SIGNAL TRANSMISSION SYSTEM

摘要

PURPOSE:To detect the opening and closing signal of the solenoid valve of a signal source at a remote place with a simple constitution by installing a two-line-type transmission line also serving as a power source line between a control part and a signal source and providing the signal source with a partial control circuit. CONSTITUTION:A signal source control circuit 16 is the partial control circuit of the solenoid valve 17 installed away from the control part 11, and includes monostable multiplexer 18 and 19, a counter circuit 20 and a signal transmission timing circuit 21, Then the receiving circuit 13 of the control part 11 side receives the return of digital signals which are sequentially turned on and off from the circuit 16 by matching to a timing signal transmitted from the control part 11 at every certain period, and the control part 11 side catches the signal of the signal cource 17 in the prescribed timing. Thus the opened and closed state of the solenoid valve of the signal source 17 can be detected in the remote place.