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Multiple DAQ Sessions in Background

Asked by Christian on 14 Dec 2016
Latest activity Commented on by Christian on 29 Dec 2016
I am aware that acquiring multiple channels with different sampling rates is not currently supported as such. I came across the possible workaround of creating an individual session for each channel and setting those sessions' sampling rate.
This would also allow me to easily control the place where the data should be stored for each channel.
The questions on this are:
  1. Is is even possible?
  2. What would that mean for the background acquisition process? In my scenario up to eight channels and therefore eight different sessions would acquire in the background. A listener waits for 3 Mio. datapoint being taken before triggering a storage script, which stores those 3 Mio datapoints into a new file.
  3. Individual sampling rates are not an absolute must. Is there an easy way to extract data from individual channels?
I am using a NI-PCI 6123 on a Windows 7 machine, MATLAB 2016b. Typical Sampling rates are 100 kHz.

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2 Answers

Answer by Christian on 15 Dec 2016

To answer my own questions:
  1. No.
  2. See 1.
  3. No other than extracting it from the large data matrix

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Answer by Vinod
on 29 Dec 2016

You can have multiple DAQ sessions with different devices, just not multiple sessions with the same device.
In your application I would set the sampling rate to the highest you need and downsample the data for the other channels using the ' resample' function.

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Interesting approach, thanks for the hint. The only reason for lower sampling rates is space anyways.

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