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Wiring an Omega Pressure Transducer to NI USB-6229

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Details:

Transducer: OMEGA PX03C1-100G5T Specs

Hardware: NI USB-6229

 

Wiring:

Pin A (+OUT) of the sensor goes to AI2.

Pin B (-OUT) of the sensor goes to AI10.

Pin C (-INPUT (EXC)) of the sensor goes to a 24V power supply negative (has no ground).

Pin D (+INPUT (EXC)) of the sensor goes to a 24V power supply positive (has no ground).

 

Hi All,

I am interfacing a 0-5V Omega pressure transducer with the NI USB-6229 module in the differential configuration but the value I am seeing in MAX is not what I expected. I have reviewed the "Field Wiring and Noise Considerations for Analog Signals" white paper, http://www.ni.com/white-paper/3344/en/, and connected my sensor accordingly but I am still struggling.

 

Issue: In MAX, the voltage measured is not the same as my multimeter when measuring across the -OUT and +OUT of the sensor. It appears that my voltage signal is capping out at 2.4-2.5V in MAX, with or without the bias resistors. With a multimeter, my measurement across the outputs reads up to 5V. I switched to a different pair of differential inputs with no success. Hopefully, someone can help me figure out what is wrong.

 

 

Regards,

David

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Hi David,

 

Can you send in a screenshot of the Test Panel you're using in NI-MAX so I can check out your configuration settings?  If you're confident your wiring matches the M-Series DAQ User Manual and the Field Wiring and Noise Considerations Guide, a good next step is to check the software settings.

Tyler O.
Applications Engineer
National Instruments
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Hi Tyler,

The following are the screenshots I was able to collect. Is there a particular setting that you would want to see?

 

NI MAX Test Panel w/ highest value recordedNI MAX Test Panel w/ highest value recorded

 

NI MAX AboutNI MAX About

Best Regards,

David

 

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Wiring:

Pin A (+OUT) of the sensor goes to AI2.

Pin B (-OUT) of the sensor goes to AI10.

Pin C (-INPUT (EXC)) of the sensor goes to a 24V power supply negative (has no ground).

Pin E (+INPUT (EXC)) of the sensor goes to a 24V power supply positive (has no ground).

 


Are you sure about the wiring?  The spec sheet you linked to says:

A: + Output

B: - Output

C: - Input

😧 + Input

 

 

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Bryan,

Nice catch. Just a typo on my end. 

 

The wiring is correct and is connected as follows:

Pin A (+OUT) of the sensor goes to AI2.

Pin B (-OUT) of the sensor goes to AI10.

Pin C (-INPUT (EXC)) of the sensor goes to a 24V power supply negative (has no ground).

Pin D (+INPUT (EXC)) of the sensor goes to a 24V power supply positive (has no ground).

 

All connections confirmed with a continuity test.

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What happens if you connect a 9v battery to AI2 (Terminal 7) and AI10(Terminal 8)?  Does the test panel read about 9v?

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Bryan,

Please see the screenshot below. The test panel reads a little over 9v on AI2 when I connect the battery. It looks like the input is working, though. Any other ideas?

Testing with a 9v batteryTesting with a 9v battery

Best Regards,

David

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Have you tried setting the channel as RSE or NRSE?

 

When connected to the transducer does the test panel voltage change with pressure or just sit at ~2 volts?  Does the test panel voltage change when you read the voltage with the multimeter?

 

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Solution
Accepted by topic author mr.dtran

Bryan,

Thank you for your help. The problem was with the power supply and not the wiring or settings. The wall adapter we used is 24VDC/500mA, but the transducer/NI setup did not like it. I switched to a bench power supply and the voltage began reading correctly on the test panel using the DIFF mode.

 

Best Regards,

David

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