Patent GB-753806-A (GB)
Title: Improvements relating to remote control systems
IPC: B61L7/08
Filed: 1954-09-02
Abstract: 753,806. Selective control and indicating systems. WESTINGHOUSE AIR BRAKE CO. Sept. 2, 1954 [Sept. 29, 1953], No. 25502/54. Class 40(1) A party line control system in which for control of apparatus at a number of stations from an office and for indication of the condition of such apparatus at the office use is made of a code consisting of a number of steps for identifying a called or calling station and an equal number of further steps for controlling or indicating is modified by the provision at one or more stations of means increasing the number of code steps devoted to indication and control. The invention is described with reference to a system resembling that described in Specification 589,750 in which a counting chain at a controlled station builds up once during the station identification steps of the code and again during the control or indication steps. A station is modified by the addition of one or more extension sets which cause further successive operations of the counting chain and associate different groups of apparatus with the signalling system for indication or control. Corresponding modifications are made at the control office. As in the system described in Specification 754,181 superfluous steps of the code are eliminated. , General operation. The code consists of a train of impulses of current and absence of current alternately, the impulses of either kind being long or short in accordance with the control or information to be conveyed. These impulses are generated at the control office by a relay OT and at each station by a relay T, these relays interacting with the local counting chain, and the impulses being prolonged in accordance with the codes to be sent as described in Specification 589,750. In the present case, however, the control and indication part of the codes is prolonged by the provision of extension units at the stations and consequential modification at the office. Each extension unit causes the counting chain to build up once more and associate it with a fresh set of control or indication signalling contacts. To avoid waste of line time, office and station are restored to normal when the last significant step for the station concerned has been transmitted. Transmission of control code. On the O1L, O2L, OLP, OLB, OLBP and station selecting relays (in the case assumed) E, 2F, 23G, 234S to send the station selecting part of the code as described in Specification 589,750. 234S energizes SP which releases 23G, 234S remaining locked up. 08 energizes chain repeat relay OCR which locks up. Some of the necessary control signals are then sent during steps 9 to 16 of the code described in the prior Specification in accordance with the settings of various control buttons and levers but to permit of a number of controls in excess of that possible during the steps, a relay 16 operated instead of 08 on the sixteenth step of the code arranges for the re-operation of the counting chain releases KR which pulled up on the operation of OLBP and arranges for 234 SA to be energized instead of 234S to associate a different set of control buttons with the counting and sending relays. O1 releases 16 whereupon KR pulls up again, and a further cycle of code steps proceeds as before. If even this is not sufficient, 234 SA is replaced by 234 SB for a third cycle by the operation of relay 24 in place of 16 and so on, though no further relays 234 S are provided in the system illustrated. In the case assumed the last significant step of the code controlling station 234 is the twenty-fifth and accordingly a circuit is made via a jumpering frame and contacts of 234 SB to cause the operation of the starting button such as 234 STB of the station to be controlled, corresponding relay 234 ST pulls up and locks and energizes transmission master-relay OM which is followed by its slave relay OMP. Sending relay OT then. co-operates with counting chain O1...O8, timing group operation of code-stopping relay OCS when OR changes over for the next step. This releases OM and the remaining relays to bring conditions to normal. Reception of control code. Line relay R repeats the code impulses to counting chain 1...8 and timing group 1L, 2L, LB, LBP. CD operates and locks up initially since this is a control code. If the station-selecting part of the code is appropriate, F, G and S pull up in turn, S remaining locked and CR arranges for the chain to build up again for the second part of the code. Relays P1, P2 now register odd and even long impulses respectively for the duration of the next step and operate the selected control relays via contacts of a relay D operated on the ninth step of the code. All this is as described in Specification 589,750, but in the present system the relay D is the first of a series of relays operated respectively on the ninth, sixteenth and twenty-fourth steps of the code and connecting up different groups of control relays for the respective sections of the code. The control circuits may be such that any particular relay is operated by a particular code step only if the impulse is long or by a particular code step only if the impulse is short or it may be arranged that the relay operates in one direction, for a long and in the other for a short impulse in a particular code position. Specimen circuits are traced for relays of the magnetic stick type and for relays which lock up when operated and are brought down by a reverse impulse over the operating winding. Each additional code cycle involves the addition of an extension unit involving in addition to the D relay referred to above for associating the required function control relays a relay CE operated via contacts of relay 7 on the sixteenth, twenty-fourth, &c. step of the code and a relay MSP for associating a particular group of controlled apparatus with the code sending arrangements for the transmission of an indication code. The CE relays after energizing the associated D relays release on the step following that which operated them leaving the associated D relays locked up until the operation of the next D relays of the sequence. On the completion of the control code, R is steadily energized and the resulting relapse in due course of LBP releases the remaining relays. Transmission of indication code. This is initiated by the unlocking of the normally operated relay ST by the reception of a control code or the change-over of any controlled apparatus. This releases MSTP. If the line is idle, M pulls up, locks, and reverses the connections of the line relay and completes a low impedance impulsing loop shunting-out relay R. At the control office, OR changes over operating the timing relays and first counting relay and relays PC, PCP reversing the connections of the battery to the line. M completes the pulsing circuit for T which intermittently removes the shunt from the line. Provided that the control office has signalled its readiness by reversing the line current, R responds and controls the timing and counting relays as usual. During the station selecting part of the code, relays F, G, S pull up. The last mentioned energizes MSP which associates a group of position and condition indicating circuits with the counting chain for transmission during the second operation of the chain consequent on the changeover of CR. CR also re-operates ST. On the sixteenth step (which is always long and does not affect the function control relays) CE1 is actuated as the eighth relay of the counting chain, locks and energizes MSP1 which associates a new set of indicating circuits with the transmitting arrangements. Similarly on step twentyfour, CE2 replaces CE1 and associates a third set of indicating circuits. On the next even step after the last step with indicating significance code stop relay CS is actuated via an adjustable connector and a contact of the last of the MSP relays and brings about the release of all actuated relays (except ST). Reception of indication code. Relays PC, PCP are actuated initially and OR in responding to the indication code controls the timing group and counting chain in the usual way for the first sixteen steps of the code. SP, operated with S on the last of the long station-identifying impulses causes OCD to operate on the next short impulse and lock up. During the indication part of the code, OCR being operated, long impulses are registered by relays 9...15 which apply markings over wires 49...55 to operate the appropriate indicator relays. The markings consequent on steps 9...15 are applied via contacts of a relay 234 D individual to the calling station, which is operated momentarily on step 16 by a relay 16 which also releases KR (operated on step 1) to unlock the register relays and arranges for a third count by the chain O1...O8. As during the transmitting operation, 234 SA replaces 234 S, unlocking 16. KR re-operates on step 17 and long impulses are similarly registered during steps 17 to 23. On step 24, relay 24 energizes 234 DA momentarily to transfer the registered impulses to a new set of indicator relays and initiate a new counting cycle. On the even step following the last significant step of the indication code, OCS is operated and causes the momentary operation of 234 DB to transfer the final setting of the register relays to the indicator and the re-setting of the code-signalling apparatus. Modified code terminating arrangements. As described above, the number of steps in the control code of a particular station may differ from the number of. steps in its indication code but does impose a limitation on the latter number. Modified connections Figs. 3 and 4 (not shown) eleminate this limitation. Specification 415,787 also is referred to.