| 摘要 |
PURPOSE:To give a function of protection and of displaying an abnormal condition by applying AC voltage to a four-way selector valve coil, detecting whether the AC voltage is provided or not by a voltage detecting means, detecting abnormality for whether provided or not in a circuit based on a detecting result of this voltage detecting means and based on a connecting condition of a coil electrifying means, and interrupting a main switch means. CONSTITUTION:In a normal condition, a half waveform in a positive pole side of an AC power supplied from a plug 10 is voltage divided by series resistors 31 to 33 and further converted into a low voltage pulse by a photocoupler 35. The pulse is supplied as a pulse signal to an input port P1 of a microcomputer 36. The pulse signal for whether input or not to this input port P1 is judged by the microcomputer 36. In the normal condition, a relay contact 22a is turned off, and a relay contact 23a is connected to a side of a diode 24b. Accordingly, a connection condition of the relay contacts 22a, 23a and the pulse signal of whether input or not to the input port P1 are combined to judge abnormality for whether it is provided or not.
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