compact daq acquire multiple signals

[Chris S.]

Hi

I am trying to acquire and log a bunch of different signals in signal express but I am having trouble specifying the sampling rates.  I have compactDAQ and I want it to acquire all the voltage signals on my different modules ((3-9211's 2-9215's)<---using all inputs and one 9205<--using 3 inputs).  However, when I create a step it sets all the sampling rates the same.  For instance I want the 9215's at 100k and the 9205 at 10k and the 9211's like 1hz how do I do this? or do I just set them at 100k and let them operate at thier own speed?  If I set everything at 100k, how fast will the rest of my modules operate?

For now I am trying to simulataneously log 12 thermocouples (3-9211s 1hz) 8 accellerometers (2-9215s 100k simulataneous) and 3 other (9205).  How do i go about this in signal express?

Thanks

Chris

[Yardov]

Hi Chris,

A DAQmx task needs to have the same timing specifications because they are using the same time engine. In cDAQ, there is the analog input engine and the analog output engine.
You are actually using one of these engines and will therefore need to sample at your maximum rate. The modules that cannot go that fast will give back the most updated sample.
Hope this helps,

[--Chris]

Once you have acquired all of the data at 100k you can use the Subset and Resample Step to resample some of the channels to a lower rate if needed.  If you want to turn some of the channels into single point values, you can use the Time Averaging Step.  A combination of these should allow you to have all of the signals at the desired rates.