Abstract: Apparatus or systems have function elements, for example final control elements as motors, generators as radiation generators, control/regulating means, etc. Their function, as well as satisfying their function, are monitored by processors. In particular, reliability-relevant or safety-relevant monitorings are undertaken. A processor is disclosed which generates a malfunction signal at an output when a malfunction of a function element occurs. A monitoring circuit responds to this malfunction signal, whereupon at least the function element is switched into a quiescent condition, and all processors are switched into the identical condition.