The LVDT and Carrier Demodulator system produces a DC voltage that is linearly proportional to displacement (over a limited range). To calibrate the LVDT, correlate the displacement and voltage measurements at multiple positions by finding an expression relating the voltage output to tip deflection.
First, adjust the ZERO on the carrier demodulator to read a zero output for a zero displacement. Then, deflect the beam to a measured distance. Adjust the SPAN to maximize the voltage for the given displacement.
Tip: Make sure that the displacements used to perform the calibration are in the linear range (e.g., the core remains within the secondary coils). Do a detailed calibration at least once to determine the linear range (e.g., perform one calibration taking numerous data points for maximum displacements).
Tip: Calibrate the LVDT each time you work on the experiment. Its zero can change easily!
