multichannel daq - huge crosstalk

[livelive]

Hello all,

I am using the attached .vi to collect three analog channels simultaneously using NI-USB 6216. The problem is when I apply some voltage reference (e.g. 1 volt) to only one channel, all three channels show identical values (the same exact 1 volt). Also when I leave all of them disconnected they start decaying slowly to -5.320 volt.

I just need to collect three analog channels indepenedently. I appreciate your help on this case.

Thanks.

Amir

[crossrulz]

Is your ground tied to AI Sense?  I've seen floating grounds do some strange things.

[Dennis_Knutson]

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@livelive wrote:

Hello all,

I am using the attached .vi to collect three analog channels simultaneously using NI-USB 6216. The problem is when I apply some voltage reference (e.g. 1 volt) to only one channel, all three channels show identical values (the same exact 1 volt). Also when I leave all of them disconnected they start decaying slowly to -5.320 volt.

I just need to collect three analog channels indepenedently. I appreciate your help on this case.

Thanks.

Amir

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What you are seeing is normal with muxed inputs when some or all are disconnected. Do a search for 'ghosting' or 'crosstalk'.