| 摘要 |
First and second switches are switches to be detected. An AC signal source supplies AC signals to the switches. A controller includes: one photocoupler for outputting a signal when a supplied current is positive and is equal to or greater than a first current, and when the supplied current is negative and equal to or smaller than a second current; a first diode for receiving an output signal from the AC signal source when the first switch is turned on, and outputting a positive current to the photocoupler; a second diode for receiving an output signal from the AC signal source when the second switch is turned on, and outputting a negative current to the photocoupler; a first latch for latching an output signal from the photocoupler when the AC signal is positive; a second latch for latching output data from the photocoupler when the AC signal is negative; and a CPU. The CPU detects the ON/OFF states of the first and second switches in accordance with output data from the first and second latches, and performs a control operation. |
