Monitor system for operation of solenoid operated devices

摘要

Command words with address signals are transmitted periodically from a control room to field solenoid valves which are each provided with a single actuation circuit. The solenoid valves that are to be actuated in the field each correspond to the address of the transmitted command words which energize the coil of the corresponding solenoid valve. The actuation circuit inserts an address signal for that particular circuit with regard to current information flowing in the energized coil and sends it back to the control room as an acknowledge word. The control room previously predicts acknowledge words which will be sent back by the actuation circuits when the actuation circuits properly respond to the transmitted command words and the control room registers the predicted acknowledge words as reference words. The acknowledge word sent back by the actuation circuit is compared with the reference word and if an inconsistency exists a fault in the actuation circuit is indicated. The command words includes a control signal N to continuously energize the solenoid valve and a test signal for momentarily energizing the solenoid valve for test. These signals are transmitted from the control room alternately at predetermined intervals and the indication of the compared result of the acknowledge word and the reference word is inhibited during a predetermined time period after the alternation of the address.