| 摘要 |
PROBLEM TO BE SOLVED: To exchange a duplex input and output controller even when a central processing unit or a serial transmission path is abnormal. SOLUTION: This device is provided with a receiving buffer circuit 61a, an input and output address switch 67a, a frame receiving circuit 63a, an input and output control circuit 65a, a frame transmitting circuit 64a, a transmitting buffer circuit 62a, a state monitoring circuit 66a for monitoring the state of its own input and output controller, a priority setting switch 68a, and logic circuits 69a-73a for controlling the transmission of the transmitting buffer circuit; based on a transmission control signal from the frame transmitting circuit, a state normal signal from the state monitoring circuit, the other state normal signal from the state monitoring circuit of the duplex other input and output controller, and the priority from the priority setting switch.
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