oscilations in transducer reading

[schiebera]

I have two transducers reading pressures.  The DAQ I have is NI USB-6009.  One channel is showing oscillations that are unnatural in our experiments.  We have ruled out outside interference and noise causing this.  It is not related to the transducer because we tried switching them and the same channel showed the oscillations despite the transducer being switched.  The other channel is reading perfect. The oscillations seem to get worse when pressures are higher.  We are running LabView 7.1.  The Transducer is Omega #162PC01D.  The power module is Omega model P5HO.  Any help would be greatly appreciated.

Thanks, Andy 

[RT4CY]

Hi Andy,

Thank you for posting on the forums!  I understand you are seeing oscillations that are unnatural in your experiments on one channel of your USB-6009.  I would like to narrow down the issue by removing LabVIEW from the equation.  Please launch Measurement & Automation Explorer (MAX) by going to Start»Programs»National Instruments»Measurement & Automation.  Under Devices and Interfaces, locate your USB-6009 under NI-DAQmx Devices.  Right-click on the device and choose Test Panels.  Let's try the following troubleshooting steps from the Test Panels.

1) Acquire data from teh problem channel.  Let me know if you still see the fluctuations.  A screenshot of acquired data on the problem channel as well as a good channel would be very helpful.
2) Apply a known voltage from a function generator or a battery, and read it with the problem channel.  Try a DC value as well as a sine wave if you can.
3) Perform a loopback test.  Switch to the Analog Output tab and generate a DC Value/Sinewave from ao0.  Now switch to the Analog Input tab and select the ao0_vs_aognd channel.  This requires no external connections.