Pulse stays high at the AO

[fr123]

Hello, I am doing simultaneaous AO-AI. I generate a pulse of definite width out of the ao0 output and aquire it at the ai0 input.  The problem is that when I generate pulse of width larger than 10ms the output stays high and don't returns to zero. How can I generate exactly what I want? 

I am using an M serie card (PCI-6251) 

[Hillman]

Hi fr123,

Thanks for the post and I hope your well today.

I noticed you hadn't logged in again since the day you posted this - so I wanted to offer you support incase you were still having problems.

I am wondering how you know this waveform pulse you generate doesn't return to zero.. are you looking at your acquired data graph? or with a scope? It could be that your not reading enough samples on the AI to catch the end of the pulse.

Also, I would change the timing information for the AO to Use Waveoform (AO) instead of sample clock. At the moment it defauls to number of samples 1000. OR at least use the sample input to number of samples as the AI setup. 

I am more than happy to support you on this issue if you are still having problems, but if you did resolve it if you could please post your solution that would also be great!

Thanks again, 

[fr123]

Hi James,

Thanks for the reply. I was looking at the output of a scope. I think I found the problem, it seems that the output task was interupted before the end of the pulse when I was using the subVI "DAQmx Is task done?" By replacing it with "DAQmx Wait Until Done", my VI works fine. I attached here the working VI.

[Hillman]

Hi Fr123,

Thanks for the reply and I hope your well.

Thanks  so much for posting your solution - this is great to do for future readers. I am glad you've managed to resolve the issue and  I am sorry you didn't receive support from the forum sooner.. I just noticed the post so just wanted to make sure you were being successful.

Best Regards,
James.