| 摘要 |
PURPOSE:To transmit the control to all units with no effect of a faulty unit by closing the bus buffer circuit of the faulty unit to cut a power supply from a common bus in case a data bus or a control bus has a trouble. CONSTITUTION:When a unit 2-1 has a trouble, a bus monitor control unit 3 monitors a parity bit through a data bus 1A. At the same time, a control bus 1B monitors the rule properties of the control signal 4A and sets forcibly the signal 4A at 1. Thus the reset signal RST having the abnormal timing is reset and the bus buffer gate signal EN is set at 1 to a bus buffer circuit 23. Then the circuit 23 is closed and cut off electrically from the bus 1A. Therefore other units 2-2 and 2-3 can use the bus 1A. If the power supply is cut off owing to the abnormality of the power supply of the unit 2-1, a relay contact 30A is made to form a bypass circuit of a gate 29. Then the signal 4A is transmitted directly to a control signal 4B and therefore other units 2-2 and 2-3 are not affected.
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