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cRIO voltage from NI 9264 is wrong


atokad

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My NI-9264 voltage is outputting incorrectly, and I am not sure what the issue is.

Here is what I am sending to the FPGA vi:

FPGA_Reading.png

The top circled number is the velocity of a mass flow controller that operates from 0-5V with a velocity range of 0-75 SCCM. Hence my conversion from actual velocity to voltage is to divide linearly by 15:

FPGA_Code.png

 

MultimeterReading.jpg

Multimeter reading (Idk why it is side ways I cannot seem to rotate it)

We are using a ribbon wire to connect the module to the Sierra Smart Trak C100 MFC so I'm not sure if that is the issue or if there is something else wrong

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Alright I plugged in a DC power supply to a random slot and sent 1.5 volts (McKenna_Air_V_in)

New_FPGA.PNG

But as you can see the voltage inputs from the other two readings are showing that the voltage on the NI 9205 is floating even though I have the common ground connected tot the power supplies ground.

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I assume you've configured the 9205 for single ended vs differential correctly?

Are you within the current spec of the 9264?

How are you connecting the modules? A cable or one of NI's breakout boards?

Try and simplify things as much as possible. For example, use a battery as a voltage source directly to the input and disconnect the outputs to rule out loading issues.

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3 minutes ago, infinitenothing said:

I assume you've configured the 9205 for single ended vs differential correctly?

NI-9205.PNG

3 minutes ago, infinitenothing said:

Are you within the current spec of the 9264?

If you are referring to the voltage, then yes.

3 minutes ago, infinitenothing said:

How are you connecting the modules? A cable or one of NI's breakout boards?

Try and simplify things as much as possible. For example, use a battery as a voltage source directly to the input and disconnect the outputs to rule out loading issues.

The modules are placed directly in the cRIO-9035's slots

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No, by current spec I mean:

Quote

±16 mA all channels maximum; ±4 mA per channel typical

 

By "how are you connecting", I meant connecting to the analog side of the module. For example do you have one of these: http://sine.ni.com/nips/cds/view/p/lang/en/nid/210164

I see that you have the module setup for differential, that's a little more tricky right? Can you try single ended? maybe with a battery or a potentiometer. Otherwise you have to watch out for things like common mode voltages and such.

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