REDUNDANT DECENTRALIZED CONTROLLER

摘要

PURPOSE:To make a backup through a reducdant unit if a process control unit is faulty in a decentralized controller which has plural control stations each connecting process control units through an internal communication line and grouping them in one. CONSTITUTION:Process control units 41-4n, a cluster control unit 5, and a redundant unit 6 are connected mutually through an internal communication line 7 to constitute one control station. The redundant unit 6 makes a backup under the command of the cluster control unit 5 when a fault occurs to one of process control units 41-4n, e.g., 4j. The backup is performed by driving the input and output equipment I/O of the process control unit 4j by the intelligence terminal of the redundant unit 6 through communication. Data processing for the backup is carried out on the basis of the data of the input and output equipment I/O and a data base of the process control unit gathered in an up-load memory NMUU.