DAQmx read multiple input channels at different rates

[gjf]

Hello,

For a spectroscopy project, I've tweaked the example Multi-Function-Synch-AO-AI.vi to continually write values out a single DAC channel and simultaneously read in two ADC channels.  Works fine.

Now, I'd like to add the ability to read a few more ADC channels (house-keeping data) at a much lower frequency.  Again, I started with an example (Acq&Graph Voltage-Inc) to read three consecutive channels just one read each channel.  Also works fine.

When I add my Housekeeping vi to my Spectroscopy vi, I get an error saying

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Error -50103 occurred at DAQmx Start Task.vi:22

Possible reason(s):

NI Platform Services:  The specified resource is reserved. The operation could not be completed as specified.

Task Name: _unnamedTask<5CE>

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I not new to LabVIEW, but am new to DAQ hardware.  Thanks in advance for any help!

Using NI USB-6211 running on WinXP with LabVIEW 2011.

[Dennis_Knutson]

Did you search for the error code or message? It's quite common. Since the board has a single A/D with one clock, you have to use a single task with all channels.

[gjf]

Ah, that would explain it. 

thanks much!

[mkw21]

Hello,

I am using Labview to collect data from two channels: Dev1/ai0 and Dev1/ai1. I want to collect the data at different frequencies for each channel. It seems that you have done something similar, if I understand your question correctly. Would you be willing to post your vi as a reference if you were able to collect data at different frequencies for different channels on the same DAQmx read task?

Thanks very much,