TIMER to start it must be Armed For information on timer arming see the ARM subsystem in this command reference e The default interval is 10E 3 seconds lt trig_interval gt may be specified in seconds milliseconds ms or microseconds us For example 0 0016 1 6 ms or 1600 us The resolution for lt trig_interval gt is 100 us e When Accepted Before INIT only e Related Commands TRIG SOUR TIMER ARM SOUR ARM IMM INIT TRIG SOUR ALG EXPL TIMe e RST Condition TRIG TIM 1 0E 3 Usage TRIG TIMER 1 0E 1 Set the module to scan inputs and execute all algorithms every 100 ms TRIG TIMER 1 Set the module to scan inputs and execute
424. re Compensation The isothermal reference temperature is required for thermocouple temperature EU conversions The Reference Temperature Register must be loaded with the current reference temperature before thermocouple channels are scanned The Reference Temperature Register can be loaded two ways 1 By measuring the temperature of an isothermal reference junction during an input scan 2 By supplying a constant temperature value that of a controlled temperature reference junction before a scan is started 66 Programming the VT1415A for PID Control Chapter 3 Setting Up a Reference Temperature Measurement This operation requires two commands the SENSe REFerence command and the SENSe REFerence CHANnels command The SENSe REFerence type sub type range Q ch list command links channels to the reference temperature EU conversion e The cA list parameter specifies the sense channel that is connected to the reference temperature sensor e The type parameter can specify THERmistor RTD or CUSTom THER and RTD are resistance temperature measurements and use the on board 122 wA current source for excitation CUSTom is pre defined as a Type E thermocouple which has a thermally controlled ice point reference Junction e The sub type parameter must specify For RTDs 85 or 92 for 100 Q RTDs with 0 00385 or 0 00392 ohms ohm C temperature coefficients respectively For Thermistors
425. re INIT OK RST ALG DEF GLOBALS static float My_global ALG DEF ALG2 PIDA 1100 0108 ALG DEF ALGS My global My_global 1 Error INIT ALG DEF ALGS PIDB I101 0109 0124 B0 Can t define new algorithm while running Chapter 6 VT1415A Command Reference 167 ALGorithm NOTES b The alg name gt has not already been defined since a RST command Here alg name gt specifies either an algorithm name or GLOBALS OK RST ALG DEF GLOBALS static float My global Error RST ALG DEF GLOBALS static float My global No error ALG DEF GLOBALS static float A different global Algorithm already defined Because GLOBALS already defined Error RST ALG DEF ALG3 PIDA I100 0108 No error ALG DEF ALG3 PIDB 1100 0108 0124 B0 Algorithm already defined Because ALG3 already defined If alg name gt has been enabled to swap originally defined with the swap size parameter included then the lt alg_name gt can be re defined do not include swap size now either while the module is in the Trigger Idle State or while in Waiting For Trigger State INITed Here a g name gt is an algorithm name only not GLOBALS OK RST ALG DEF ALG3 200 i 0108 15 0 0108 0108 0 1 else 0108 15 0 INIT starts algorithm ALG DEF ALG3 if O108 12 0 010820108 0 2 else 0108 12 0 ALG UPDATE Required to cause n
426. re device circuits during execution of CAL TARE for those channels e When Accepted Not while INITiated e Related Commands OUTP CURR AMPL CAL TARE e RST Condition OUTP CURR OFF all channels Usage OUTP CURR OFF 100 108 turn off current source channels 0 and 8 OUTPut CURRent STATe OUTPut CURRent STATe lt channel gt returns the state of the Current Source SCP channel specified by channel If the channel is not on a VT1505A Current Source SCP the query will return zero Parameters Parameter Parameter Range of Default Name Type Values Units channel channel list string 100 163 none Comments channel must specify a single channel only e Returned Value returns 1 for enabled 0 for disabled C SCPI type is uint16 e Related Commands OUTP CURR STATE OUTP CURR AMPL Usage OUTP CURR 108 query for state of Current SCP channel 8 execute enter statement here enter query value either 1 or 0 Chapter 6 VT1415A Command Reference 217 OUTPut POLarity channels in cA list OUTPut POLarity lt select gt lt ch_list gt sets the polarity on digital output Parameters Parameter Parameter Range of Default Name Type Values Units select discrete string NORMal INVerted none ch list string 100 163 none Comments e If the channels specified do not support this function an error will be generated e Related Commands IN
427. re no longer calibrated CAL must be executed again See Linking Input Channels to EU Conversion on page 62 for more information When Accepted Not while INITiated Related Commands CAL INPUT GAIN RST Condition SENSE FUNC VOLT AUTO 100 163 Usage FUNC VOLT 140 163 Channels 40 63 measure voltage in auto range defaulted SENSe REFerence NOTE SENSe REFerence lt type gt lt sub_type gt lt range gt lt ch_list gt links channel in lt ch_list gt to the reference junction temperature EU conversion based on type and sub type When scanned the resultant value is stored in the Reference Temperature Register and by default the FIFO and CVT This is a resistance temperature measurement and uses the on board 122 uA current source The reference junction temperature value generated by scanning the reference channel is stored in the Reference Temperature Register This reference temperature is used to compensate all subsequent thermocouple measurements until the register is overwritten by another reference measurement or by specifying a constant reference temperature with the SENSE REF TEMP command If used the reference 246 VT1415A Command Reference Chapter 6 Parameters Comments SENSe junction channel must be scanned before any thermocouple channels Use the SENSE REF CHANNELS command to place the reference measuring channel into the scan list ahead of the thermocouple measuring channel
428. re readings Returns number of VME memory bytes allocate to reading storage Enable or disable reading storage in VME memory at INIT Returns state of VME memory 1 enabled 0 disabled Set amplitude of Current Source SCP channels Returns the setting of the Current Source SCP channel Enable or disable the Current Source SCP channels Returns the state of the Current Source SCP channel Sets output polarity on a digital SCP channel Returns digital polarity currently set for channel Adds shunt resistance to leg of Bridge Completion SCP channels Returns the state of the shunt resistor on Bridge Completion SCP channel Sets the internal trigger source that can drive the VXIbus TTLTrg lines Returns the source of TTL Trg drive When module triggered source a VXIbus trigger on TTLTrg lt n gt Returns whether the TTL trigger line specified by n is enabled sets the output drive type for a digital channel Returns the output drive type for channel Sets the voltage amplitude on Voltage Output and Strain SCPs Returns the voltage amplitude setting Returns comma separated list of channels in analog I O dig I O ch lists Returns number of channels defined in above lists Sets number of samples that will be made on channels in lt ch_list gt Returns number of samples that will be made on channels in lt ch_list gt Sets the channel settling time for channels in ch_list Returns the channel settling time for channel Returns elements of Curr
429. read and write digital states read frequency and counts and output modulated pulse signals FM and PWM This term applies to algorithms that are enabled to swap These algorithms can be exchanged with another of the same name while the original is running The new algorithm becomes active after an update command is sent This new algorithm may again be swapped with another and so on This capability allows changing algorithm operation without stopping and leaving this and perhaps other processes without control The screw terminal blocks the system field wiring is connected to The terminal blocks are inside the Terminal Module 336 Glossary Appendix C Terminal Module Update Update Queue User Function The plastic encased module which contains the terminal blocks the field wiring is connected to The Terminal Module then is plugged into the VT1415A s front panel This is an intended change to an algorithm algorithm variable or global variable that is initiated by one of the commands ALG SCALAR ALG ARRAY ALG DEFINE ALG SCAN RATIO or ALG STATE This change or update is considered to be pending until an update command is received Several updates can be sent to the Update Queue waiting for an update command to cause them to take effect synchronously The update commands are ALG UPDATE and ALG UPD CHANNEL A list of scalar variable values and or buffer pointer values for arrays and swapping algo
430. rence channel with its thermocouple measurement channels in the scan list e If thermocouple measurements are made through more than one isothermal reference panel set up a reference channel for each Execute the SENS REF CHAN command for each reference measurement channel group e Related commands SENS FUNC TEMP SENS REF e RST Condition Scan List contains no channel references SENS FUNC TEMP TC E 0625 108 115 E type TCs on channels 8 through 15 SENS REF THER 5000 1 106 Reference ch is thermistor at channel 6 SENS REF RTD 85 25 107 Reference ch is RTD at channel 7 SENS REF CHAN 106 108 111 Thermistor measured before chs 8 11 SENS REF CHAN 107 112 115 RTD measured before chs 12 15 SENSe REFerence TEMPerature NOTE SENSe REFerence TEMPerature degrees c stores a fixed reference junction temperature in the Reference Temperature Register Use when the thermocouple reference junction is kept at a controlled temperature This reference temperature 1s used to compensate all subsequent thermocouple measurements until the register is overwritten by another SENSE REF TEMP value or by scanning a channel linked with the SENSE REFERENCE command If used SENS REF TEMP must be executed before scanning any thermocouple channels 248 VT1415A Command Reference Chapter 6 SENSe Parameters Parameter Parameter Range of Default Name Type Values Units degrees c numeric float32 126 to 126 non
431. resistance measurements discussed in the previous section See the discussion of Figure 3 4 in Linking Resistance Measurements For resistance temperature measurements the sub type parameter specifies e For RTDs 85 or 92 for 100 Q RTDs with 0 00385 or 0 00392 ohms ohm C temperature coefficients respectively e For Thermistors 2250 5000 or 10000 the nominal value of these devices at 25 C NOTES 1 Resistance temperature measurements RTDs and THERmistors require the use of Current Source Signal Conditioning Plug Ons The following table shows the Current Source setting that must be used for the following RTDs and Thermistors Required Current Amplitude Temperature Sensor Types and Subtypes MAX 488 yA RTD 85 92 and THER 2250 MIN 30 pA THER 5000 10000 2 The sub type parameter values of 2250 5000 and 10000 refer to thermistors that match the Omega 44000 series temperature response curve These 44000 series thermistors have been selected to match the curve within 0 1 or 0 2 C To set channels 0 through 15 to measure temperature using 2 250 Q thermistors in this case paired to current source SCP channels 16 through 31 OUTP CURR AMPL 488 6 116 131 set excite current to 488 uA on current SCP channels 16 through 31 Chapter 3 Programming the VT1415A for PID Control 65 SENS FUNC TEMP THER 2250 100 115 link channels 0 through 15 to temperature EU conver
432. rithms that is built in response to updates see Update When an update command is sent scalar values and pointer values are sent to their working locations A function callable from the Algorithm Language in the general form function name expression These user defined functions provide advanced mathematical capability to the Algorithm Language Appendix C Glossary 337 Notes 338 Glossary Appendix C Appendix D PID Algorithm Listings The following source listings show the actual code for the VT1415A s default PID algorithms PIDA PIDB and PIDC PIDC is an advanced algorithm that is not built into the VT1415A like PIDA and PIDB but is included here so that it can be downloaded using the ALG DEF command Contents 9 PIDA ASIS ccn ee ee CREER page 339 PIDB Listing aid ade dada RO wake bones Rea etd page 341 PIDC TIM reci be m eae ea ewes ore ER page 346 PIDA J kk kkk IIIA CK A Kk KK I I IAI IA IA IA IA A A A A A ek A e ke ke ke ke ke e o e A I O Channels f Must be defined by the user Joe T inchan Input channel name E outchan Output channel name gs AA A El NN AA A PID algorithm for E1415A controller module This algorithm is called Re once per scan trigger by main It performs Proportional Integral and Derivative control el rl is T The output is derived from the following equations x pe PID out
433. rmine the output value In this example the bit would never change The same applies to analog outputs The buffered I O sequence explained previously can be used advantageously Multiple algorithms can access the very same buffered channel input value without having to pass the value in a parameter Any algorithm can read and used as its input the value that any other algorithm has sent to the output buffer In order for these features to be of use the order in which the algorithms will be executed must be known When algorithms are defined they are given one of 32 pre defined algorithm names These range from ALG1 to ALG32 The algorithms will execute in order of its name For instance if ALGS5 is defined then ALG2 then ALGS and finally ALG1 when run they will execute in the order ALGI ALG2 ALGS and ALGS For more on input and output value sharing see Algorithm to Algorithm Communication on page 128 Chapter 4 Creating and Running Custom Algorithms 121 PHASE 1 INPUT State Digital Frequency yo SCPs Totalize 8 Analog 8 4 Input SCP 5 x o 2 Voltage B z Resistance 8 Analog 8 ES EU m Input E Conversion Temp SCP lt 5 e Strain e 5 5 e o 8 Analog 8 4 Input 64 Channel SCP Scan List Voltage 8 Current State Pulses 8 Digital yo PWM 16 SCPs FM PHASE 4 OUTPUT Trigger TRIG TIMER
434. rnal cal source and relay drives 45 46 Checks fine offset calibration DAC 47 48 Checks coarse offset calibration DAC 49 Checks internal and 15V supplies 50 53 Checks internal calibration source 54 55 Checks gain calibration DAC 56 57 Checks that autorange works 58 59 Checks internal current source 60 63 Checks front end and A D noise and A D filter 64 Checks zeroing of coarse and fine offset calibration DACs 65 70 Checks current source and CAL BUS relay and relay drives and OHM relay drive 71 See 33 72 73 Checks continuity through SCPs bank relays and relay drivers 74 Checks open transducer detect 75 Checks current leakage of the SCPs 76 Checks voltage offset of the SCPs 80 Checks mid scale strain dac output Only reports first channel of SCP 81 Checks range of strain dac Only reports first channel of SCP 82 Checks noise of strain dac Only reports first channel of SCP 83 Checks bridge completion leg resistance each channel 84 Checks combined leg resistance each channel 86 Checks current source SCP s OFF current 87 Checks current source SCP s current dac mid scale 88 Checks current source SCP s current dac range on HI and LO ranges Chapter 6 VT1415A Command Reference 285 Common Command Reference 89 Checks current source compliance 90 Checks strain SCP s Wagner Voltage control 91 Checks autobalance dac range with input shorted ANALOG TESTS continued 92 93 Sample and Hold chan
435. rned Value Value Meaning Further Action 0 Cal OK None 1 Cal Error Query the Error Queue SYST ERR See Error Messages in Appendix B The C SCPI type for this returned value is int16 e Executing this command does not alter the module s programmed state function range etc e Related Commands CAL e RST Condition A D offset performed Usage CAL ZERO enter statement here returns 0 or 1 192 VT1415A Command Reference Chapter 6 DIAGnostic DIAGnostic The DIAGnostic subsystem allows for special operations to be performed that are not standard in the SCPI language This includes checking the current revision of the Control Processor s firmware and that it has been properly loaded into Flash Memory Subsystem Syntax DIAGnostic CALibration SETup MODE 01 MODE TARe OTD MODE 0 1 MODE CHECksum CUSTom LlNear table range table block Q ch list PlECewise lt table_range gt lt table_block gt lt ch list REFerence TEMPerature IEEE 1 0 JEEE INTerrupt LINe intr line LINe OTDetect STATe 1 0 ON OFF W lt ch_list gt STATeP lt channel gt y SCPREAD lt reg_addr gt VERSion DIAGnostic CALibration SETup MODE DIAGnostic CALibration SETup MODE mode sets the type of calibration to use for analog output SCPs like the VT1531A and VT1532A when CAL or CAL SET are executed
436. rogramming the VT1415A for PID Control Chapter 3 Residual Sensor Offsets Operation NOTE Resetting CAL TARE To remove residual sensor offsets in an unstrained strain gage bridge execute the CAL TARE command on those channels The module will then measure the offsets and as in the wiring case above remove these offsets from future measurements In the strain gage case this balances the bridge so all measurements have the initial unstrained offset removed to allow the most accurate high speed measurements possible After CAL TARE ch list measures and stores the offset voltages it then performs the equivalent of a CAL operation This operation uses the Tare constants to set a DAC which will remove each channel offset as seen by the module s A D converter The absolute voltage level that CAL TARE can remove is dependent on the A D range CAL TARE will choose the lowest range that can handle the existing offset voltage The range that CAL TARE chooses will become the lowest usable range range floor for that channel For any channel that has been CAL TARE d Autorange will not go below that range floor and selecting a manual range below the range floor will return an Overload value see table on page 202 As an example assume that the system wiring to channel 0 generates a 0 1 volt offset with 0 volts a short applied at the UUT Before CAL TARE the module would return a reading of 0 1 volt for channel
437. rom a known instrument state The following provides this jud INST CLEAR e1415 Selected device clear INST SEND e1415 RST CLS Mn if 0 Set to 1 to do self test Does the E1415 pass self test int test_result Result of E1415 self test test_result 1 Make sure it gets assigned INST QUERY e1415 TST n Sd amp test result if test_result 406 Example Program Listings Appendix G void fprintf stderr E1415A failed self testin exit 1 endif Setup SCP functions INST SEND e1415 sens func volt 116 n Analog in volts INST SEND e1415 sour func cond 141 n Digital output dif 0 Set to 1 to do calibration Perform Calibrate if necessary int cal_result Result of E1415 self test cal result 1 Make sure it gets assigned INST QUERY e1415 CAL n d amp cal result if cal result void fprintf stderr E1415A failed calibration Nn void fprintf stderr Check FIFO for channel errors Nn exit 1 Hendif Configure Trigger Subsystem and Data Format INST SEND e1415 trig sour timer trig timer 001 n INST SEND e1415 samp timer 10e 61n default S INST SEND e1415 form real 32 n Download Globals INST SEND e1415 alg def globals static float x n Download Custom Funct
438. ror Dependent Error Error Control Complete Chapter 6 VT1415A Command Reference 279 Common Command Reference ESE ESR GMC lt name gt IDN NOTE Standard Event Status Enable Query Returns the weighted sum of all enabled unmasked bits in the Standard Event Status Register The C SCPI type for this returned value is int16 Standard Event Status Register Query Returns the weighted sum of all set bits in the Standard Event Status Register After reading the register ESR clears the register The events recorded in the Standard Event Status Register are independent of whether or not those events are enabled with the ESE command to set the Standard Event Summary Bit in the Status Byte Register The Standard Event bits are described in the ESE command The C SCPI type for this returned value is int16 Get Macro query Returns arbitrary block response data which contains the command or command sequence defined for lt name gt For more information on arbitrary block response data see page 158 Identity Returns the device identity The response consists of the following four fields fields are separated by commas e Manufacturer e Model Number e Serial Number returns 0 if not available e Driver Revision returns 0 if not available DN returns the following response strings depending on model and options Agilent E1415B serial number gt lt revision number e The C SCPI type for
439. rough 3 and 16 through 19 to Wagner Ground INPut LOW INPut LOW lt channel gt returns the LO input configuration for the channel specified by lt channel gt Parameters Parameter Parameter Range of Default Name Type Values Units channel channel list string 100 163 none Comments The channel parameter must specify a single channel only e Returned Value Returns FLO or WV The C SCPI type is string e Related Commands INP LOW Usage INP LOW 103 enter statement will return either FLO or WV for channel 3 INPut POLarity INPut POLarity lt mode gt lt ch_list gt sets logical input polarity on a digital SCP channel Parameters Parameter Parameter Range of Default Name Type Values Units mode discrete string NORMal INVerted none ch list string 100 163 none Comments e If the channels specified are on an SCP that doesn t support this function an error will be generated See the SCP s User s Manual to determine its capabilities Related Commands for output sense SOURce PULSe POLarity e RST Condition INP POL NORM for all digital SCP channels Usage INP POL INV 140 143 invert first 4 channels on SCP at SCP position 5 Channels 40 through 43 Chapter 6 VT1415A Command Reference 209 INPut INPut POLarity INPut POLarity lt channel gt returns the logical input polarity on a digital SCP channel Parameters Parameter Parameter Range of Default Name Type Values Units channel strin
440. ruct is if expression statement else statement2 where statement is executed if expression evaluates to non zero true and statement2 is executed if expression evaluates to zero false Statement1 and or statement2 can be compound statements That is multiple simple statements within curly braces See Figure 5 1 146 Algorithm Language Reference Chapter 5 BASIC Syntax IF boolean expression THEN statement IF boolean expression THEN statement END IF IF boolean expression THEN statement statement statement END IF IF boolean expression THEN statement statement ELSE statement END IF Comments Simplest form used often Two line form not recommended use multiple line form instead Multiple line form used often Multiple line form with else used often Figure 5 1 The if Statement C versus BASIC C Syntax if boolean expression statement if boolean expression statement if boolean expression statement statement statement if boolean_expression statement statement else statement Note that in BASIC the lt boolean_expression gt is delimited by the IF and the THEN keywords In C the parentheses delimit the expression In C the is the implied THEN In BASIC the END IF keyword terminates a multi line IF In C the if is terminated at the end of the following statement when no else clause is present or at the end o
441. s Parameter Parameter Range of Default Name Type Values Units type discrete string THERmistor RTD CUSTom none sub type numeric float32 for THER use 5000 ohm numeric float32 for RTD use 85 92 none for CUSTom use 1 none range numeric float32 see comments V dc ch list channel list string 100 163 none See Linking Input Channels to EU Conversion on page 62 for more information The range parameter The VT1415A has five ranges 0 0625 V dc 0 25 V dc 1 V dc 4 V dc and 16 V dc To select a range simply specify the range value for example 4 selects the 4 V dc range Ifa value larger than one of the first four ranges is specified the VT1415 selects the next higher range for example 4 selects the 16 V dc range Specifying a value larger than 16 causes an error Specifying 0 selects the lowest range 0 0625 V dc Specifying AUTO selects auto range The default range no range parameter specified is auto range If using amplifier SCPs set them first and keep their settings in mind when specifying a range setting For instance if the expected signal voltage is to be approximately 0 1 V dc and the amplifier SCP for that channel has a gain of 8 range must be set no lower than 1 V dc or an input out of range condition will exist The type parameter specifies the sensor type that will be used to determine the temperature of the isothermal reference panel type
442. s variable and initialize it to 22 95 3 2 Each time the algorithm executes By placing an assignment statement within the algorithm This will be executed each time the algorithm is executed Example statement my_variable 22 95 reset variable to 22 95 every pass 3 When the algorithm first executes after an INIT command By using the global variable First_loop the algorithm can distinguish the first execution since an INIT command was sent Example statement if First loop my variable 22 95 reset variable only when INIT starts alg Sending Data to the The Current Value Table CVT and FIFO data buffer provides CVT and FIFO communication from an algorithm to the application program running in the VXIbus controller Writing a CVT element The CVT provides 502 addressable elements where algorithm values can be stored To send a value to a CVT element execute the intrinsic Algorithm Language statement writecvt lt expression gt lt cvt_element gt where lt cvt_element gt can take the value 10 through 511 Note that the default PIDB algorithm will use certain CVT elements see History Mode on page 77 The following is an example algorithm statement writecvt O124 330 send output channel 24 s value to CVT element 330 Each time the algorithm writes a value to a CVT element the previous value in that element is overwritten Reading CVT elements An application program reads one or mor
443. s usage argv 0 exit 1 endif INST STARTUP Initialize the C SCPI routines dif 0 Set to 1 to open interface session If you need to open a VXI device session here s how to do it You need a VXI device session if the V382 is to source or respond to VXI backplane triggers SICL ixtrig or ionintr calls ef if vxi iopen vxi void fprintf stderr SICL error failed to open vxi interface Nn void fprintf stderr SICL error d s Nn igeterrno igeterrstr igeterrno exit 1 Hendif Open the E1415 device session with error checking Copy and modify these lines if you need to open other instruments f INST OPEN el415 E1415 ADDR Open the E1415 if e1415 Did it open void fprintf stderr Failed to open the E1415 at address s n E1415 ADDR void fprintf stderr C SCPI open error was d n cscpi open error void fprintf stderr SICL error was d s Wn igeterrno igeterrstr igeterrno exit 1 Check for startup errors INST QUERY e1415 syst err n d 5 amp error string if error void printf syst err d s n error string exit 1 Usually you ll want to start from a known instrument state The following provides this e INST CLEAR e1415 Selected device clear INST SEND e1415 RST GLSXn if O Set to 1 to do self test
444. s OUTPut CURRent AMPLitude lt amplitude gt lt ch_list gt sets the VT1505A Current Source SCP channels specified by lt ch_list gt to either 488 uA or 30 uA This current is typically used for four wire resistance and resistance temperature measurements This command does not set current amplitude on SCPs like the VT1532A Current Output SCP Parameter Parameter Range of Default Name Type Values Units amplitude numeric float32 MIN 30E 6 MAX 488E 6 ADC ch list channel list string 100 163 none Chapter 6 VT1415A Command Reference 215 OUTPut Comments Select 488E 6 or MAX for measuring resistances of less than 8000 Q Select 30E 6 or MIN for resistances of 8000 Q and above The lt amplitude gt may be specified in wA ua For resistance temperature measurements SENSe FUNCtion TEMPerature the Current Source SCP must be set as follows Required Current Temperature Sensor Types and Amplitude Subtypes MAX 488 uA RTD 85 92 and THER 2250 MIN 30 uA THER 5000 10000 When CAL is executed the current sources are calibrated on the range selected at that time When Accepted Not while INITiated Related Commands CAL OUTP CURR AMPL RST Condition MIN Usage OUTP CURR AMPL 488ua 116 123 Set Current Source SCP at channels 16 through 23 to 488 uA OUTP CURR AMPL 30E 6 105 Set Current Source SCP at channel 5 to 30 uA
445. s e Returned Value returns numeric number of samples The type is int16 SENSe DATA CVTable SENSe DATA CV Table lt element_list gt returns from the Current Value Table the most recent values stored by algorithms Parameters Parameter Parameter Range of Default Name Type Values Units element list channel list 10 511 none Comments SENSe DATA CVTable lt element_list gt allows the latest values of internal algorithm variables to be viewed while algorithms are executing e The Current Value Table is an area in memory that can contain as many as 502 32 bit floating point values Algorithms can copy any of their variable values into these CVT elements while they execute e There is a pre defined organization for the first part of the CVT It is divided into 32 10 element segments This allows up to 32 PID algorithms to place up to 10 variable values each into the CVT The pre defined PIDB algorithm can return 4 variable values The PIDC algorithm defined as a custom algorithm can return up to 9 With up to 32 PIDs possible 320 elements are allocated for standard PIDs ALGI can use elements 10 19 ALG2 can use elements 20 29 ALG3 can use elements 30 39 etc through ALG32 which can use elements 320 329 The values stored in each segment are Element Variable Description xx0 Sense Process value monitored PIDB C xxl Error Setpoint value minus Sense value PIDB amp C XX2
446. s Unshielded wiring will pick up environmental noise causing measurement errors Shielded twisted pair signal wiring although it is expensive is required for these measurements unless an even more expensive amplifier at the signal source or individual A D at the source is used Generally the shield should be connected to ground at the DUT and left open at the VT1415A Floating DUTS or transducers are an exception Connect the shield to VT1415A GND or GRD terminals for this case whichever gives the best performance This will usually be the GND terminal A single point shield to ground connection is required to prevent ground loops This point should be as near to the noise source as possible and this is usually at the DUT Wi ring Checklist The following lists some recommended wiring techniques 1 Use individually shielded twisted pair wiring for each channel 2 Connect the shield of each wiring pair to the corresponding Guard G terminal on the Terminal Module 3 The Terminal Module is shipped with the Ground Guard GND GRD shorting jumper installed for each channel These may be left installed or removed dependent on the following conditions a Grounded Transducer with shield connected to ground at the transducer Low frequency ground loops dc and or 50 60 Hz can result if the shield is also grounded at the Terminal Module end To prevent this remove the GND GRD jumper for that channel b Floating Transducer with shield
447. s 228 SENSe CHANneESETTling 0 0 0 ce ee ee ee eee 229 SENSe CHANnel SETTling 20 0 00 c cece eee 229 SENSe DATA CVTable 2 0 0 0 0 cece eee nee 230 SENSe DATA CVTable RESet 0 0000 231 SENSe DATA FIFO ALL 00000000 c ccc eee ee eee 231 SENSe DATA FIFO COUNQ 0 00 0 cee eee 232 SENSe DATA FIFO COUNt HALF 0 0002 eee eae 233 SENSe DATA FIFO HALF 00000 eee ee 233 SENSe DATA FIFO MODE 0 0000 cece eens 234 SENSe DATA FIFO MODE 0 000 ccc eee eee 235 SENSe DATA FIFO PART 0 0 0 0 ccc eee ee 235 SENSe DATA FIFO RESet ni er nent nener ence nee 236 SENSe FREQuency APERture 0 00000 236 SENSe FREQuency APERture cee eee 236 SENSe FUNCtion CONDition 0 0 0000 237 SENSe FUNCtion CUSTom 00 0 0 cece ee 237 SENSe FUNCtion CUSTom REFerence 005 238 SENSe FUNCtion CUSTom TCouple esses 239 SENSe FUNCtion FREQuency 0 00 2 cece eee 240 SENSe FUNCtion RESistance 1 0 0 0 241 SENSe FUNCtion STRain FBENding FBPoisson FPOisson HBENding HPOisson QUARter 242 SENSe FUNCtion TEMPerature 00 0 0 e eee eee 243 SENSe FUNCtion TOTalize 2 0 0 0 cece eee 245 SENSe FUNCtion VOLTage DC 2 0 0 0 00 cee ee 245 SENSe JREFerence cs sacos REIR E Rees 246 SENSe REFerence CHANnels 0 00 00 c eee
448. s can be used to determine whether algorithm a g name is defined e When Accepted Before INIT only e Returned Value numeric value The type is float32 Chapter 6 VT1415A Command Reference 173 ALGorithm ALGorithm FUNCtion DEFine ALGorithm FUNCtion DEFine lt function_name gt lt range gt lt offset gt func data defines a custom function that can be called from within a custom algorithm See Appendix F Generating User Defined Functions for full information Parameters Parameter Parameter Range of Default Name Type Values Units function name string Valid C identifier none If not already defined in GLOBALS range numeric float32 See comments none offset numeric float32 See comments none func_data 512 element array See comments none of uintl6 Comments e By providing this custom function capability the VT1415A s algorithm language can be kept simple in terms of mathematical capability This increases speed Rather than having to calculate high order polynomial approximations of non linear functions this custom function scheme loads a pre computed look up table of values into memory This method allows computing virtually any transcendental or non linear function in only 17 us Resolution is 16 bits The function name parameter is a global identifier and cannot be the same as a previously define global variable A user function is globally ava
449. s to be reported execute STAT OPER ENAB 1280 1280 decimal sum of values for bits 10 and 8 Standard Event Group Examples For the Query Error Execution Error and Command Error conditions to be reported by the ESB bit bit 5 of the Status Byte execute ESE 52 52 decimal sum of values for bits 2 4 and 5 Reading the To check if any enabled events have occurred in the status system first read Status Byte the Status Byte using the STB command If the Status Byte is all zeros there is no summary information being sent from any of the status groups If the Status Byte is other than zero one or more enabled events have occurred Interpret the Status Byte bit values and take further action as follows Bit 3 QUE Read the Questionable Data Group s Event Register bit value 8 using the STAT QUES EVENT command This will return bit values for events which have occurred in this group After reading the Event Register is cleared Note that bits in this group indicate error conditions If bit 8 9 or 10 1s set error messages will be found in the Error Queue If bit 7 is set error messages will be in the error queue following the next RST or cycling of power Use the SYST ERR command to read the error s Bit 4 MAV There is a message available in the Output Queue bit value 16 Execute the appropriate query command Bit 5 ESB Read the Standard Event Group s Event Register bit value 32 using th
450. s to each successive file name ALG1 ALG2 etc when you execute this program as lt progname gt langl lang2 lang3 e EJ alg_num 1 Starting algorithm number while argc gt alg num algorithm get algorithm argv alg num Read the algorithm Define the algorithm char alg 6 Temporary algorithm name void sprintf alg ALG d alg num INST SEND e1415 alg def S BWn alg strlen algorithm 1 algorithm Check for algorithm errors INST QUERY e1415 syst err n d 5 amp error string if error void printf While loading file s syst err d s n argv alg num error string exit 1 Free the malloc ed memory free algorithm alg num Next algorithm Appendix G Example Program Listings 389 void printf All d algorithm s loaded without errors n n alg num 1 else Download algorithms with in line code INST SEND e1415 alg def algl PIDB 1I116 0100 0141 B0 n Hendif Preset Algorithm variables INST SEND el415 alg scal algl M f n 1 234 INST SEND el415 alg scal algl B f n 5 678 INST SEND e1415 alg upd n Initiat Trigger System start scanning and running algorithms INST SEND e1415 init n Alter run time variables and Retrieve Data float32 sync array 4 irit ij for i 0 i lt 10 i
451. s which channels to link to the voltage EU conversion e The optional range parameter can be used to choose a fixed A D range Valid values are 0 0625 0 25 1 4 16 or AUTO When not specified the module uses auto range AUTO To set channels 0 through 15 to measure voltage using auto range SENS FUNC VOLT AUTO 100 115 To set channels 16 and 24 to the 16 volt range and 32 through 47 to the 0 0625 volt range SENS FUNC VOLT 16 116 124 SENS FUNC VOLT 625 132 147 must send a command per range or to send both commands in a single command message SENS FUNC VOLT 16 116 124 VOLT 0625 123 147 NOTE When using manual range in combination with amplifier SCPs the EU conversion will try to return readings which reflect the value of the input signal However the user must choose range values that will provide good measurement performance avoiding over ranges and selecting ranges that provide good resolution based on the input signal In general measurements can be made at full speed using auto range Auto range will choose the optimum A D range for the amplified signal level Linking Resistance To link channels to the resistance EU conversion send the Measurements SENSe FUNCtion RESistance lt excite_current gt lt range gt lt ch_list gt command Resistance measurements assume that there is at least one Current Source SCP installed eight current sources per SCP See Figure 3 4 Chapter 3 Programmi
452. set after Default Settings Power on or after a RST command Where these default settings coincide with the configuration settings required it is unnecessary to execute a command to set them These are the default settings e No algorithms defined e No channels defined in channel lists e Programmable SCPs configured to their Power on defaults see individual SCP User s Manuals All analog input channels linked to EU conversion for voltage All analog output channels ready to take values from an algorithm AII digital I O channels set to input static digital state ARM SOURce IMMediate TRIGger SOURce TlMer TRIGger COUNt INF 0 TRIGer TIMer 010 10 ms FORMat ASC 7 ASCII SENSe DATA FIFO MODE BLOCking Figure 3 3 provides a quick reference to the Programming model Refer to this together with the Programming Model Block Diagram to keep an overview of the VT1415A SCPI programming sequence Again where default settings match the desired settings that configuration step can be skipped Chapter 3 Programming the VT1415A for PID Control 57 Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Step 9 Step 10 Step 11 Step 12 Power On or RST Set up SCP Amps Filters and Measurement Excitation Sources Link Engineering Units Functions to Analog Input Channels Set up Digital I O Channels Calibrate Channel Set up after 1 hour warm up Setup Trigger System Select Data Format Select
453. single lines of code enclose the code string within single apostrophes or double quotes Because of string length limitations within SCPI and some programming platforms it is recommended that the quoted string length not exceed a single program line Example ALG DEF ALG1 if First loop 0108 0 0108 0108 01 2 SCPI Indefinite Length Block Program Data This form terminates the data transfer when it received an End Identifier with the last data byte Use this form only when it is certain that the controller platform will include the End Identifier If it is not included the ALG DEF command will swallow whatever data follows the algorithm code The syntax for this parameter type is 0 lt data byte s gt lt null byte with End Identifier gt Example from Quoted String above ALG DEF ALG1 00108 1100 4A where is a null byte 3 SCPI Definite Length Block Program Data For longer code segments like complete custom algorithms this parameter works well because it specifies the exact length of the data block that will be transferred The syntax for this parameter type is lt non zero digit gt lt digit s gt lt data byte s gt Where the value of lt non zero digit gt is 1 9 and represents the number of lt digit s gt The value of lt digit s gt taken as a decimal integer indicates the number of lt data byte s gt in the block Example from Quoted String above ALG DEF ALG1 2110108
454. sion for 2 250 Q thermistor To set channels 32 through 47 to measure temperature using 10 000 Q thermistors in this case paired to current source SCP channels 48 through 63 OUTP CURR AMPL 30 6 148 163 set excite current to 30 uA on current SCP channels 48 through 63 SENS FUNC TEMP THER 10000 132 147 link channels 32 through 47 to temperature EU conversion for 10 000 Q thermistor To set channels 48 through 63 to measure temperature using 100 Q RTDs with a TC of 0 00385 ohm ohm C in this case paired to current source SCP channels 32 through 47 OUTP CURR AMPL 488 6 132 147 set excite current to 486 uA on current SCP channels 32 through 47 SENS FUNC TEMP RTD 85 148 163 link channels 48 through 63 to temperature EU conversion for 100 Q RTDs with 0 00385 TC Thermocouple Measurements Thermocouple measurements are voltage measurements that the EU conversion changes into temperature values based on the lt sub_type gt parameter and latest reference temperature value e For Thermocouples the lt sub_type gt parameter can specify CUSTom E EEXT J K N R S T CUSTom is pre defined as Type K no reference junction compensation EEXT is the type E for extended temperatures of 800 C or above To set channels 32 through 40 to measure temperature using type E thermocouples SENS FUNC TEMP TC E 132 140 see following section to configure a TC reference measurement Thermocouple Reference Temperatu
455. sistance on the specified Strain SCP channel Parameters Parameter Parameter Range of Default Name Type Values Units channel channel list string 100 163 none Comments e channel must specify a single channel only e f channel specifies a non strain SCP a 3007 Invalid signal conditioning plug on error is generated e Returned Value Returns 1 or 0 The C SCPI type is uint16 e Related Commands OUTP SHUNT Usage OUTPUT SHUNt 116 Check status of shunt resistance on channel 16 OUTPut TTLTrg SOURce OUTPut TTLTrg SOURce lt trig_source gt selects the internal source of the trigger event that will operate the VXIbus TTLTRG lines Parameters Parameter Parameter Range of Default Name Type Values Units trig source discrete ALGorithm TRIGger FTRigger SCPlugon none string Chapter 6 VT1415A Command Reference 219 OUTPut Comments The following table explains the possible choices Parameter Value Source of Trigger ALGorithm Generated by the Algorithm Language function interrupt FTRigger Generated on the First Trigger of a multiple counted scan set by TRIG COUNT trig count SCPlugon Generated by a Signal Conditioning Plug On SCP Do not use this when Sample and Hold SCPs are installed TRIGger Generated every time a scan is triggered see TRIG SOUR rrig source e FTRigger F
456. ssion if the V382 is to source or respond to VXI backplane triggers SICL ixtrig or ionintr calls ef if vxi iopen vxi void fprintf stderr SICL error failed to open vxi interface Nn void fprintf stderr SICL error d s Nn igeterrno igeterrstr igeterrno exit 1 Hendif Open the E1415 device session with error checking Copy and modify these lines if you need to open other instruments f INST OPEN el415 E1415 ADDR Open the E1415 if e1415 Did it open void fprintf stderr Failed to open the E1415 at address s n E1415 ADDR void fprintf stderr C SCPI open error was d n cscpi open error void fprintf stderr SICL error was d s Wn igeterrno igeterrstr igeterrno exit 1 Check for startup errors INST QUERY e1415 syst err n d 5 amp error string if error void printf syst err d s n error string exit 1 Usually you ll want to start from a known instrument state The following provides this e INST CLEAR e1415 Selected device clear INST SEND e1415 RST GLSXn if O Set to 1 to do self test Does the E1415 pass self test int test_result Result of E1415 self test test_result 1 Make sure it gets assigned INST QUERY e1415 TST n Sd amp test result if test_result void fpri
457. st be triggered before executing the INIT command as shown above unless an external trigger EXT trigger is being used When using EXT trigger the trigger can occur at any time 200 VT1415A Command Reference Chapter 6 FORMat FORMat The FORMat subsystem provides commands to set and query the response data Subsystem Syntax FORMat FORMat DATA DATA lt format gt lt size gt DATA FORMat DATA lt format gt lt size gt sets the format for data returned using the SENSe DATA FIFO SENSe DATA CVTable and FETCh commands Parameters Parameter Parameter Range of Default Name Type Values Units format discrete string REAL ASCii PACKed none size numeric for ASCii 7 none for REAL 32 64 for PACKed 64 Comments e The REAL format is IEEE 754 Floating Point representation REAL 32 provides the highest data transfer performance since no format conversion step is placed between reading and returning the data The default size for the REAL format is 32 bits Also see DIAG IEEE command PACKed 64 returns the same values as REAL 64 except for Not a Number NaN IEEE INF and IEEE INF The NaN IEEE INF and IEEE INF values returned by PACKed 64 are in a form compatible with HP Workstation BASIC and HP BASIC UX see table on following page REAL 32 REAL 64 and PACK 64 readings are returned in the IEEE 488 2 1987 Arbitrary Block Data format Th
458. stom transducers so that when the voltage measurement is actually made the EU conversion takes place see SENS FUNC CUST Algorithms deal with the resulting floating point numbers generated during the measurement phase and may require further complex mathematical operations to achieve the desired result With some complex waveforms it may be beneficial to break up the waveform into several functions in order to get the desired accuracy For example suppose it is necessary to generate a square root function for both voltage and strain calculations The voltages are only going to range from 0 to 16 volts worst case The strain measurements return numbers in Appendix F Generating User Defined Functions 359 microstrain will be in the 1000 s range Trying to represent the square root function over the entire range would severely impact the accuracy of the approximation Remember the entire range is broken up into only 128 segments of Mx B operations If accuracy is desired the range over which calculations are made MUST be limited Many transcendental functions are simply used as a scaling multiplier For example a sine wave function is typically created over a range of 360 degrees or 2 PI or 27 radians After which the function repeats itself It s a simple matter to make sure the x term is scaled to this range before calculating the result This concept should be used almost exclusively to obtain the best results Havers
459. sum of bits set in the Enable register Returns weighted sum of bits that represent Operation status events Sets mask bits to enable pos Condition Reg transitions to Event reg Returns positive transition mask value Sets mask bits to enable neg Condition Reg transitions to Event reg Returns negative transition mask value Presets both the Operation and Questionable Enable registers to 0 Questionable Data Status Group Bit assignments 8 Calibration Lost 9 Trigger Too Fast 10 FIFO Overflowed 11 Over voltage 12 VME Memory Overflow 13 Setup Changed Returns state of Questionable Status signals Bits set to 1 enable status events to be summarized into Status Byte Returns the decimal weighted sum of bits set in the Enable register Returns weighted sum of bits that represent Questionable Data events Sets mask bits to enable pos Condition Reg transitions to Event reg Returns positive transition mask value Sets mask bits to enable neg Condition Reg transitions to Event reg Returns negative transition mask value Returns the identification of the SCP at channel Returns one element of the error queue 0 if no errors 292 VT1415A Command Reference Chapter 6 Command Quick Reference SCPI Command Quick Reference Command Description VERSion Returns the version of SCPI this instrument complies with TRIGger COUNt trig count Specify the number of trigger events that will be accepted COUNt Re
460. t if t 0 int32 ltemp round32f log10 t 1og10 2 0 if Xfactor ltemp gt 30 Xfactor 30 ltemp Mfactor round32f two to the N Xfactor slope if Mfactor 32768 There is an endpoint problem Re compute if on endpoint Xfactor Mfactor round32f two to the N Xfactor slope if Mfactor lt 32767 amp amp Mfactor gt 32768 only save if M is within limits Adjust EX to match runtime asm EX jj uint16 Xofst Xfactor M jj uinti16 Mfactor OxFFFF remove leading 1 s B round32f two to the N Xfactor result ii 1 Bhigh jj uint16 B gt gt 16 amp OxOOO0FFFF Blow jj uint16 B amp OxOO000FFFF end for Build actual tables for downloading into the E1415 memory ef for ii1 0 ii 128 iit copy 64 sets of coefficients conv_array ii 4 M ii conv array ii 4 1 EX ii conv array ii 4 2 Bhigh ii conv array ii 4 3 Blow ii printf d d Sd d dWMn ii M ii EX ii Bhigh ii Blow ii xf return Main program ARGSUSED Keeps lint happy int main int argc char argv Main program local variable declarations char algorithm Algorithm string int alg num Algorithm number being loaded Appendix G Example Program Listings 405 char string 333 Holds error information
461. t 205 207 209 210 MEMory 211 213 214 OUTPut 215 216 217 219 220 221 223 ROUTe 224 225 SAMPle 226 227 SENSe 228 229 230 232 234 236 237 238 239 240 241 242 243 244 245 246 241 248 249 250 251 252 253 254 SOURce 255 256 257 258 259 STATus 260 261 262 264 265 266 267 268 270 SYSTem 271 272 TRIGger 273 274 275 276 277 Summary 104 Summary language syntax 141 Supplying the reference temperature 68 support xvii support resources xvii Swapping defining an algorithm for 124 Switch setting the logical address 20 Symbols the operations 146 Syntax Variable Command 157 SYST CTYPe 271 SYST ERRor 271 SYST VERSion 272 SYSTem subsystem 271 272 System wiring offsets 104 System setting up the trigger 80 System using the status 93 T Tables creating conversion 103 Tables custom EU 102 Tables loading custom EU 103 TARE CAL TARE RESet 189 CAL TARE 190 Tare cal offset maximum 298 TARE CAL TARE 188 TCouple SENS FUNC CUST TC 239 technical support xvii Techniques Wiring and noise reduction 354 TEMPerature DIAG CUST REF TEMP 197 SENS FUNC TEMPerature 243 SENS REF TEMPerature 248 Temperature accuracy 299 Temperature measuring the reference 67 Temperature supplying the reference 68 Terminal block considerations for TC measurements 38 Terminal Blocks 336 Terminal Module 337 Attaching and removing the VT1415A 45 Attachi
462. t sets the gate time for frequency measurement The gate time is the time period that the SCP will allow for counting signal transitions in order to calculate frequency Parameters Parameter Parameter Range of Default Name Type Values Units gate time numeric float32 0 001 to 1 0 001 resolution seconds ch list string 100 163 none Comments e If the channels specified are on an SCP that doesn t support this function an error will be generated See the SCP s User s Manual for its capabilities e Related Commands SENSe FUNCtion FREQuency e RST Condition 0 001 s Usage SENS FREQ APER 01 144 set channel 44 aperture to 10 ms SENSe FREQuency APERture SENSe FREQuency APERture lt ch_list gt returns the frequency counting gate time Parameters Parameter Parameter Range of Default Name Type Values Units channel string 100 163 none 236 VT1415A Command Reference Chapter 6 SENSe Comments e If the channels specified are on an SCP that doesn t support this function an error will be generated See the SCP s User s Manual for its capabilities e Related Commands SENSe FREQuency APERture e Returned Value returns numeric gate time in seconds The type is float32 SENSe FUNCtion CONDition SENSe FUNCtion CONDition cA list sets the SENSe function to input the digital state for channels in lt ch_list gt Also configures digital SC
463. t Center 1120 Temp range Max input Center 1130 Test range ABS Temp range Generating User Defined Functions 375 1140 1150 1160 1170 1180 1190 1200 1210 1220 1230 1240 1250 1260 1270 1280 1290 1300 1310 1320 1330 1340 1350 1360 1370 1380 1390 1400 10 20 30 40 50 60 70 80 1490 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 1650 1660 1670 1680 1690 1700 1710 1720 1730 1740 1750 Now calculate the closest binary representation of the test range Tbl range 1 2 128 WHILE Test range Tbl range Tbl range Tbl range 2 END WHILE Table range Tbl range Xofst 157 exponent bias for DSP calculations Now divide the full range of the table into 128 segments 129 points from Rnge to Rnge using the Custom function function We then generate the M B and Ex values for the table to be downloaded Note that we actually calculate 129 points but generate 128 sets of M B and Ex values FOR Ii 0 TO 64 STEP 1 Input Ii Centert Tbl_ range 64 0 Ii Result Ii FNMy function Input Ii IF Ii 0 THEN GOTO Loopend1 This is the first point l for second and subsequent points Jj 64 Ii 1 generate numbers for prev segment T ABS Result Ii 1 using abs value of prev seg bas 1 compute the exponent of the offset B is 31 bits IF T lt gt 0 THEN don t take log of zero Exponent 31 0 LG
464. t Derivative term Appendix D PID Algorithm Listings 349 SD out SD factor Setpoint Setpoint old Clip to specified limits if SD out gt SD max Clip Setpoint derivative SD out SD max Status B3 1 else if SD min SD out SD out SD min Status B3 1 else Status B3 0 Calculate the Error Derivative term D out D factor PV old inchan Clip to specified limits if D out gt D max Clip derivative D out D max Status B2 1 else if D min gt D out D out D min Status B2 1 else Status B2 0 Calculate Proportional term P out Error P factor Sum PID amp SD terms outchan P out I out D out SD out Save values for next pass PV old inchan Setpoint old Setpoint In case we switch to manual on the next pass prepare to hold output at latest value Man out outchan if Man state Clip output to specified limits if outchan gt Out max outchan Out max Status B0 1 else if Out min gt outchan outchan Out min Status B0 1 else Status B0 0 Clear alarm output if no alarms if Status B6 Status B5 alarmchan 0 Log appropriate data 350 PID Algorithm Listings Appendix D if History mode gt 1 Output everything to FIFO amp CVT else if writefifo writeboth writeboth writeb
465. tart SCP Calibration on Ist VT1415A A start SCP Calibration on more VT1415As CAL SET start SCP Calibration on last VT1415A CAL SET query for results from Ist VTI415A E query for results from more VT1415As CAL SET query for results from last VTI415A CALibration SETup CALibration SETup Returns a value to indicate the success of the last CAL SETup or CAL operation CAL SETup returns the value only after the CAL SETup operation is complete Comments Returned Value Value Meaning Further Action 0 Cal OK None 1 Cal Error Query the Error Queue SYST ERR See Error Messages in Appendix B Also run TST 2 No results available No CAL or CAL SETUP done The C SCPI type for this returned value is int16 e Related Commands CAL SETup CAL Usage see CAL SETup 186 VT1415A Command Reference Chapter 6 CALibration STORe CALibration CALibration STORe lt type gt stores the most recently measured calibration constants into Flash Memory Electrically Erasable Programmable Read Only Memory When type ADC the module stores its A D calibration constants as well as constants generated from CAL CAL SETup into Flash Memory When type TARE the module stores the most recently measured CAL TARE channel offsets into Flash Memory NOTE The VT1415A s Flash Memory has a finite lifetime of approximately ten thousand write cycles unlimited
466. ted as if they were a single update request If the array 1s again updated the new values are loaded into the original space and the pointer 1s again switched e lt progname gt is not case sensitive However array name is case sensitive e Related Commands ALG DEFINE ALG ARRAY e RST Condition No algorithms or variables are defined send array values to my array in ALG4 ALG ARR ALG4 my array block array data send array values to the global array glob array ALG ARR GLOBALS glob array block array data ALG UPD force update of variables 164 VT1415A Command Reference Chapter 6 ALGorithm ALGorithm EXPLicit ARRay ALGorithm EXPLicit ARRay lt alg_name gt lt array_name gt returns the contents of array name from algorithm alg name gt ALG ARR can return contents of global arrays when alg name specifies GLOBALS Parameters Parameter Parameter Range of Default Name Type Values Units alg name string ALGI ALG32 GLOBALS none array name string Valid C variable name none Comments An error is generated if alg name or array name is not defined e Returned Value Definite length block data of IEEE 754 64 bit float ALGorithm EXPLicit DEFine ALGorithm EXPLicit DEFine lt alg_name gt lt swap_size gt lt source_code gt 1s used to define control algorithms and global variables
467. ted Most of the bits in the OPER and QUES registers represent conditions which can change while the VT1415A is measuring initiated In many circumstances it is sufficient to have the status system bits updated the next time the status system is accessed or the INIT or ABORt commands are given When it is desired to have the status system bits updated closer in time to when the condition changes on the VT1415A the VT1415A interrupts can be used The VT1415A can send VXI interrupts upon the following conditions e Trigger too Fast condition is detected Trigger comes prior to trigger system being ready to receive trigger e FIFO overflowed In either FIFO mode data was received after the FIFO was full e Over voltage detection on input If the input protection jumper has not been cut the input relays have all been opened and an RST is required to reset the VT1415A Scan complete The VT1415A has finished a scan list SCP trigger A trigger was received from an SCP FIFO half full The FIFO contains at least 32 768 values Measurement complete The trigger system exited the Wait For Arm This clears the Measuring bit in the OPER register e Algorithm executes an interrupt statement 100 Programming the VT1415A for PID Control Chapter 3 These VT1415A interrupts are not always enabled since under some circumstances this could be detrimental to system operation For example the Scan Complete SCP triggers FIFO h
468. ted to the Peel off correct Label from Card and Stick on the appropriate place on the Cover SNOILONYLSNI A Stick on Label furnished with the SCP VXI Technology part number VT15xx 24 Getting Started Chapter 1 Disabling the Input Protect Feature Optional VOIDS WARRANTY Disabling Flash Memory Access Optional Disabling the Input Protect feature voids the VT1415A s warranty The Input Protect feature allows the VT1415A to open all channel input relays if any input s voltage exceeds 19 volts 6 volts for digital I O SCPs This feature will help to protect the card s Signal Conditioning Plug ons input multiplexer ranging amplifier and A D from destructive voltage levels The level that trips the protection function has been set to provide a high probability of protection The voltage level that is certain to cause damage is somewhat higher If in an application the importance of completing a measurement run outweighs the added risk of damage to the VT1415A the input protect feature may be disabled Disabling the Input Protection Feature voids the VT1415A s warranty To disable the Input Protection feature locate and cut JM2202 Make a single cut in the jumper and bend the adjacent ends apart See following illustration for location of JM2202 The Flash Memory Protect Jumper JM2201 is shipped in the PROG position It is recommen
469. ter 1s Zero a positive transition of the Condition register bit will not change the Event register bit Parameters Parameter Parameter Range of Default Name Type Values Units transition mask numeric uint16 0 32767 none Comments e rransition mask may be sent as decimal hex H octal HQ or binary 8B e If both the STAT QUES PTR and STAT QUES NTR registers have a corresponding bit set to one any transition positive or negative will set the corresponding bit in the Event register e If neither the STAT QUES PTR or STAT QUES NTR registers have a corresponding bit set to one transitions from the Condition register will have no effect on the Event register e Related Commands STAT QUES PTR STAT QUES NTR e Set to all ones by STAT PRESet and power on e RST Condition No change Usage STAT QUES PTR 1024 When FIFO Overflowed bit goes true set bit 10 in Status Operation Event register STATus QUEStionable PTRansition STATus QUEStionable PTRansition returns the value of bits set in the Positive Transition Filter PTF register Comments Returned Value Decimal weighted sum of all set bits The C SCPI type is uint16 e Related Commands STAT QUES PTR e RST Condition No change Usage STAT OPER PTR Enter statement returns current value of bits set in the PTF register 210 VT1415A Command Reference Chapter 6 SYSTem SYSTem The SYSTem subsystem is used to
470. terface session If you need to open a VXI device session here s how to do it You need a VXI device session if the V382 is to source or respond to VXI backplane triggers SICL ixtrig or ionintr calls x if vxi iopen vxi void fprintf stderr SICL error failed to open vxi interface Nn void fprintf stderr SICL error d s Wn igeterrno igeterrstr igeterrno exit 1 Hendif Open the E1415 device session with error checking Copy and modify these lines if you need to open other instruments INST OPEN el415 E1415 ADDR Open the E1415 if el415 Did it open void fprintf stderr Failed to open the E1415 at address s n E1415 ADDR 370 Generating User Defined Functions Appendix F void fprintf stderr C SCPI open error was d n cscpi open error void fprintf stderr SICL error was d s Wn igeterrno igeterrstr igeterrno exit 1 Check for startup errors INST QUERY e1415 syst err n d S amp error string if error void printf syst err d s n error string exit 1 Usually you ll want to start from a known instrument state following provides this y INST CLEAR e1415 Selected device clear INST SEND e1415 RST CLSNn if O Set to 1 to do self test Does the E1415 pass self test int test_result
471. tes specifies how many updates may need to be performed during phase 2 UPDATE The DSP will process this command and assign a constant window of time for UPDATE Parameters Parameter Parameter Range of Default Name Type Values Units num updates numeric int16 1 512 none Comments e The default value for num updates is 20 If it is known that fewer updates are needed specifying a smaller number will result in slightly faster loop execution speeds This command creates a time interval in which to perform all pending algorithm and variable updates To keep the loop times predictable and stable the time interval for UPDATE is constant That is it exists for all active algorithms each time they are executed whether or not an update is pending RST Condition ALG UPD WIND 20 When Accepted Before INIT only Usage It is decided that a maximum of eight variables updates will be needed during run time ALG UPD WIND 8 178 VT1415A Command Reference Chapter 6 ALGorithm NOTES 1 When the number of update requests exceeds the Update Queue size set with ALG UPD WINDOW by one the module will refuse the request and will issue the error message Too many updates in queue Must send UPDATE command Send ALG UPDATE then re send the update request that caused the error 2 The Too many updates in queue error can occur before the module is INITialized It s not uncommon with several
472. the Output Queue all send summary information to the Status Byte By this method the Status Byte can report many more events than its eight bits would otherwise allow Figure 3 12 shows the Status System in detail Chapter 3 Programming the VT1415A for PID Control 93 Questionable Data Group FC N E Output Queue gt Status Byte gt Read with gt STB Group Summary Bits Z Operation Status Group N M Standard Event Group Figure 3 11 Simplified Status System Diagram 94 Programming the VT1415A for PID Control Chapter 3 QUESTIONABLE DATA GROUP STATus QUEStionable CONDition reads register STATus QUEStionable EVENt reads clears register STATus QUEStionable ENABle sets mask iL ccopoopopop mop sl E LL AA A Lost Calibration Trigger Too Fast FIFO Overflowed Over voltage VME Memory Overflow Setup Changed YO 1291607 AAA A AAA LU DS NN NS LN LS 1 real time latched 1 enable OPERATION STATUS GROUP Summary Bit STATus OPERation CONDition reads register STATus OPERation NTR and STATus QUEStionable PTR set filters STATus OPERation EVENt reads clears STATus OPERation ENABle sets mask Calibrating JE JAE Measuring JEE SE Scan Complete E SCP Trigger Ea E FIFO Half Full o a EAE Algorithm Interrupt Ej ae E E cEEGEGEEEEREREEE TTTTTTTITITITITTI TTT TTT TIT TTT TTT CORO OOOO
473. the channel The VT1534A has 8 I O bits that are individually configured as channels To configure the higher 8 bit channel of a VT1533A for inverted polarity OUTP POLARITY INV 109 SCP in SCP position 1 To configure the upper 4 bits of a VT 1534 for inverted polarity OUTP POL INV 132 135 SCP in SCP position 4 The VT1533A and VT1534A use output drivers that can be configured as either active or passive pull up To configure this use the command OUTPut TYPE lt mode gt lt ch_list gt This setting is valid even while the specified channel in not an output channel If and when the channel is configured for output an output FUNCtion command the setting will be in effect Chapter 3 Programming the VT1415A for PID Control 71 e The lt mode gt parameter can be either ACTive or PASSive When set to ACT the default the output provides active pull up When set to PASS the output is pulled up by a resistor e The cA list parameter specifies the channels to configure The VT1533A has 2 channels of 8 bits each All 8 bits in a channel take on the configuration specified for the channel The VT1534A has 8 I O bits that are individually configured as channels To configure the higher 8 bit channel of a VT15334 for passive pull up OUTP TYPE PASS 109 SCP in SCP position 1 To configure the upper 4 bits of a VT1534A for active pull up OUTP TYPE ACT 132 135 SCP in SCP position 4 Setting Output Functions Both the V
474. the following if 1 to fif 0 This function is most useful when you re trying to get your program running dif 1 Set to 0 to skip trapping errors ARGSUSED Keeps lint happy void cscpi error INST id int err char errorbuf 255 Holds instrument error message char idbuf 255 Holds instrument response to IDN cscpi exe id IDN n 6 idbuf 255 cscpi exe id SYST ERR n 10 errorbuf 255 void fprintf stderr Instrument error s from s n errorbuf idbuf endif The following routine allows you to type SCPI commands and see the results If you don t call this from your program set the following if 1 to dif 0 if 1 Set to 0 to skip this routine void do interactive void char command 5000 char result 5000 int32 error char string 256 for void printf SCPI command void fflush stdout repeat until it actually gets something while gets command if command break result 0 0 cscpi exe el415 command strlen command result sizeof result INST QUERY e1415 syst err d s error string while error 386 Example Program Listings Appendix G void printf syst err d s NMn error string INST QUERY el415 syst err d s amp error string if result 0 void printf result s n result Hendif Print usag
475. their excitation voltage sources cA list specifies the voltage sensing channels that are to measure the bridge outputs Measuring channels on a Bridge Completion SCP only returns that SCP s excitation source voltage The range parameter The VT1415A has five ranges 0 0625 V dc 0 25 V dc 1 V dc 4 V dc and 16 V dc To select a range simply specify the range value for example 4 selects the 4 V dc range Ifa value larger than one of the first four ranges is specified the VT1415A selects the next higher range for example 4 1 selects the 16 V dc range Specifying a value larger than 16 generates an error Specifying 0 selects the lowest range 0 0625 V dc Specifying AUTO selects auto range The default range no range parameter specified is auto range If using amplifier SCPs set them first and keep their settings in mind when specifying a range setting For instance if the expected signal voltage is to be approximately 0 1 V dc and the amplifier SCP for that channel has a gain of 8 range must be set no lower than 1 V dc or an input out of range condition will exist The channel calibration command CAL calibrates the excitation voltage source on each Bridge Completion SCP When Accepted Not while INITiated Related Commands CAL SENSE STRAIN RST Condition SENSE FUNC VOLT 0 2100 163 Usage FUNC STRAIN 1 100 105 107 quarter bridge sensed at channels 0 5 and 7 SENSe FUNCtion TEMPerature SE
476. thm Language source code is translated by the VT1415A s driver into an executable form and sent to the module For PIDA and PIDB the driver sends the stored executable form of these PID algorithms e The lt source_code gt parameter can be one of three different SCPI types Quoted String For short segments single lines of code enclose the code string within single apostrophes or double quotes Because of string length limitations within SCPI and some programming platforms it is recommended that the quoted string length not exceed a single program line Examples ALG DEF ALG1 0108 1100 or ALG DEF ALG3 PIDA I100 0124 Definite Length Block Program Data for longer code segments like complete custom algorithms this parameter works well because it specifies the exact length of the data block that will be transferred The syntax for this parameter type is lt non zero digit gt lt digit s gt lt data byte s gt 166 VT1415A Command Reference Chapter 6 NOTE NOTE When accepted and Usage ALGorithm Where the value of non zero digit is 1 9 and represents the number of lt digit s gt The value of lt digit s gt taken as a decimal integer indicates the number of data byte s in the block Example from Quoted String above ALG DEF ALG1 2110108 1100 0 where is a null byte For Block Program Data the Algorithm Parser requires that the lt source_code gt
477. time variables and Retrieve Data 396 Example Program Listings Appendix G float32 sync array 4 int i for i 0 i lt 10 i make 10 changes to x INST SEND el415 alg scal algl x f n float32 i INST SEND el415 alg scal algl sync f n 1 set sync INST SEND e1415 alg updNn fed he following alg scal command will not complete if the update has not occured Then it s a matter of waiting for the algorithm to complete and set sync 2 This should happen almost instantly since the algorithm is executing very lmsec based upon trig timer 001 above ty sync 0 while sync 2 0 wait until algorithm sets sync to 2 INST QUERY e1415 alg scal algl sync read results of Mx B calculations INST QUERY print INST algorithm INST printf nE Repeat wi for INST INST INST yey happen almost instantly since the al every lmsec based upon trig timer he following alg scal command will update has not occured Sf amp sync el415 data cvt G810 13 S f amp array f Array contents Sf sf Sf f n array 0 array 1 array 2 array 3 SEND e1415 alg def ALG1 B n strlen algorithm 1 SEND e1415 alg updin xecuting now with different algorithminin th different algorithm running i
478. tion to the VTI1415A ground can t be a very low impedance due to large de and or low frequency common mode voltages Appendix E Wiring and Noise Reduction Methods 357 The tri filar transformers don t limit the differential normal mode signal bandwidth Thus removing the requirement for slowly varying signal voltages The nature of the tri filar transformer or more accurately common mode inductor is that it provides a fairly high impedance to common mode signals and a quite low impedance to differential mode signals The ratio of common mode impedance to differential mode impedance for the transformer used is 3500 1 Thus there is NO differential mode bandwidth penalty incurred by using the tri filar transformers 358 Wiring and Noise Reduction Methods Appendix E Appendix F Generating User Defined Functions Introduction The VT1415A Algorithmic Closed Loop Control Card has a limited set of mathematical operations such as add subtract multiply and divide Many control applications require functions such a square root for calculating flow rate or a trigonometric function to correctly transition motion of moving object from a start to ending position In order to represent a sine wave or other transcendental functions one could use a power series expansion to approximate the function using a finite number of algebraic expressions Since the above mentioned operations can take from 1 5 us to 4 us for each floatin
479. to around 31 uV per LSB so the stray capacitances discharging after the 15 5 volt measurement are now only one sixteenth as significant and thus reduce any required settling delay Of course for most thermocouple measurements a gain of 64 can be used with the Range Amplifier set to the 4 volt range At this setting the A D resolution for one LSB drops to about 122 uV and further reduces or removes any need for additional settling Chapter 3 Programming the VT1415A for PID Control 109 delay This improvement is accomplished without any reduction of the overall measurement resolution NOTE Filter amplifier SCPs can provide improvements in low level signal measurements that go beyond just settling delay reduction Amplifying the input signal at the SCP allows using less gain at the Range Amplifier higher range for the same measurement resolution Since the Range Amplifier has to track signal level changes from the multiplexer at up to 100 kHz its bandwidth must be much higher than the bandwidth of individual filter amplifier SCP channels Using higher SCP gain along with lower Range Amplifier gain can significantly increase normal mode noise rejection Adding Settling Delay for This method adds settling time only to individual problem measurements as Specific Channels opposed to the SAMPle TIMer command that introduces extra time for all analog input channels If problems are seen on only a few channels use the SENS CHAN SETTLING lt
480. tude lt amplitude gt lt ch_list gt AMPLitude lt channel gt STATe ON OFF lt ch_list gt STATe lt channel gt POLarity NORmal INVerted lt ch_list gt POLarity lt channel gt SHUNt ON OFF lt ch_list gt SHUNt lt channel gt TTLTrg SOURce FTRigger LIMit SCPlugon TRIGger SOURce TTLTrg lt n gt STATe ON OFF STATe TYPE PASSive ACTive lt ch_list gt TYPE lt channel gt VOLTage AMPLitude lt amplitude gt lt ch_list gt AMPLitude lt channel gt ROUTe SEQuence DEFine AIN AOUT DIN DOUT POINts AIN AOUT DIN DOUT SAMPle TIMer lt num_samples gt lt ch_list gt TIMer lt channel gt SENSe CHANnel SETTling lt settle_time gt lt ch_list gt SETTling lt channel gt DATA CVTable lt ch_list gt RESet FIFO SCPI Command Quick Reference Description Turn filtering OFF pass through or ON filter Return state of SCP filters Set gain for amplifier per channel SCP Returns the channel s gain setting Controls the connection of input LO on a Strain Bridge Opt 21 SCP Returns the LO connection for the Strain Bridge at channel Sets input polarity on a digital SCP channel Returns digital polarity currently set for lt channel Specify address of VME memory card to be used as reading storage Returns address of VME memory card Specify number of bytes of VME memory to be used to sto
481. turned Value Numeric value of gage factor The C SCPI type is flt32 e lt channel gt must specify a single channel only e Related Commands STRAIN GFACTOR STRAIN GFAC 107 query gage factor for channel 7 enter statement here returns the gage factor set by STR GFAC 250 VT1415A Command Reference Chapter 6 SENSe SENSe STRain POISson SENSe STRain POISson lt poisson_ratio gt lt ch_list gt sets the Poisson ratio to be used for EU conversion of values measured on sense channels specified by lt ch_list gt Parameters Parameter Parameter Range of Default Name Type Values Units poisson_ratio numeric f1t32 0 1 0 5 none ch list channel list string 100 163 none Comments lt ch list must specify channels used to sense strain bridge output not channel E pecify channel ge outp positions on a Bridge Completion SCP e Related Commands FUNC STRAIN STRAIN POISson e RST Condition Poisson ratio 1s 0 3 Usage STRAIN POISSON 5 124 131 set Poisson ratio for sense channels 24 through 31 SENSe STRain POlSson SENSe STRain POISson lt channel gt returns the Poisson ratio currently set for the sense channel specified by channel Parameters Parameter Parameter Range of Default Name Type Values Units channel channel list string 100 163 none Comments Returned Value numeric value of the Poisson ratio C SCPI t
482. turns the current trigger count setting IMMediate Triggers instrument when TRIG SOUR is TIMer or HOLD same as TRG and IEEE 488 1 GET commands SOURce BUS EXT HOLD IMM SCP TIMer TTLTrg lt n gt Specify the source of instrument triggers SOURce Returns the current trigger source TIMer Sets the interval between scan triggers when TRIG SOUR is TIMer PERiod trig interval Sets the interval between scan triggers when TRIG SOUR is TIMer PERiod Returns setting of trigger timer Chapter 6 VT1415A Command Reference 293 Command Quick Reference IEEE 488 2 Common Command Quick Reference Category Command Title Description Calibration CAL Calibrate Performs internal calibration on all 64 channels out to the terminal module connector Returns error codes or 0 for OK Internal IDN Identification Returns the response Agilent E1415B lt serial gt lt driver Operation revit RST Reset Resets all scan lists to zero length and stops scan triggering Status registers and output queue are unchanged TST Self Test Performs self test Returns 0 to indicate test passed Status Reporting CLS Clear Status Clears all status event registers and so their status summary bits except the MAV bit ESE mask Event Status Enable Set Standard Event Status Enable register bits mask ESE Event Status Enable query Return current setting of Standard Event Status Enable register ESR Event Status
483. tus values from ALGI execute program input statement here must input 4 values To return the latest values from PIDB Algl and PIDB ALG2 SENS DATA CVT 10 13 20 23 returns Sense Error Output and Status values from ALGs I and 2 execute program input statement here must input 8 values To reset the CVT and set all values to NaN send the command SENSe DATA CVTable RESet Reading History The algorithm history mode enables PIDB algorithms to send their Mode Values From P erating values to the FIFO buffer To enable the PIDB algorithm to send its operating values to the FIFO set the lt History_mode gt variable to 1 If it the FIFO is necessary to retrieve the value of the working variables from every execution of an algorithm the FIFO is the best choice Since it is a buffer that can store up to 65 024 values the application program can read the FIFO values intermittently and still keep up with the data rate from the algorithm The commands provided for reading the FIFO are FIFO Transfer Commands SENSe DATA FIFO ALL returns all values remaining in the FIFO This command should be used only when no more values are being placed in the FIFO algorithms stopped SENSe DATA FIFO HALF returns 32 768 values approximately half of the FIFO capacity when they become available This command completes only after the 32 768 values are transferred SENSe DATA FIFO PART n values returns the number of values specified by
484. type parameter specifies the type of thermocouple wire so that the correct built in table will be used for reference junction compensation Reference junction compensation is based on the reference junction temperature at the time the custom channel is measured For more information see Thermocouple Reference Temperature Compensation on page 66 Custom Reference The VT1415A can measure reference junction temperatures using custom Temperature EU characterized RTDs and thermistors The custom EU table generated for the Conversions individually characterized transducer is loaded to the appropriate channel s using the DIAG CUST PIEC command Since the EU conversion from this custom EU table is to be considered the reference junction temperature the channel is linked to this EU table using the command SENSe FUNCtion CUSTom REFerence lt range gt lt ch_list gt This command uses the custom EU conversion to generate the reference junction temperature as explained in the Thermocouple Reference Temperature Compensation section on page 66 102 Programming the VT1415A for PID Control Chapter 3 Creating Conversion Tables Contact a VXI Technology System Engineer for more information on Custom Engineering Unit Conversion for specific applications Loading Custom EU Tables There is a specific location in the VT1415A s memory for each channel s EU Conversion table When standard EU conversions are specified the VT1415A loa
485. ualified repair personnel Executing TST returns the module to its RST state RST causes the FIFO data format to return to its default of ASC 7 To read the FIFO for TST diagnostic information and have data in a format other than ASCIL 7 make certain that the data FIFO format is set to the desired format FORMAT command after completion of TST but before executing a SENSE DATA FIFO query command e The C SCPI type for this returned value is int16 e Following TST the module is placed in the RST state This returns many of the module s programmed states to their defaults See page 57 for a list of the module s default states 284 VT1415A Command Reference Chapter 6 Common Command Reference e TST performs the following tests on the VT1415A and installed Signal Conditioning Plug Ons DIGITAL TESTS Testi Description 1 3 Writes and reads patterns to registers via A16 amp A24 4 5 Checks FIFO and CVT 6 Checks measurement complete Measuring status bit T Checks operation of FIFO half and FIFO full IRQ generation 8 9 Checks trigger operation ANALOG FRONT END DIGITAL TESTS Test Description 20 Checks that SCP ID makes sense 30 32 Checks relay driver and fet mux interface with EU CPU 33 71 Checks opening of all relays on power down or input over voltage 34 37 Check fet mux interface with A D digital ANALOG TESTS Test Description 40 42 Checks internal voltage reference 43 44 Checks zero of A D inte
486. ufacture and intended use of the product VXI Technology assumes no liability for the customer s failure to comply with these requirements Ground the equipment For Safety Class 1 equipment equipment having a protective earth terminal an uninterruptible safety earth ground must be provided from the mains power source to the product input wiring terminals or supplied power cable DO NOT operate the product in an explosive atmosphere or in the presence of flammable gases or fumes For continued protection against fire replace the line fuse s only with fuse s of the same voltage and current rating and type DO NOT use repaired fuses or short circuited fuse holders Keep away from live circuits Operating personnel must not remove equipment covers or shields Procedures involving the removal of covers or shields are for use by service trained personnel only Under certain conditions dangerous voltages may exist even with the equipment switched off To avoid dangerous electrical shock DO NOT perform procedures involving cover or shield removal unless you are qualified to do so DO NOT operate damaged equipment Whenever it is possible that the safety protection features built into this product have been impaired either through physical damage excessive moisture or any other reason REMOVE POWER and do not use the product until safe operation can be verified by service trained personnel If necessary return the product to a VXI Technology Sales
487. ule page 43 e Attaching Removing the VT1415A Terminal Module page 45 e Adding Components to the Terminal Module page 47 e Terminal Module Wiring Maps 00 0 e eee page 48 e Terminal Module Options 0 0000 eese page 49 e Faceplate Connector Pin Signal LiSt o o ooooo oo page 51 Planning the Wiring Layout SCP Positions and Channel Numbers The first point to understand is that the VT1415A makes no assumptions about the relationship between Signal Conditioning Plug on SCP function and the position in the VT1415A that it can occupy Any type of SCP can be placed into any SCP position There are however some factors that should be considered when planning what mix of SCPs should be installed in each of the VT1415As The following discussion is intended to clarify these factors The VT1415A has a fixed relationship between Signal Conditioning Plug on positions and the channels they connect to Each of the eight SCP positions can connect to eight channels Figure 2 1 shows the channel number to SCP relationship Chapter 2 Field Wiring 31 Note Each channel line 2 represents both a Hi and Lo input SCP SCP SCP SCP A D System P Multip
488. ult if cal_result void fprintf stderr E1415A failed calibrationin void fprintf stderr Check FIFO for channel errors n exit 1 endif Configure Trigger Subsystem and Data Format INST SEND e1415 trig sour timer trig timer 001 n INST SEND e1415 samp timer 10e 6 n default INST SEND e1415 form real 321n Download Globals INST SEND e1415 alg def globals static float x in Download algorithms if O Set to 1 if algorithms passed in as files Get an algorithm s from the passed filename s We assign sequential algorithm numbers to each successive file name ALG1 ALG2 etc when you execute this program as lt progname gt langl lang2 lang3 d wf alg num 1 Starting algorithm number while argc gt alg num algorithm get algorithm argv alg num Read the algorithm Define the algorithm char alg 6 Temporary algorithm name void sprintf alg ALG d alg num INST SEND e1415 alg def S B n alg Appendix G Example Program Listings 395 strlen algorithm 1 algorithm Check for algorithm errors INST QUERY e1415 syst err n d 5 amp error string if error void printf While loading file s syst err d s Nn argv alg num error string exit 1 Free the malloc ed memory free algorithm alg num t Next algorithm void
489. um Read the algorithm Define the algorithm char alg 6 Temporary algorithm name void sprintf alg ALG d alg num INST SEND e1415 alg def S BWn alg strlen algorithm 1 algorithm Check for algorithm errors INST QUERY e1415 syst err n d 5 amp error string if error void printf While loading file s syst err d s n argv alg num error string exit 1 Free the malloc ed memory free algorithm alg num Next algorithm Appendix G Example Program Listings 383 void printf All d algorithm s loaded without errors n n alg num 1 else Download algorithms with in line code INST SEND el1415 alg def algl PIDB I116 0100 0141 B0 n endif Preset Algorithm variables INST_SEND e1415 alg scal algl Setpoint f n 3 0 INST Sl el415 alg scal algl P factor f n 0 0001 zz z INST el415 alg scal algl I factor fNn 0 00025 INST e1415 alg upd n E p pi Dd nun un z D D D Initiate Trigger System start scanning and running algorithms INST _SEND e1415 initin Alter run time variables and Retrieve Data while 1 float32 setpoint 0 process info 4 int i type in 100 to exit printf Enter desired setpoint scanf f amp setpoint if setpoint 100 00
490. unary expression Unary Operator Multiplicative Expression unary expression multiplicative expression multiplicative operator unary expression Multiplicative Operator Additive Expression multiplicative expression additive expression additive operator multiplicative expression Additive Operator Relational Expression additive expression relational expression relational operator additive expression 142 Algorithm Language Reference Chapter 5 Relational Operator Equality Expression relational expression equality expression equality operator relational expression Equality Operator Logical AND Expression equality expression logical AND expression amp amp equality expression Expression logical AND expression expression logical AND expression Declarator identifier identifier integer constant expression NOTE Integer constant expression in array identifier above must not exceed 1 023 Init Declarator declarator declarator constant expression NOTES 1 May not initialize array declarator 2 Arrays limited to single dimension of 1024 maximum Init Declarator List init declarator init declarator list init declarator Declaration static float init declarator list Chapter 5 Algorithm Language Reference 143 Declarations declaration declarations declaration Intrinsic Statement interrupt writefifo expression writ
491. update phase Chapter 3 Programming the VT1415A for PID Control 89 Setting Algorithm The ALGorithm SCAN RATio alg name num trigs command sets the Execution umber of trigger events that must occur before the next execution of Freauenc algorithm a g name gt For PID ALG3 to execute once every twenty q y triggers send ALG SCAN RATIO ALG3 20 followed by an ALG UPDATE command ALG3 would then execute on the first trigger after INIT then the 21st then the 41st etc This can be useful to adjust the response time of a control algorithm relative to others The RST default for all algorithms is to execute on every trigger event Example Command Sequence This example command sequence puts together all of the steps discussed so far in this chapter RST Reset the module Setting up Signal Conditioning only for programmable SCPs INPUT FILTER FREQUENCY 2 116 119 INPUT GAIN 64 116 119 INPUT GAIN 8 120 123 set up digital channel characteristics INPUT POLARITY NORM 125 RST default OUTPUT POLARITY NORM 124 RST default OUTPUT TYPE ACTIVE 124 link channels to EU conversions measurement functions SENSE FUNCTION VOLTAGE AUTO 100 107 RST default SENSE REFERENCE THER 5000 AUTO 108 SENSE FUNCTION TEMPERATURE TC T AUTO 109 123 SENSE REFERENCE CHANNELS 108 109 123 configure digital output channel for alarm channel SOURCE FUNCTION CONDITION 132 execute channel cali
492. urned Value ASCII values are returned in the form 1 234567E 123 For example 13 325 volts would be 1 3325000E 001 Each value is followed by a comma A line feed LF and End Or Identify EOI follow the last value The C SCPI data type is a string array REAL 32 REAL 64 and PACK 64 values are returned in the IEEE 488 2 1987 Definite Length Arbitrary Block Data format This data return format is explained in Arbitrary Block Program Data on page 158 of this chapter For REAL 32 each value is 4 bytes in length the C SCPI data type is a float32 array For REAL 64 and PACK 64 each value is 8 bytes in length the C SCPI data type is a float64 array NOTE Algorithm values which are a positive over voltage return IEEE INF and a negative over voltage return IEEE INF see table on page 202 for actual values for each data format Chapter 6 VT1415A Command Reference 233 SENSe e Related Commands DATA FIFO COUNT HALF e RST Condition FIFO buffer is empty Command Sequence DATA FIFO COUNT HALF poll FIFO for half full status DATA FIFO HALF returns 32768 values SENSe DATA FIFO MODE SENSe DATA FIFO MODE lt mode gt sets the mode of operation for the FIFO buffer Parameters Parameter Parameter Range of Default Name Type Values Units mode discrete string BLOCK OVERwrite none Comments In BLOCk ing mode if the FIFO becomes full and measurements are still being made the n
493. ute CAL when 75 REFerence SENS FUNC CUST REF 238 SENS REFerence 246 Reference junction 42 Reference measurement before thermocouple measurements 67 Reference temperature measurement NOTE 34 Reference temperature sensing 37 Reference temperature sensing with the VT1415A 37 Reference Algorithm language 135 Register the status byte group s enable 99 Registers clearing event 99 Registers clearing the enable 99 Registers configuring the enable 97 Registers reading condition 99 Registers reading event 99 Rejection Noise 356 Rejection common mode 298 Relational expression 142 Relational operator 143 Removing the VT1415A terminal module 45 Reset RST 282 Resetting the CVT 86 RESet SENS DATA CVT RESet 231 SENS DATA FIFO RESet 236 Resetting CAL TARE 105 Residual sensor offsets 105 Resistance CAL VAL RESistance 190 RESistance CAL CONF RES 184 SENS FUNC RESistance 241 Resolution measurement 297 420 Index Resources accessing the VT1415A s 115 Restrictions 74 ROUT SEQ DEF 224 ROUT SEQ POINts 225 ROUTe subsystem 224 225 RTD and thermistor measurements 65 Running the algorithm 127 Running changing an algorithm while it s 124 S Safe Handling static discharge CAUTION 21 SAMP TIMer 226 SAMP TIMer 227 SAMPle subsystem 226 227 sample timer accuracy 297 SCALar ALGorithm EXPLicit SCALar 169 SCALar ALGorithm EXPLicit SCALar 170 SCP 336
494. value larger than one of the first four ranges is specified the VT1415A selects the next higher range for example 4 1 selects the 16 V dc range Specifying a value larger than 16 generates an error Specifying 0 selects the lowest range 0 0625 V dc Specifying AUTO selects auto range The default range no range parameter specified is auto range e f amplifier SCPs set them first and keep their settings in mind when specifying a range setting For instance if the expected signal voltage is to be approximately 0 1 V dc and the amplifier SCP for that channel has a gain of 8 range must be set no lower than 1 V dc or an input out of range condition will exist e The sub type parameter values of 85 and 92 differentiate between 100 Q 0 C RTDs with temperature coefficients of 0 00385 and and 0 00392 ohm ohm C respectively The sub type values of 2250 5000 and 10000 refer to thermistors that match the Omega 44000 series temperature response curve These 44000 series thermistors are selected to match the curve within 0 1 or 0 2 C For thermistors sub type may be specified in KQ kohm The sub type EEXTended applies to E type thermocouples at 800 C and above CUSTom is pre defined as Type K with no reference junction compensation reference junction assumed to be at 0 C e The CAL command calibrates temperature channels based on Current Source SCP and Sense Amplifier SCP setup at the time of execution
495. values are available In OVERwrite mode the module must be halted ABORT sent before reading the FIFO see Reading the Latest FIFO Values on page 88 This mode is very useful when viewing an algorithm s response to a disturbance is desired Run the algorithm with History mode set to 1 Disturb the loop with a step change Stop the algorithm with the ABORT command The FIFO records the latest 13 004 5 value entries from a PIDB To set the FIFO mode blocking is the RST Power on condition SENSe DATA FIFO MODE OVERWRITE select overwrite mode SENSe DATA FIFO MODE BLOCK select blocking mode Setting up the Trigger System Arm and Trigger Figure 3 7 shows the trigger and arm model for the VT1415A Note that Sources When the Trigger Source selected is TIMer the default the remaining sources become Arm Sources Using ARM SOUR allows an event to be specified that must occur in order to start the Trigger Timer The default Arm source is IMMediate always armed 80 Programming the VT1415A for PID Control Chapter 3 ARM SOURce source 2 1 a TRIGger TIMer interval gt y o gt 5 Trigger o Timer gt o gt S p gt amp 3 TRIGger SOURce source TlMer BUS d e BR4 BR 1111111111111 gt gt 3 2 EXTernal a 3 gt 2 3 HOLD Y Internal E gt amp Trigger Trigger Signal 9 MMed
496. ve and coil closed relay drive and coil open I O Disconnect line 286 VT1415A Command Reference Chapter 6 Common Command Reference 354 Watchdog SCP I O Disconnect supply WAI NOTE Wait to continue Prevents an instrument from executing another command until the operation begun by the previous command is finished sequential operation Do not use WAI to determine when the CAL SETUP or CAL TARE commands have completed Instead use their query forms CAL SETUP or CAL TARE CAL SETUP and CAL TARE return a value only after the CAL SETUP or CAL TARE operations are complete Chapter 6 VT1415A Command Reference 287 Command Quick Reference Command Quick Reference The following tables summarize SCPI and IEEE 488 2 Common commands for the VT1415A Algorithmic Loop Controller Command ABORt ALGorithm EXPLicit ARRay lt alg_name gt lt array_name gt lt block_data gt ARRay alg name carray name DEFine alg name gt lt swap_size gt lt program_data gt SCALar lt alg_name gt lt var_name gt lt value gt SCALar lt alg_name gt lt var_name gt SCAN RATio lt alg_name gt lt ratio gt RATio lt alg name gt SIZe lt alg name gt STATe alg name ON OFF STATe alg name gt TIMe alg name gt MAIN FUNCtion DEFine lt function_name gt lt range gt lt offset gt lt func_data gt OUTPut DELay delay AUTO DELay UPDate IMMediate
497. ved keywords is the same as ANSI C Custom variables cannot be created using these names Note that the keywords that are shown underlined and bold are the only ANSI C keywords that are implemented in the VT1415A auto double int struc break else long switch case enum register typeof char extern return union const float short unsigned continue for signed void default goto sizeof volatile do SE static while While all of the ANSI C keywords are reserved only those keywords that are shown in bold are actually implemented in the VT1415A The VT1415A implements some additional reserved keywords Variables cannot be created using these names abs interrupt writeboth Bn n 0 through 9 max writecvt Bnn nn 10 through 15 min writefifo Identifiers variable names are significant to 31 characters They can include alpha numeric and the underscore character Names must begin with an alpha character or the underscore character Alpha abcdefghijkImnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ Numeric 0123456789 Other _ Identifiers are case sensitive The names My_array and my_array reference different identifiers 136 Algorithm Language Reference Chapter 5 Special Identifiers for Channels NOTE Operators Assignment Operator Arithmetic Operators Unary Operators Comparison Operators Logical Operators Unary Logical Operator Intrinsic Functions and Statements Channel
498. ver eo oc TRA eo LIO ES EA OA AA 4 S 4 Figure 2 13 Removing the VT1415A Terminal Module 46 Field Wiring Chapter 2 Adding Components to the Terminal Module The back of the terminal module printed circuit board PCB provides surface mount pads which can be used to add serial and parallel components to any channel s signal path Figure 2 14 shows additional component locator information see the schematic and pad layout information on the back of the terminal module PCB Figure 2 15 shows some usage example schematics Upper layout also applies here Upper layout also applies here Lower layout also applies here Lower layout also applies here SCHEMATIC OF MODIFIABLE PARTS LOCATOR LOCATOR Figure 2 14 Additional Component Location Information SH PES HI HI m n lt T 0 Oh 7 x TO USER WIRING i TO VT1413A VT1415A 10 kOhms A TO USER WIRING 212 TO VT1413A VT1415A LO SL LO TE gt OWO 1 gt el oko Eo hme MOkOms dh 1 ka 2 k 2 Q8 o Default Circuit Normal Mode Low Pass Filter Circuit SH on Y owo x HI 0 Ohms 8 TO USER WIRING 3 al TO VT1413A VT1415A pes LO SL al LO gt VA 7 M 4 20 mA NOTE Input must not exceed common mode limits usually 16 Volts unless attenuated with a VT1513A h Y 4 to 20 mA Sense 5 V Full Scale with 250 Ohm must use 16 Volt range 4
499. w considered the new zero value for that channel The new offset value can be stored in non volatile calibration memory CAL STORE TARE but is in effect whether stored or not System offset constants which are considered long term should be stored Offset constants which are measured relatively often would not require non volatile storage CAL TARE automatically executes a CAL Chapter 6 VT1415A Command Reference 183 CALibration CAL or scp La 8 CAL SETup SCP k s e scp e A 5 E x SCP 2 E CALTARE amp a E po 5 SCP a i 2 o lt scp ke D 9 AE 2 oe scp le B Figure 6 3 Levels of Working Calibration Subsystem Syntax CALibration CONFigure RESistance VOLTage range ZERO FS SETup SETup STORe ADC TARE TARE lt ch_list gt RESet TARE VALue RESistance ref ohms VOLTage ref volts ZERO CALibration CONFigure RESistance CALibration CONFigure RESistance connects the on board reference resistor to the Calibration Bus A four wire measurement of the resistor can be made with an external multimeter connected to the H Cal L Cal H ohm and L ohm terminals on the Terminal Module or the V H V L O H and Q L terminals on the Cal Bus connector Comments Related Commands CAL
500. wapped after INIT that takes longer to execute than the original the output delay will behave as if set by ALG OUTP DEL 0 rather than AUTO see ALG OUTP DEL command Use the same procedure from note 1 to make sure the longest algorithm execution time is used to set ALG OUTP DEL AUTO before INIT ALGorithm EXPLicit SCALar NOTE Parameters Comments ALGorithm EXPLicit SCALar lt alg_name gt lt var_name gt lt value gt sets the value of the scalar variable var name for algorithm alg name gt into the Update Queue This update is then pending until ALG UPD is sent or an update event as set by ALG UPD CHANNEL occurs ALG SCALAR places a variable update request in the Update Queue Do not place more update requests in the Update Queue than are allowed by the current setting of ALG UPD WINDOW or a Too many updates send ALG UPDATE command error message will be generated Parameter Parameter Range of Default Name Type Values Units alg_name string ALGI ALG32 or GLOBALS none var name string Valid C variable name none value numeric float32 IEEE 754 32 bit floating point number none To send values to a global scalar variable set the a g name gt parameter to GLOBALS To define a scalar global variable see the ALGorithm DEFine command An error is generated if alg name gt or var name is not defined Related Commands ALG DEFINE ALG SCAL RST Condit
501. while the module 1s running See Appendix G for program listings A Very Simple First Algorithm This section will demonstrates how to create and download an algorithm that simply sends the value of an input channel to a CVT element It includes an example application program that configures the VT1415A downloads defines the algorithm starts and then communicates with the running algorithm 126 Creating and Running Custom Algorithms Chapter 4 Writing the Algorithm Running the Algorithm The most convenient method of creating a custom algorithm is to use a text editor or word processor to input the source code The following algorithm source code is on the examples disc in a file called mxplusb Example algorithm that calculates 4 Mx B values upon signal that sync 1 M and B terms set by application program static float M B x sync if First loop sync 0 if sync 1 writecvt M x B M writecvt M x B 11 writecvt M x B 2 12 bids 2 M x B 13 sync A C SCPI example program file_alg cs shows how to retrieve the algorithm source file mxplusb and use it to define and execute an algorithm When file alg cs has been compiled type file alg mxplusb to run the example and load the algorithm The aforementioned files can be found on the VXIplug amp play Drivers and Product Manuals CD Modifying a Standard PID Algorithm PIDA with Digital On Off Control While t
502. y 218 Power Available for SCPs 297 Power on and RST default settings 57 PRESet STAT PRESet 266 Pre setting PID variables 79 Pre setting PID variables and coefficients 79 Primary expression 142 Problem fixing the 109 Problems checking for 109 Problems resolving programming 57 Process monitoring algorithm 131 Profiles implementing setpoint 132 Program flow control 138 Program structure and syntax 145 Programming model 55 Programming the trigger timer 82 PTRansition STAT OPER PTRansition 265 STAT QUES PTRansition 270 PTRansition STAT OPER PTRansition 266 STAT QUES PTRansition 270 PULSe SOURce FUNC SHAPe 256 Q Questionable data group examples 97 Quick Reference Command 288 290 291 292 293 294 2 Quiet measurements HINTS 39 Quieter readings with amplifier SCPs NOTE 110 R Rack Mount Terminal Panel Accessories 49 Ranges measurement 297 RATio ALGorithm EXPLicit SCAN RATio 170 RATio ALGorithm EXPLicit SCAN RATio 171 Reading algorithm values from the CVT 85 Reading algorithm variables 85 Reading condition registers 99 Reading CVT elements 118 Reading event registers 99 Reading history mode values from the FIFO 86 Reading running algorithm values 85 Reading status groups directly 99 Reading the latest FIFO values FIFO mode OVER 88 Reading the status byte 98 Reading values from the FIFO 86 119 Recommended measurement connections 39 Re Exec
503. y changing the num events variable 132 Creating and Running Custom Algorithms Chapter 4 SOUR FUNC COND 141 define algorithm ALG DEF alg1 static float setpoints 1024 index num events if First loop index 0 n num events preset 1 0 0100 setpoints index J output new index index 1 if index gt 1023 index 0 n n if n lt make Digital I O channel 141 a digital output The default condition for 140 is digital input Tur FF array start point interval count trigger events value increment index look for endpoint 0140 B0 0140 B0 toggle update bit n num events reset ALG SCAL alg1 num_events 10 ALG ARRAY alg setpoints block data ALG UPD TRIG TIMER 001 TRIG SOUR TIMER INIT interval count output change every 10 ms set first profile force change trigger event at 1 ms trigger source timer start algorithm Download new setpoint profile and new timer interval ALG SCAL alg1 num events 20 ALG ARRAY alg setpoints block data ALG UPD CHAN 1140 B0 output change every 20 ms set first profile change takes place with change in bit 0 of O140 This example program was configured using Digital Output and Digital Inputs for the express reason that mu Itiple VT1415A s may be used ina system In this case the VT1415A toggling the digital bit would
504. y the algorithms Depending on the process this uncontrolled situation could even be dangerous Make certain that the process is in a safe state before halting stop triggering execution of a controlling algorithm The Agilent HP E1535 Watchdog Timer SCP was specifically developed to automatically signal that an algorithm has stopped controlling a process Use of the Watchdog Timer is recommended for critical processes Chapter 6 VT1415A Command Reference 273 TRIGger Event Sequence Figure 6 6 shows how the module responds to various trigger arm configurations v Trigger Idle A State neat Execute Control Loop Algorithm Execute Control Loop Algorithm v ARM Event Execute Control Loop Algorithm TRIG SOUR TIMer A no Trig Counter Subsystem Syntax Waiting For Trigger Trigger Events Scan Inputs and Increment Trig Counter Execute Control Loop Algorithm l Update Control Outputs Figure 6 6 Trigger Scan Sequence Diagram COUNt lt trig count gt COUNt IMMediate SOURce BUS EXTernal HOLD SCP IMMediate TIMer TTLTrg lt n gt SOURce TIMer PERiod trig interval PERiod TRIG COUNT 274 VT1415A Command Reference Chapter 6 TRIGger TRIGger COUNt TRIGger COUNt frig count sets the number of ti
505. ype is f1t32 e lt channel gt must specify a single channel only e Related Commands FUNC STRAIN STRAIN POISSON Usage STRAIN POISSON 131 query for the Poisson ratio specified for sense channel 31 enter statement here enter the Poisson ratio value SENSe STRain UNSTrained SENSe STRain UNSTrained lt unstrained_v gt lt ch_list gt specifies the unstrained voltage value to be used to convert strain bridge readings for the channels specified by lt ch_list gt This command does not control the output voltage of any source Chapter 6 VT1415A Command Reference 251 SENSe Parameters Parameter Parameter Range of Default Name Type Values Units unstrained v numeric f1t32 16 through 16 volts ch list channel list string 100 163 none Comments Usea voltage measurement of the unstrained bridge sense channel to determine the correct value for unstrained v7 e ch list must specify the channel used to sense the bridge voltage not the channel position on a Bridge Completion SCP e Related Commands SENSE STRAIN UNST SENSE FUNC STRAIN e RST Condition Unstrained voltage is zero Usage STRAIN UNST 024 100 set unstrained voltage for channel 0 SENSe STRain UNSTrained SENSe STRain UNS Trained lt channel gt returns the unstrained voltage value currently set for the sense channel specified by lt channel gt This command does not make a measur
506. ystem after executing a complicated CAL command The Calibrating bit bit 0 in the Operation Condition Register goes to 1 when CAL is executing and returns to 0 when CAL is complete In order to record only the negative transition of this bit in the STAT OPER EVEN register send STAT OPER PTR 32766 All ones in Pos Trans Filter register except bit 0 0 STAT OPER NTR 1 All zeros in Neg Trans Filter register except bit 0 1 Now when CAL completes and Operation Condition Register bit zero goes from 1 to 0 Operation Event Register bit zero will become a 1 Note that in Figure 3 12 each Status Group has an Enable Register These control whether or not the occurrence of an individual status condition will be reported by the group s summary bit in the Status Byte Questionable Data Group Examples For only the FIFO Overflowed condition to be reported by the QUE bit bit 3 of the Status Byte execute STAT QUES ENAB 1024 1024 decimal value for bit 10 For the FIFO Overflowed and Setup Changed conditions to be reported execute STAT QUES ENAB 9216 9216 decimal sum of values for bits 10 and 13 Operation Status Group Examples For only the FIFO Half Full condition to be reported by the OPR bit bit 7 of the Status Byte execute STAT OPER ENAB 1024 1024 decimal value for bit 10 Chapter 3 Programming the VT1415A for PID Control 97 For only the FIFO Half Full and Scan Complete condition
507. ystem include files Whenever using system or library calls check the call description to see which include files should be included E Instrument control include files include lt cscpi h gt C SCPI include file Declare any constants that will be useful to the program In particular it is usually best to put instrument addresses in this area to make the code more maintainable El define E1415 ADDR vxi 208 The SICL address of your E1415 INST DECL el415 E1415A REGISTER E1415 Use something like this for GPIB and Agilent E1405 6 Command Module define E1415 ADDR gpib 22 26 The SICL address of your E1415 INST DECL e1415 E1415A MESSAGE E1415 Declare instruments that will be accessed with SICL These declarations can also be moved into local contexts INST vxi VXI interface session Trap instrument errors If this function is used it will be called every time a C SCPI instrument puts an error in the error queue As written the Function will figure out which instrument generated the error retrieve the error print a message and exit You may want to modify the way the error Appendix F Generating User Defined Functions 363 is printed or comment out the exit if you want the program to continue Note that this works only on REGISTER based instruments because it was a C

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