| 摘要 |
PROBLEM TO BE SOLVED: To reduce power consumption of a photocoupler when a digital contact signal, etc., are inputted in a microcomputer by using the photocoupler. SOLUTION: In a digital input circuit formed by connecting a light emitting element LED 1 of a photocoupler PC1 with a digital contact signal circuit 3 and connecting a light receiving eleusent Tr1 of the photocoupler PC1 with a digital input circuit 4 of the microcomputer, a light emitting element LED2 of a photocoupler PC2 is provided on a digital output circuit 5 of the microcomputer, a light receiving element Tr2 of the photocoupler PC2 is provided in serial with the light emitting element LED1 of the digital contact signal circuit 3, the light emitting element LED2 of the photocoupler PC2 is turned on just before a state of a contact signal circuit is read by a digital input port DI of the microcomputer and the light emitting element LED2 of the photocoupler 2 is turned off just after the state of the contact signal circuit is read by the input circuit 4 of the microcomputer.
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