07-22-2013 12:03 AM
One of my experiments deals with two load cells and an RPM sensor. I created two labview VIs: one for a test and the other to calibrate the load cells and RPM sensor.
I put in known loads using free weights (or knows RPM using a display that shows the output from the RPM sensor (laser and a reflective tape)).
I create a linear curve fit. The R sqaured values are generally above 0.99. Pretty straight forward, right?
The problem is that during test, the RPM display and the conversion from the linear fit does not match up, even though the curve fit has a high R sqaure value. There is an offset, and the offset changes with RPM.
I have played around with no of samples and sampling rate. However, nothing seems to help. Am I missing something mundane?
07-22-2013 01:20 AM
My first thougth: Static calibration (using free weights) and dynamic measurements?
How about the resonaces of your load cell constructions? Sample fast and apply a step (drop a free weight) ?