| 摘要 |
In a master-slave-type control system, a normal supervisory control station which is a master device, control terminal devices, and a stand-by supervisory control station which is a slave device for effecting an operation of the normal supervisory control station in place thereof are connected with a common transmission passage. The normal supervisory control station receives data from each control terminal device repeatedly sent on the transmission passage to the normal supervisory control station, collects the data from each control terminal device, and sends its internal data on the transmission passage to an imaginary station at the end of each period of data collection. The stand-by supervisory station intercepts the data of each control terminal device repeatedly send on the transmission passage to the normal supervisory control station, collects the data from each control terminal device, and intercepts the data sent from the normal supervisory control station on the transmission passage to the imaginary station at the end of each period of data collection, whereby switching from control by the normal supervisory control station to control by the stand-by supervisory control station is carried out. |
