| 摘要 |
PURPOSE:To detect an operation mistake, etc. by controlling a switching means in accordance with a state of a switch for connecting/disconnecting a data transfer line to a control device, and informing a connected/disconnected state of the switch to the control device by an address from the control device. CONSTITUTION:Input/output devices 4-6 are provided with control devices 1, 2 and switches 7, 8 for connecting/disconnecting a circuit for sending and receiving a data, and when the switch 7 or 8 is closed, a gate 11 or 12 becomes a movable state. For instance, when the switch 7 is closed, and the switch 8 is opened, an address is sent to a decoder 10 of the input/output device 5 through an address line from the control device 1. As a result, it is informed to the control device 1 that the switch 8 is in a disconnected state. When the switch 8 is closed due to an operation mistake, etc., the gate 11 informs a fact that the switch 8 is in a connected state, to the control device 1. |
