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From 11:00 PM CST Friday, Feb 14th - 6:30 PM CST Saturday, Feb 15th, ni.com will undergo system upgrades that may result in temporary service interruption.
We appreciate your patience as we improve our online experience.
04-19-2009 02:02 PM
Hi community members,
I recently put together a program using LabView 8.0 that runs on my Dell laptop computer.
I am continuously collecting data from four different channels - Ai in., 100Hz, 100s/channel
I am collecting data from:
1) Linear encoder #1
2) Linear encoder #2
3) Load cell output, after signal conditioning - always in tension, so voltage output is always positive
4) Load cell excitation voltage - DC
My questions:
A) For some reason the voltage that I read with a DMM directly on (4) w.r.t. Ground is off by 2v. All other voltages are not offset. Why?
B) When I run the program on a Sony Vio laptop, signals from (3) are very noisy +/- .2V. Why? All other signals the same, (4) is still offset by 2v.
Thank you for your attention and any valuable input
-Erick
Solved! Go to Solution.
04-19-2009 04:46 PM - edited 04-19-2009 04:51 PM
Hi Erick,
Sometimes it's simplest to use the Measurement and Automation Explorer (MAX.) to get things working. There you can setup a quick Data-acq. (for NI hardware.) Do you use differential-input mode? Is the load-cell output DC? If yes to both, then it is surprising that the DMM measures differently than the DAQ-device.
Open MAX (Start\Programs\NI\Measure...), find your (NI) hardware, open test-panel...
If the problem isn't solved by using differential-inputs - what NI-DAQ hardware is connected?
Luck/Cheers!
04-20-2009 12:02 AM
Yes! you are right, I did have my measurment mode set to single ended. I changed it to differential and it works like a charm.
Thank you tbd
04-20-2009 01:37 AM
Very happy to hear it - thanks Erick.