real-time - how to control speed of digital waveform

[krivan]

Deploying the VI attached to my RT desktop target I generate digital waveform on 8 channels on port0 and acquire data on AI [PXIe-6358].

The digital output frequency and analog input sample frequency are 10000 Hz therefore I expect that while one 8-bit digital code is active [valid] for 100us, one single analog sample is acquired. That means that I would expect one cycle of the while loop to finish in 100us x 2^8 = 100us x 256 = 25600us = 25.6ms.

However what happens is that the while loop finishes in 6ms regardless the set frequency. The loop finishes in 6ms even if I set 5/10/15kHz or if I put a 100us delay into the while loop. I also tried to set the source of the analog input sample clock to 'Dev/do/SampleClock' but nothing seemed to work so far.

How can I force the digital generation to be in correlation with the analog acquisition? I need to acquire 1 data point per channel while the respective digital code is active.

Thanks,

Krivan

[krivan]

I forgot to mention in my previous post that if I run the digital generation, I can measure the correct output frequency with oscilloscope however I am unsure whether my analog acquisition is OK for the above mention reasons.

[ShalB]

Hello krivan,

Thank you for your post on the forum.

Do you want the digital generation to start at the same time as the analog acquisition?