Electrical – How to reduce noise in strain gauge measurements

noisestrain-gage

I have two strain gauges on a 1 m length wind turbine blade which will rotate at 800 RPM. The amplifier and DAQ system will rotate with the blades. I'll have relatively noise environment and the turbine generator will be close. I am using strain gauge for first time and was wondering if any body has any suggestion to reduce noise in my measurements.

For example, What is the best solution to connect the strain gauge shield wires to PCB (amplifier) in order to reduce noise? I was wondering to use screw terminal, but probably there is a better way.

Best Answer

One approach (I saw this used in a nuclear-testing setup) is to drive the strain gauge bridge with 20,000Hz sin (something much faster than the generator risetimes, so the correlation is very small), then use narrow-band amplifiers to boost the 20,000Hz, then perform a synchronous-demodulation.

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The nuclear testing channel used 5,000,000 Hz drive to the bridge, so the response could be proportionally faster. From what I've read over the decades, such a test generates the energy in "2 shakes of a lamb's tail" or 20 nanoseconds. After that, its all about the energy going wherever the energy wants to go.