NI 9219 configure with Wheatstone with a 3 wired Strain gage and quarter bridge set up

[Kumat]

Hello,

Currently I am using a strain gage with 5K (ohm) resistance to measure strain on a beam. I want to use NI 9219 DAQ to measure these strains. But the SG that I have is a 3 wire. First I tried to set it up as a quarter bridge configuration with a dummy resistor. Also, I tried to set it up as a half bridge configuration. However, the strain value tends to fluctuate a lot in the range of +-5 microstrain. According to the NI 9219 module which has a resolution of 24-bit and it should give me a resolution of about 0.1 microstrain, for a excitation voltage of 2.5V. 

I really thank and appreciate all of you for taking time out and reading/commneting on my post.

Regards,

Kumat

[Stark.123c]

Hello Kumat, 

   I was looking up some information, I discover some good articles that focused on strain gauges and their proper connections, it will be great to review them to see if there is something that we are missing. 

Measuring strain with strain gages

Also, there is this great white paper to review, that is an attachment on the previous link, but still I'm going to put it here:

Engineer’s Guide to Accurate Sensor Measurements

As this specific module is a universal analog input try a voltage or current reading to see if effectively you got the proper resolution with these measurements and try NI MAX to discard a LabVIEW code issue if you can read voltage or current properly, probably something is wrong with the SG or with some configuration.

Best regards!