| 摘要 |
PURPOSE:To realize a backup system for a master station fault easily by giving a master station plural addresses, and providing a means by which the master station selects them by itself. CONSTITUTION:If a computer 1a functioning as a master station is shut down, a computer 1b acquires the rights of the master station and, while setting the address 2a of the computer 1a in its own address register 6b, disconnects the shut-down computer 1a from a transmission line. Each subordinate station 4, on the other hand, transmits data together with the added address of the computer 1a as usual without knowing that the computer 1a is shut down, but the computer 1a is disconnected from the transmission line already and the data is received and processed by said substitute master station (computer) 1b. Therefore, even if the master station has a fault, each subordinate station 4 transmits data to the master station under no influence of the fault. |
