A method for fault detection of safety-related sensors

The invention relates to a method for error detection in the operation of sensors (Z) with at least two contact-type decoupled signal-generating elements (K1, K2) with a closed conductor loop, and a first test output (A2) by a defined switching delay (tx) from a second test output (A1) is switched delayed and the input channels (E1, E2) are evaluated according to a defined expectation, wherein from deviations of actual and expected waveforms and time intervals (tx) draw conclusions on errors.