When thinking about the applicability of diagnostics, it is not possible to leave out the increasingly important issues regarding the safety of industrial installations. Diagnostics plays a leading role here as a basic measure for the improvement of the overall system safety integrity level. In practice especially, the diagnosis of issues related to the safety of functional devices, machines and systems plays a very important role. Obtaining the designed diagnostic coverage or providing an appropriate level of inviolability of the integrity of a system is now completely unimaginable without the use of methods of detection and fault isolation.