| 摘要 |
PURPOSE:To ensure a detection of the fault in an extremely short time by returning the answer to the data of a fixed format to the secondary transmission line by the slave unit which received the loop back command from the primary transmission line and via the logic circuit and then sending the answer back to the master unit. CONSTITUTION:Slave units 12-0-12-6 are linked to master unit 11 containing the computer via a pair of loop-type transmission lines 31-I and 31-II (primary and secondary). The loop back command ordering to give a loop back to a pair of data transmission formats is written in unit 11, and then the addresses of the slave units to be designated in sequence into a pair of data transmission formats. Thus, the slave unit which received the designation receives the loop back command through the primary transmission line 31-I, and the answer to the fixed data of a fixed format is returned to the secondary tansmission line 31-II via logic circuit 42 to be then sent back to unit 11. In this way, the fault can be detected in an extremely short time. |
