5112 and 6250 RSE mode

[nyborn]

Hi:

Attached is my graph. I would like to know why the current flowing out the node of 100 ohm is 0.01micro amp, 0.38micro amp and 0.033micro amp.
The second question is  why the voltage at UUT negative point is -0.2mv, but the current is still flowing from the -0.2mV the 0V ground. I don't understand.

I am in an urgent. Could someone who know help me to solve this product questions. Thanks!
  
 
Regards,
John

[TongY]

Hi John,

I'd like to help you but can you be more specific as how the 5112 and 6250 are used in this application? Is you are doing analog input, ground loop is always something to keep your eyes on, please check if the RSE is the correct configuration to be used.  

[nyborn]

Hi Tony:

Let me be specific about my application. I have two boards. One is 6250 and the other is 5112. I also have a test fixture which needs to measure the UUT current and output waveform. My test fixture has two output. One is the red bind post and the black bind post to 6250 AI+ and AIGND input. The other is to 5112 board using BNC cable. As you know the BNC cable is connected to AIGND 6250 and test fixture ground and my test fixture is floating source. Therefore, there is a ground loop issue. My question is that I don't understand the current from the node under 100ohm is 0.01 micro amp, 0.38 micro amp and 0.033 milli amp. are like this. The second quesion is that I know the ground from BNC and the AIGND ground are different potential, but how come the current will flow from negative voltage to 0V which is the test fixture ground.

I would appreicate your quick response.