Count out of pulse train on 6025E,labview(pc)

hi!!
I need monitoring continuos count out from
puse train on mine 6025E
Thanks for all

If you are generating a continuous pulse train then you are probably using only one of the counters on the 6025E. Depending on the speed of the pulse train being generated, you will want to use simple event counting or buffered event counting. There are shipping examples within LabVIEW that perform both operations. The Count Edges (DAQ-STC) VI would work if the pulse train was slow enough. If the pulse train has a high frequency, you will want to use the Count Buffered Edges (DAQ-STC) VI so you'll be sure not to miss any edges. I hope this helps.
Regards.
Todd D.

Similar Messages

Retriggerable gated counter or analog pulse trains

Hi all,
I have a problem I could not resolve in the last days. It might be even a question of creativity of how to come up with a solution.
I have an external pulse train 1 at ca. 8 kHz (frequency not fully stable). With this pulse train, I want to trigger with each pulse an analog waveform. Using X-series boards, this works perfectly.
But now I want to gate this analog signal with another pulse train 2 that is much slower than the other one (pausetrig option). Theoretically, this works nicely, too. But in reality, the analog signal simply ends at the point where it is stopped by the pause trigger, whereas I want it to stop at the end point of the waveform.
Please have a look at the drawing attached
I would be really glad about any ideas on how to solve this problem.
Best regards,
Peter

I don't think I've ever defined both a start trigger and a pause trigger defined for the same task. Good to know it's allowed.
Given what you've already found, the solution is to control the timing of the end of the pause trigger pulse's active state (shown here as high).
Here's one approach:
1. Create the pause trigger pulse with a retriggerable single pulse task. Use a minimal "low time" and "initial delay". Set the high (active) time to be approximately (N+1) periods of your AO sample clock.  Technically, N+1 periods is a bit more than necessary, but it's sure to be enough and doesn't require research into deep details of AO timing.
2. Configure the AO task to use the pulse as *both* its start trigger (rising edge) and its pause trigger (pause when low).
Comments: this makes for a different timing diagram than you've drawn. Each external 8 kHz pulse causes a minimally-delayed pause trigger pulse which lasts long enough to generate the full AO waveform but ends before the next 8 kHz pulse. The choice of when to start and stop this trigger pulse will be up to your own logic and will be governed by software timing.
   Oh dang! That still leaves you susceptible to a partial waveform since you can't sync the software timing to occur during the desired small fraction of the 8 kHz interval with no AO waveform.
Second approach:
1. Similar to #1 above, but set the high (active) time to cover multiple 8 kHz periods and *don't* make the task retriggerable. To get the timing right in hardware, you'll need to generate a pulse that's *approximately* the requested length, but you'll reserve the right to tweak it so the edges fall in the right place.   You'll also define your pulse in terms of the external 8 kHz signal rather than in terms of internal board time.
     Specifically, configure to generate a pulse based on units of "Ticks" using the rising edges of the external 8 kHz signal as the "source of ticks." Set a minimal value (probably 2) for both the "low ticks" and "initial delay" inputs. The "high ticks" setting is where you do your tweaking.
    Suppose the desired pause trigger time is 10.3 msec. Nominally, that's 82.4 intervals of the 8 kHz external signal. Well, just round up or down as you see fit and wire this integer # into the "high ticks" input.
2. AO task is configured to retrigger off the external 8 kHz signal and be pause triggered by #1's counter pulse.
Comments: When you start the pause trigger pulse task, it will remain in its low idle state for the first two 8 kHz pulses. It will go high on the 3rd pulse and then revert low on the 82nd subsequent pulse.
   Because this pulse *also* acts as a pause trigger for the AO task, you're now synced such that the AO task is paused exactly as it is being retriggered, meaning that the previous waveform must have been allowed to complete. (The deep details of timing will prevent the AO task from generating 1 sample at this instant.)
-Kevin P

Pulse train on 6024E, Labview (PC)

Hi,
I was wondering if it's possible to change
the output frequency (GPCTR0) without the
output going low for a few milliseconds.
I am using the 'pulse config' and 'counter start'
vi when I need to change the frequency. I plan
to use this setup to calibrate speedometers and
tachs. It would be nice if I could stop the needle
from trying to jump to zero every time I have to
change the drive frequency.
Somewhere in the manuals is mentioned that the
parameters of the DAQ-STC can be changed 'seamlessly'.
I tried (in vain) finding this section again.
Any advice would be welcome.
thanks,
Walter

Thanks John,
I hope to try it today. Will let you know how it
goes.
Walter
John Lum wrote:
>
> Walter,
>
> I'm not 100% sure if this example will eliminate the dead spot during
> counter reconfiguration or not, but I think it might:
>
> http://digital.ni.com/explprog.nsf/websearch/b679344977a79f708625675100466034
>
> ("Pulse Width Modulator for LabVIEW" on the NI example programs site)
>
> It should work with your E Series card.
>
> Regards,
> John Lum
> National Instruments
>
> > I was wondering if it's possible to change
> > the output frequency (GPCTR0) without the
> > output going low for a few milliseconds.
> >
> > I am using the 'pulse config' and 'counter start'
> > vi when I need to change the frequency. I plan
> > to use this setup t
o calibrate speedometers and
> > tachs. It would be nice if I could stop the needle
> > from trying to jump to zero every time I have to
> > change the drive frequency.

Can daq 6035e,or 6024e used to count pulse train

i need to count two digital pulse train coming from an encoder, whose frequency keeps changing. the encoder is a typical feed back from servomotor

Hi,
Both of those DAQ boards can measure digital pulse train frequencies using the counters. These cards can support 2-pulse encoder measurements on DIO6 and DIO7. This means that if there is a rising edge on Channel A the counter increments and a rising edge on Channel B decrements the count. You can also set the counter application for frequency measurement and that will measure the frequency of the pulse train on the line. These cards also have 2 such counters.
There are many LabVIEW and CVI examples demonstrating this. If you search the site for position or encoder measurements there should be some example programs for you. Hope that helps.
Ron

Need to unreserve a counter in a finite pulse train generation

Hi. Let´s introduce my application first: I´m trying to generate a N-pulse train with the M series PCI-6221, in order to achieve a high frequency clock for an SSI transducer. That´s why i can´t use a software generation (because of the high frequency) and i have to use a finite pulse train. Besides, I would need to use another counter for a variable and finite count (but not simultaneously). The problem is that, as i think i have understood, this finite pulse train involves the two counters working together, so I can´t programm another task with that resources.
My question is, Is there any way to do the finite pulse train generation, unreserve the counters, wait for a finite count to finish and so on?
Thanks.

Hello,
My knowledges tell me that you need two counter to generate a finite pulse train.
The first counter generates a pulsed of desired width and the second counter generates the pulse train which is gated by the pulse of the first counter (Counter 0=Pulse Generation, Counter 1=Pulse train generation).
However, the finite pulse train generation and the continuous pulse train generation seem similar. The key difference is the generation mode from continuous to finite and the use fo a DAQmx Wait Until Done vi instead of a loop to monitor user input. From a point of view of the hardware there is a difference between the two. Continuous pulse train generation requires only 1 COUNTER.
Maybe you can try with a continuous pulse train generation and with this method you have another counter to do a finite count.
Regards
DiegoM.

Hello, I would like to produce 2 different pulse trains on the CTRo and CTR1 output pins.

(DAQ-CARD E6024 PCMCIA)I have the 2 output pins monitored on my scope, when CTR0 puts out a pulse train, CTR1 goes high. When CTR1 puts out a pulse train CTR0 goes high. Also, the pulses are interleaved with each other. Is there a way to make then start at the same time
Attachments:
Stim_Output_pulses_CTR_0,1.vi ‏94 KB

Hello Zoltan,
I would suggest using the counter gates to synchronize the counters. You will need to externally run a wire from one of the DIO lines you're not using to one of the counters' gates. When the counter gate is high, the pulse train will be generated on each counter. Both counters will need to use the same PFI line as the gate.
There is an example program that ships with LabVIEW 7 called "Gen Dig Pulse Train-Continuous-Pause Trigger" for DAQmx. This demonstrates how to configure the counter to only generate the pulse train when the gate is high.
With this configuration, you could synchronize the counters by writing to the DIO line which is wired to one of the counter gates when you're ready to start the pulse train generation.
Hope t
his helps.
Kristi Hummel
Applications Engineer
National Instruments

Generating multiple Pulse Trains.

I am trying to generate two different pulse trains. Once the first pulse train has begun I need to start the
second pulse train approximately .69444 ms after the first has started. I am currently using the two counter channels on the NI ELVIS, but the second pulse doesn't always start after the first, but it does work sometimes. How can I fix this? Attached is my vi file.
Thanks,
David
Note: Each pulse train has a 33% duty cycle.
Attachments:
SaO2.vi ‏91 KB

Hello,
Here is what I would try:
1. Set up counter 0 to perform a continuous pulse train (see the LabVIEW example called Gen Dig Pulse Train-Continuous.vi)
2. Set up counter 1 to perform a continuous pulse train with a digital start (see the LabVIEW example Gen Dig Pulse Train-Continuous-Dig Start.vi)
A. Modify this example code so that the trigger source is your counter 0 output.
B. Modify this example code so that the initial delay value of the pulse train is 0.7 milliseconds (or whatever delay you want). Create the delay with the input to the DAQmx Create Channel VI (the delay is currently set with a default of 0.00 seconds).
What you are doing is triggering the second counter off of the rising edge of the first counter. So, counter 0 will start generating a pulse train. Counter 1 will not start until the rising edge of counter 0's first pulse has occurred. Once this trigger has occurred, Counter 1 will start (after the initial delay time of 0.7 ms has passed). You can cut and paste to put the code of the two examples together.
Hope this works for you,
Sam

Using a SCC counter pulse train to control a SCC digital out signal

I am trying to send a digital high signal on a SCC-Digital ouput module for a certain number of pulses generated by a SCC-Counter/timer pulse train. I have found examples of how to route such signals through PFI12 etc on an M-series board but I am trying to achieve this without referring to the card, just the SCC modules themselves.
I cannot find a way to use the sample clock from the counter generated pulse train to synchronise the digital output.
Is there any way I can do this without referring to the connected M-series DAQ card channels?
Thanks in advance for your assistance.
Cheers.

Hi Phil,
The SCC carrier is only conditioning your signals (i.e. if your signals are not in optimal ranges, bandwidth or need external excitation). The actual counters and all digital lines are controlled directly by the M-series board. This means you will never be able to refer to a counter in the SCC module.
If you route the signals of the M-Series board, is as if you had done so externally from the SCC. Look at this example and might give you more insight to how to implement it (This is software timing). The hardware timing would be doing correlation DIO. Here is an example that needs to be modified to adapt to your timing: http://zone.ni.com/devzone/cda/epd/p/id/4414
Hope this helps,
Yardov
Gerardo O.
RF Systems Engineering
National Instruments
Attachments:
Finite Dig Output High.vi ‏31 KB

Can I generate pulse trains on more than one counter output at the same time?

I have a PCI 6601 card with a BNC 2121 to connect the signals to two devices. The card is used as a trigger for both devices and I want to be able to generate pulse trains on two output channels at the same time, with a time delay between the two. How do I do that in Labview 7.1 Development with DAQmx?

I feel foolish for not being able to figure this out, but it still doesn't work. Attached is the VI I use now. Counter 0 generates a finite pulse train and I programmed Counter 1 to generate a retriggerable single pulse triggered by CtrOinternaloutput. I still get the same error message: -50103 The specified resource is reserved. The operation could not be completed as specified.
The same happens if I set the trigger for counter 1 at PFI36 (default output of counter 0) or any other PFI line. If I try a pulse train generation on only one of the counters, both work fine.
If I try the example in traditional DAQ for multiple counter outputs with phase delay, it works fine.
Can you tell me what I'm doing wrong?
Attachments:
Shutter_AND_lamp_trigger.vi ‏103 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;

Finite pulse train, stop and count

Hi, i'm using Labview 8.2 with a DaqCard-6063E on Windows Vista. I generate a finite pulse train with a possibility to stop when ever I want, but how do I do to count the number of pulses?
(The application going to drive a stepper motor forward/backward so I need the number of pulses)
/Pelle

I think you probably mean the 6036e, right? I've got 2 basic ideas for you:
1. Always generate continuous pulses and always count on using your software to decide when to stop. This is *probably* not the solution you want, but it would make life simpler if you can live with it. The reason is that continuous pulse trains only require 1 counter so you can just count those pulses with the 2nd counter. Finite pulsetrains use up both counters. I suspect you need the finite pulsetrain though to define a nominal exact distance, but in case your software decides you must stop prematurely, you'd like to know where you are.
2. Configure an AI task or an AO task that uses your counter output as its sampling clock. Then you can query the AI/AO task for a property like "Total Samples Acquired" or "...Generated" to get your step count. You would do the query with a DAQmx property node -- either a Read or Write property node if I recall correctly (not presently near LV to check). Note also that you should start your AI or AO task before starting the Counter task, and if you stop the counter task, do your query before stopping the AI / AO.
-Kevin P.

Finite pulse train generation... how to count number of pulses?

hi guys,
this has probably been solved a hundred times but i just couldnt find it!!
i have a pulse train generation happening on my ni usb-6211... using FREQ OUT, using a divisor on this, and routing it to PFI4.
id like to update my VI so i can specify the number of pulses....
im pretty much a noob at this stuff so any help would be greatly appreciated!! thanks!
dan
Attachments:
pulse train generation.vi ‏25 KB

Hi,
No problem at all, we are here to help. What I’m going to do first is to point you to a bunch of examples for that might give you a better insight of the capabilities of the card in terms of finite pulse generation. What you should be looking at is called retriggerable pulse generation and here are some examples to look at: Retriggerable Finite Pause Trigger Digital Pulse Train Generation, Creating a Delayed, Retriggerable and Finite Pulse Generator, DAQmx - Retriggerable Pulse Train Generation - LabVIEW - CVI - ANSI C - VB.NET - C#.NET and Retriggerable Finite Pulse Train with Changing Pulse Specs.
Let me know it helps
Jaime Hoffiz
National Instruments
Product Expert
Digital Multimeters and LCR Meters

Can't get DAQcard-1200 to put out pulse train.

These Nat Instruments cards are supposed to be easy but nowhere
can I see how to get started. The manuals LV and card don't have
enough info.
I tried to use the Pulse Train VI to put out a square wave on
counter 0 and I get:
Error 10403 occured at CTR Group Config. NI-DAQ LV: The
specified device does not support the requested action ( the driver
recognises the device but the action is inappropriate for the device)
I have the inputs wired as follows:
gate mode: ungated/software
pulse polarity: high
device: 1
Counter:1
number of pulses:0 continuous
frequency: 10000
Anybody got any clues?

thank you, Charlie!!!!!!
i'm so mac ignorant and have been learning a lot through my mistakes today! your solution also helped me get the fan option back on as well!
Thanks again!!!

How to generate a bipolar pulse train in LabView using USB DAQ 6211?

Hi,
I am setting up a system to generate either a single square pulse or a train of square pulses using LabView, with controls to adjust the frequency, amplitude, number of pulses etc. I have had a lot of help from NI tech support setting up the actual VI itself which seems to be working fine, and outputting the pulses via a USB DAQ 6211 using a square waveform generator and the AO1 channel on the DAQ.
The problem that I now have is that I need to pulses generated in a train to be bipolar (as they are connected to electrodes so need to be bipolar o avoid salt build up on the electrodes from the voltage going in one direction only, at least that is how I understand it!).
How can I set up my LabView VI to generate a bipolar pulse train instead of always being positive voltage? I am new to this area and so am trying to learn but there is so much to learn!
Thanks,
spamjam

Hi Shalini,
Apologies for taking a while to get back to you, I hope I can explain what it is that we need to create with the pulses. I understand what you mean about the existing pulses having a positive and negative on the graph - but we need the pulses to start from a resting voltage and the first pulse to be positive, then back to zero, then the second pulse to be negative then back to zero etc. This is to do with reversing the direction of the current between two electrodes to prevent build up of salts on one electrod from the current always passing in the same direction.
I have attached a .Tif file to this post to try to illustrate what I mean - the top picture shows how the pulses are currently generated, then bottom on is what we would like to produce if this is possible?
Thanks for your help,
Spamjam
Attachments:
Slide1.jpg ‏38 KB

Counter/Timer Pulse Train generation

Hello,
I am having some trouble understanding why a particular VI I have isnt working(upper part of image below), I was wondering if someone could give me an idea of the cause from the error message. I have a counter/timer which I am using to generate a pulse train. It works fine on 'Continuous samples' but when I switch it to 'finite samples' I get a 'resource is reserved' error when it gets to the DAQmx 'Play' VI
I made a separate VI (lower part of image) and it works just fine with finite samples. So I am basically wondering what is different about finite versus continous sampling which could cause a resource to be reserved or not. (the board is a PXI 6281 if that matters)
Thanks,
Adam
Solved!
Go to Solution.

You're correct on what the problem is.
For what it's worth, the newer X Series boards (63xx) and 2nd Generation Compact DAQ Chassis don't require the use of two counters for finite pulse generation (although technically there is a paired internal counter to accomplish the finite pulse generation, it's not really evident to the user). These products also have 4 counters available instead of 2.
Best Regards,
John Passiak

Count out of pulse train on 6025E,labview(pc)

Similar Messages

Maybe you are looking for