9237 &9205 with chassis 9178 sampling rate problem

[dffs]

Hi MarkGrot,

Thank you for your reply.

So, I can acquire data with a sample rate of 25kHz if the 9237 and 9205 in the same task, of course the channels no. of 9205 should be less than 10. 

Am I right ?

I have another question: as the 9205 is a multiplexed module with a max rate of 250kHz, so the data can't be acquired simutaneously in fact ?

I mean there are delays between the channels.

Look forward your reply.

Thanks.

[MarkGrot · Accepted solution]

Yes, you can acquire at 25kHz with 9237 and 9205 channels in the same task as long as the number of 9205 channels is <= 10.

You are correct that the 9205 channels are not sampled simultaneously.  See the "Timing Considerations for C Series Devies" topic in the DAQmx help.  From there:

"The default AI Convert Clock rate for the C Series Scanned devices uses 10 µs of additional settling time between channels, compared to the fastest AI Convert Clock rate for the device. When the Sample Clock rate is too high to allow for 10 µs of additional settling time, the default AI Convert Clock rate uses as much settling time as is allowed by the Sample Clock rate."

You can always query the convert clock rate to see how much of a delay there is between samples.