| 摘要 |
PURPOSE:To enable a redundant unit to use the same program as a control unit, by performing communication with a backup unit by a priority interruption when an access is given to a memory space allotted to a non-packaged device of the redundant unit. CONSTITUTION:For an (n+1)redundancy control system, a redundant unit 5 having a communication function and an intelligence is connected to plural process control units 41-4n having communication functions, intelligences and I/O devices respectively with a communication line 6. The units 41-4n contain a memory space including I/O regions, and the unit 5 has a memory space of the same size with a non-packaged I/O region. The communication is carried out to a faulty unit 4jo by means of a parameter for access of memory space in response to a priority interruption based on the no-response of memory when an access is given to the non-packaged I/O region of the unit 5 in case the unit 5 backs up the faulty unit 4jo. As a result, the unit 5 can use the same process control program as the unit 4jo. |
