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HAL User Manual - Construction Van de Walle

1. HAL Manual V2 5 2011 05 15 14 57 al Select Item to Probe siggen 0 amplitude slggen 0 cosine siggen 0 frequency siggen 0 offset siggen 0 sawtooth slggen 0 sine slggen 0 square siggen O triangle Figure 2 1 HAL Meter Select Window This dialog has three tabs The first tab displays all of the HAL pins in the system The second one displays all the signals and the third displays all the parameters We would like to look at the pin siggen 0 cosine first so click on it then click the Close button The probe selection dialog will close and the meter looks something like the following figure Hal Meter 0 6874131 siggen 0 casine Figure 2 2 Halmeter HAL Manual V2 5 2011 05 15 15 57 To change what the meter displays press the Select button which brings back the Select Item to Probe window You should see the value changing as siggen generates its cosine wave Halmeter refreshes its display about 5 times per second To shut down halmeter just click the exit button If you want to look at more than one pin signal or parameter at a time you can just start more halmeters The halmeter window was intentionally made very small so you could have a lot of them on the screen at once 2 4 Stepgen Example Up till now we have only loaded one HAL component But the whole idea behind the HAL is to allow you to load and connect a number of simple components to make up a complex system The next example will use two comp
2. option count_function yes default no Normally the number of instances to create is specified in the module parameter count if count_function 1s specified the value returned by the function int get_count void is used instead and the count module pa rameter is not defined option rtapi_app no default yes Normally the functions rtapi_app_main and rtapi_app_exit are automatically defined With option rtapi_app no they are not and must be provided in the C code When implementing your own rtapi_app_mair call the function int export char prefix long extra_arg to register the pins parameters and func tions for prefix option data type default none deprecated If specified each instance of the component will have an associated data block of type which can be a simple type like float or the name of a type created with typedef In new components variable should be used instead option extra_setup yes default no If specified call the function defined by EXTRA_SETUP for each instance If using the automatically defined rtapi_app_main ext ra_arg is the number of this instance option extra_cleanup yes default no If specified call the function defined by EXTRA_CLEANUP from the automatically defined rtapi_app_exit or if an error is detected in the automatically defined rtapi_app_main option userspace yes default no If specified this file describes a userspace component rather than a real one A
3. Accept instead of OK the small window will display the name and value of the selected item but the large window will remain on the screen This is convenient if you want to look at a number of different items quickly You can have many halmeters running at the same time if you want to monitor several items If you want to launch a halmeter without tying up a shell window type halmeter to run it in the background You can also make halmeter start displaying a specific item immediately by adding pin sig par am lt name gt to the command line It will display the pin signal or parameter lt name gt as soon as it starts If there is no such item it will simply start normally And finally if you specify an item to display you can add s before the pinlsiglparam to tell halmeter to use a small window The item name will be displayed in the title bar instead of under the value and there will be no buttons Usefull when you want a lot of meters in a small amount of screen space 5 3 Halscope Halscope is an oscilloscope for the HAL It lets you capture the value of pins signals and parameters as a function of time Complete operating instructions should be located here eventually For now refer to section sec Tutorial HalscopeJ in the tutorial chapter which explains the basics HAL Manual V2 5 2011 05 15 38 57 Chapter 6 comp a tool for creating HAL modules 6 1 Introduction Wri
4. ri EUNC TETONA int i a 1 o 0 x 0 mon O peas on ola s Op alae 4 slic alg GL 4 ile Ieee 1 else a 0 if personality 0x100 and a if personality 0x200 or o if personality 0x400 xor x A typical load line for this component might be loadrt logic count 3 personality 0x102 0x305 0x503 which creates the following pins e A 2 input AND gate logic 0 and logic 0 in 00 logic 0 in 01 47 57 HAL Manual V2 5 2011 05 15 48 57 e 5 input AND and OR gates logic 1 and logic 1 or logic 1 in 00 logic 1 in 01 logic 1 in 02 logic 1 in 03 logic 1 in 04 e 3 input AND and XOR gates logic 2 and logic 2 xor logic 2 in 00 logic 2 1n 01 logic 2 in 02 HAL Manual V2 5 2011 05 15 49 57 Chapter 7 Creating Userspace Python Components with the hal module 7 1 Basic usage A userspace component begins by creating its pins and parameters then enters a loop which will periodically drive all the outputs from the inputs The following component copies the value seen on its input pin passthrough in to its output pin passthrough out approximately once per second usr bin python import hal time h hal component passthrough h newpin in hal HAL_FLOAT hal HAL_IN h newpin out hal HAL_FLOAT hal HAL_OUT h ready Teya while 1 time sleep 1 AP OWE E i except KeyboardInterrupt raise SystemExit Copy the above listing into a file named pas
5. we will use a HAL component called siggen which is a simple signal generator A complete description of the siggen component can be found in Siggen section of the Integrators Manual It is a realtime component implemented as a Linux kernel module To load siggen use the halcmd loadrt command halcmd loadrt siggen 2 2 2 Examining the HAL Now that the module is loaded it is time to introduce halcmd the command line tool used to configure the HAL This tutorial will introduce some halcmd features for a more complete description try man halcmd or see the halcmd reference in section sec Halcmd of this document The first halcmd feature is the show command This command displays information about the current state of the HAL To show all installed components halcmd show comp Loaded HAL Components 1D Type Name PID State 3 RI siggen ready 2 User halcmd2177 2177 ready Since halcmd itself is a HAL component it will always show up in the list The number after halcmd in the component list is the process ID It is possible to run more than one copy of halcmd at the same time in different windows for example so the PID is added to the end of the name to make it unique The list also shows the siggen component that we installed in the previous step The RT under Type indicates that siggen is a realtime component Next let s see what pins siggen makes available halcmd show pin Component Pins Owner Type Dir Value Name
6. 3 float IN 1 siggen 0 amplitude 3 float OUT 0 siggen 0 cosine 3 float IN 1 siggen 0 frequency 3 float IN 0 siggen 0 offset 3 float OUT 0 siggen 0 sawtooth 3 float OUT O siggen 0 sine 3 float OUT 0 siggen 0 square 3 float OUT O siggen 0 triangle HAL Manual V2 5 2011 05 15 10 57 This command displays all of the pins in the HAL a complex system could have dozens or hundreds of pins But right now there are only eight pins All eight of these pins are floating point and carry data out of the siggen component Since we have not yet executed the code contained within the component some the pins have a value of zero The next step is to look at parameters halcmd show param Parameters Owner Type Dir Value Name 3 32 RO O siggen 0 update time 3 32 RW O siggen 0 update tmax The show param command shows all the parameters in the HAL Right now each parameter has the default value it was given when the component was loaded Note the column labeled Dir The parameters labeled W are writable ones that are never changed by the component itself instead they are meant to be changed by the user to control the component We will see how to do this later Parameters labeled R are read only parameters They can be changed only by the component Finally parameter labeled RW are read write parameters That means that they are changed by the component but can also be changed by the user Note the parameters siggen 0 update time and
7. Del SPINS A e BO erate ek oe Bee etre ww ee aS os F Shc we a eB H12 Parameters dra Seeds ere Ses Bes Bei wee oie See Se we See PE ele aie See SE A 13 JPUNCHONS sa e b24 bce rs be BH bd oO he 8 be bb es Bede e EGS 5 6 HAL Manual V2 5 2011 05 15 4 2 Digital Output 0c ol os ra AA AA e A a S 4 2 1 Pins 4 2 2 Parameters 42 3 __FUnCtiOns e 2 Se Ae ae bole es Bee ls ee aoe EA ee we ek eye te Ee Bee ee 4 3 Analog Input 46 5044588444 4h AON SE eR bee eR ae A eee ee ASA Pins a 4 4 ed wae be RS BS hae eS Bee SH hee wee ee 2 4 3 2 Parameters ese late ea A ee ee eR A HO ew A ee eS 4 3 3 EUNCUONS sie ee a eS ae EE oe Sa eae Be ea eee ae ee Ge 44 Analog Output 2 2 tos oe oe fee ee ome ye tt oR Seer Ss ewe Es oe ee Sead amp 4 4 4 1 Pins 4 4 2 Parameters 4 43 BUNCUONS 342 28 26 240 Seed be ee She ew SSL eh ee bee SHES de eA Tools and Utilities ST Halcmdl 2 2 2 cia e Be ge Bh AE is de Bile Shes ae 2 we es ee Stine oe Se eae Sow o 52 HMalmetenl aio dou os Ace A eS RRS ROR ERS SE Re RE eR a es 5 3 HAAISCOPEY sa dian 25 me eo pa ae oe oo a eo de rr Soe ee oe Ge oe comp a tool for creating HAL modules OL Introduction 2 05 4 6 ee ace e 4 2 ee Dk ee A a ee oA ee Se PR ee e 62 Definitions a0 so vw ee Ed eck Bee Reed AA SS Oe ERG E E TY BH OE RS SS SS 6 3 Instance creation pos asi inr Se ghd Gee OS ae eee BA te ee Rh a de GSS BROS re Bs a Gage a ae 0 47 Parametersl ecc 4 ae oto ee Foe a
8. Document under the terms of section 4 Replacing Invariant Sections with translations requires special permission from their copyright holders but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections You may include a translation of this License provided that you also include the original English version of this License In case of a disagreement between the translation and the original English version of this License the original English version will prevail 9 TERMINATION You may not copy modify sublicense or distribute the Document except as expressly provided for under this License Any other attempt to copy modify sublicense or distribute the Document is void and will automatically terminate your rights under this License However parties who have received copies or rights from you under this License will not have their licenses terminated so long as such parties remain in full compliance 10 FUTURE REVISIONS OF THIS LICENSE The Free Software Foundation may publish new revised versions of the GNU Free Documentation License from time to time Such new versions will be similar in spirit to the present version but may differ in detail to address new problems or concerns See http www gnu org copyleft Each version of the License is given a distinguishing version number If the Document specifies that a particular numbered version of this License or any
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10. OUT 0 siggen 0 square 4 float OUT 0 siggen 0 triangle 3 32 OUT O stepgen 0 counts 3 pit OUT FALSE stepgen 0 dir 3 bit IN FALSE stepgen 0 enabl 3 float OUT O stepgen 0 position fb 3 bit OUT FALSE stepgen 0 step 3 float IN O stepgen 0 velocity cmd 2The at the end of a long line indicates line wrapping needed for formatting this document When entering the commands at the command line simply skip the V do not hit enter and keep typing from the following line HAL Manual V2 5 2011 05 15 s32 bit bit float bit float WWW WW WwW halcmd Parameters Owner Type s32 s32 u32 u32 float float float float s32 u32 u32 u32 u32 float float float float s32 u32 u32 s32 s32 s32 s32 s32 s32 WWWWWW Y AY Y Y Y Y Y Y LY Y Y Y YY Y 0 0 UN UU ds RA OUT IN show param Dir FALSE FALS zj o FALS o Value 0 0 0x00000001 0x00000001 0x00000001 0x00000001 0x00000001 0x00000001 0x00000001 0x00000001 0 O O OOO 16 57 stepgen 1 counts stepgen 1 dir stepgen 1 enabl stepgen 1 position fb stepgen 1 step stepgen 1 velocity cmd Name siggen 0 update time siggen 0 update tmax stepgen 0 dirhold stepgen 0 dirsetup stepgen 0 frequency stepgen 0 maxaccel stepgen 0 maxvel stepgen 0 position scale stepgen 0 rawcounts stepgen 0 steplen stepgen 0 stepspace stepgen 1 dirhold stepgen 1 dirsetup stepgen 1 fre
11. a signal is connected to one or more pins the show command lists the pins immediately following the signal name The arrow shows the direction of data flow in this case data flows from pin siggen 0 cosine to signal X vel Now let s connect the X vel to the velocity input of a step pulse generator halcmd net X vel gt stepgen 0 velocity cmd We can also connect up the Y axis signal Y vel It is intended to run from the sine output of the signal generator to the input of the second step pulse generator The following command accomplishes in one line what two net commands accomplished for X vel halcmd net Y vel siggen 0 sine gt stepgen 1 velocity cmd Now let s take a final look at the signals and the pins connected to them halcmd show sig Signals Type Value Name linked to float O X vel lt siggen 0 cosine gt stepgen 0 velocity cmd float O Y vel lt siggen 0 sine gt stepgen 1 velocity cmd The show sig command makes it clear exactly how data flows through the HAL For example the X vel signal comes from pin siggen 0 cosine and goes to pin stepgen 0 velocity cmd 2 4 3 Setting up realtime execution threads and functions Thinking about data flowing through wires makes pins and signals fairly easy to understand Threads and functions are a little more difficult Functions contain the computer instructions that actually get things done Thread are the method used to make those instructio
12. ae E Mos WROD as eee es oe ee ee di O ee ads es y ei Me A Beas ttt OO ea A RH Bh Sw SU a al eA ae we Al ee al e I Legal Section S Legal Section 8 1 Copyright Terms 8 2 GNU Free Documentation License 49 49 50 50 50 50 51 51 51 51 52 53 53 53 57 HAL Manual V2 5 2011 05 15 vi EMC The Enhanced Machine Controller www linuxcnc org This handbook is a work in progress If you are able to help with writing editing or graphic preparation please contact any member of the writing team or join and send an email to emc users lists sourceforge net Copyright c 2000 2011 LinuxCNC org Permission is granted to copy distribute and or modify this document under the terms of the GNU Free Documentation License Version 1 1 or any later version published by the Free Software Foundation with no Invariant Sections no Front Cover Texts and one Back Cover Text This EMC Handbook is the product of several authors writing for linuxCNC org As you find it to be of value in your work we invite you to contribute to its revision and growth A copy of the license is included in the section entitled GNU Free Documentation License If you do not find the license you may order a copy from Free Software Foundation Inc 59 Temple Place Suite 330 Boston MA 02111 1307 HAL Manual V2 5 2011 05 15 1 57 Chapter 1 Introduction This manual is for the person who wants to know more about HAL than is needed to j
13. and distribute verbatim copies of this license document but changing it is not allowed 0 PREAMBLE The purpose of this License is to make a manual textbook or other written document free in the sense of freedom to assure everyone the effective freedom to copy and redistribute it with or without modifying it either commercially or noncommercially Secondarily this License preserves for the author and publisher a way to get credit for their work while not being considered responsible for modifications made by others This License is a kind of copyleft which means that derivative works of the document must themselves be free in the same sense It complements the GNU General Public License which is a copyleft license designed for free software We have designed this License in order to use it for manuals for free software because free software needs free documentation a free program should come with manuals providing the same freedoms that the software does But this License is not limited to software manuals it can be used for any textual work regardless of subject matter or whether it is published as a printed book We recommend this License principally for works whose purpose is instruction or reference 1 APPLICABILITY AND DEFINITIONS This License applies to any manual or other work that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License The Document below refers to
14. capabilities The I O type is used to identify the kind of T O that a pin or parameter is associated with Ideally drivers that implement the same I O type even if for very different devices should provide a consistent set of pins and parameters and identical behavior For example all digital inputs should behave the same when seen from inside the HAL regardless of the device lt chan num gt Virtually every I O device has multiple channels and the channel number identifies one of them Like device numbers channel numbers start at zero and increment If more than one device is installed the channel numbers on additional devices start over at zero If it is possible to have a channel number greater than 9 then channel numbers should be two digits with a leading zero on numbers less than 10 to preserve sort ordering Some modules have pins and or parameters that affect more than one channel For example a PWM generator might have four channels with four independent duty cycle inputs but one frequency parameter that controls all four channels due to hardware limitations The frequency parameter should use 0 3 as the channel number lUnderscores have all been removed but there are still a few instances of mixed case for example pid 0 Pgain instead of pid 0 p gain 2Some devices use jumpers or other hardware to attach a specific ID to each board Ideally the driver provides a way for the user to specifically s
15. changes state and the step pulses speed up again You might want to increase the gain on channel 1 to about 20m per division to better see the change in the velocity command The result should look like the following figure HAL Manual V2 5 2011 05 15 30 57 File Help Horizontal Run Mode Trigger Zoom 5 00 mSec 4000 samples Normal Normal Fos E per div at 20 2 KHz O Single O Auto TRIGGER sa Roll Force Stop Level Pos Wertical Gain Pos i i Scale Lewel E i i i 20m div 0 000 ll 2 113 49 si FU BYSIHLE LY Lili lili 16 Offset Rising 0 000 Selected Channel ES 1 x vel f 01014 Chan Of Chan 3 Figure 2 13 Step Pulses 2 5 8 More samples If you want to record more samples at once restart realtime and load halscope with a numeric argument which indicates the number of samples you want to capture such as halcmd loadusr halscope 80000 if the scope_rt component was not already loaded halscope will load it and request 80000 total samples so that when sampling 4 channels at a time there will be 20000 samples per channel If scope_rt was already loaded the numeric argument to halscope will have no effect HAL Manual V2 5 2011 05 15 31 57 Chapter 3 General Reference Information 3 1 Notation 3 1 1 Typographical Conventions Command line examples are presented in bold typewriter font Responses from the computer will be in typewriter font As of early 2006 there are no
16. constant This component functions like the one in blocks including the default value of 1 0 The declaration function _ creates functions named constant 0 etc component constant ulm Ole dELOEnE OE param r float value 1 0 CUCA license GPL iat i FUNCTION _ out value 6 14 2 sincos This component computes the sine and cosine of an input angle in radians It has different capabilities than the sine and cosine outputs of siggen because the input is an angle rather than running freely based on a frequency parameter The pins are declared with the names sin_ and cos_ in the source code so that they do not interfere with the functions sin and cos The HAL pins are still called sincos lt num gt sin component sincos ua Owe loci Sila a OWE Elo Cos fp pin in float theta icwuacicalioigl 6 license GPL ii include lt rtapi_math h gt RUNCTION M sin_ sin theta cos_ cos theta 6 14 3 outs This component is a driver for a fictional card called out8 which has 8 pins of digital output which are treated as a single 8 bit value There can be a varying number of such cards in the system and they can be at various addresses The pin is called out _ because out is an identifier used in lt asm io h gt It illustrates the use of EXTRA_SETUP and EXTRA_CLEANUP to request an I O region and then free it in case of error or when the module is unloaded comp
17. design more complex systems with HAL we will use many commands to configure things just the way we want them HAL has the memory of an elephant and will retain that configuration until we shut it down But what about next time We don t want to manually enter a bunch of commands every time we want to use the system We can save the configuration of the entire HAL with a single command halcmd save components loadrt threads namel test thread period1 1000000 loadrt siggen pin aliases signals nets parameter values setp siggen 0 update tmax 14687 realtime thread function links addf siggen 0 update test thread The output of the save command is a sequence of HAL commands If you start with an empty HAL and run all these commands you will get the configuration that existed when the save command was issued To save these commands for later use we simply redirect the output to a file halcmd save all saved hal 2 2 6 Exiting HalRun When you re finished with your HAL session type exit at the halemd prompt Do not simply close the terminal window without shutting down the HAL session halcmd exit emc2 2 2 7 Restoring the HAL configuration To restore the HAL configuration stored in saved hal we need to execute all of those HAL commands To do that we use f lt file name gt which reads commands from a file and I upper case i which shows the halemd prompt after executing the commands HAL Manual V
18. every visit and it is always used during a visit There must be Lego parts in there from a couple dozen different sets The little booklets that came with them are long gone but the magic of building with interlocking pieces all the same size is something to watch 1 5 Timing Issues In HAL Unlike the physical wiring models between black boxes that we have said that HAL is based upon simply connecting two pins with a hal signal falls far short of the action of the physical case True relay logic consists of relays connected together and when a contact opens or closes current flows or stops immediately Other coils may change state etc and it all just happens But in PLC style ladder logic it doesn t work that way Usually in a single pass through the ladder each rung is evaluated in the order in which it appears and only once per pass A perfect example is a single rung ladder with a NC contact in series with a coil The contact and coil belong to the same relay If this were a conventional relay as soon as the coil is energized the contacts begin to open and de energize it That means the contacts close again etc etc The relay becomes a buzzer With a PLC if the coil is OFF and the contact is closed when the PLC begins to evaluate the rung then when it finishes that pass the coil is ON The fact that turning on the coil opens the contact feeding it is ignored until the next pass On the next pass the PLC sees that the con
19. follows NAME A standard C identifier STARREDNAME A C identifier with zero or more before it This syntax can be used to declare instance variables that are pointers Note that because of the grammar there may not be whitespace between the and the variable name HALNAME An extended identifier When used to create a HAL identifier any underscores are replaced with dashes and any trailing dash or period is removed so that this_name_ will be turned into this name and if the name is _ then a trailing period is removed as well so that function _ gives a HAL function name like component lt num gt instead of component lt num gt n HAL Manual V2 5 2011 05 15 40 57 If present the prefix hal_ is removed from the beginning of the component name when creating pins parameters and functions In the HAL identifier for a pin or parameter denotes an array item and must be used in conjunction with a SIZE declaration The hash marks are replaced with a 0 padded number with the same length as the number of characters When used to create a C identifier the following changes are applied to the HALNAME 1 Any characters and any _ or characters immediately before them are removed nn 2 Any remaining and characters are replaced with _ n 3 Repeated _ characters are changed to a single character A trailing _ is retained so that HAL identifiers which would
20. in title with any Invariant Section If the Modified Version includes new front matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document you may at your option designate some or all of these sections as invariant To do this add their titles to the list of Invariant Sections in the Modified Version s license notice These titles must be distinct from any other section titles You may add a section entitled Endorsements provided it contains nothing but endorsements of your Modified Version by various parties for example statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard You may add a passage of up to five words as a Front Cover Text and a passage of up to 25 words as a Back Cover Text to the end of the list of Cover Texts in the Modified Version Only one passage of Front Cover Text and one of Back Cover Text may be added by or through arrangements made by any one entity If the Document already includes a cover text for the same cover previously added by you or by arrangement made by the same entity you are acting on behalf of you may not add another but you may replace the old one on explicit permission from the previous publisher that added the old one The author s and publisher s of the Document do not by this License give permission to use their names for publicity for or to assert or imply endors
21. longer commands that require root privileges so all examples will be preceded by the normal user prompt Text inside square brackets like this is optional Text inside angle brackets lt 1ike this gt represents a field that can take on different values and the adjacent paragraph will explain the appropriate values Text items separated by a vertical bar means that one or the other but not both should be present All command line examples assume that you are in theremc2 directory and you configured compiled emc2 for the run in place scenario Paths will be shown accordingly when needed 3 1 2 Names All HAL entities are accessed and manipulated by their names so documenting the names of pins signals parameters etc is very important HAL names are a maximum of 41 characters long as defined by HAL_NAME_LEN in hal h Many names will be presented in a general form with text inside angle brackets lt 1ike this gt representing fields that can take on different values When pins signals or parameters are described for the first time their names will be preceeded by their type in small caps and followed by a brief description A typical pin definition will look something like these examples e bit parport lt portnum gt pin lt pinnum gt in The HAL pin associated with the physical input pin lt pinnum gt on the 25 pin D shell connector e float pid lt loopnum gt output The output of the PID loop At times
22. otherwise collide with reserved names or keywords e g min can be used HALNAME C Identifier HAL Identifier X_y_z X_y_z X y Z X y Z X_y_z X y Z Xy 2_ X_Y_Z_ X y Z XHH y x_y MM x MM z x fH x MM x MM if CONDITION An expression involving the variable personality which is nonzero when the pin or parameter should be created SIZE A number that gives the size of an array The array items are numbered from 0 to SIZE 1 MAXSIZE CONDSIZE A number that gives the maximum size of the array followed by an expression involving the variable personality and which always evaluates to less than MAXSIZE When the array is created its size will be CONDSIZE DOC A string that documents the item String can be a C style double quoted string like Selects the desired edge TRUE means falling FALSE means rising or a Python style triple quoted string which may include embedded newlines and quote characters such as param rw bit zot TRUE The effect of this parameter also known as the orb of zot will require at least two paragraphs to explain Hopefully these paragraphs have allowed you to understand zot better The documentation string is in groff man format For more information on this markup format see groff_man 7 Re member that comp interprets backslash escapes in strings so for instance to set the italic font for the word example write flexample fB TYPE
23. response to a timer all HAL_OUT pins should be driven by assigning them a new value This should be done whether or not the value is different than the last one assigned When a pin is connected to a signal its old output value 1s not copied into the signal so the proper value will only appear on the signal once the component assigns a new value 7 4 2 Driving bidirectional HAL_IO pins The above rule does not apply to bidirectional pins Instead a bidirectional pin should only be driven by the component when the component wishes to change the value For instance in the canonical encoder interface the encoder component only sets the index enable pin to FALSE when an index pulse is seen and the old value is TRUE but never sets it to TRUE Repeatedly driving the pin FALSE might cause the other connected component to act as though another index pulse had been seen 7 5 Exiting A halcmd unload request for the component is delivered as a KeyboardInterrupt excep tion When an unload request arrives the process should either exit in a short time or call the exit method on the component if substantial work such as reading or writing files must be done to complete the shutdown process 7 6 Project ideas e Create an external control panel with buttons switches and indicators Connect everything to a microcontroller and connect the microcontroller to the PC using a serial interface Python has a very capable serial interface
24. siggen 0 update tmax are for debugging purposes and won t be covered in this section Most realtime components export one or more functions to actually run the realtime code they contain Let s see what function s siggen exported halcmd show funct Exported Functions Owner CodeAddr Arg FP Users Name 00003 f801b000 fae820b8 YES 0 siggen 0 update The siggen component exported a single function It requires floating point It is not currently linked to any threads so users is Zero 1 2 2 3 Making realtime code run To actually run the code contained in the function siggen 0 update we need a realtime thread The component called threads that is used to create a new thread Lets create a thread called test thread with a period of 1mS 1000000nS halcmd loadrt threads namel test thread period1 1000000 Let s see if that worked halcmd show thread Realtime Threads Period FP Name Time Max Time 999855 YES test thread O 0 e It did The period is not exactly 1000000nS because of hardware limitations but we have a thread that runs at approximately the correct rate and which can handle floating point functions The next step is to connect the function to the thread halcmd addf siggen 0 update test thread Up till now we ve been using halcmd only to look at the HAL However this time we used the addf add function com mand to actually change something in the HAL We told halcmd to add the function
25. siggen 0 update to the thread test thread and if we look at the thread list again we see that it succeeded halcmd show thread The codeaddr and arg fields were used in development and should probably be removed from the halcmd listing HAL Manual V2 5 2011 05 15 11 57 Realtime Threads Period FP Name Time Max Time 999855 YES test thread 0 0 1 siggen 0 update There is one more step needed before the siggen component starts generating signals When the HAL is first started the thread s are not actually running This is to allow you to completely configure the system before the realtime code starts Once you are happy with the configuration you can start the realtime code like this halcmd start Now the signal generator is running Let s look at 1ts output pins halcmd show pin Component Pins Owner Type Dir Value Name 3 float IN 1 siggen 0 amplitude 3 float OUT 0 1640929 siggen 0 cosine 3 float IN 1 siggen 0 frequency 3 float IN 0 siggen 0 offset 3 float OUT 0 4475303 siggen 0 sawtooth 3 float OUT 0 9864449 siggen 0 sine 3 float OUT 1 siggen 0 square 3 float OUT 0 1049393 siggen 0 triangle halcmd show pin Component Pins Owner Type Dir Value Name 3 float IN 1 siggen 0 amplitude 3 float OUT 0 0507619 siggen 0 cosine 3 float IN 1 siggen 0 frequency 3 float IN 0 siggen 0 offset 3 float OUT 0 516165 siggen 0 sawtooth 3 float OUT 0 9987108 siggen 0 sine 3 float OUT 1 si
26. the dialog displays all of the signals in the HAL only two for this example HAL Manual V2 5 2011 05 15 22 57 Select Channel Source Select a pin signal or parameter as the source for channel 1 siggen O armplitude siggen 0 cosine siggen 0 frequency siggen 0 offset siggen 0 sawtooth siggen 0 sine siggen 0 square siggen O triangle stepgen 0 counts Figure 2 5 Select Channel Source To choose a signal just click on it In this case we want channel to display the signal X vel Click on the Signals tab then click on X vel and the dialog closes and the channel is now selected HAL Manual V2 5 2011 05 15 23 57 Select Channel Source Select a pin signal or parameter as the source for channel 1 Signals Parameters Figure 2 6 Select Signal The channel 1 button is pressed in and channel number 1 and the name X vel appear below the row of buttons That display always indicates the selected channel you can have many channels on the screen but the selected one is highlighted and the various controls like vertical position and scale always work on the selected one HAL Manual V2 5 2011 05 15 24 57 File Help Horizontal Run Mode Trigger Zoom Qu 2 500 mSec 4000 samples Normal Normal Pos E i per div at 1 01 KHz O Single O Auto IDLE Roll Force Stop Level Pos Vertical Gain Pos u ul Level 23467 SIII 16 Rising Selected Channel ES 1
27. value with approximately 53 bits of resolution and over 1000 bits of dynamic range e u32 a 32 bit unsigned integer legal values are 0 to 4 294 967 295 e s32 a 32 bit signed integer legal values are 2 147 483 647 to 2 147 483 647 Function Real hardware components tend to act immediately on their inputs For example if the input voltage to a servo amp changes the output also changes automatically However software components cannot act automatically Each compo nent has specific code that must be executed to do whatever that component is supposed to do In some cases that code simply runs as part of the component However in most cases especially in realtime components the code must run in a specific sequence and at specific intervals For example inputs should be read before calculations are performed on the input data and outputs should not be written until the calculations are done In these cases the code is made available to the system in the form of one or more functions Each function is a block of code that performs a specific action The system integrator can use threads to schedule a series of functions to be executed in a particular order and at specific time intervals Thread A thread is a list of functions that runs at specific intervals as part of a realtime task When a thread is first created it has a specific time interval period but no functions Functions can be added to the thread and will be executed in
28. 2 5 2011 05 15 13 57 emc2 halrun I f saved hal Notice that there is not a start command in saved hal It s necessary to issue it again or edit saved hal to add it there halcmd start halcmd exit emc2 2 2 8 Removing HAL from memory If an unexpected shut down of a HAL session occurs you might have to unload HAL before another session can begin To do this type the following command in a terminal window emc2 halrun U 2 3 Halmeter You can build very complex HAL systems without ever using a graphical interface However there is something satisfying about seeing the result of your work The first and simplest GUI tool for the HAL is halmeter It is a very simple program that is the HAL equivalent of the handy Fluke multimeter or Simpson analog meter for the old timers We will use the siggen component again to check out halmeter If you just finished the previous example then you can load siggen using the saved file If not we can load it just like we did before emc2S halrun halcmd loadrt siggen halcmd loadrt threads namel test thread period1 1000000 halcmd addf siggen 0 update test thread halcmd start halcmd setp siggen 0 amplitude 5 2 3 1 Starting halmeter At this point we have the siggen component loaded and running It s time to start halmeter Since halmeter is a GUI app X must be running halcmd loadusr halmeter The first window you will see is the Select Item to Probe window
29. 3 1 Starting halmeter seasea p RA e E sy Ree eee oS 2 4 Stepgen Example i e a a Se ACR E A A A a a 2 4 1 Installing the components ee 2 4 2 Connecting pins with SlgMalsS ee 2 4 3 Setting up realtime execution threads and functions e o 24 4 Setting patametets 54 24 5405 8 2eseee ee bebe te anes e ees bean e eevee 245 RUMI oes ke a a a a OR Ae ee a a Ee Bee A wae a IE A SV ee ass sas Gade ee E acca E i a e ae ess oes ates ee eee a ae 2 5 1 Starting Halscope scora oeie ee ER ae PRES ee ee eee Eee ES ba BW So ee Al he te Pa a Bo ts BAU ae Sal Be pie ae tee chy te Rope Sede ok ep le e em G8 cima ad EERE RSE SESS a RE SEES ES AA ct RR A Ra Ee EA a ea aE Ee aU ae eae R 2 5 6 Horizontal Adjustments 2 ee 2 3 7 More Chamelsl e s p ac 234 2448S eee ee EEA ERR ee ee eee eS 2 98 More samples i bee e ERE a ee ae eae ea NOOO rn A He EA SO ee A ee a eee Ae Ses ea SF es e 3 1 1 Typographical Conventions 2 2 2 0 0 0 2 2 ee 31 2 Names cios ea ek RE e a oe a ESBS ew ee eee ed AERE A NA 3 3 Hardware Driver Naming Conventionsfootnote Most o e e e 8 3 1 Pin Parameter names 2 24 ceros A e e ch 93l Examples eones e RA E E ew S 3 32 Function Names esos ae ARS E A REARS A A Be ee 8 39 21 Examplesi 2 430 4 ete etebe dao PEERS See bees 8 4 Canonical Device Interfaces 4 1 Digital Input s se 6 era ede A Pee ae a AP
30. HAL Manual V2 5 2011 05 15 HAL Manual V2 5 2011 05 15 HAL Manual V2 5 2011 05 15 Contents 1 Introduction LE Wha SHALA 223 22S kee rai a e eee a eee dos 1 1 1 HAL is based on traditional system design techniques 1 1 1 1 Part Selection 1 1 1 2 Interconnection Design ee 1 1 1 3 Implementation 1 1 1 4 Testing 1 12 Summary 1 2 HAL Concepts vieiras ee a eee A e ae oe 13 HAL components s e seis oe eee ee ORE Re Ew bee bee eee eee os 1 3 1 External Programs with HAL hooks 1 3 2 Internal Components 1 33 Hardware Drivers 1 34 Tools and Utilities ee 1 4 Tinkertoys Erector Sets Legos and the HAL LAT TOWED ao o e eo E A A ir a de ar Re Se e A RO A A 1 43 gt TinkertoyS ll 0er at e RA A MES A AA amp x 144 A Lego Example 2 0 2 0 0 ee ee 1 5 Timing Issues In HAL 2 HAL Tutorial 2 1 Introduction 2 1 1 Notation 2 1 2 Tab completiony sori a po A a as a ee ts AAE TE 2 1 3 The RTAPI environment s 2 a 22 A Simple Example x da ee a e ala aa a 2 2 1 Loading a realtime component 2 2 2 Examining the HAD p pe sip eae e RE ie e lar Re Ae eb ed ae e 2 2 3 Making realtime coderun esc eer ee HAL Manual V2 5 2011 05 15 dal cece T E e o eb A al eR capes oe da O E aCe es aye eS Eo ets Sie ee ee eee Ges ibe RAPES Se EPH A A ce bE ES ES atole ads ise ae Bites ia a MO ardent nie cz ada A O aa Sha Ee A eee le dla daa da aa a eee a ES 2
31. HAL concepts can be mind boggling Building anything with blocks can be a challenge but some of the toys that we played with as kids can be an aid to building things with the HAL 1 4 1 Tower Tower I m watching as my son and his six year old daughter build a tower from a box full of random sized blocks rods jar lids and such The aim is to see how tall they can make the tower The narrower the base the more blocks left to stack on top But the narrower the base the less stable the tower I see them studying both the next block and the shelf where they want to place it to see how it will balance out with the rest of the tower The notion of stacking cards to see how tall you can make a tower is a very old and honored way of spending spare time At first read the integrator may have gotten the impression that building a HAL was a bit like that It can be but with proper planning an integrator can build a stable system as complex as the machine at hand requires 1 4 2 Erector Sets What was great about the sets was the building blocks metal struts and angles and plates all with regularly spaced holes You could design things and hold them together with the little screws and nuts The Erector Set was an invention of A C Gilbert HAL Manual V2 5 2011 05 15 6 57 Erector Sets I got my first erector set for my fourth birthday I know the box suggested a much older age than I was Perhaps my father was really giving h
32. MC The traditional hardware design as described above ends at the edge of the main control Outside the control are a bunch of relatively simple boxes connected together to do whatever is needed Inside the control is a big mystery one huge black box that we hope works HAL extends this traditional hardware design method to the inside of the big black box It makes device drivers and even some internal parts of the controller into smaller black boxes that can be interconnected and even replaced just like the external hardware It allows the system wiring diagram to show part of the internal controller rather than just a big black box And most importantly it allows the integrator to test and modify the controller using the same methods he would use on the rest of the hardware Terms like motors amps and encoders are familiar to most machine integrators When we talk about using extra flexible eight conductor shielded cable to connect an encoder to the servo input board in the computer the reader immediately understands what it is and is led to the question what kinds of connectors will I need to make up each end The same sort of thinking is essential for the HAL but the specific train of thought may take a bit to get on track Using HAL words may seem a bit strange at first but the concept of working from one connection to the next is the same This idea of extending the wiring diagram to the inside of the controller is what HAL
33. Once the wiring diagram is complete it is time to build the machine The pieces need to be acquired and mounted and then they are interconnected according to the wiring diagram In a physical system each interconnection is a piece of wire that needs to be cut and connected to the appropriate terminals HAL provides a number of tools to help build a HAL system Some of the tools allow you to connect or disconnect a single wire Other tools allow you to save a complete list of all the parts wires and other information about the system so that it can be rebuilt with a single command 1 1 1 4 Testing Very few machines work right the first time While testing the builder may use a meter to see whether a limit switch is working or to measure the DC voltage going to a servo motor He may hook up an oscilloscope to check the tuning of a drive or to look for electrical noise He may find a problem that requires the wiring diagram to be changed perhaps a part needs to be connected differently or replaced with something completely different HAL provides the software equivalents of a voltmeter oscilloscope signal generator and other tools needed for testing and tuning a system The same commands used to build the system can be used to make changes as needed 1 1 2 Summary This document is aimed at people who already know how to do this kind of hardware system integration but who do not know how to connect the hardware to E
34. One of the HAL types bit signed unsigned or float The old names s32 and u32 may also be used but signed and unsigned are preferred PINDIRECTION One of the following in out or io A component sets a value for an out pin it reads a value from an in pin and it may read or set the value of an io pin PARAMDIRECTION One of the following r or rw A component sets a value for a r parameter and it may read or set the value of a rw parameter HAL Manual V2 5 2011 05 15 41 57 STARTVALUE Specifies the initial value of a pin or parameter If it is not specified then the default is 0 or FALSE depending on the type of the item fp Indicates that the function performs floating point calculations nofp Indicates that it only performs integer calculations If neither is specified fp is assumed Neither comp nor gcc can detect the use of floating point calculations in functions that are tagged nofp OPT VALUE Depending on the option name OPT the valid VALUEs vary The currently defined options are option singleton yes default no Do not create a count module parameter and always create a single instance With singleton items are named component name item nam and without singleton items for numbered instances are named component name lt num gt item name option default_count number default 1 Normally the module parameter count defaults to O If specified the count will default to this value instead
35. a shortened version of a name may be used for example the second pin above might be referred to simply as output when it can be done without causing confusion 3 2 General Naming Conventions Consistent naming conventions would make HAL much easier to use For example if every encoder driver provided the same set of pins and named them the same way it would be easy to change from one type of encoder driver to another Unfortunately like many open source projects HAL is a combination of things that were designed and things that simply evolved As a result there are many inconsistencies This section attempts to address that problem by defining some conventions but it will probably be a while before all the modules are converted to follow them HAL Manual V2 5 2011 05 15 32 57 Halcmd and other low level HAL utilities treat HAL names as single entities with no internal structure However most modules do have some implicit structure For example a board provides several functional blocks each block might have several channels and each channel has one or more pins This results in a structure that resembles a directory tree Even though halemd doesn t recognize the tree structure proper choice of naming conventions will let it group related items together since it sorts the names In addition higher level tools can be designed to recognize such structure if the names provide the neccessary information To do that all HAL modules sho
36. altime component illustrates use of fixed size arrays component arraydemo 4 bit Shift register Dia al a lowe aly mia Owls ble Ctt 1417 UNSL MORO license GPL vr ale SL Por t s aes 2 ope out 1 11 out 0 in 6 14 6 rand This userspace component changes the value on its output pin to a new random value in the range 0 1 about once every Ims HAL Manual V2 5 2011 05 15 component rand option userspace Saya Ce dele oles license GPL iF tinclude lt unistd h gt void user_mainloop void while 1 usleep 1000 FOR_ALL_INSTS out drand48 6 14 7 logic This realtime component shows how to use personality to create variable size arrays and optional pins component logic EMC2 HAL component providing experimental logic functions pin in bit in 16 personality amp Oxff pin out bit and if personality amp 0x100 pim g r ble Or e personality E 2007 pin out bit xor if personality 0x400 USE ola ADS description Experimental general logic function component Can perform and or and xor of up to 16 inputs Determine the proper value for personality by adding SEP NS The number of input pins usually from 2 to 16 02 AA Coil 256 0x100 if the and output is desired 102 da 512 0x200 if the or output is desired a NS 1024 0x400 if the xor exclusive or output is desired license GPL
37. any such manual or work Any member of the public is a licensee and is addressed as you A Modified Version of the Document means any work containing the Document or a portion of it either copied verbatim or with modifications and or translated into another language A Secondary Section is a named appendix or a front matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document s overall subject or to related matters and contains nothing that HAL Manual V2 5 2011 05 15 54 57 could fall directly within that overall subject For example if the Document is in part a textbook of mathematics a Secondary Section may not explain any mathematics The relationship could be a matter of historical connection with the subject or with related matters or of legal commercial philosophical ethical or political position regarding them The Invariant Sections are certain Secondary Sections whose titles are designated as being those of Invariant Sections in the notice that says that the Document is released under this License The Cover Texts are certain short passages of text that are listed as Front Cover Texts or Back Cover Texts in the notice that says that the Document is released under this License A Transparent copy of the Document means a machine readable copy represented in a format whose specification is available to the general public whose co
38. ay device num 0 is the board with ID XXX and the device numbers always start at 0 However at present some drivers use the board ID directly as the device number That means it is possible to have a device number 2 without a device 0 This is a bug and will be fixed in version 2 1 3One glaring exception to the channel numbers start at zero rule is the parallel port Its HAL pins are numbered with the corresponding pin number on the DB 25 connector This is convenient for wiring but inconsistent with other drivers There is some debate over whether this is a bug or a feature HAL Manual V2 5 2011 05 15 33 57 lt specific name gt An individual 1 O channel might have just a single HAL pin associated with it but most have more than one For example a digital input has two pins one is the state of the physical pin the other is the same thing inverted That allows the configurator to choose between active high and active low inputs For most io types there is a standard set of pins and parameters referred to as the canonical interface that the driver should implement The canonical interfaces are described in chapter cha Canonical Device Interfaces 3 3 1 1 Examples motenc 0 encoder 2 position the position output of the third encoder channel on the first Motenc board stg 0 din 03 in the state of the fourth digital input on the first Servo to Go board ppmc 0 pwm 00 03 frequency the carrier frequency us
39. ction stepgen update freq is responsible for doing scaling and some other calculations that need to be performed only when the frequency command changes HAL Manual V2 5 2011 05 15 18 57 What this means for our example is that we want to run siggen 0 update at a moderate rate to calculate the sine and cosine values Immediately after we run siggen 0 update we want to run stepgen update_freq to load the new values into the step pulse generator Finally we need to run stepgen make_pulses as fast as possible for smooth pulses Because we don t use position feedback we don t need to run stepgen capture_position at all We run functions by adding them to threads Each thread runs at a specific rate Let s see what threads we have available halcmd show thread Realtime Threads Period FP Name Time Max Time 996980 YES slow 0 0 49849 NO fast O 0 The two threads were created when we loaded threads The first one s1ow runs every millisecond and is capable of running floating point functions We will use it for siggen 0 update and stepgen update_freq The second thread is fast which runs every 50 microseconds and does not support floating point We will use it for stepgen make_pulses To connect the functions to the proper thread we use the addf command We specify the function first followed by the thread halcmd addf siggen 0 update slow halcmd addf stepgen update freq slow halcmd addf stepgen make pul
40. e and optionally the prefix used for pin and parameter names If the prefix is not specified the component name is used h newpin in hal HAL FLOAT hal HAL_IN Then pins are created by calls to methods on the component object The arguments are pin name suffix pin type and pin direction For parameters the arguments are parameter name suffix parameter type and parameter direction Table 7 1 HAL Option Names Pin and Parameter HAL_BIT HAL_FLOAT HAL_S32 HAL_U32 Types Pin Directions HAL_IN HAL_OUT HAL_IO Parameter HAL_RO HAL_RW Directions 6699 The full pin or parameter name is formed by joining the prefix and the suffix with a passthrough in SO in the example the pin created is called h ready Once all the pins and parameters have been created call the ready method 7 3 1 Changing the prefix The prefix can be changed by calling the setprefix method The current prefix can be retrieved by calling the getprefix method 7 4 Reading and writing pins and parameters For pins and parameters which are also proper Python identifiers the value may be accessed or set using the attribute syntax h out h in For all pins whether or not they are also proper Python identifiers the value may be accessed or set using the subscript syntax h out h in HAL Manual V2 5 2011 05 15 51 57 7 4 1 Driving output HAL_OUT pins Periodically usually in
41. e offset and value and output to the adc scale value offset If enable is false then output 0 HAL Manual V2 5 2011 05 15 37 57 Chapter 5 Tools and Utilities 5 1 Halcmd Halcmd is a command line tool for manipulating the HAL There is a rather complete man page for halcmd which will be installed if you have installed EMC2 from either source or a package If you have compiled EMC2 for run in place the man page is not installed but it is accessible From the main EMC2 directory do man M docs man halcmd Chapter cha HAL Tutorial has a number of examples of halcmd usage and is a good tutorial for halemd 5 2 Halmeter Halmeter is a voltmeter for the HAL It lets you look at a pin signal or parameter and displays the current value of that item It is pretty simple to use Start it by typing halmeter in a X windows shell Halmeter is a GUI application It will pop up a small window with two buttons labeled Select and Exit Exit is easy 1t shuts down the program Select pops up a larger window with three tabs One tab lists all the pins currently defined in the HAL The next lists all the signals and the last tab lists all the parameters Click on a tab then click on a pin signal parameter Then click on OK The lists will disappear and the small window will display the name and value of the selected item The display is updated approximately 10 times per second If you click
42. ects If the required texts for either cover are too voluminous to fit legibly you should put the first ones listed as many as fit reasonably on the actual cover and continue the rest onto adjacent pages If you publish or distribute Opaque copies of the Document numbering more than 100 you must either include a machine readable Transparent copy along with each Opaque copy or state in or with each Opaque copy a publicly accessible computer network location containing a complete Transparent copy of the Document free of added material which the general network using public has access to download anonymously at no charge using public standard network protocols If you use the latter option you must take reasonably prudent steps when you begin distribution of Opaque copies in quantity to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy directly or through your agents or retailers of that edition to the public It is requested but not required that you contact the authors of the Document well before redistributing any large number of copies to give them a chance to provide you with an updated version of the Document 4 MODIFICATIONS You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above provided that you release the Modified Version under precisely this License with the Mod
43. ed for PWM channels 0 through 3 3 3 2 Function Names Hardware drivers usually only have two kinds of HAL functions ones that read the hardware and update HAL pins and ones that write to the hardware using data from HAL pins They should be named as follows lt device name gt lt device num gt lt io type gt lt chan num range gt read write lt device name gt The same as used for pins and parameters lt device num gt The specific device that the function will access lt io type gt Optional A function may access all of the I O on a board or it may access only a certain type For example there may be independent functions for reading encoder counters and reading digital I O If such independent functions exist the lt io type gt field identifies the type of I O they access If a single function reads all I O provided by the board lt io type gt is not used lt chan num range gt Optional Used only if the lt io type gt I O is broken into groups and accessed by different functions read write Indicates whether the function reads the hardware or writes to it 3 3 2 1 Examples motenc 0 encoder read reads all encoders on the first motenc board generic8255 0 din 09 15 read reads the second 8 bit port on the first generic 8255 based digital I O board ppmc 0 write writes all outputs step generators pwm DACs and digital on the first ppme board 4Note to driver programmers do NOT i
44. ed on its own to refer to the variable When variable_name is an array the normal C style subscript is used variable_name idx data If option data is specified this macro allows access to the instance data fperiod The floating point number of seconds between calls to this realtime function FOR_ALL_INSTSO For userspace components This macro uses the variable struct state xinst to iterate over all the defined in stances Inside the body of the loop the pin_name parameter_name and data macros work as they do in realtime functions 6 9 Components with one function If a component has only one function and the string FUNCTION does not appear anywhere after then the portion after is all taken to be the body of the component s single function HAL Manual V2 5 2011 05 15 44 57 6 10 Component Personality If a component has any pins or parameters with an if condition or maxsize condsize it is called a component with personality The personality of each instance is specified when the module is loaded Personality can be used to create pins only when needed For instance personality is used in the logic component to allow for a variable number of input pins to each logic gate and to allow for a selection of any of the basic boolean logic functions and or and xor 6 11 Compiling comp files in the source tree Place the comp file in the source directory emc2 src hal components and re run ma
45. ement of any Modified Version 5 COMBINING DOCUMENTS You may combine the Document with other documents released under this License under the terms defined in section 4 above for modified versions provided that you include in the combination all of the Invariant Sections of all of the original documents unmodified and list them all as Invariant Sections of your combined work in its license notice The combined work need only contain one copy of this License and multiple identical Invariant Sections may be replaced with a single copy If there are multiple Invariant Sections with the same name but different contents make the title of each such section unique by adding at the end of it in parentheses the name of the original author or publisher of that section if known or else a unique number Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work In the combination you must combine any sections entitled History in the various original documents forming one section entitled History likewise combine any sections entitled Acknowledgements and any sections entitled Dedications You must delete all sections entitled Endorsements 6 COLLECTIONS OF DOCUMENTS You may make a collection consisting of the Document and other documents released under this License and replace the indi vidual copies of this License in the various documents with a single copy that is incl
46. g about 4 seconds worth of data one record is 4000 samples at 20KHz or about 0 20 seconds HAL Manual V2 5 2011 05 15 29 57 Select Sample Rate Select a thread name and multiplier then click OK or Click Quit to exit HALSCOPE Thread fast Sample Period 49 4 USec Sample Rate Thread Period slow 989 uSec fast 49 4 uSec Multiplier Record Length O 16000 samples 1 channel 8000 samples 2 channels w 4000 samples 4 channels A 2000 samples 8 channels O 1000 samples 16 channels OK Quit Figure 2 12 Sample Rate Dialog 2 5 7 More Channels Now let s look at the step pulses Halscope has 16 channels but for this example we are using only 4 at a time Before we select any more channels we need to turn off a couple Click on the channel 2 button then click the Chan Off button at the bottom of the Vertical box Then click on channel 3 turn if off and do the same for channel 4 Even though the channels are turned off they still remember what they are connected to and in fact we will continue to use channel 3 as the trigger source To add new channels select channel 5 and choose pin stepgen 0 dir then channel 6 and select stepgen 0 step Then click run mode Normal to start the scope and adjust the horizontal zoom to 5mS per division You should see the step pulses slow down as the velocity command channel 1 approaches zero then the direction pin
47. ggen 0 square 3 float OUT 0 03232994 siggen 0 triangle We did two show pin commands in quick succession and you can see that the outputs are no longer zero The sine cosine sawtooth and triangle outputs are changing constantly The square output is also working however it simply switches from 1 0 to 1 0 every cycle 2 2 4 Changing Parameters The real power of HAL is that you can change things For example we can use the setp command to set the value of a parameter Let s change the amplitude of the signal generator from 1 0 to 5 0 halcmd setp siggen 0 amplitude 5 Check the parameters and pins again halcmd show param Parameters Owner Type Dir Value Name 3 32 RO 1754 siggen 0 update time 3 s32 RW 16997 siggen 0 update tmax HAL Manual V2 5 2011 05 15 12 57 halcmd show pin Component Pins Owner Type Dir Value Name 3 float IN 5 siggen 0 amplitude 3 float OUT 0 8515425 siggen 0 cosine 3 float IN 1 siggen 0 frequency 3 float IN 0 siggen 0 offset 3 float OUT 2 772382 siggen 0 sawtooth 3 float OUT 4 926954 siggen 0 sine 3 float OUT 5 siggen 0 square 3 float OUT 0 544764 siggen 0 triangle Note that the value of parameter siggen 0 amplitude has changed to 5 and that the pins now have larger values 2 2 5 Saving the HAL configuration Most of what we have done with halcmd so far has simply been viewing things with the show command However two of the commands actually changed things As we
48. he scaling parameters for both to 10000 halcmd setp stepgen 0 position scale 10000 halcmd setp stepgen 1 position scale 10000 halcmd setp stepgen 0 enable 1 halcmd setp stepgen 1 enable 1 This velocity scaling means that when the pin stepgen 0 velocity cmd is 1 000 the step generator will generate 10000 pulses per second 10KHz With the motor and leadscrew described above that will result in the axis moving at exactly 1 000 inches per second This illustrates a key HAL concept things like scaling are done at the lowest possible level in this case in the step pulse generator The internal signal X vel is the velocity of the table in inches per second and other components such as siggen don t know or care about the scaling at all If we changed the leadscrew or motor we would change only the scaling parameter of the step pulse generator HAL Manual V2 5 2011 05 15 19 57 2 4 5 Run it We now have everything configured and are ready to start it up Just like in the first example we use the start command halcmd start Although nothing appears to happen inside the computer the step pulse generator is cranking out step pulses varying from 10KHz forward to 10KHz reverse and back again every second Later in this tutorial we ll see how to bring those internal signals out to run motors in the real world but first we want to look at them and see what is happening 2 5 Halscope The previous example generates some very inte
49. ified Version filling the role of the Document thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it In addition you must do these things in the Modified Version HAL Manual V2 5 2011 05 15 55 57 A Use in the Title Page and on the covers if any a title distinct from that of the Document and from those of previous versions which should if there were any be listed in the History section of the Document You may use the same title as a previous version if the original publisher of that version gives permission B List on the Title Page as authors one or more persons or entities responsible for authorship of the modifications in the Modified Version together with at least five of the principal authors of the Document all of its principal authors if it has less than five C State on the Title page the name of the publisher of the Modified Version as the publisher D Preserve all the copyright notices of the Document E Add an appropriate copyright notice for your modifications adjacent to the other copyright notices F Include immediately after the copyright notices a license notice giving the public permission to use the Modified Version under the terms of this License in the form shown in the Addendum below G Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document s license notice H Include an unaltered copy of this
50. imself a present I had a hard time with the little screws and nuts I really needed four arms one each for the screwdriver screw parts to be bolted together and nut Perseverance along with father s eventual boredom got me to where I had built every project in the booklet Soon I was lusting after the bigger sets that were also printed on that paper Working with those regular sized pieces opened up a world of construction for me and soon I moved well beyond the illustrated projects Hal components are not all the same size and shape but they allow for grouping into larger units that will do useful work In this sense they are like the parts of an Erector set Some components are long and thin They essentially connect high level commands to specific physical pins Other components are more like the rectangular platforms upon which whole machines could be built An integrator will quickly get beyond the brief examples and begin to bolt together components in ways that are unique to them 1 4 3 Tinkertoys Tinkertoys Wooden Tinkertoys had a more humane feel than the cold steel of Erector Sets The heart of construction with Tinkertoys was a round connector with eight holes equally spaced around the circumference It also had a hole in the center that was perpendicular to all the holes around the hub Hubs were connected with rods of several different lengths Builders would make large wheels by using these rods as spokes sticki
51. is all about If you are comfortable with the idea of interconnecting hardware black boxes you will probably have little trouble using HAL to interconnect software black boxes 1 2 HAL Concepts This section is a glossary that defines key HAL terms but it is a bit different than a traditional glossary because these terms are not arranged in alphabetical order They are arranged by their relationship or flow in the HAL way of things HAL Manual V2 5 2011 05 15 3 57 Component When we talked about hardware design we referred to the individual pieces as parts building blocks black boxes etc The HAL equivalent is a component or HAL component This document uses HAL component when there is likely to be confusion with other kinds of components but normally just uses component A HAL component is a piece of software with well defined inputs outputs and behavior that can be installed and interconnected as needed Parameter Many hardware components have adjustments that are not connected to any other components but still need to be accessed For example servo amps often have trim pots to allow for tuning adjustments and test points where a meter or scope can be attached to view the tuning results HAL components also can have such items which are referred to as parameters There are two types of parameters Input parameters are equivalent to trim pots they are values that can be adjusted by the user and remain fixed once
52. ke Comp files are automatically detected by the build system Ifa comp file is a driver for hardware it may be placed in emc2 src hal components and will be built unless emc2 is configured as a userspace simulator 6 12 Compiling realtime components outside the source tree comp can process compile and install a realtime component in a single step placing rtexample ko in the emc2 realtime module directory comp install rtexample comp Or it can process and compile in one step leaving example ko or example so for the simulator in the current directory comp compile rtexample comp Or it can simply process leaving example c in the current directory comp rtexample comp comp can also compile and install a component written in C using the install and compile options shown above comp install rtexample2 c man format documentation can also be created from the information in the declaration section comp document rtexample comp The resulting manpage example 9 can be viewed with man example 9 or copied to a standard location for manual pages 6 13 Compiling userspace components outside the source tree comp can process compile install and document userspace components comp usrexample comp comp compile usrexample comp comp install usrexample comp comp document usrexample comp This only works for comp files not for c files HAL Manual V2 5 2011 05 15 45 57 6 14 Examples 6 14 1
53. later version applies to it you have the option of following the terms and conditions either of that specified version or of any later version that has been published not as a draft by the Free Software Foundation If the Document does not specify a version number of this License you may choose any version ever published not as a draft by the Free Software Foundation ADDENDUM How to use this License for your documents To use this License in a document you have written include a copy of the License in the document and put the following copyright and license notices just after the title page Copyright c YEAR YOUR NAME Permission is granted to copy distribute and or modify this document under the terms of the GNU Free Documentation License Version 1 1 or any later version published by the Free Software Foundation with the Invariant Sections being LIST THEIR TITLES with the Front Cover Texts being LIST and with the Back Cover Texts being LIST A copy of the license is included in the section entitled GNU Free Documentation License If you have no Invariant Sections write with no Invariant Sections instead of saying which ones are invariant If you have no Front Cover Texts write no Front Cover Texts instead of Front Cover Texts being LIST likewise for Back Cover Texts If your document contains nontrivial examples of program code we recommend releasing these examples in parallel under your choice of free software license s
54. ly only be a single object of that kind in the system for instance a component whose purpose is to provide a pin with the current UNIX time or a hardware driver for the internal PC speaker HAL Manual V2 5 2011 05 15 39 57 6 3 Instance creation For a singleton the one instance is created when the component is loaded For a non singleton the count module parameter determines how many numbered instances are created 6 4 Parameters Comp s are passed the period parameter which is the time in nanoseconds of the last period to execute the comp This can be useful in comps that need the timing information 6 5 Syntax A comp file consists of a number of declarations followed by on a line of its own followed by C code implementing the module s functions Declarations include component HALNAME DOC e pin PINDIRECTION TYPE HALNAME SIZE MAXSIZE CONDSIZE if CONDITION STARTVALUE DOC T e paramPARAMDIRECTION TYPE HALNAME SIZE MAXSIZE CONDSIZE if CONDITION STARTVALUI DOC E e function HALNAME fp nofp DOC e option OPT VALU ira y e variable CTYPE STARREDNAME SIZ Gl wu e description DOC e see_also DOC e license LICENSE e author AUTHOR Parentheses indicate optional items A vertical bar indicates alternatives Words in CAPITALS indicate variable text as
55. module called Ubuntu package name python serial in the universe repository e Attach a LCDProc compatible LCD module and use it to display a digital readout with information of your choice Ubuntu package name ledproc in the universe repository e Create a virtual control panel using any GUI library supported by Python gtk qt wxwindows etc HAL Manual V2 5 2011 05 15 52 57 Part I Legal Section HAL Manual V2 5 2011 05 15 53 57 Chapter 8 Legal Section 8 1 Copyright Terms Copyright c 2000 2011 LinuxCNC org Permission is granted to copy distribute and or modify this document under the terms of the GNU Free Documentation License Version 1 1 or any later version published by the Free Software Foundation with no Invariant Sections no Front Cover Texts and one Back Cover Text This EMC Handbook is the product of several authors writing for linuxCNC org As you find it to be of value in your work we invite you to contribute to its revision and growth A copy of the license is included in the section entitled GNU Free Documentation License If you do not find the license you may order a copy from Free Software Foundation Inc 59 Temple Place Suite 330 Boston MA 02111 1307 8 2 GNU Free Documentation License GNU Free Documentation License Version 1 1 March 2000 Copyright 2000 Free Software Foundation Inc 59 Temple Place Suite 330 Boston MA 02111 1307 USA Everyone is permitted to copy
56. mplement separate functions for different I O types unless they are interruptable and can work in independent threads If interrupting an encoder read reading digital inputs and then resuming the encoder read will cause problems then implement a single function that does everything HAL Manual V2 5 2011 05 15 34 57 Chapter 4 Canonical Device Interfaces Note By version 2 1 the HAL drivers should have all been updated to match these specs Send an email if you spot any problems The following sections show the pins parameters and functions that are supplied by canonical devices All HAL device drivers should supply the same pins and parameters and implement the same behavior Note that the only the lt io type gt and lt specific name gt fields are defined for a canonical device The lt device name gt lt device num gt and lt chan num gt fields are set based on the characteristics of the real device 4 1 Digital Input The canonical digital input I O type field digin is quite simple 4 1 1 Pins e bit in State of the hardware input e bit in not Inverted state of the input 4 1 2 Parameters None 4 1 3 Functions e funct read Read hardware and set in and in not HAL pins 4 2 Digital Output The canonical digital output I O type field digout is also very simple HAL Manual V2 5 2011 05 15 35 57 4 2 1 Pins e bit out Value to be written
57. ng out from the center hub My favorite project was a rotating space station Short spokes radiated from all the holes in the center hub and connected with hubs on the ends of each spoke These outer hubs were connected to each other with longer spokes I d spend hours dreaming of living in such a device walking from hub to hub around the outside as it slowly rotated producing near gravity in weightless space Supplies traveled through the spokes in elevators that transferred them to and from rockets docked at the center hub while they transferred their precious cargoes The idea of one pin or component being the hub for many connections is also an easy concept within the HAL Examples two and four see section cha HAL Tutorial connect the meter and scope to signals that are intended to go elsewhere Less easy is the notion of a hub for several incoming signals but that is also possible with proper use of functions within that hub component that handle those signals as they arrive from other components Another thought that comes forward from this toy is a mechanical representation of HAL threads A thread might look a bit like a centipede caterpillar or earwig A backbone of hubs HAL components strung together with rods HAL signals Each component takes in it own parameters and input pins and passes on output pins and parameters to the next component Signals travel along the backbone from end to end and are added to or modified by each compone
58. ns run when they are needed First let s look at the functions available to us halcmd show funct Exported Functions Owner CodeAddr Arg FP Users Name 00004 9992000 fc731278 YES 0 siggen 0 update 00003 f998b20f fc7310b8 YES 0 stepgen capture position 00003 998b000 fc7310b8 NO 0 stepgen make pulses 00003 998b307 fc7310b8 YES 0 stepgen update freq In general you will have to refer to the documentation for each component to see what its functions do In this case the function siggen 0 update is used to update the outputs of the signal generator Every time it is executed it calculates the values of the sine cosine triangle and square outputs To make smooth signals it needs to run at specific intervals The other three functions are related to the step pulse generators The first one stepgen capture_position is used for position feedback It captures the value of an internal counter that counts the step pulses as they are generated Assuming no missed steps this counter indicates the position of the motor The main function for the step pulse generator is stepgen make_pulses Every time make_pulses runs it decides if it is time to take a step and if so sets the outputs accordingly For smooth step pulses it should run as frequently as possible Because it needs to run so fast make_pulses is highly optimized and performs only a few calculations Unlike the others it does not need floating point math The last fun
59. nt in turn Threads are all about timing and doing a set of tasks from end to end A mechanical representation is available with Tinkertoys also when we think of the length of the toy as a measure of the time taken to get from one end to the other A very different thread or backbone is created by connecting the same set of hubs with different length rods The total length of the backbone can be changed by the length of rods used to connect the hubs The order of operations is the same but the time to get from beginning to end is very different 1 4 4 A Lego Example When Lego blocks first arrived in our stores they were pretty much all the same size and shape Sure there were half sized one and a few quarter sized as well but that rectangular one did most of the work Lego blocks interconnected by snapping the holes in the underside of one onto the pins that stuck up on another By overlapping layers the joints between could be made very strong even around corners or tees Tinkertoy is now a registered trademark of the Hasbro company 3The Lego name is a trademark of the Lego company HAL Manual V2 5 2011 05 15 7 57 Legos I watched my children and grandchildren build with legos the same legos There are a few thousand of them in an old ratty but heavy duty cardboard box that sits in a corner of the recreation room It stays there in the open because it was too much trouble to put the box away and then get it back out for
60. ntents can be viewed and edited directly and straightforwardly with generic text editors or for images composed of pixels generic paint programs or for drawings some widely available drawing editor and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters A copy made in an otherwise Transparent file format whose markup has been designed to thwart or discourage subsequent modification by readers is not Transparent A copy that is not Transparent is called Opaque Examples of suitable formats for Transparent copies include plain ASCII without markup Texinfo input format LaTeX input format SGML or XML using a publicly available DTD and standard conforming simple HTML designed for human modi fication Opaque formats include PostScript PDF proprietary formats that can be read and edited only by proprietary word processors SGML or XML for which the DTD and or processing tools are not generally available and the machine generated HTML produced by some word processors for output purposes only The Title Page means for a printed book the title page itself plus such following pages as are needed to hold legibly the material this License requires to appear in the title page For works in formats which do not have any title page as such Title Page means the text near the most prominent appearance of the work s title preceding the beginning of the body of the
61. onent out8 pin out unsigned out_ Output value only low 8 bits are used param r unsigned ioaddr IE UUMSIE Loja oprilon ke O unan e culo option extra_setup option extra_cleanup option constructable no license GPL ri include lt asm io h gt define MAX 8 int io MAX 0 RTAPI_MP_ARRAY_INT io MAX I O addresses of out8 boards HAL Manual V2 5 2011 05 15 46 57 int get_count void aloe ak 0 6 for i 0 i lt MAX amp amp io i i Nothing return i EXTRA_SETUP if rtapi_request_region io extra_arg 1 out8 M see thus 1 0 pore to 0 so that EXTRALCHBANUP does noe release the TO ports that were never requested io extra_arg 0 return EBUSY ioaddr io extra_arg return 0 EXTRA CLEANUP align slp for i 0 i lt MAX amp amp io i i rtapi_release_region io i 1 PUNCTIONY NL outo outs toa0cr gt 3 6 14 4 hal_loop component hal_loop pin out float example This fragment of a component illustrates the use of the hal_ prefix in a component name loop is the name of a standard Linux kernel module so a Loop component might not successfully load if the Linux loop module was also present on the system When loaded halcmd show comp will show a component called hal_loop However the pin shown by halcmd show pin will be loop 0 example not hal loop 0 example 6 14 5 arraydemo This re
62. onents Before we can begin building this new example we want to start with a clean slate If you just finished one of the previous examples we need to remove the all components and reload the RTAPI and HAL libraries halcmd exit emc2S halrun 2 4 1 Installing the components Now we are going to load the step pulse generator component For a detailed description of this component refer to Stepgen section of the Integrators Manual For now we can skip the details and just run the following commands In this example we will use the velocity control type of stepgen halcmd loadrt stepgen step type 0 0 ctrl_type v v halcmd loadrt siggen halcmd loadrt threads namel fast fpl1 0 period1 50000 name2 slow period2 1000000 The first command loads two step generators both configured to generate stepping type 0 The second command loads our old friend siggen and the third one creates two threads a fast one with a period of 50 micro seconds and a slow one with a period of 1mS The fast thread doesn t support floating point functions As before we can use halcmd show to take a look at the HAL This time we have a lot more pins and parameters than before halcmd show pin Component Pins Owner Type Dir Value Name 4 float IN 1 siggen 0 amplitude 4 float OUT O siggen 0 cosine 4 float IN 1 siggen 0 frequency 4 float IN O siggen 0 offset 4 float OUT 0 siggen 0 sawtooth 4 float OUT 0 siggen 0 sine 4 float
63. onverters or PWM generators 4 4 1 Pins e float value The value to be written The actual value output to the hardware will depend on the scale and offset parameters e bit enable If false then output 0 to the hardware regardless of the value pin HAL Manual V2 5 2011 05 15 36 57 4 4 2 Parameters e float offset This will be added to the value before the hardware is updated e float scale This should be set so that an input of 1 on the value pin will cause 1V e float high_limit optional When calculating the value to output to the hardware if value offset is greater than high_limit then high_limit will be used instead e float low_limit optional When calculating the value to output to the hardware if value offset is less than low_limit then low_limit will be used instead e float bit_weight optional The value of one least significant bit LSB in volts or mA for current outputs e float hw_offset optional The actual voltage or current that will be output if O is written to the hardware 4 4 3 Functions funct write This causes the calculated value to be output to the hardware If enable is false then the output will be 0 regardless of value scale and offset The meaning of 0 is dependent on the hardware For example a bipolar 12 bit A D may need to write Ox 1FF mid scale to the D A get 0 volts from the hardware pin If enable is true read scal
64. order every time the thread runs As an example suppose we have a parport component named hal_parport That component defines one or more HAL pins for each physical pin The pins are described in that component s doc section their names how each pin relates to the physical pin are they inverted can you change polarity etc But that alone doesn t get the data from the HAL pins to the physical pins It HAL Manual V2 5 2011 05 15 4 57 takes code to do that and that is where functions come into the picture The parport component needs at least two functions one to read the physical input pins and update the HAL pins the other to take data from the HAL pins and write it to the physical output pins Both of these functions are part of the parport driver 1 3 HAL components Each HAL component is a piece of software with well defined inputs outputs and behavior that can be installed and intercon nected as needed This section lists some of the available components and a brief description of what each does Complete details for each component are available later in this document 1 3 1 External Programs with HAL hooks motion A realtime module that accepts NML motion commands and interacts with HAL iocontrol A user space module that accepts NML I O commands and interacts with HAL classicladder A PLC using HAL for all I O halui A user space program that interacts with HAL and sends NML commands it is intended to work as a f
65. ow and leave the multiplier at 1 We will also leave the record length at 4000 samples so that we can use up to four channels at one time When you select a thread and then click OK the dialog disappears and the scope window HAL Manual V2 5 2011 05 15 looks something like the following figure File Help Horizontal Zoom A 500 mSec 4000 samples Pos p per div at 1 01 KHz IDLE 12 SU 4 aay ZE SIII 1 1 11 Selected Channel Figure 2 4 Initial scope window 2 5 2 Hooking up the scope probes 21 57 Run Mode Trigger Normal Normal O Single O Auto O Roll Force Stop Wertical Gain Pos Level Pos Scale Lewel Offset Rising Source Chan Off None At this point Halscope is ready to use We have already selected a sample rate and record length so the next step is to decide what to look at This is equivalent to hooking virtual scope probes to the HAL Halscope has 16 channels but the number you can use at any one time depends on the record length more channels means shorter records since the memory available for the record is fixed at approximately 16 000 samples The channel buttons run across the bottom of the halscope screen Click button 1 and you will see the Select Channel Source dialog as shown in the following figure This dialog is very similar to the one used by Halmeter We would like to look at the signals we defined earlier so we click on the Signals tab and
66. ponents can access it Normal Linux does not support realtime programming or the type of shared memory that HAL needs Fortunately there are realtime operating systems RTOS s that provide the necessary extensions to Linux Unfortunately each RTOS does things a little differently To address these differences the EMC team came up with RTAPI which provides a consistent way for programs to talk to the RTOS If you are a programmer who wants to work on the internals of EMC you may want to study emc2 src rtapi rtapi to understand the API But if you are a normal person all you need to know about RTAPI is that it and the RTOS needs to be loaded into the memory of your computer before you do anything with HAL HAL Manual V2 5 2011 05 15 9 57 2 2 A Simple Example 2 2 1 Loading a realtime component For this tutorial we are going to assume that you have successfully installed the Live CD or compiled the emc2 source tree and if necessary invoked the emc environment script to prepare your shell In that case all you need to do is load the required RTOS and RTAPI modules into memory Just run the following command from a terminal window ad emc2 emc2S halrun halcmd With the realtime OS and RTAPI loaded we can move into the first example Notice that the prompt has changed from the shell s to halcmd This is because subsequent commands will be interpreted as HAL commands not shell commands For the first example
67. possibly inverted to the hardware output 4 2 2 Parameters e bit invert If TRUE out is inverted before writing to the hardware 4 2 3 Functions e funct write Read out and invert and set hardware output accordingly 4 3 Analog Input The canonical analog input I O type adcin This is expected to be used for analog to digital converters which convert e g voltage to a continuous range of values 4 3 1 Pins e float value The hardware reading scaled according to the scale and offset parameters Value input reading in hardware dependent units scale offset 4 3 2 Parameters e float scale The input voltage or current will be multiplied by scale before being output to value e float offset This will be subtracted from the hardware input voltage or current after the scale multiplier has been applied e float bit_weight The value of one least significant bit LSB This is effectively the granularity of the input reading e float hw_offset The value present on the input when 0 volts is applied to the input pin s 4 3 3 Functions e funct read Read the values of this analog input channel This may be used for individual channel reads or it may cause all channels to be read 4 4 Analog Output The canonical analog output I O Type adcout This is intended for any kind of hardware that can output a more or less continuous range of values Examples are digital to analog c
68. quency stepgen 1 maxaccel stepgen 1 maxvel stepgen 1l position scale stepgen 1l rawcounts stepgen 1l steplen stepgen 1 stepspace stepgen capture position time stepgen capture position tmax stepgen make pulses tim stepgen make pulses tmax stepgen update freq time stepgen update freg tmax 2 4 2 Connecting pins with signals What we have is two step pulse generators and a signal generator Now it is time to create some HAL signals to connect the two components We are going to pretend that the two step pulse generators are driving the X and Y axis of a machine We want to move the table in circles To do this we will send a cosine signal to the X axis and a sine signal to the Y axis The siggen module creates the sine and cosine but we need wires to connect the modules together In the HAL wires are called signals We need to create two of them We can call them anything we want for this example they will be X vel and Y vel The signal X vel is intended to run from the cosine output of the signal generator to the velocity input of the first step pulse generator The first step is to connect the signal to the signal generator output To connect a signal to a pin we use the net command halcmd net X vel lt siggen 0 cosine To see the effect of the net command we show the signals again halcmd show sig Signals Type Value Name linked to float O X vel lt siggen 0 cosine HAL Manual V2 5 2011 05 15 17 57 When
69. rand of servo amp what kind of limit switches and how many etc The integrator s decisions about which specific components to use is based on what that component does and the specifications supplied by the manufacturer of the device The size of a motor and the load it must drive will affect the choice of amplifier needed to run it The choice of amplifier may affect the kinds of feedback needed by the amp and the velocity or position signals that must be sent to the amp from a control In the HAL world the integrator must decide what HAL components are needed Usually every interface card will require a driver Additional components may be needed for software generation of step pulses PLC functionality and a wide variety of other tasks 1 1 1 2 Interconnection Design The designer of a hardware system not only selects the parts he also decides how those parts will be interconnected Each black box has terminals perhaps only two for a simple switch or dozens for a servo drive or PLC They need to be wired together The HAL Manual V2 5 2011 05 15 2 57 motors connect to the servo amps the limit switches connect to the controller and so on As the machine builder works on the design he creates a large wiring diagram that shows how all the parts should be interconnected When using HAL components are interconnected by signals The designer must decide which signals are needed and what they should connect 1 1 1 3 Implementation
70. red AUTHOR Specify the author of the module for the documentation 6 6 Per instance data storage variable CTYPE STARREDNAME variable CTYPE STARREDNAME SIZE variable CTYPE STARREDNAME DEFAULT variable CTYPE STARREDNAME SIZE DEFAULT Declare a per instance variable STARREDNAME of type CTYPE optionally as an array of SIZE items and optionally with a default value DEFAULT Items with no DEFAULT are initialized to all bits zero CTYPE is a simple one word C type such as float u32 s32 int etc Access to array variables uses square brackets If a variable is to be of a pointer type there may not be any space between the and the variable name Therefore the following is acceptable variable int xexample but the following are not variable int badexample variable int badexample C style one line comments and C style multi line comments x are both supported in the declaration section HAL Manual V2 5 2011 05 15 43 57 6 7 Other restrictions on comp files Though HAL permits a pin a parameter and a function to have the same name comp does not 6 8 Convenience Macros Based on the items in the declaration section comp creates a C structure called struct state However instead of referring to the members of this structure e g inst gt name they will generally be referred to using the macros below The details of struct state and these macro
71. resting signals But much of what happens is far too fast to see with halmeter To take a closer look at what is going on inside the HAL we want an oscilloscope Fortunately HAL has one called halscope 2 5 1 Starting Halscope Halscope has two parts a realtime part that is loaded as a kernel module and a user part that supplies the GUI and display However you don t need to worry about this because the userspace portion will automatically request that the realtime part be loaded halcmd loadusr halscope The scope GUI window will open immediately followed by a Realtime function not linked dialog that looks like the following figure HAL Manual V2 5 2011 05 15 20 57 Realtime function not linked The HALSCOPE realtime sampling function must be called from a HAL thread in to determine the sampling rate Please do one of the following Select a thread name and multiplier then click OK or Click Quit to exit HALSCOPE Thread slow Sample Period 989 uSec Sample Rate 1 01 KHz Thre Period slow 989 uSec fast 49 4 uSec Multiplier Record Length 16000 samples 1 channel 8000 samples 2 channels 4000 samples 4 channels 2000 samples 8 channels 1000 sarnples 16 channels o or Figure 2 3 Realtime function not linked dialog This dialog is where you set the sampling rate for the oscilloscope For now we want to sample once per millisecond so click on the 989uS thread sl
72. s Be oo ee ee a TA Se Loe be Be oh ES eee bE OS ee eae PER SHS es Sed a tido es a Ge eho Gas Bec hale oe de aa G rh Ss te Esch eves ie e re te A andi deus ee Oe Ge asta aa ce dE Ae acne da cos car A 6 8 Convenience Macros Ladin de E AS RA a E A ewes Sete a eee Se a we 6 10 Component Personality bh OO ee ERA RS REG eee ee oA ee ES HGS pa 6 4b bade se bebe R eee eee ees be oy ee ecko oie Banana ee oe e a eek oe te E FE A cap Soe AA ee aE ET a do Mets est Boa Me ee ee ee aa 6 14 1 constant 5 eds wale De awe Rede Be Be Ge ad SG ARS Ee ede ae Be eS ee O14 2 2SiNCOSlic amp 5 x he Re ae BE ws OG RR ee Ce ee Ae A Re ae E aaa OLAS SOULS ed din a8 ORS oe Sete Pk Ge a E ee Bn eo ee wee be ee we E fe 6 14 4 Dal loopje i e hea eae RA ERA ER RGA HEHE HEGRE He eRe ea i a O AF tax cobs Pe Grits wate tex SPs dare a E toe a Pedy oe heres den im e a a das 6214 6 stand hee Ge 2 eee oe YER LER AW ee e eA ees Oe eee 6 aed 6147 108G sek hoe a oe a eee ea Oa ee ee toe Ae ee a he ee ee oa Ge 34 35 35 35 35 35 35 35 35 35 36 36 37 37 37 37 HAL Manual V2 5 2011 05 15 7 Creating Userspace Python Components with the hal module ed BASIC USASe Ae bon a GOR a A A A A A e A a ee i Ub o A a GR e eck a eee Neve a ns As ae ias tech oe E 7 3 Changing the prefix s ssn 8 a ge a aS ee AG A a eG eke ak ee dase O ee eee bb SSS 7 4 1 Driving output HAL OUT pins ee sean Decisis Deets Stet ama Bye th Be Ge BOG O
73. s may change from one version of comp to the next FUNCTION name Use this macro to begin the definition of a realtime function which was previously declared with function NAME The function includes a parameter period which is the integer number of nanoseconds between calls to the function EXTRA_SETUPQ Use this macro to begin the definition of the function called to perform extra setup of this instance Return a negative Unix errno value to indicate failure e g return EBUSY on failure to reserve an I O port or O to indicate success EXTRA_CLEANUP Use this macro to begin the definition of the function called to perform extra cleanup of the component Note that this function must clean up all instances of the component not just one The pin_name parameter_name and data macros may not be used here pin_name parameter_name For each pin pin_name or param parameter_name there is a macro which allows the name to be used on its own to refer to the pin or parameter When pin_name or parameter_name is an array the macro is of the form pin_name idx or param_name idx where idx is the index into the pin array When the array is a variable sized array it is only legal to refer to items up to its condsize When the item is a conditional item it is only legal to refer to it when its condition evaluated to a nonzero value variable_name For each variable variable_name there is a macro which allows the name to be us
74. ses fast After we give these commands we can run the show thread command again to see what happened halcmd show thread Realtime Threads Period FP Name Time Max Time 996980 YES slow 0 0 1 siggen 0 update 2 stepgen update freqg 49849 NO fast 0 0 1 stepgen make pulses Led Now each thread is followed by the names of the functions in the order in which the functions will run 2 4 4 Setting parameters We are almost ready to start our HAL system However we still need to adjust a few parameters By default the siggen component generates signals that swing from 1 to 1 For our example that is fine we want the table speed to vary from 1 to 1 inches per second However the scaling of the step pulse generator isn t quite right By default it generates an output frequency of 1 step per second with an input of 1 000 It is unlikely that one step per second will give us one inch per second of table movement Let s assume instead that we have a 5 turn per inch leadscrew connected to a 200 step per rev stepper with 10x microstepping So it takes 2000 steps for one revolution of the screw and 5 revolutions to travel one inch that means the overall scaling is 10000 steps per inch We need to multiply the velocity input to the step pulse generator by 10000 to get the proper output That is exactly what the parameter stepgen n velocity scale is for In this case both the X and Y axis have the same scaling so we set t
75. sthrough make it executable chmod x and place it on your PATH Then try it out S halrun halcmd loadusr passthrough halcmd show pin Component Pins Owner Type Dir Value Name 03 float IN OP passiehsoug ees ON ial Oates CUT 0 passthrough out halcmd setp passthrough in 3 14 halcmd show pin Component Pins Owner Type Dir Value Name 03 float IN 3 14 passthrough in 03 gloeit QUT 3 14 passthrough out HAL Manual V2 5 2011 05 15 50 57 7 2 Userspace components and delays If you typed show pin quickly you may see that passthrough out still had its old value of 0 This is because of the call to time sleep 1 which makes the assignment to the output pin occur at most once per second Because this is a userspace component the actual delay between assignments can be much longer for instance if the memory used by the passthrough component is swapped to disk the assignment could be delayed until that memory is swapped back in Thus userspace components are suitable for user interactive elements such as control panels delays in the range of milliseconds are not noticed and longer delays are acceptable but not for sending step pulses to a stepper driver board delays must always be in the range of microseconds no matter what 7 3 Create pins and parameters h hal component passthrough The component itself is created by a call to the constructor hal component The arguments are the HAL component nam
76. tact is open and de energizes the coil So the relay still switches rapidly between on and off but at a rate determined by how often the PLC evaluates the rung In HAL the function is the code that evaluates the rung s In fact the HAL aware realtime version of ClassicLadder exports a function to do exactly that Meanwhile a thread is the thing that runs the function at specific time intervals Just like you can choose to have a PLC evaluate all its rungs every 10mS or every second you can define HAL threads with different periods What distinguishes one thread from another is not what the thread does that is determined by which functions are connected to it The real distinction is simply how often a thread runs In EMC you might have a 50us thread and a 1ms thread These would be created based on BASE_PERIOD and SERVO_PERIOD the actual times depend on the ini The next step is to decide what each thread needs to do Some of those decisions are the same in nearly any EMC system For instance motion command handler is always added to servo thread Other connections would be made by the integrator These might include hooking the STG driver s encoder read and DAC write functions to the servo thread or hooking stepgen s function to the base thread along with the parport function s to write the steps to the port HAL Manual V2 5 2011 05 15 8 57 Chapter 2 HAL Tutorial 2 1 Introduction Configuration moves from theor
77. ted Channel ES 1 x vel Chan off None Figure 2 9 Vertical Adjustment 2 5 5 Triggering Using the Force button is a rather unsatisfying way to trigger the scope To set up real triggering click on the Source button at the bottom right It will pop up the Trigger Source dialog which is simply a list of all the probes that are currently connected Select a probe to use for triggering by clicking on it For this example we will use channel 3 the triangle wave as shown in the following figure HAL Manual V2 5 2011 05 15 27 57 TEE er Source X vel wal Ri siggen O triangle slggen 0 square 3 4 5 6 T 8 9 o amp FE ha Ro E ta al in FE mn Cancel Figure 2 10 Trigger Source Dialog After setting the trigger source you can adjust the trigger level and trigger position using the sliders in the Trigger box along the right edge The level can be adjusted from the top to the bottom of the screen and is displayed below the sliders The position is the location of the trigger point within the overall record With the slider all the way down the trigger point is at the end of the record and halscope displays what happened before the trigger point When the slider is all the way up the trigger point is at the beginning of the record displaying what happened after it was triggered The trigger point is visible as a vertical line in the progress box above the screen The trigger polari
78. text 2 VERBATIM COPYING You may copy and distribute the Document in any medium either commercially or noncommercially provided that this License the copyright notices and the license notice saying this License applies to the Document are reproduced in all copies and that you add no other conditions whatsoever to those of this License You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute However you may accept compensation in exchange for copies If you distribute a large enough number of copies you must also follow the conditions in section 3 You may also lend copies under the same conditions stated above and you may publicly display copies 3 COPYING IN QUANTITY If you publish printed copies of the Document numbering more than 100 and the Document s license notice requires Cover Texts you must enclose the copies in covers that carry clearly and legibly all these Cover Texts Front Cover Texts on the front cover and Back Cover Texts on the back cover Both covers must also clearly and legibly identify you as the publisher of these copies The front cover must present the full title with all words of the title equally prominent and visible You may add other material on the covers in addition Copying with changes limited to the covers as long as they preserve the title of the Document and satisfy these conditions can be treated as verbatim copying in other resp
79. they are set Output parameters cannot be adjusted by the user they are equivalent to test points that allow internal signals to be monitored Pin Hardware components have terminals which are used to interconnect them The HAL equivalent is a pin or HAL pin HAL pin is used when needed to avoid confusion All HAL pins are named and the pin names are used when interconnecting them HAL pins are software entities that exist only inside the computer Physical_Pin Many I O devices have real physical pins or terminals that connect to external hardware for example the pins of a parallel port connector To avoid confusion these are referred to as physical pins These are the things that stick out into the real world Signal In a physical machine the terminals of real hardware components are interconnected by wires The HAL equivalent of a wire is a signal or HAL signal HAL signals connect HAL pins together as required by the machine builder HAL signals can be disconnected and reconnected at will even while the machine is running Type When using real hardware you would not connect a 24 volt relay output to the 10V analog input of a servo amp HAL pins have the same restrictions which are based upon their type Both pins and signals have types and signals can only be connected to pins of the same type Currently there are 4 types as follows e bit a single TRUE FALSE or ON OFF value e float a 64 bit floating point
80. ting a HAL component can be a tedious process most of it in setup calls to rtapi_ and hal_ functions and associated error checking comp will write all this code for you automatically Compiling a HAL component is also much easier when using comp whether the component is part of the emc2 source tree or outside it For instance the ddt portion of blocks is around 80 lines of code The equivalent component is very short when written using the comp preprocessor component ddt Compute the derivative of the input function pin in float in pin out float out variable float old function _ license GPL float tmp in out tmp old fperiod old tmp and it can be compiled and installed very easily by simply placing ddt comp in src hal components and running make or by placing it anywhere on the system and running comp install ddt comp 6 2 Definitions component A component is a single real time module which is loaded with halcmd loadrt One comp file specifies one component instance A component can have zero or more instances Each instance of a component is created equal they all have the same pins parameters functions and data but behave independently when their pins parameters and data have different values singleton It is possible for a component to be a singleton in which case exactly one instance is created It seldom makes sense to write a singleton component unless there can literal
81. ty can be changed by clicking the button just below the trigger level display Now that we have adjusted the vertical controls and triggering the scope display looks something like the following figure HAL Manual V2 5 2011 05 15 28 57 File Help Horizontal Run Mode Trigger Zoom qu 500 mSec 4000 samples Y Normal Normal Pos a 111 per div at 1 01 KHz HO Single Auto Oopretricg O Poll Force Level Pos Vertical Gain Pos O Stop Level 0 000 BABB BOUE slililifalla lis offset Rising 0 000 Selected Channel ES 1 X vel FC 1 12939 chan off Chan 3 Figure 2 11 Waveforms with Triggering 2 5 6 Horizontal Adjustments To look closely at part of a waveform you can use the zoom slider at the top of the screen to expand the waveforms horizontally and the position slider to determine which part of the zoomed waveform is visible However sometimes simply expanding the waveforms isn t enough and you need to increase the sampling rate For example we would like to look at the actual step pulses that are being generated in our example Since the step pulses may be only 50uS long sampling at 1KHz isn t fast enough To change the sample rate click on the button that displays the number of samples and sample rate to bring up the Select Sample Rate dialog figure For this example we will click on the 50uS thread fast which gives us a sample rate of about 20KHz Now instead of displayin
82. uch as the GNU General Public License to permit their use in free software HAL Manual V2 5 2011 05 15 Chapter 9 Index B blocks C ClassicLadder CNC i E encoder H HAL HAL Component HAL Function HAL Parameter HAL Physical Pin 3 HAL Pin HAL Signal 3 HAL Thread HAL Type hal ax52 Aon hal m5i20 hal motenc hal parport hal ppmc hal stg hal vti halemd halmeter halscope halui I iocontrol M motion P pid S siggen stepgen supply 57 57
83. uded in the collection provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects HAL Manual V2 5 2011 05 15 56 57 You may extract a single document from such a collection and distribute it individually under this License provided you insert a copy of this License into the extracted document and follow this License in all other respects regarding verbatim copying of that document 7 AGGREGATION WITH INDEPENDENT WORKS A compilation of the Document or its derivatives with other separate and independent documents or works in or on a volume of a storage or distribution medium does not as a whole count as a Modified Version of the Document provided no compilation copyright is claimed for the compilation Such a compilation is called an aggregate and this License does not apply to the other self contained works thus compiled with the Document on account of their being thus compiled if they are not themselves derivative works of the Document If the Cover Text requirement of section 3 is applicable to these copies of the Document then if the Document is less than one quarter of the entire aggregate the Document s Cover Texts may be placed on covers that surround only the Document within the aggregate Otherwise they must appear on covers around the whole aggregate 8 TRANSLATION Translation is considered a kind of modification so you may distribute translations of the
84. uld follow these rules e Dots separate levels of the heirarchy This is analogous to the slash in a filename 669 e Hyphens separate words or fields in the same level of the heirarchy 1 HAL modules should not use underscores or MixedCase e Use only lowercase letters and numbers in names 3 3 Hardware Driver Naming Conventionsfootnote Most drivers do not follow these conventions as of version 2 0 This chapter is really a guide for future development 3 3 1 Pin Parameter names Hardware drivers should use five fields on three levels to make up a pin or parameter name as follows lt device name gt lt device num gt lt io type gt lt chan num gt lt specific name gt The individual fields are lt device name gt The device that the driver is intended to work with This is most often an interface board of some type but there are other possibilities lt device num gt It is possible to install more than one servo board parallel port or other hardware device in a computer The device number identifies a specific device Device numbers start at O and increment lt io type gt Most devices provide more than one type of I O Even the simple parallel port has both digital inputs and digital outputs More complex boards can have digital inputs and outputs encoder counters pwm or step pulse generators analog to digital converters digital to analog converters or other unique
85. ull User Interface using external knobs amp switches 1 3 2 Internal Components stepgen Software step pulse generator with position loop See section encoder Software based encoder counter See section pid Proportional Integral Derivative control loops See section siggen A sine cosine triangle square wave generator for testing See section supply a simple source for testing blocks assorted useful components mux demux or and integ ddt limit wcomp etc 1 3 3 Hardware Drivers hal_ax5214h A driver for the Axiom Measurement amp Control AX5241H digital I O board hal_m5i20 Mesa Electronics 5120 board hal_motenc Vital Systems MOTENC 100 board HAL Manual V2 5 2011 05 15 5 57 hal_parport PC parallel port See section hal_ppme Pico Systems family of controllers PPMC USC and UPC hal_stg Servo To Go card version 1 amp 2 hal_vti Vigilant Technologies PCI ENCDAC 4 controller 1 3 4 Tools and Utilities halemd Command line tool for configuration and tuning See section sec Halemd halgui GUI tool for configuration and tuning not implemented yet halmeter A handy multimeter for HAL signals See section sec Halmeter halscope A full featured digital storage oscilloscope for HAL signals See section sec Halscope Each of these building blocks is described in detail in later chapters 1 4 Tinkertoys Erector Sets Legos and the HAL A first introduction to
86. userspace component may not have functions defined by the function directive Instead after all the instances are constructed the C function user_mainloop is called When this function returns the component exits Typically user_mainloop will use FOR_ALL_INSTS to perform the update action for each instance then sleep for a short time Another common action in user_mainloop may be to call the event handler loop of a GUI toolkit HAL Manual V2 5 2011 05 15 42 57 option userinit yes default no If specified the function userinit argc argv is called before rtapi_app_main and thus before the call to ha1_init This function may process the commandline arguments or take other actions Its return type is void it may call exit if it wishes to terminate rather than create a hal component for instance because the commandline arguments were invalid If an option s VALUE is not specified then it is equivalent to specifying option yes The result of assigning an inappropriate value to an option is undefined The result of using any other option is undefined LICENSE Specify the license of the module for the documentation and for the MODULE_LICENSE module declaration For example to specify that the module s license is GPL license GPL For additional information on the meaning of MODULE_LICENSE and additional license identifiers see lt linux module h gt Starting in emc 2 3 this declaration is requi
87. ust set up an EMC configuration file HAL can run without EMC so this manual focuses on the stand alone HAL For information on EMC related HAL see the Integrators manual 1 1 Whatis HAL HAL stands for Hardware Abstraction Layer At the highest level it is simply a way to allow a number of building blocks to be loaded and interconnected to assemble a complex system The Hardware part is because HAL was originally designed to make it easier to configure EMC for a wide variety of hardware devices Many of the building blocks are drivers for hardware devices However HAL can do more than just configure hardware drivers 1 1 1 HAL is based on traditional system design techniques HAL is based on the same principles that are used to design hardware circuits and systems so it is useful to examine those principles first Any system including a CNC machine consists of interconnected components For the CNC machine those components might be the main controller servo amps or stepper drives motors encoders limit switches pushbutton pendants perhaps a VFD for the spindle drive a PLC to run a toolchanger etc The machine builder must select mount and wire these pieces together to make a complete system 1 1 1 1 Part Selection The machine builder does not need to worry about how each individual part works He treats them as black boxes During the design stage he decides which parts he is going to use steppers or servos which b
88. vel Pos Wertical Gain Pos i i Ei I J Scale Level 1 Idiv BABB BAUE glilailla e offset Rising 0 000 Selected Channel eames 4 siggen 0 square Chan Of None Figure 2 8 Captured Waveforms The Selected Channel box at the bottom tells you that the purple trace is the currently selected one channel 4 which is displaying the value of the pin siggen 0 square Try clicking channel buttons 1 through 3 to highlight the other three traces 2 5 4 Vertical Adjustments The traces are rather hard to distinguish since all four are on top of each other To fix this we use the Vertical controls in the box to the right of the screen These controls act on the currently selected channel When adjusting the gain notice that it covers a huge range unlike a real scope this one can display signals ranging from very tiny pico units to very large Tera units The position control moves the displayed trace up and down over the height of the screen only For larger adjustments the offset button should be used see the halscope reference in section sec Halscope for details HAL Manual V2 5 2011 05 15 26 57 File Help Horizontal Run Mode Trigger Zoom qu 500 mSec 4000 samples Y Normal Normal Pos a 111 per div at 1 01 KHz HO Single Auto TRIGGER O Rall Force Stop Level Pos Wertical Gain Pos Scale Lewel 1 idiv BOUE alillifififililis offset Rising 0 000 7 Selec
89. x vel Chan Off None Figure 2 7 Halscope To add a signal to channel 2 click the 2 button When the dialog pops up click the Signals tab then click on Y vel We also want to look at the square and triangle wave outputs There are no signals connected to those pins so we use the Pins tab instead For channel 3 select siggen 0 triangle and for channel 4 select siggen 0 square 2 5 3 Capturing our first waveforms Now that we have several probes hooked to the HAL it s time to capture some waveforms To start the scope click the Normal button in the Run Mode section of the screen upper right Since we have a 4000 sample record length and are acquiring 1000 samples per second it will take halscope about 2 seconds to fill half of its buffer During that time a progress bar just above the main screen will show the buffer filling Once the buffer is half full the scope waits for a trigger Since we haven t configured one yet it will wait forever To manually trigger it click the Force button in the Trigger section at the top right You should see the remainder of the buffer fill then the screen will display the captured waveforms The result will look something like the following figure HAL Manual V2 5 2011 05 15 25 57 File Help Horizontal Run Mode Trigger Zoom 500 mSec 4000 samples Y Normal Normal Pos a 111 per div at 1 01 KHz O Single O Auto TRIGGER O Poll Force Stop Le
90. y to device HAL device that is For those who have had just a bit of computer programming this section is the Hello World of the HAL Halrun can be used to create a working system It is a command line or text file tool for configuration and tuning The following examples illustrate its setup and operation 2 1 1 Notation Command line examples are presented in bold typewriter font Responses from the computer will be in typewriter font Text inside square brackets like this is optional Text inside angle brackets lt 1ike this gt represents a field that can take on different values and the adjacent paragraph will explain the appropriate values Text items separated by a vertical bar means that one or the other but not both should be present All command line examples assume that you are in the emc2 directory and paths will be shown accordingly when needed 2 1 2 Tab completion Your version of halemd may include tab completion Instead of completing file names as a shell does it completes commands with HAL identifiers You will have to type enough letters for a unique match Try pressing tab after starting a HAL command halcmd loa lt TAB gt halcmd load halcmd loadrt halcmd loadrt deb lt TAB gt halcmd loadrt debounce 2 1 3 The RTAPI environment RTAPI stands for Real Time Application Programming Interface Many HAL components work in realtime and all HAL compo nents store data in shared memory so realtime com

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