can I buffer a digital waveform using a NI 9401 in CompacDAQ and LabVIEW

[manliff]

I am trying to have a variable timed digital pulse (low-hi-low) using a buffered digital waveform through an NI 9401.  The NiDAQ mx assistant seems to indicate that I can push down a digital waveform to the CompacDAQ/NI9401 but all I get are errors saying I have done something wrong.  Or one error I got was that the buffer size was set to 2. Which correlates with the results of the DIgital output. But I can find no way to set the buffer size I need. Can it be done? Where can I find documentation that will show me how to work with it?  The example VI's don't seem to apply to CompacDaq and NI9401.

To add to this; Is it possible to simultaneously do this digital waveform output and perform analog input watching the response of my system?  I have great trouble synchronizing the CompacDAQ to stimulate my system digitally and watching it with analog.  I will likley post this question elsewhere but for my application they are closely related to problems.

[Sandra_T]

Hello Manliff,

I see that you are using our cDAQ-9401 to program a variable duty cycle pulse train, is this what you mean by "variable timed digital pulse"? I have included a link to an example that you can reference:

NI-DAQmx: Software-Timed Variable Duty Cycle Pulse Train Using Analog Output

If you are using the DAQ Assistant, much of the configuration is done for you when you select the differnent settings. If you want greater control over the signals you are generating/acquiring, work with the low level VIs. Take a look at the shipping examples to start developing your application. In LabVIEW select Find Example, this opens NI Example Finder. In the Browse tab, Hardware Input and Output>>DAQmx>>Generating Digital Pulses

Addressing the errors you are getting, I need more information:

- what is the error code?
- what were you doing when you got the error?

With regards to your other question, it is possible, and I think someone has already replied to that thread.

Regards,
  Sandra T.

Applications Engineer | National Instuments