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generate pulse with NI-6024

Hi,

can I generate defined pulses with the NI-6024 Card? I'd like to generate 100 Pulses with 0.27 Hz frequency.
I'm using LabView 7.1


Yves
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Message 1 of 9
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Use the 'Gen Dig Pulse Train-Finite.vi' in the examples. It uses a counter to generate the pulses.
Randall Pursley
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Message 2 of 9
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Thanks.
It works with some frequencies. BUT how about 5.5 Hz? I always get an error. Isn't it possible to have other steps?

Yves
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Message 3 of 9
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Yes, you can set the number of pulses, frequency, and duty cycle.
Randall Pursley
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Message 4 of 9
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This is what I tried. But when I change the frequency to 5.5 Hz I get following message:

failure -200305 on DAQmx Start Task.vi:
Property: CO.Pulse.Freq.InitialDelay
Corresponding Value: 0.0

I have set the duty cycle to 0.5 and the number of pulses to 20.

yves
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Message 5 of 9
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Your right, there seems to be limitations on frequency selection. I'm not sure why at the moment. You can always use one of the analog output examples.

I will try some other configurations of the counter examples.
Randall Pursley
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Message 6 of 9
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I tried ot generate some pulses in MAX 3.1. It works there. I don't know what's going on with the example-vi

Yves.
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Message 7 of 9
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Using the DAQ Assistant I was able to generate a finite number of pulses, but I could not define the pulses by frequency. I could only define the pulses by inputting Low time and High time.

I think any frequency whose inverse cannot be timed precisely by the timebase, cannot be selected with the sample vi you tried to use (i.e. 5.5 Hz -> 0.18181818181818181818181818181818181818... cannot be defined by the timebase). If you take the inverse of 0.1818 (5.5005500550055001) and enter it into the Frequency control, it does work.
Randall Pursley
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Message 8 of 9
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You can add the attached vi between the 'Frequency control and the DAQmx function in 'Gen Dig Pulse Train-Finite.vi' in the examples. This will change the frequency slightly to one that will work. You can add a local variable for the 'frequency' control to see what it changed to. You have have to increase the number of visible decimal places to see the change.
Randall Pursley
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Message 9 of 9
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