Entered analog PCI 6251 not extent of tension of a mass flow controller


I have a data PCI 6251 M acquisition with a break in Council SCXI 1302.

I'm trying to measure a 0 - 5v analogue output voltage from a mass flow controller (check picture of PIN)

When I measured with a digital multimeter the voltage of the flow signal (PIN2) and common signal (PIN12) I get a stable right tension between 0 and 5v depending on the flow set up. I can control the amount of the charge by providing a data output set point PIN8 and common PIN12 of the 0 - 5V analog signal.

Now when I connect the signal flow PIN2 and on my DAQ signal common PIN12 AI and AIGND, I don't get readings on my labview VI of the AI. In addition the flow does not meet the setpoint voltage, it get stuck in a range of values no matter how I vary the OD 0 - 5V of data acquisition in setpoint PIN8 and PIN12 common signals.

I have to add that I tried different ports HAVE with results of sam, and I also tried to measure my supply voltage with my HAVE and all the good work.

It seems that the entry of AI affects the AO output voltages to my charge. What would cause this? That would be a problem of impedance adaptation?

Management or ideas are appreciated.

Thank you

Ali T.

Update for anyone that might interest you:

I not connected to the ground of the power of the mass of the signal of FJA FJA.

Once I did the acquisition of data reads all data as expected.

So it turns out not to be a problem of acquisition of data, OR at all, but a game of question for my part, as I suspect is the case with most of the problems.

Jeff Merci for your comments.

Ali T.

Tags: NI Hardware

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