Patent GB-650756-A (GB)
Title: Improvements in remote control systems having a reply impulse train checking the initiating impulse train
IPC: G08C25/02
Filed: 1946-04-29
Abstract: 650,756. Electric selective signalling. ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET. April 29, 1946, No. 12817. Convention date, May 9, 1945. [Class 40 (i)] The invention relates to a system for the remote control or indication of the position " open " or " closed " of circuit-breakers or other apparatus in one or more sub-stations, in which an initiating impulse train consisting of two kinds of impulses (e.g. long and short or positive and negative) is transmitted from one station to another, there being one impulse in the train for each position " open " and " closed " of each circuit breaker at the station in question, impulses of one kind, e.g. long, being transmitted when a control operation or indication is to be effected, and of the other kind, e.g. short, when no operation or indication is required and wherein a corresponding reply impulse train is reverted to the first station for comparison with the initiating impulse train before the executive signal is sent. According to the invention the individual impulses of the initiating train are emitted continuously and independently of the reply train and the two trains overlap to achieve a saving of time. The individual impulses of the revertive train which are locally generated are also corrected as to spacing and duration by the corresponding impulses of the initiating train. Control signal, initiation. As shown, Figs. 4a, b, c, initiation of a control signal at the control station opens contacts KMOa for the duration of the signal cycle. A normally energized relay KTG1 is thereby released after a time-lag determined by a resistor-condenser combination KTG1-R, KTG1-C2, to deenergize over contacts KTG1a the normally energized coil SI of a delayed release relay KTG2 which then closes the energizing circuit of relay KTG1 at contacts KTG2a which in turn re-energizes KTG2. Relays KTG1, KTG2 thus interact for the duration of the signal, the line impulses being sent over contacts KTG1b to impulse a relay UMH at the receiver. The basic " short " line impulses thus sent out, Fig. 1 (not shown), are of constant duration determined by the release time of KTG1. Long impulses are produced by a relay, not shown, which bridges over one or more of the interruptions in the basic train. The manner in which the train is built up of long and short pulses dependent on the order to be sent is disclosed in Specification 650,755. Control signal, reception, Figs. 4c, d, e. The first impulse of the initiating train energizes a relay UMO (not shown), for the duration of the signal. Contact UMOa is thereby opened, whereupon relays UTG1, UTG2 interact similarly to the corresponding control station relays KTG1, KTG2 to revert the reply impulse train over contact UTG1 to operate a relay KMH at the control station. Further contacts a-d, of the relay UMH, control charge and discharge circuits for the coils S2 of relays UTG1, UTG2 over condensers UTG1-C1, UTG2-C2, these coils functioning to accelerate or delay the release of the associated relays so that the individual impulses of the revertive signal are corrected so as to agree in duration and spacing with the corresponding impulse steps of the transmitted train from the control station. Indication, signalling. In the case of a signal initiated from a sub-station the reply impulse train from the control station is similarly corrected by the unit shown in Fig. 4b, which is connected in circuit by an indicating cycle relay closing contacts K10b. Modifications. The impulse correcting members may be located at the control station only, or in all sub-stations only or, as shown, at both control station and sub-station(s). Other forms of impulse generators, e.g. electron tubes, may be used and transformers may be used in the correcting circuits in lieu of condensers.