Real-time accurate digital pulsing

[qComputing]

We use the NI-6220, and the two on-board counters (which would be perfect for our purposes) are in use for other important devices.  We need to simulate the effectiveness of the counters.  We need to provide pulses of a nearly exact length of time, and software timing is not sufficient.  We want to trigger a digital signal on a clock to have a TTL pulse sequence with software triggering.  By using the on-board clock, we suspect that using DAQmx modules are the way to go--being able to trigger based on counting clock cycles.  Good timing accuracy is very important.  I have no familiarity with these functions and their operation seem clunky and unnecessarily complicated to my untrained eye.  Are there any suggestions on providing a competent means of this pulsing operation?

[samantham]

Hello,

I was a little confused by your wording.  However, I am assuming that since your two counters are in use that you are wanting to output / generate a digital pulse on a digital line.  Please provide further details about your application if this is not what you want to accomplish. 

To output as pulse on a digital line a sample clock will be needed.  Please refer to the forum post linked below.  This customer is asking a similar question.  The code attached there is writing out a waveform, where each point of the waveform is updated in correlation with the sample clock rate.  This is why the two tasks have the same sample clock rate specified.

You would be interested in changing the Sample Mode to Continuous and changing the waveform points to match your desired pulse.  I have attached a simple example that might work out for you.  Please note that small changes will need to be made to customize this example to you application.

Finite digital generate waveform

[qComputing]

Thank you for your reply!  Sorry for the confusing wording, we do indeed intend on using Digital output (with a clock) as our pulse to emulate a Counter.  It sounds like the discussion you reference is helpful, but we have an older version of LabVIEW and hence I cannot view the VI included.  Could you discuss more the operation of the VI please?

[samantham]

Hello,

What version or versions of LabVIEW do you have?  I can save the code posted on the other forum and the example code I posted here to match your version.

[qComputing]

Thank you!  We use version 7.0.

[samantham]

Hello,

The first program attached below is the 7.0 version of the code I previously posted and the second program is from the forum I linked.  I hope seeing the code in 7.0 helps.

[qComputing]

Thank you very much for your help!