| 摘要 |
PROBLEM TO BE SOLVED: To quickly discover malfunction of an apparatus to cope with it by installing a means for periodically monitoring abnormality such as contact fusion of a momentary switch, instructing operation stop to a controlled apparatus when a phenomenon considered an abnormal state is discovered, and displaying a failure state. SOLUTION: When an ON switch 4 is operated, a switching transistor 1 is temporarily made ON, power is supplied to a power continuing instruction generating means 7, a power continuing signal is outputted to a resistance- incorporating type NPN transistor 16, and an ON state of the switching transistor 1 is continued. When the ON switch is made ON again, base potential of a resistance-incorporating type NPN transistor 20 is dropped, the transistor 20 is made OFF, signal voltage to an ON switch abnormality judging means 9 is switched from 'Lo' to 'Hi'. When the ON state is continued 5 seconds or more, a contact is considered fusion, this information is transmitted to a control means 10, sending of an electric wave is stopped, and abnormality is displayed on a display 11.
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