False DAQmx channels

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Is there a way to substitute a false channel in a DAQmx task? I think this would be handy. For example, if you have a 12-channel task, and once in a while you didn't want channels 8 and 10. Since the code downstream may be expecting 12 channels, 12 elements, a cluster of 12 etc etc, it would be nice to just seed those channels with false data - put something in there, even though there's no real data, so the task still has 12 channels.

Any ideas?

Thanks!

[torekp]

Maybe I misunderstood your question, but you can use NI-MAX to create simulated DAQ devices, complete with all the usual channels. I've done that and gotten some good mileage out of it.

I'm not at my NI-MAX computer right now, so the following is from memory.

Just right-click in the place in the tree where your devices are listed, and choose Add DAQ device. You can choose a virtual/simulated device.

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QUOTE (torekp @ Jan 28 2009, 12:53 PM)

Maybe I misunderstood your question, but you can use NI-MAX to create simulated DAQ devices, complete with all the usual channels. I've done that and gotten some good mileage out of it.

I'm not at my NI-MAX computer right now, so the following is from memory.

Just right-click in the place in the tree where your devices are listed, and choose Add DAQ device. You can choose a virtual/simulated device.

You understood perfectly. That's a good idea. As long as the task type is the same as the other channels in the task, that'll work. I'm not too fond of having to carry around or modify a MAX setup wherever the ap goes though.

The idea I came up with was to use some of the internal channels that these cards have (CJ temperature, excitation voltage, etc). Set the unused channels to one of those and it should be off and running. Haven't tried it yet though.

Thanks