| 摘要 |
PURPOSE:To improve the reliablity of the system, by disconnecting a loop synchronization control station from the transmission line and controlling the synchronization of the transmission line by a station, which executes the function of the control station, to continue data transmission when a fault occurs in the control station. CONSTITUTION:A synchronization control station 1 which has input and output terminals short-circuited by by-pass circuits 9-12 when it is disconnected from a transmission line 13, terminal stations 2 and 4, and a stand-by synchronization control station 3 are connected to constitute a loop data transmission system. The data format transmitted in this system consists of a synchronizing bit S, an other-party station address DA, an originating station address SA, a flag bit F, and a data word D, and flag bits F are set to all ''1'' to transmit data from the control station, and received flags F are monitored by the stand-by control station 3, and further, flag bits F are set to all ''0'' to transmit data to the transmission line 13. When a fault occurs in the control station 1, the control station 1 is disconnected from the transmission line 13, and the function of the control station 1 is executed by the stand-by control station3, and thus, the synchronization is acquired to continue data transmission. |
