| 摘要 |
<p>An input/output circuit system included in the main control section of a semiconductor manufacturing apparatus or the like comprises self-diagnosis circuit. This circuit is provided with link switches each between an output channel for outputting a control signal to drive an apparatus-side drive part constructed on an I/O board and an input channel for inputting a return signal and a sensor signal responsive to the control signal. This circuit is provided also with self-diagnosis switches for cutting off a power supply line to the apparatus-side drive part. When self-diagnosis is carried out because of a failure, each self-diagnosis switch is opened and each link switch is closed to cut off the electtical connection to the apparatus. Thus, it is judged that no electrical fault occurs when a return signal corresponding to the self-diagnosis signal outputted from the main control section is returend, and that electrical fault occurs when the return signal is not returned.</p> |
