Issue with acquiring ~40hz sinusoidal data. USB 6215 error 200279

[nlis12]

Greetings,

I have a fairly simple control and DAQ program that I have written (Attached)
Basically, I am using a USB 6215.  
I use an analog out port to control a sinusoidal pressure and then use an analog input port to read the controlled pressure and display it.

The program seems to run well for the first 20sec or so, then error 200279 pops up (see attachment) and highlights the analog input DAQ VI as the issue.

There are more details in the attached VI and I have commented my thoughts there in the block diagram.

Any help diagnosing would be appreciated!

Thanks!

[santo_13 · Accepted solution]

The reason you're facing this error is that your software is fetching the samples from the hardware at a slower rate.

From your implementation, I would assume you would like to apply a stimulus and capture the response synchronously, in this case, you need some kind of hardware synchronization but the DAQ Assistant approach you're using is very limited and does not allow you to synchronize.

You can achieve this by discarding the DAQ Assistant based approach and using the DAQmx drivers directly. This is a good article to begin the DAQmx driver study but skip the DAQ Assistant part.

Please refer this post for AO-AI synchronization - https://forums.ni.com/t5/LabVIEW/Sync-Daqmx-AO-with-AI/td-p/3809098