METHOD FOR MONITORING WHETHER THE SWITCHING THRESHOLD OF A SWITCHING SENSOR LIES WITHIN A PREDEFINED TOLERANCE REGION

摘要

The invention relates to a method for monitoring whether or not the switching threshold of a switching sensor lies within a predefined tolerance region. The switching sensor comprises a signal input, to which an input signal is applied, and a signal output via which a switch output signal is emitted that can take a first value when the input signal is larger than the switching threshold and, otherwise, takes a second value. A modulator signal generated by a modulator (MD) is used as an input signal, characterized in that said modulator signal changes continuously or cyclically between an output value, which defines the upper limit of the tolerance region, and a test value which is smaller than the output value and defines the lower limit of the tolerance region. According to the invention, the switch output signal pulses at the rate of the modulator signal between the first and the second value when the switching threshold of the switching sensor lies within the tolerance region. Otherwise, said switch output signal does not pulse. The pulsation of the switch output signal is monitored by means of an evaluation device (A), an alarm signal being triggered when the switch output signal does not pulse for at least a predefined test period.