Signal Conditioning

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channels 2 and 3 100 times more sensitive than 0 and 1

I am using a PCI-6052e device with a SCXI 1000 chassie.  The module is a SCXI 1121 with a SCXI 1321 terminal block. 
 
I am using differential voltage.  On the PCI device test using a DC power supply, I have good agreement between channels 0,1 and the indicator on the power supply.  However, channels 2 and 3 show about 100 times more voltage than is applied.  (ie .05volts on the power supply = 5 volts on channels 2 and 3)
 
what could possibly be going on?  They should be identical.
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Message 1 of 3
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There could be a few different things that may be happening.  You mentioned that it is reading 5V.  Is there a linear relationship between the input and what you read?  For example if you increase the power supply to 0.07V does it read 7V or does it stay around 5V.  If it reads 7V, make sure that you don't have any scales configured in the software when you read.  Also check the gain jumpers on the module to see what configuration they are in.  You can read more about the jumpers in the users manual on page 24.
 
SCXI-1121 Users Manual
 
If the voltage doesn't change much it might be floating and not have a good connection to your power supply.  In this case double check your pinouts and make sure you have the correct channels connected and that the terminal block is properly connected to the module with no bent pins.  If you are still having issues, what behavior are you seeing on the other channels?  Are they reading correctly or being multiplied?
 
Have a great day,
 
Brian P.
Message 2 of 3
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Thank you very much.  I am getting very good correlation.  I will investigate the jumpers as described in the manual
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