| 摘要 |
PURPOSE:To facilitate the self-diagnosis job by providing a means switching its input to any device and a changeover means controlling the inhibition of the access of a controller being diagnosed between an input/output controller and an input/output device so as to eliminate the disconnection/connection job at self-diagnosis. CONSTITUTION:The input/output controller is connected between a central processing unit and the input/output device via a system bus and the self- diagnosis device is interposed between the controller and the input output device. An output signal from the controller is transferred to a bus out-line 1 and the input is transferred to a bus in-line 2. Further, the input/output device uses a tag-out line 3 and a tag-in line 5. A changeover means 1A of the device is provided with a changeover means 1B controlling a driver 5 and a receiver 6 of the respective controller and input/output device. Then the means 1A switches any input of the controller and the input/output device and the means 1B outputs a signal inhibiting the operation of the device being diagnosed.
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