Patent GB-567424-A (GB)
Title: Improvements in or relating to electric remote control and indication systems
IPC: H02J13/00
Filed: 1943-01-22
Abstract: 567,424. Electric remote control and supervisory systems. STANDARD TELEPHONES & CABLES, Ltd., McWHIRTER, E. M. S., and WARD, H. J. Jan. 22, 1943, No. 1118. [Class 40 (i)] In an electric remote control and supervisory system, the signals representing letters or numerals or both are transmitted in a start-stop printing telegraph code and are printed in a normal teleprinter in addition to being used, in part, to select and operate indicating or control equipment. In the two-way system shown in Fig. 1, sources A, B, &c., which may be twoposition apparatus such as circuit breakers or multi-condition apparatus such as meters or tapped transformers, transmit markings over combinations of circuits to a distributer and thence to a sender. The markings indicate (1) the destination of the signal, (2) the identity of the source, and (3) its condition, and one converted into a start-stop printing code in the sender which may interpolate the time in an end of message signal. The signals are then transmitted by normal telegraph equipment which may also be controlled from a keyboard. The received signals are passed to a normal printer and also to a receiver which translates the code into markings on individual leads. According to the initial " destination " portion of the message, the remainder is switched to an outgoing channel B or a. sorter is brought in to select the particular apparatus it is desired to control. Specification 555,999 is referred to. Signalling equipment of a circuit breaker, Fig. 2. When the breaker shown on the right changes over, LA pulls up, holds over its lower winding, sends a starting signal over STP to the sender, and operates L which by connecting distributor leads ST, CA causes the sender to return to ground to operate ZZ whereupon LA and L fall back but, in the meantime, twoposition relay M has changed over to prepare for a breaker change in the opposite direction. The signals are transmitted over the distributer to the sender by means of switch. SA wired to provide letter and numeral signals in a 5- unit code over leads V to Z and a " letters " signal over lead L. The switch is stepped by ground at the sender on lead SW, the ground being removed on receipt of each character. The destination and the identity of the breaker in letters and numerals is signalled, with suitable spaces or spacing characters, in positions 1 to 18, followed in position 19 by an " in " or " out signal over lead W or Z dependent on the position of relay M. In position 20, absence of battery on any signalling lead indicates " end of message ", whereupon ZZ is released from the sender and the switch goes home. Fig. 11 (not shown) comprises a modification for dealing with transient changes, and Fig. 14 (not shown) a modification for dealing with multi-position equipment, e.g. a meter. Distributer, Fig. 3, deals with six circuit breaker signal equipments A . . . F, shown in outline on the left, and which are given the opportunity of transmitting in cyclic alphabetical order. The order is determined by relays SA ... SF, the corresponding one of which remains operated after a call has been dealt with in order that priority is given to the next in order ; AA ... AF are the corresponding switching relays which connect the signalling leads V ... Z, L to the sender. Assuming no previous calls, BA operates when the power supply is switched on ; BB follows, locks and releases BA; SF pulls up over a chain of contacts of 8A ... SE ; S is operated from the sender followed by SRA which locks. The operating circuits of SA ... SE are now open at s3. If a call comes from equipment B, L(B) operates to connect the corresponding leads ST, CA whereby switching relay AB is operated. This relay locks up, releases S and connects ground to the ZZ lead to start equipment B which returns ground over lead S to operate S B which releases SF. When the breaker equipment signals the " end of message " the sender removes ground from lead B to release all relays except SB which gives C priority for the next call. Sender, Figs. 4 to 7. Normally BR, Fig. 5, is operated and supplies ground to leads B, BR to the distributer; pendulum relay P is energized (shown de-energized) ; telegraph relay SR, Fig. 7, is held on " mark " ; CW, Fig. 5, operated over contacts of the L relays and SA ... SF, Fig. 3, is awaiting release by a call and AS is operated to hold open the transfer circuits (Fig. 4) from the distributer. The starting signal from the breaker equipment operates STP, Fig. 5, whereupon condenser qst. Fig. 7, discharges over a " space " winding of SR to send a start pulse over the line. At the same time CW is released and AS falls back to connect up the transfer relays V ... Z, L, VV, Fig. 4, the operated ones of which represent spaces. The transfer circuits include cold cathode discharge tubes CTV ... CTL. Relay PP, Fig. 6, is operated by any transfer relay (other than the '' letters relay L) and PC, PCR follow, FF or LL being also operated dependent on L to indicate figures or letters. BR is released by PC. The transfer relays and, FF or LL, selectively connect five leads b ... f, Fig. 5, to conductors M, S connected to marking and spacing windings of telegraph relay SR, the elements of the code being transmitted in succession under the control of a chain of relays A-G, Gig. 5, which are picked up and released in turn by pendulum relay P initially energized bv 13R but now released. Ground from contacts of P is connected in turn to the relays of the chain, relay A being connected to a spacing winding of SR, relays G, H to a marking winding to send a long final mark, and intermediate relays B ... F to the leads b ... f and thence to the marking or spacing leads according to the code. Assuming the first character to be a letter, LL is operated and the relay chain performs a preliminary cycle to send the shift code, the connections between b ... f and M, S being determined by contacts of PCR (up), CR (back) and LL. When chain relays F and G operate, FR and GR pull up in turn and the latter operates CRR and CR which hold and place the connection between b ... f and M, S under the control of the transfer relays V ... Z. When GR falls back, it grounds lead SW, Fig. 5, leading to the back stroke magnet of the code-switch, Fig. 2. On the next cycle, the first character is sent out ; AS is temporarily operated by chain relay FR to release the transfer relays, and the code-switch lead is opened by GR to step the switch. CR and CRR remain operated so long as letters are transmitted, the code switch being stepped once every cycle, but when a figure is to be sent, FF is operated to release LL and operate SH which releases CR, CRR. The next cycle is therefore a preliminary one in which the figure shift is transmitted and the code switch is not stepped, CR, CRR being re-operated towards the end of the cycle as in the case of letter shift so that the character code is sent during the following cycle and the code switch stepped as previously described. Relay SH is held temporarily by GA operated by GR. End of message signal. When the code switch of the breaker has, towards the end of the last cycle, been stepped on to unmarked contacts, the transfer relays V ... Z and PP all release, PC is held temporarily by GA and holds PCR. The end of message signal comprises 11 characters of which the first is " figures " independently of the nature of the last character of the message. If it is a figure, FF is held and, when CA releases, PC falls back but CR, CRR hold ; if it was a letter, the relapse of L operates FF and SH and LL falls back, but when GA. releases PC and SH release since CR, CRR have been released by the operation of SH, PCR and FF remaining held. On the next cycle therefore, the figure shift signal is sent by marking b ... f in one case over front contacts of CR and in the other case over back contacts of CR and front contacts of PCR. The remaining 10 characters comprising (if the traffic is light) full stop, 3 time characters, 3 spaces, carriage return, line feed and space are transmitted by markings applied by relays ZA ... ZK operated in succession. The message is shortened in case of medium and heavy traffic as described later. When GA operates towards the end of the figures shift cycle FF, PCR, CR, CRR, if operated, are released, whereupon ZA pulls up over a chain of contacts of ZB ... ZK and applies the marking for the next character. Towards the end of the ensuing transmitting cycle FRA operated by F, FR energizes ZB (left) in series with ZA, CW being normally operated from the " clock circuit ", Figs. 8 and 9, and when FRA is released by G, GR and GA, ZB holds over its right-hand winding to apply the next marking, ZA being released. The remaining marking relays are operated and released in turn in similar manner, BR being finally operated to hold the pendulum relay P and ground lead B to the distributer for the purpose previously described. In the event of another call occuring after the operation of ZB but before that of ZE (medium traffic), the relapse of CW consequent on the call causes ZE-ZG and the three spaces to be skipped. In the case of heavy traffic call relay CW relapses before ZB is operated so that ZB ... ZG are skipped and the time characters are also omitted. If a call from one sender is followed immediately by a call from the same one, the time characters are replaced by spaces. This and related features are described in the next paragraph. Clock circuit, Figs. 8 and 9. When key ON, Fig. 8, is thrown, BR pulls up and half-minute pulses are supplied to HM which operates HA, HB in half-minute succession for periods of one minute. HB steps the units minutes switch SU, the tens switch ST being stepped every tenth step of SU ; lamp indications of the time are given over SU1 and ST6. The banks are strapped to operate units and tens relays UV ... UZ, TV ... TZ in varying combinations. The clock circui