GB601409A - Improvements relating to remote control systems - Google Patents

Abstract

601,409. Electric control systems. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd. Oct. 2, 1945, No. 25563. Convention date, Nov. 15, 1944. [Class 40 (i)] Relates to a remote control system of a central office and a plurality of remote stations in which any remote station can communicate with the central office by transmitting an impulse to actuate a relay at the central office to reverse line current which is then interrupted in accordance with code by a relay at the remote station, and consists in providing a rectifier in series with the line relay at each remote station to eliminate weakening of line current by the parallel circuits of other remote stations. Transmission from central office and reception at station.-Relay OM is energized to complete circuit of relay OT for operation by coding unit CU. Relay OT operates to reverse contacts b, d and interrupt the line current in accordance with the code signal. At remote stations relays R are operated by the coding signal to select that station appropriate to the signal. Transmission from a remote station to central office.-Relay M at the remote station is energized to reverse the connections of relay R and short circuit the line YZ over contacts of relays E and LBP, so that relay R releases and the line current is increased to reverse relav OR at the central office. Relay PC picks-up to reverse the polarity of the line current and release relays R at all stations, and the office coding unit CU is simultaneously connected to energize relay OLBP to complete a holding circuit for relay PC until the code from the remote station is fully received when relay 016 operates to de-energize relay PC. Relay M at the transmitting station also completes a circuit for the operation of relay T by the station coding unit CU so that the reversed line is interrupted under the control of the station coding unit, which also operates relay LBP so that relay R operates in unison with the releases of relay T. Relay OR thus responds to interruptions of the reversed line current to control the coding unit CU at the office. At the end of the signal, relay PC releases to restore the polarity of the line current. The rectifier 6 at each remote station prevents those stations in which relay M has not operated from weakening the interruptions in the reversed line current. Where a near station overloads the filter coils 12, a relay ORA, Fig. 2 (not shown) may be operated to reduce line current by switching out part of the battery 80. Simultaneous initiation of transmission from several remote stations.-The codes are assigned so that the station nearer the central office will prevail. Specification 589,332 is referred to.