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Differential using NI 9205 in FPGA mode

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If I need to do a differential measurement, do I need to subtract the matching input like this?

 

Differential meas.PNG

(This would be running on the FPGA)

 

Are there any issues (like clipping) if my input range is small, lets say ±200mV but my IO is floating at, lets say, 3.0V on AI0 and 3.1V on AI8?

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Solution
Accepted by AbandoningCausality

To take a differential measurement with FPGA, you need to first go to your project and right click on the module and go to its properties. You should see a list of all your channels, along with their input range and terminal mode. Set the + channel for whatever pair you are wanting to use as DIFF and drop an I/O node just for the + channel. You do not have to do a manual subtraction.

 

You should not expect any issues with the behavior you described.

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Dear all,

 

I'm trying to configure NI 9205 to take differential measurements in FPGA. However, I can't access module properties in FPGA target as in RT target, i.e. in FPGA target "right-click-on-the-module-and-then-properties" doesn't exist.

 

After some googling, I found about the FPGA I/O Method Node which could be used to configure the module programatically. However, I'm not sure how to configure all channels at once (please see the figure below), i.e. I'm not sure what should I do with the "AI Channel" property in the FPGA I/O Method Node. Is there any other way to configure differential measurements in FPGA except this approach using FPGA I/O Method Node?

 

example.png

 

Best regards,

Marko.

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Since I cannot edit my previous post, I'm writing a new one with a solution.

 

I was trying to access C module properties dialog box by "right-clicking" the wrong thing (see the figure below). You can access the dialog box by "right-clicking" modules in the blue square, instead of those in the red square.

 

solution.png

 

Best regards,

Marko.

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