Strain gauge sensors are generally made of four wires (except shielded wires). As far as sensors are concerned, they are usually red, black, green and white. Red and black for power positive and negative (excitation). Green and white signal positive and negative (output). Use a multimeter to measure the impedance between the red line and the black line, and the impedance between the green line and the white line. If the measured result is infinite impedance, it indicates that the pressure sensor bridge is disconnected. If the impedance is zero, it indicates that the pressure sensor bridge is short-circuited. Both cases indicate that the pressure sensor is broken and needs to be sent back to the manufacturer for repair.

If the measured impedance is normal, the following tests can be performed. Supply power to the pressure sensor (5-15VDC, 10V is preferred), use a multimeter millivolt block to measure the millivolt value between the green and white lines of the pressure sensor. No load measurement, if the millivolt value is too large, it indicates that the sensor pressure overload (the pressure sensor is adjusted to zero before delivery). A large negative value of millivolts indicates that the sensor is pulling toward overload. If the pressure sensor force point millivolt output does not change, the pressure sensor has been damaged. The severe deformation of the elastomer caused by overload of the pressure sensor is usually irreparable, so the sensor can only be replaced.

After the above two tests, we can basically judge whether the force sensor is damaged.