A safety switch for safety circuit arrangement has a control part for processing an input signal and at least one switching element with at least one active and one inactive switching state. The control part controls the switching element in order to generate an output signal dependent on the input signal at an output. In addition, the safety switch has a diagnostic function for identifying a functional fault. The control part is configured to transfer the switching element into the inactive state when a functional fault is identified. According to one aspect of the invention, the control part is also configured to generate a data message at the output, which data message is dependent on the functional fault.