| 摘要 |
PROBLEM TO BE SOLVED: To provide a device transmitting plural contact point signals even by one optical transmission line by frequency-dividing the signal of a transmitter in a frequency division circuit, generating a waveform showing the open/close state of the contact point of a relay circuit in an AND circuit and sampling the output signal of the AND circuit in a CPU. SOLUTION: The CPU 5 in the optical transmitter 21 samples the signal from the AND circuit 4 and detects the constitution of a frequency component. Thus, the CUP 5 can discriminate the open/close state of the contact point of the relay circuit 3 and transmits the contact point state to a transmission part 8. The transmission part 8 drives a light-emitting device and sends an optical signal to the optical transmission line 7. The reception part 9 of an optical receiver 22 converts the optical signal received through the optical transmission line 7 into an electric signal and sends it to the CPU 5. The CPU 5 decodes the electric signal and discriminates the content of a communication message namely, the open/close state of the contact point A and the contact point B in the relay circuit. DC voltage is outputted to a contact point A output terminal 19 or a contact point B output terminal 11 for showing the opening/ closing state. |
