| 摘要 |
PURPOSE:To improve the reliability and to attain miniaturization, by using plural photocoupling circuits for generating an on/off signal and an alarm signal. CONSTITUTION:A pair of input terminals of two photocoupling circuits 5 connected in parallel are connected in series with a contact 1 of a device control relay. The pair of input terminals of the photocoupling circuits 5 is connected to a light emitting section 51. A signal transmitted from one of photodetecting section 52 between the two photocoupling circuits 5 is inputted to a controller as the on/off signal and given to one input terminal of an exclusive OR gate 6. The signal given from the other photocoupling circuit 5 is given to the other input terminal of the exclusive OR gate 6. The signal given from the exclusive OR gate 6 is inputted to the controller as the alarm signal. |
