Patent ID: 8509927

Claim:
A control system ( 10 ) for controlling safety-critical processes in an automated system by means of a communications network ( 20 ) with: an unsecured communications master ( 22 ) for controlling the communications on the network ( 20 ); and a plurality of network subscribers ( 12 , 14 , 16 , 18 ), wherein at least three of the network subscribers are configured as decentralized, secure network subscribers ( 16 ) and each has a separate, decentralized safety controller ( 17 ) for controlling a safety-relevant application, each of the decentralized, secure network subscribers ( 16 ) has a unique safety address, each of the decentralized, secure network subscribers ( 16 ) executes safety functions or safety logic operations relevant for said subscriber ( 16 ), the secure network subscribers ( 16 ) are grouped into at least three safety islands ( 1 , 2 , 3 ), and a logical point-to-point communication ( 36 ) via a data line on the network ( 20 ) between the decentralized, secure network subscribers ( 16 ) is configured as a fail-safe point-to-point communication ( 36 ) based on a chain of point-to-point relationships ( 36 ) from one safety island to another safety island, wherein a decentralized, secure network subscriber ( 16 ) of a first safety island ( 1 ) in a point-to-point relationship forms a master ( 32 ) and a decentralized, secure network subscriber ( 16 ) of a safety island ( 2 ) that follows the first safety island in the chain forms a slave ( 33 ), the master-slave relationships between safety islands ( 1 , 2 , 3 ) forming the chain of point-to-point relationships, so that decentralized, secure network subscribers ( 16 ) are pairwise individually connected with each other, thus providing each other safety functions.