Sensor assembly for detecting the safe condition of an automatically operated system

The arrangement (18) has an input circuit (60) receiving two input signals (66a, 66c), which depend on a safe installation state to be detected and an operational state, respectively. Two outputs output first and second output signals (76, 78) to a control unit. Evaluation units (64a, 64b) evaluate the input signals in a fail-safe manner to generate the first, second, third and fourth output signals (80, 82) at the outputs. The output signals form a redundant signal pair and a non-redundant signal pair, which is differ from the redundant signal pair.