High precission data capture synchronization NI9775 and 9234 in CRIO9054

[tfernandez@vicomtech.org]

I have a CRIO9054 working with NI Linux Real-Time and with NI9775 and NI9234 modules. I want to synchronize the data capture trigger of both modules as much as possible, having them different sampling rates. I have syncronized the capture of both modules by putting the start task of them in the same frame of a flat sequence.

However, the time differences are about 10-30 milliseconds. Is there any better way of doing this task?

[GerdW]

Hi tfernandez,

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tfernandez@vicomtech.org wrote:

However, the time differences are about 10-30 milliseconds. Is there any better way of doing this task?

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You are reading waveforms and they contain timing information: you can easily adjust the waveforms in postprocessing to start at (nearly) the same time…

[mcduff]

Don't have LabVIEW on this computer, but the link below is a nice tutorial. 

https://www.ni.com/en/support/documentation/supplemental/21/signal-based-synchronization-of-analog-i...

Your method shown is noted in the tutorial along with its shortcomings. Scroll near the bottom to look for multirate synchronization. 

Note you have a DSA and SAR module; the data from the DSA will have a time lag that depends on the sampling rate. Look at the specs for your 9234. This lag will have to be post processed out; you can just change the t0 of the waveform to account for this lag.