Compensation of temperature for the strain gauges

I'm trying to compensate for the effects of temperature on an extensometer placed on a sample of carbon fiber.  The sample will be only responsible uniaxialement.  The temperature is a major concern here, for an electrical current will be executed by him for purposes of measurement, which should also heat the sample.  I read in the document 'Strain gauges measure' on the website of NOR (http://www.ni.com/white-paper/3642/en), but he speaks with a Measurer of mannequin, he speaks not just how this second pledge, placed perpendicularly to the axis of the applied force, we are not talking of how connect to the strain gauge module , in my case the NI 9235, to use for temperature compensation.  My first thought was just connect each pledge to the module as their own separate channels, using quarter-bridge in the LabVIEW software set up, calibrate the two gauges while not external physical load or temperature effects are applied, and then, after the test, by subtracting the measure pledge Sham in the values of assets pledged.  But then I started wondering, is there a better way to do this?  Can I use the half-bridge configuration, or some other configuration with the 9235 to automatically merge the readings two pledge during the test?

I'd appreciate it really any advice that anyone can give me on this.  I don't want to build my own external wheatstone bridge (other than the built-in NI 9235), and I would like to make these measurements as accurate as possible.  I have also considered the possibility of the compensators measurers, but I don't think this would be applicable in this case, the complexity of the matter - being a composite.

Hello WyoEng,

You want to use the temperature compensation is referred to as a quarter bridge II configuration (image below). This configuration is very similar to a half of the bridge, while the second element (R3) is inactive because it is placed transversely to the direction of the load, without strain and in the same location the active gage (R4) to take account of thermal affect.

NI 9235 supports only a quarter bridge I configuration for measures of constraints.  You will get an error if you try to use this module for any other configuration of pledge of strain that is not quarter bridge I. Thus, active policy that you asked to use two channels to read the pledge and the dummy gage will be the best option to use NI 9235 to compensate for thermal effects on your extensometer.

Another option would be to look on the NI 9237 which supports a quarter bridge II configuration.

Best regards

Izzy O.

Technical sales engineer

National Instruments

NI.com/support

Tags: NI Hardware

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