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How to stop crosstalk between analog input channels on an NI 6221 BNC?

I'm using two 6221's to control an XY displacement table. Table motion is controlled by applying voltages to its X and Y input channels. Position feedback is output on the table's X and Y feedback lines. The problem is that input voltages on one channel show up in the feedback signals of the other channel. For example input voltages on the X channel appear superimposed at low but significant levels on the Y feedback signal, and vice versa.


I'm using one 6221 to drive the table and another 6221 to receive position feedback. No channel crosstalk is observed when feedback voltages are measured with a multi-meter. It only occurs when both X and Y feedback lines are connected to the 6221. Ground switch settings (grounded/floating source) located below each input BNC connector on the 6221 have no impact.


A reward is offered for information leading to the solution of this problem (a great big thank you). 

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you say that the BNC config. switches have no effect - and what is the configuration of the input channels? Is everything grounded properly? I suggest going through this document.

If everything is connected and configured correctly, the observed behavior can be due to ghosting. Have a look here, it's relatively easy to get rid of.


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