problem of digital waveform generation

[datoudream]

I want to generate finite pulses by digital
output. Please help me to find the problem of the attached VI.


If I set the write node allowing
regeneration, I find that no matter what the pulse number is( it is alse the samples
number of the digital waveform), 2 or 20,000, the actually generated pulses are
the same. I doubt that the ?wait until done? function doesn?t work.  


If I set the write node not allowing
regeneration, more problems happen. When the digital waveform has less than 130
samples, an error occurs(error -200609). Has digital waveform output buffer to
be bigger than 130? When the digital waveform has more than 130 samples but
still few samples,such as less than 800, Error -200560 occurs, and it seems not
dependent on the rate of the sampling rate.


Anyone tell me about it?


Thanks.

My Device is NI PCI 6281


DO pulse generation.vi:
http://forums.ni.com/attachments/ni/70/8999/1/DO pulse generation.vi


DO-pulse-generation.jpg:
Loading Image...

[centerbolt]

There is an example that ships with LV that should do what you want to do.  It is named Gen Dig Pulse Train-Finite.vi

[datoudream]

I know the example. But if I use DO to generate pulses, the pulses' width can be changed.And I think the VI has no mistake, but why it runs unexpectedly.

[centerbolt]

Altering the Duty Cycle input on Gen Dig Pulse Train-Finite.vi  will change the pulse width.  Maybe I don't understand what you are trying to accomplish. 

[datoudream]

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