| 摘要 |
PURPOSE:To detect the abnormality of a terminal equipment without deteriorating the processing capacity of a central controller, by detecting the potential of a terminal control and maintanance bus provided between the central controller and the terminal equipment. CONSTITUTION:When a central processor 201 provided on a central control unit 200 executes an input/output instruction, address information is outputted through an address bus driver 202 data information is inputted and outputted through a data bidirectional bus driver 203, the input/output instruction is outputted through an input/output instruction transmitting gate circuit 204, and an output instruction is outputted through an output instruction sending-out gate circuit 205, and is connected to terminal equipments 250-2no. Displacement of a terminal control and maintenance bus 215 is detected by comparators 209, 210, and such faults as disconnection of a control bus, a fault of a system and detachment of a terminal equipment, etc., and a simultaneous control fault and a short-circuit fault of the terminal equipment are detected. |
