| 摘要 |
PROBLEM TO BE SOLVED: To smoothly and stably control plant facilities even when a failure occurs in a transmitting passage or a failure occurs in a master controller in a plant control system for controlling the plant facilities by transmitting data via a network. SOLUTION: The transmitting passages 4p and 4s are doubled in advance. The data with the same contents is respectively transmitted from respective controllers 1 to 3 to the transmitting passages 4p and 4s in a predetermined time interval so that the same data is not set simultaneously, and the transmitted data includes status information in which values are changed at every transmitting and receiving interval. The slave controllers 2 and 3 determines that the master controller 1 is out of order when the status information included in the data received via the transmitting passages 4p and 4s is not changed, and one of the slave controllers 2 and 3 is switched to perform master switching processing so as to become a master controller. COPYRIGHT: (C)2007,JPO&INPIT
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