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all channels showing same voltage

Hello,

 

I'm using two Measurement computing DAQs, one for input and one for output.

Since I have only one ATD converter on the input DAQ, I have used a method shown in the capture.jpg picture.

When I run the program, I get the following outputs:

 

- No wire connected to any input: All channels showing same noise pattern, basically the common analog graph shows a nearly single line for all inputs.

withoutexternalsupply.jpg

 

- Wire connected to channel 3: I rolled my finger on the wire and got some patterns, but again the patterns for all channels are in a nearly single line

wireonchannel3.jpg

 

- +5V (actually 4.77) taken from the output DAQ's voltage output channel: Again, all channels show nearly the same voltage of 4.6-4.7

with5Vsupplytochannel0.jpg

I haven't connected anything to the ground connection, but I'm guessing that's not the problem since the channels shouldn't be affected by a ground.

 

Any idea why this might happen?

 

I can only attach 3 images in the post, so I'll attach another picture in the comment below.

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You are seeing something called ghosting. Numerous posts on this. Connect an actual signal to the inputs. Perhaps a ground that you don't think you need or the 5 volts. Ignore any unconnected channel.
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