Patent ID: 6356795
Filing Date: 2002-03-12
Classification: G05B,G06F

Abstract:
A synchronization method for a redundant automation system, the redundant automation system including at least two subsystems, each of the at least two subsystems including at least one processor, the at least two subsystems being linked together by a communication arrangement and executing functionally identical sequences of machine instructions to control a process and being synchronized with one another via the communication arrangement, synchronization being performed at least when one of the at least two subsystems registers a special event, the synchronization method comprising the steps of:relaying by each of the at least two subsystems an instantaneous value of a respective synchronization counter; determining by each of the at least subsystems a synchronization counter target value as a function of the instantaneous value of the respective synchronization counter and as a function of the instantaneous value of a respective synchronization value of the respective synchronization counter of another of the at least two subsystems; interrupting by each of the at least two subsystems the execution of the functionally identical sequences of machine instructions upon attaining a synchronization position within the functional identical sequences of machine instructions, the synchronization position being a value at which the respective synchronization counter attains the synchronization target value; signaling with a synchronization signal by each of the at least two subsystems to the others of the at least two subsystems that the instantaneous target value has been attained; determining by each of the at least two subsystems a response specific to the special event after attaining the synchronization position; after the others of the at least two subsystems register the synchronization signal, carrying out the response by each of the at least two subsystems; recommencing by each of the at least two subsystems the functionally identical sequences of machine instructions after the synchronization position; and relaying by the one of the at least two subsystems the special event to another of the at least two subsystems immediately after registering the special event, the special event being relayed, at the latest, in conjunction with the synchronization signal.