An electric motor drive system is provided wherein safety is achieved by commanding the process system of the relevant axis or set of axes to execute motion that follows a defined path, namely trajectory of position, velocity and acceleration against time, re-constructing an identical trajectory in the safety system and in, the safety system, supervising deviations between the safely reconstructed target position and the safe measurement of position.

An electric motor drive system is provided wherein safety is achieved by commanding the process system of the relevant axis or set of axes to execute motion that follows a defined path, namely trajectory of position, velocity and acceleration against time, re-constructing an identical trajectory in the safety system and in, the safety system, supervising deviations between the safely reconstructed target position and the safe measurement of position.