Division de fréquence : problème ? (pci-6602)

Bonjour,
je dispose d'une pci-6602, de CVI.6 et DAQ Traditionnel.
Je souhaiterais qu'une fréquence générée par le compteur 7 soit divisée par 16 en sortie du compteur 2(en réalité, par 32, puisque je voudrais utiliser le mode Toggle). Je pense qu'en utilisant les fonctions SelectSignal et GPCTR_Change_Parameter, cela devrait marcher, mais j'ai systématiquement un problème avec ces fonctions lors de la compilation. Je dois donc mal m'y prendre.
Que dois-je donc mettre en argument de ces 2 fonctions (si ce sont bien celles là que je dois utiliser) ?
Et de plus, je sais que je dois relier les masses des compteurs à la masse de référence. Si je néglige cela (dans un premier temps en tout cas, même si ce n'est pas très propre), cela va-t-il empêcher le compteur 2 de diviser la fréquence provenant du compteur 7 ?
Merci d'avance pour toute aide.
Julien

Bonjour,
Vous trouverez un exemple de mise en oeuvre d'une division de fréquence en NI-DAQ Traditionnel sous LabWindows/CVI avec une carte NI 660x sur le lien suivant: http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3DDCB56A4E034080020E74861&p_node=DZ52328&p_source=External.
La valeur que vous fixerez pour les variables ND_COUNT_X permettront de fixer le diviseur pour la fréquence.
Les masses des compteurs sont communes, il n'est donc pas nécessaire de les relier pour tester cet exemple.
Cordialement,

Similar Messages

Problème pour diviser une fréquence : "Timebase is invalid" (PCI-6602) ???

Bonjour,
je dispose d'une pci-6602, de CVI 6 et de DAQ Traditionnel.
Je voudrais diviser une fréquence par 16 à l'aide du compteur 2 (en mode 'toggle', ce qui revient donc à la diviser par 32).
J'utilise pour cela la fonction 'FrequencyDividerConfig'. je passe en argument de cette fonction 'Use Counter Source', puisque la fréquence que je souhaite diviser est externe (elle provient du compteur 3, et est de 4000 Hz environ). De plus, je relie la sortie du compteur 3 à la source du compteur 2.
Pourtant, lors de la compilation, j'ai à chaque fois le message "Timebase is invalid". Que dois-je faire pour que ça marche ???
Je précise que dans le function panel de 'FrequencyDividerConfig', il est écrit en bleu que cette fonction ne peut être utilisée qu'avec les compteurs DAQ-STC et Am9513. Comme les compteurs de ma carte sont des NI-TIO, on pourrait penser que c'est pour cela que j'ai un problème. Mais je pense que ce n'est pas le cas, vu que lorsque je souhaite diviser une timebase interne au compteur (de 20 MHz), cela marche sans problème : on peut donc utiliser cette fonction avec les compteurs NI-TIO !! (Je sais c'est bizarre !!!)
Merci pour toute aide,
Julien.

Bonjour,
Vous trouverez un exemple de mise en oeuvre d'une division de fréquence en NI-DAQ Traditionnel sous LabWindows/CVI avec une carte NI 660x sur le lien suivant: http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3DDCB56A4E034080020E74861&p_node=DZ52328&p_source=External.
La valeur que vous fixerez pour les variables ND_COUNT_X permettront de fixer le diviseur pour la fréquence.
Les masses des compteurs sont communes, il n'est donc pas nécessaire de les relier pour tester cet exemple.
Cordialement,

Frequency divide by N doesn't work on Counter-Timer PCI-6602

Hello everybody,
I tried to do something basic ( ?) with this Counter-Timer 6602 Board, and it doesn’t work.
So I hope some people with more experience than me could understand what happens here.
1) What I need:
I need to generate 4 synchonised clocks, whose periods will be multiple of 1 ms.
2) What I have:
LabVIEW 7.0 and a PCI-6602 Counter-Timer Board in a DELL PC running under XP pro.
The PCI-6602 Counter-Timer Board has 8 counter timers named CTR 0, CTR 1, ... CTR7.
3) What I have already done, and that worked:
- Generate a 1 kHz “Master Clock” signal from CTR 4, configured by “Continuous Pulse Generator Config.vi” (found in “Data Acquisition, Counters...).
- configure CTR 0 and CTR 1 to work as frequency dividers, by use of “Down Counter or Divider Config.vi”.
- Apply the output signal of CTR 4 (OUT ) to the SOURCE inputs of CTR 0 and CTR 1 by means of physical wiring in the SCB-68 connection box.
When I do this, I get two nice secondary clock signals on my oscilloscope screen, ( with periods = 3 ms, or 5 ms or whatever multiples of 1 ms I choose) from CTR 0 and CTR 1 outputs , very clean and perfectly in phase with the 1 kHz Master Clock.
So far, so good...
But I still need 2 more secondary clocks...
One would say: “No problem, do the same trick with two other counters...” Well, not so simple, it seems...
4) What I tried to do, and that didn’t work:
When I try to do the same frequency division with any of the remaining counters, (CTR2 to CTR7), the program stops and I get an error “ –10020 : Time base not valid “.
I can’t figure out what happens here: I thought any counter could be configured to work as a frequency divider, but it seems not to be so, and I am stuck here.
Has anyone an idea about how to fix this type of problem?
Attached file: hor_div02New.vi
Attachments:
hor_div02New.vi ‏123 KB

karolik,
I'm just adding a followup in English. As Marc L. mentioned, the particular vi named "Down Counter or Divider Config" isn't compatible with the 6602. While the 6602 does have the ability to generate 4 synchronized clocks, a different syntax is needed. Here's how I'd do it:
Traditional NI-DAQ
1. Configure a continuous pulsetrain on CTR 4. Route its output to, say, RTSI 4. Don't start it yet.
2. Configure CTR 0,1,2,3 for continuous pulsetrains using RTSI 4 as their "timebase source." Start them.
3. Start the CTR 4 pulsetrain.
4. Now CTR's 0-3 should generate separate clocks with synchronized phasing.
DAQmx
1. Configure a continuous pulsetrain on CTR 4. Don't start it yet.
2. Configure CTR 0,1,2,3 for continuous pulsetrains using "Ticks" for units. Use a DAQmx property node (probably Channel property node, but am not 100% sure and don't have a LV PC handy to check) to specify that the "ctr4 internal output" should be used as the timebase. Start them.
3. Start the CTR 4 pulsetrain.
4. Now CTR's 0-3 should generate separate clocks with synchronized phasing.
-Kevin P.

Comment générer un train continu pour 2 conditions devant être réunies?(pci-6602)

Bonjour,
Je voudrais générer en sortie de compteur un signal de fréquence donnée, lorsque la gate en entrée de compteur est à l'état bas (par exemple) : jusque là, je sais faire.
Mais, je voudrais aussi que le signal généré ait son premier front descendant synchronisé sur le front descendant de la gate. Est-ce possible (carte pci-6602) ? Si oui, comment faire ?

Bonjour,
Je me permets de vous recontacter suite à votre question de synchronisation.
Je vous envoie le VI avec lequel j'ai travaillé (avec 6602). Il permet la génération d'un train d'impulsion (fréquence et cycle variables) lorsque la gate est à l'état bas. La synchronisation gate et sortie a lieu sur le premier front descendant de la gate. Cependant, le front descendant de la gate ne coïncide pas tout à fait avec le front descendant du train d'impulsion. Je m'explique : il reste un "retard" d'une demi-période correspondant à la généraion de l'état haut du train. Ce "décalage" a lieu étant donné que les paramètres d'entrées des fonctions sont des "polarités" et non plus des "fronts".
En espérant que cela réponde à votre question,
Cdt
Attachments:
Generate Pulse synchronization.vi ‏114 KB

Compteur PCI-6602

j'utilise un compteur sur la carte pci-6602 et comme source du compteur la timbase interne.
je voudrais que mon programme utilise une source externe , je voudrais savoir comment modifier mon programme .
pour qu'il compte en utilisant une source externe.
cordialement
SB
Résolu !
Accéder à la solution.

Bonjour,
J'ai un problème avec ma carte 6602 et a carte BNC-2121.
J'essaye de créer un signal de niveau sur une sortie digitale lorsqu'une condition est remplie.
Voici en pièce jointe lun exemple simple où je génère un nombre aléatoire et lorsque ce dernier est supérieur à 0.5 j'envoie un signal 5V sinon un signal 0V.
Lorsque je lance le Vi la première fois, tout fonctionne sans erreur.
Lorsque je l'arrête et le relance, j'ai le message d'erreur visible dans la pièce jointe.
Pourriez-vous me dire d'où ça provient? Je pense qu'il faut réinitialiser quelque chose mais quoi? J'ai du mal à trouver des exemples...
Notez que lorsque ça plante et que je lance un test avec MAX puis que je relance le VI, ça refonctionne.
Merci d'avance.
Pièces jointes :
error_DAQ.PNG ‏59 KB
Test_DAQ.vi ‏52 KB

PCI 6602:How can I use the digital lines of the board and in the same time to generate pulse train using a counter?

Hello!
My problem appeared when I tried to update my code from Traditional NI-DAQ Legacy to DAQmx.
I am using 2 counters (counter 5 and counter 7) from PCI-6602, to generate pulse train, and also the Digital I/O lines of the port 0 (the lines form 0 to 7). What I do in my application is that I am starting to generate the pulse train on the output of the 2 counters, and after that I am playing with the state of the digital lines.
In traditional there was no problem using the counters and the digital lines in the same time, everything was going perfectly, but in DAQmx this is not possible.
What happens: I start to generate pulse train on the output of the counters, no errors encountered, but when I try to modify the state of one line of the digital port the generation of the pulse train is stopped. This is happening when I start the task associated to the digital port.
My question is: it is possible to create a channel on the digital lines without altered the channels created for the counters?
Another thing what I manage to see using the "Measurement & Automation Explorer" and Test panels for PCI-6602, basically is the same thing, I generate pulse train on the output of the counter 7 and try to start a task on the digital line, but I get one error :
"Error -200022 occurred at Test Panel
Possible Reason(s):
Measurements: Resource requested by this task has already been reserved by a different task.
Device: Dev4
Terminal: PFI8"
Instead if I use the counter 0 or counter 1 to generate pulse train I don't encounter the same problem.
Which resources are used by the counters 2 to 7 from the PCI-6602 board and the counters 0 and 1 do not use?
Thank in advance for any replies!
Ciprian
Solved!
Go to Solution.

Hello Jordan, thank you for your reply.
I am sorry but I can not see or run your example, I don't use LabView, I use Visual C++ for developing.
Here is the code for generating the pulse train:
GeneratePulseTrain(unsigned long ulCount1, unsigned long ulCount2)
    short nStatus = 0;
    nStatus = DAQmxCreateTask("",&m_taskHandle);
    nStatus = DAQmxCreateCOPulseChanTicks (m_taskHandle, "Dev4/count5", "", NULL, DAQmx_Val_Low, 0.0, ulCount1,ulCount2);
    if( bTriggerMode == true) // if hardware trigger is enabled
       nStatus = DAQmxSetTrigAttribute (m_taskHandle, DAQmx_ArmStartTrig_Type, DAQmx_Val_DigEdge);
       nStatus = DAQmxSetTrigAttribute (m_taskHandle, DAQmx_DigEdge_ArmStartTrig_Edge, DAQmx_Val_Rising);
       nStatus = DAQmxSetTrigAttribute (m_taskHandle, DAQmx_DigEdge_ArmStartTrig_Src,"Dev4/PFI17" );
   //set the internal timebase
   nStatus = DAQmxSetCOCtrTimebaseSrc(m_taskHandle,"Dev4/count5","20MHzTimeBase" );
   nStatus = DAQmxStartTask(m_taskHandle);
    return nStatus;
And the code where I try to set the digital line:
SetChannelState(short nState)
    short nStatus = 0;
    uInt8 wrtBuf0[1]={0};
    nStatus = DAQmxCreateTask("",&m_taskHandle);
    // Configure line as output
    nStatus = DAQmxCreateDOChan (m_taskHandle, "Dev4/port0/line0", "", DAQmx_Val_ChanPerLine);
nStatus = DAQmxStartTask(m_taskHandle);
    wrtBuf0[0] = nState;
    nStatus =DAQmxWriteDigitalLines (m_taskHandle, 1, 0, 0, DAQmx_Val_GroupByScanNumber , wrtBuf0, NULL, NULL);
    nStatus = DAQmxWaitUntilTaskDone(m_taskHandle,10);
    nStatus = DAQmxStopTask(m_taskHandle);
    nStatus = DAQmxClearTask(m_taskHandle);
    m_taskHandle = 0;
    return nStatus;

Conceptual problem in using a PCI-6602?

Hi, All You Wild and Crazy NI/LabVIEW Types --
I have a problem that's been close to sending me off the deep end for more than a month now, and I think that I'm so enmeshed in it that I can't see the forest for the trees anymore. I'd like to apologize in advance for the length of this post, but there are some details that might or might not be important, and I'd rather make the mistake of giving you too much information than not enough.
We do impact-cratering experiments, using a gun to launch (usually) spherical projectiles at a variety of targets. One of our big efforts is to measure the velocities at which material is ejected from growing craters. We do that with a line-generating laser, oriented so the "sheet" of laser light is perpendicular to the target's surface and through the impact point; we strobe the laser at a programmed rate (with our PCI-6259 board) and take a time exposure of the scene with a Nikon D100 DSLR. When target material -- usually grains of sand -- is ejected, the laser illuminates a "slice" through the curtain of ejecta, illuminating a small portion of the fragments numerous times in their trajectories. Since we know the scale of the photograph and its orientation relative to the laser's illumination, and we also know the rate at which the laser is flashing, we can easily calculate the velocities of the illuminated particles. I'm attaching a picture (file 4044, cropped.jpg) of an example taken with an older camera to give you an idea. In the picture, the laser's illuminating the scene from the right of the frame and the projectile flew into the picture from the top of the frame, traveling along the left-hand edge. The brightest portion is the flash from the impact, and the rest of the parabolic trajectories are the grains of sand in flight. The target bucket, full of coarse sand, is the elliptical looking cylinder at the bottom of the picture. It's roughly 28 cm in outside diameter, if you'd like a scale.
As you might imagine, with our projectiles moving anywhere between 0.7 and 3 km/s, sequencing everything is pretty important. We're using (or trying to use) LabVIEW to do all of the sequencing, instrument control, and data storage. Things are going pretty well so far, except for what I'll describe in more detail below. A couple more things, though, first. It's important that we measure the projectile's speed in each shot, as that controls impact energy and momentum, which are critical to know in a given experiment. We do that with simple laser-photodetector pairs (which we normally call "velocity stations") arranged along the projectile's trajectory. As the projectile passes between a laser and its detector, its shadow is detected and a TTL pulse is sent to our PCI-6602 board. Depending on the experiment, we use three or four such laser-dector pairs. They use counters 0, 1, 2, and 3. We know the distances between the laser stations and, once we get the times between detections, it's s simple matter to calculate the projectile's velocity.
We also use LabVIEW to fire the gun, and we do that because opening the camera's shutter has to be synchronized with the firing pulse, which currently is sent via P1.1 on the 6259. Here's the problem: when we test the laser-detector arrays in a "standalone" mode (that is, without any other tasks or operations being done with LabVIEW), they work infallibly. It's when we try to use LabVIEW to fire the gun that we get either very erratic results from the velocity stations/6602 or no results at all.
I've tried a range of things, from starting the two-edge measurement task before the firing signal is sent, to trying to force things with a timed sequence, to doing things with brute force via a seuqence structure. When I try to start the two-edge measurement task first, though, the firing signal isn't sent until the counters time out. This of course, wrecks the experiment, because all of the timing is then messed up. The VI that I've attached (Version 1.vi) is a HIGHLY simplified version of the initial attempt I made at doing this, with all sorts of background stuff removed just so I can cut to the chase. (Only one two-edge measurement task is shown, for instance.) I think that the VI is pretty self-explanatory (and embarrassingly primitive), so it probably doesn't need much in the way of explanation. Counter 7 and PFI 0 on the 6602 are used to accept the signal from the firing button and trigger the event structure, which contains the two-edge separation and gun-firing tasks. (In reality, I use a separate VI to have three to four concurrent two-edge separation tasks running concurrently, one for each velocity station.) I start the two-edge separation tasks first so the detectors and counters are ready for the projectile. It's not necessary here, but I kept the 500 ms wait frame in this example because that's why the sequence structure exists -- to allow the shutter of the Nikon to open completely before the gun fires. After those 500 ms, the firing signal is sent to the circuit that actually fires the gun.
What happens in this configuration is that the second frame of the sequence structure doesn't execute until the 5-s timeout transpires in the two-edge separation task. I've also tried this using a line on the 6602 to fire the gun instead of P0.1 on the 6259, but that ends up with the same result. (Both counters are used on the 6259 to strobe the main illumination laser, so they're unavailable, if you're wondering. In any case, we need four counters for the four velocity stations.)
FINALLY, my question: What am I doing wrong, here? If I put the two-edge separation tasks in the same frame of the sequence structure as the firing task, the gun fires when it's supposed to, but we get no velocity measurements. I've also tried to force the timing with another version of a sequence structure; I'm attaching another very simplified version below as Fire and speed example.vi.
After you recover from your violent fits of laughter, I'd really appreciate hearing what you might recommend. (And no, surrender isn't an option.)
Thanks for taking all of your valuable time to read this huge post -- I really appreciate it!
Mark
Attachments:
4044, cropped.jpg ‏197 KB
Version 1.vi ‏35 KB
Fire and speed example.vi ‏30 KB

I agree with all 3 of Kevin's points. His first suggestion will probably fix your problem (see below). The 2nd and 3rd suggestion would improve efficiency and responsiveness, but #2 might not be possible since independently triggering four outputs in hardware would require the use of 4 counters (on the 6602 anyway) which might be busy doing other tasks in your application (although if you don't need the stations to trigger independently then you could implement this with a single counter).
I think I have an explanation of the problematic behavior you are seeing based off of the following bits of information from your post:
1. Running the small example code by itself works flawlessly, but adding other simultaneous functionality fails. You mentioned you are doing this on 4 stations, so I'm assuming 4 counter input tasks running in parallel.
2. The behavior you are seeing is that the 2nd sequence does not execute until after the read times out (note that the sequence is supposed to be executing in parallel with the read).
It sounds like the problem is coming from a combination of calling into DAQmx Read before data is available (this consumes one of the threads that LabVIEW has allocated to your application until DAQmx Read finishes executing) along with the fact that LabVIEW allocates 4 threads per execution system per priority by default. Since all of your threads (from what I can tell) are executing on the same priority, the 4 reads you are calling will block anything else from executing until they have completed. By then it's too late and the firing of your gun happens after the counter task has already timed out.
You *may* increase the number of threads allocated to your application by using a VI that is included with LabVIEW (vi.lib\Utility\sysinfo.llb\threadconfig.vi) and this would also probably remedy the behavior you are seeing. However, rather than throwing more threads at this application I think the better solution would be to change the sequencing of your tasks like Kevin suggested ("create and start the 2-edge task before entering the sequence structure, and defer the 2-edge *reading* until *after* firing the DO")--in doing this you would now expect to see data immediately upon calling DAQmx Read and you avoid the situation where Read is blocking indefinitely and consuming an application thread. You could take this a step further by checking the Available Samples per Channel property (or using the DAQmx EveryNSamplesAcquiredIntoBuffer event) to ensure that data is actually available before calling Read.
Best Regards,
John Passiak

Maximum number of PCI-6602 cards in 1 computer?

Is it possible to have 4 PCI-6602 cards in 1 computer?
Are there any DMA channels or IRQ limitations we need
to worry about?
Our computer will have 1 graphics card in the AGP slot,
possibly a PCI NIC ethernet card and possibly a PCI
based sound card. It will also have an IDE controller
with 2 hard drives and 1 CDRW.
The PCI-6602 manual seems to imply that if you are
using more than 3 counter channels that you must
use the slower Interrupt based transfer mode which
has a maximum transfer rate specified as 2000
Reading/second. If there are 4 PCI-6602 boards in
the same computer and all 8 of the channels are
used on each board does that mean the total
transfer rate is still 2000 Readings/sec? Or
wo
uld the total transfer rate be 8000 Readings/Sec
since there are 4 PCI-6602's (2000 Readings/Sec
for each of the 4 PCI-6602's)?

Hello;
The only concern you need to have is the number of IRQs available. As far as DMA channels, as the PCI bus itself has only 3 DMA channels available, all the devices that use DMA will share those 3 channels. But, as IRQs can't be shared, the number of counters you will be able to use will be the exact number of available IRQs you still have on your machine.
As far as transfer rate, the maximum transfer rate will be 2000 Readings/sec, regardless the number of counters you are using.
Hope this helps.
Filipe

How to generate a pulse on x number of events PCI-6602

I am running LabVIEW 5.1 full development with a PCI-6602 counter board.
I would like to generate an output pulse after counting x number of input pulses. I would also like to reset the counter with an external signal.
My application is I am trying to generate a second index pulse for an encoder.
I would like to count the pulses from encoder phase A and generate an output pulse on x number of counts. Then I would like to reset the counter using the encoder’s index pulse. This way I can change the phase of the “generated” index pulse with respect to the “real” index pulse by x number of counts (degrees) and maintain that regardless of encoder rpm.
Thanks
Brian

Brian,
There actually is a way to do what you want, but it gets a little complicated. I don't have LV on this machine so I'll have to just describe the idea. First a summary: the counter will repeatedly countdown to 0. Each time it reaches 0, it will generate a brief pulse which will in turn hw-reset the counter value to N. Then it will countdown to 0 again, etc. The same brief pulse could also be wired to a different encoder-measuring counter to create a "delayed" reset to 0 (or some other #).
1. Configure your counter for "position measurement" instead of "simple event counting". Set the encoder type to, um, I forget the name -- something like "two pulse encoder." It's the setting that will increment with every SOURCE edge and decrement with every AUX edge. Wire your encoder channel A to the counter's default AUX input (in position encoder mode, you must use the default input pins). Hard wire from the default SOURCE input to GND. Now every encoder edge will decrement the count, and nothing wlil ever increment it.
2. Configure the counter to use z-indexing. Set the z-index reload value to be N-1, where N is the # of encoder counts by which to delay the encoder's real z-index pulse. Set the z-index reload phase appropriately, probably to A low B low. Wire the real z-index pulse to the counter's GATE input.
3. Configure the counter to "pulse on terminal count" -- you do this using 'Counter Set Attribute.vi'. So N encoder edges after the real z-index pulse, you'll generate a pseudo-z-index with this counter.
4. You can wire this pseudo-z-index to the GATE input of the encoder-measuring counter. Now the encoder's z-index pulse is delayed by an amount you can program.
5. Note: this method requires the motion to be uni-directional.
Good luck!
-Kevin P.

Count digital events on a Counter with pci-6602 with callback on CVI

Hi,
I'm using a PCI-6602 card with CVI 8.5 and I need to trig on event.
On every pulse I received, I need to do some actions like increasing a counter, send a message on Rs232 etc.. I don't want to do any loop checking that the counter value has changed. I would like to use a callback to execute this code only on the edge or counter value event.
My problem is that I don't know which function can do this. Is there any way to get an event on a pci-6602?
Thanks
James
Solved!
Go to Solution.

Hello.
It's completely possible to create a callback that will allow you to do what you want when a edge will occur on an external signal you define.
To do this, you can for exemple create a counting edges task that will use one of the 6602 counters,and the set your external signal to be the source of your sample clock.You'll then be able to register a callback with the function DAQmxRegisterSignalEvent, and your callback will be called each time an edge will occur on your specified sample clock source.
Here's 2 links that explain the events in DAQmx and how to handle them in CVI. The example ReadDigChan-ChangeDetectionEvent.pr that ships with DAQmx examples (Hardware Input and Output<<DAQmx<<Digital measurements) can be very useful to understand how to do. This example creates a signal event callback to detect change detection for digital inputs.
Regards.

Sharing an external sample clock between PCI-6722 and PCI-6602

I need PCI-6602 work with PCI-6722。6602 shares 6722’s ao/SampleClock as external clock and triggered by 6722’s ao/StartTrigger。The master device is 6722, which refered as Dev1, and the slave device is 6602, which refered as Dev2. A RTSI line is used to connect the two devices correctly.
I use C API to finish my program and my code is as follows:
//config 6722 analog out task
1、DAQmxCreateTask("NI6672", &hAOTask);
2、DAQmxCreateAOVoltageChan(hAOTask, "Dev1/ao0", "", -10.0, 10.0, DAQmx_Val_Volts, "" );
3、DAQmxCfgSampClkTiming(hAOTask, "", 1000.0, DAQmx_Val_Rising, DAQmx_Val_ContSamps, 1000);
4、DAQmxWriteAnalogF64(hAOTask, 1000, 0, 10.0, DAQmx_Val_GroupByChannel, data, NULL, NULL);
//config 6602 counter task
5、DAQmxCreateTask("NI6602", &hCounterTask);
6、DAQmxCreateCICountEdgesChan(hCounterTask, "Dev2/ctr0", "", DAQmx_Val_Rising, 0, DAQmx_Val_CountUp);
//use /Dev1/ao/SampleClock for external clock
7、DAQmxCfgSampClkTiming(hCounterTask, "/Dev1/ao/SampleClock", 1000.0, DAQmx_Val_Rising, DAQmx_Val_ContSamps, 1000);
//use /Dev1/ao/StartTrigger
8、DAQmxSetTrigAttribute (hCounterTask, DAQmx_ArmStartTrig_Type, DAQmx_Val_DigEdge);
9、DAQmxSetTrigAttribute (hCounterTask, DAQmx_DigEdge_ArmStartTrig_Src, "/Dev1/ao/StartTrigger");
10、DAQmxSetTrigAttribute (hCounterTask, DAQmx_DigEdge_ArmStartTrig_Edge, DAQmx_Val_Rising);
//start counter task first
11、DAQmxStartTask(hCounterTask);
//start 6722 task
12、DAQmxStartTask(hAOTask);
I run it on the MAX virtual Device, and the Step 11always returned -89120。
I try to slove this problem, so I change the Step 7, use /Dev2/PFI9 to instead of /Dev1/ao/SampleClock.
7、DAQmxCfgSampClkTiming(hCounterTask, "/Dev2/PFI9", 1000.0, DAQmx_Val_Rising, DAQmx_Val_ContSamps, 1000);
The code runs well, but I don’t know which terminal is connected by /Dev2/PFI9. Does it connect to /Dev1/ao/SampleClock？
I use another API DAQmxConnectTerms to ensure that, I add a Step before Step 11.
DAQmxConnectTerms( "/Dev1/ao/SampleClock", "/Dev2/PFI9", DAQmx_Val_DoNotInvertPolarity );
The program also run well. But I am still not sure that 6602 is sharing /Dev1/ao/SampleClock。If not, which terminal of Dev1 is connected by /Dev2/PFI9?
Is my code right? If not, hwo to fix my code or supply some example for me? Thanks.

Hello Shokey,
From looking over your post, it looks like you want to program in C, using simulated instruments, a master/slave design with a PCI-6602 and PCI-6722. The PCI-6722 is the master device and the PCI-6602 is the slave device. In order to implement this with the real cards, you would need a RTSI cable between the 2 cards in order to pass the triggers and the sample clock. Unfortunately with simulated devices you can't implement this so parts of your code won't be able to work exactly like if you had the instrument.
If you did have the instrument, you can implement this by performing the following steps:
Master Device:
1.) Export the ao/SampleClock and ao/StartTrigger to a RTSI Line. (See DAQmx C Reference help for DAQmxExportSignal to export these)
Slave Device:
1.) Set the Sample clock and the trigger to the RTSI.
There is another forum that I think will help you out to implement this correctly. In this forum, the customer was trying to export a trigger through a RTSI and the problem he was experiencing was a broken RTSI cable. His code, he states, works. I hope this helps you with this and if you have any more questions, feel free to post.
Jim St
National Instruments
RF Product Support Engineer

Continuous pulse train generation on my PCI 6602 takes up too much of my system resources.

I am using a PCI 6602 to generate a clock signal that is to synchronize pattern generation on two PCI 6534's. I have done this by generating a pulse train at a user defined frequency on the PCI 6602. My problem is when I generate this pulse train, the program uses all of the computer's CPU, and slows the rest of the processes down. Just to let you know, I have isolated this program to ensure it is the only thing running, and it still has the same result. The CPU usage soars to 100%(and remains constant) and the memory consumption increases (and remains constant) as well. Also, if it helps at all, the CPU consumption is completely independent of the frequency that is being gene
rated, but the memory usage increases a little with an increase in frequency. Does anyone have any insite as to how to fix this, for I have noticed that all of the posted examples like this behave in the same manner.
Thanks,
Dave

Russell,
Thanks for the reply. Just about five minutes ago I came to the realization that the card itself was not causing this to happen. When I took a closer look, I found that my C program and all of the example programs were using the NIDAQWaitForKey() function to enable countinuous generation. So what was happening was that function was constantly polling the CPU to find a key to be pressed. So lets just say I found a way around this problem, and so everything is well. There are a handfull of things that i need to work on now, but at least I know my clock generation program is correct and I can stop banging my head against a wall trying to solve a problem that does not exist and for which there is no solution.
Thanks Again,
Dave

How to visualise continues Data aquisition from a PCI 6602 with 2121 BNC connector board in C++ ?

Hello everyone,
We are trying to get on the screen the aquired pulses from our PCI 6602 with a 2121 BNC connector board, from several devices. We are able to read the data and save without problem, but we cannot look at it while we are measuring. Anybody has an idea to how program this in C++ ? Any suggestion is welcome!
Thanks for the help

Hi,
try to look for some example programs and Tutorials:
Examples Results
http://search.ni.com/nisearch/app/main/p/bot/no/ap/tech/lang/en/pg/1/sn/catnav:ex/q/DAQmx%20C%2B%2B/...
Tutorials Results
http://search.ni.com/nisearch/app/main/p/bot/no/ap/tech/lang/en/pg/1/sn/catnav:tu/q/DAQmx%20C%2B%2B/...
You should also have a look at the "C Reference Help" which is installed with the NI DAQmx driver.
Acquire N Scans (Visual C++ 6.0, CW++, NI-DAQ)
http://zone.ni.com/devzone/cda/epd/p/id/207
Continuous Analog Acquisition with Producer Consumer Architecture in C#
https://decibel.ni.com/content/docs/DOC-4253
Good Luck!
Matteo

Connect NI PCI-6602 with NI PCI-6503

Hello,
I want to connect a NI PCI-6602 Counter/Timer with the NI PCI-6503 DIO-Card. The problem is the varying number of pins. (6602->68 pins; 6503 -> 50 pins). Is there a possibility to connect both? Maybe a complete adapter?
regards Thomas

Thomas,
You are correct both cards have male connectors. You could still use the 68M-50F connector if you use a 68-68 cable. Or if you had a 68F-50M then you would need a 50 pin cable. I have found another option, the R6850-D1 Cable(part number 777419-01) . This is a digital cable that was made to use our 68 pin digital devices with 50 pin breakout boxes. It ties the ground lines together and you also loose access to PFI 37,the up/down pin for counter 0, and you loose the +5V line. I think you may want to check the pin mappings to make sure that you really want to connect these 2 boards directly together. When using a 50 pin conversion with the 6602 you will get the following pin mapping:
Pin Number (1-50) 6602 Signal Name
1 PFI_25
2 PFI_28
3 PFI_27
4 PFI_24
5 PFI_30
6 PFI_31
7 PFI_26
8 PFI_29
9 PFI_21
10 PFI_23
11 PFI_19
12 PFI_17
13 PFI_18
14 PFI_16
15 PFI_22
16 PFI_20
17 GND
18 PFI_34
19 GND
20 PFI_35
21 GND
22 PFI_33
23 GND
24 PFI_32
25 GND
26 GND
27 PFI_38
28 GND
29 Reserved
30 GND
31 PFI_36
32 GND
33 PFI_39
34 GND
35 PFI_4
36 PFI_6
37 PFI_0
38 PFI_2
39 PFI_1
40 PFI_3
41 PFI_7
42 PFI_5
43 PFI_13
44 PFI_10
45 PFI_15
46 PFI_14
47 PFI_8
48 PFI_11
49 PFI_12
50 PFI_9
You will loose half of the cards functionality since half the pins (even numbered pins) will be connected to ground on the 6503. It would be easy for you to short lines to ground this way. It would probably be better if you get a breakout box for each card (SCB-50 and SCB-68) and then connect only the lines you want to share between the cards. So in answer to your question, yes you CAN connect then directly together, but do so with caution, and I do not feel this direct connection is the best solution for y
ou.
Hope this helps.
Kevin R

NI PCI-6602: semi-period measurement stops unexpectedly or returns wrong values

Hi,
Using an NI PCI-6602 card we try to measure the semi-periods of a digital signal.
In "continuous sampling mode", 10 samples are collected in the buffer and then are read
out.
Up to 6 counters on this card are sampling the same signal in our testing configuration.
Here we found these issues:
1. Failure
In principle, the measurement runs correctly, but one or more counters sporadically may
suffer a complete failure. I.e. these counters don't provide samples anymore.
Only after stopping and restarting the assigned task, a failed counter works again.
Apparently, a counter failure is most likely to happen when
    - the sampled signal "changes", i.e. when the pulse width of the signal changes,
    - or when the computer load is high, e.g. when opening a window of another application.
Every counter occasionally failed, but the issue was found very often at counter 1 of
the PCI-6602 card, if we used counters 0 through 5 in parallel.
Using another PCI-6602 card, the failures happened preferably on counters labeled "near"
number 5.
2. Wrong values
Occasionally the "interpretation" of the sampled values changes, i.e. the length of the
"high level" period is returned, where the "low level" period length should be given, and
vice versa.
This is our task configuration:
Configuration done with MAX:
Signal input range:    2 usec - 2 sec
Custom Scaling:        None
Sample mode:        continuous
Buffer size:        10 Samples
In addition these calls are made:
ret = DAQmxSetDigEdgeArmStartTrigSrc( task->mHandle, <use the same terminal as is used for
the signal to be measured>);
ret = DAQmxSetArmStartTrigType( task->mHandle, DAQmx_Val_DigEdge);
ret = DAQmxSetDigEdgeArmStartTrigEdge( task->mHandle, DAQmx_Val_Rising);
ret = DAQmxSetCISemiPeriodStartingEdge( task->mHandle, <the channel>, DAQmx_Val_Falling);
Best regards
Manfred

Hi Manfred7,
did you already test this behaviour with a simple example from us?
Just go through the example database and try the examples there.
These examples should work.
If it works, there is a problem with your programm.
If it won't work, please tell me more about your software:
- Version
- DAQmx Version ,...
best regards
Dippi

Division de fréquence : problème ? (pci-6602)

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