[0034]The aspect of the present invention relating to the method of claim 19 requires that for determining the position of the activation magnet along the monitored distance, at least two sensor signals are generated at each of two positions which are spaced apart in the direction of the distance that is to be monitored. These signals are generated by the magnetic field of the activation magnet at a predetermined radial spacing from the movement axis of the activation magnet. Depending on the position of the activation magnet, at least one switching signal is provided. For each magnet position of the activation magnet along the entire monitored distance, the two corresponding sensor signals are available. The two sensor signals, which are used for generating the switching signal, then provide unambiguous groups of signal values for the instantaneous magnet position of the activation magnets.