Sensors in professional use are calibrated via a diagnostic device. This performs a balancing measurement / adjustment and calibration. So: balancing measurement / adjustment and calibration are the components..
caliblrate them when you installing them new, when changing some setup settings on actuator, when performing status check and they are not responding or do it before check.
is the same as above. If your sensor doesnt work? Perhaps your equipment then doesnt work! Either you have a setup program or an diagnostic device, the steps are the same as above. Later your equipment works, perhaps?
Or you always get wrong results. Then you should used the same steps.