Patent GB-694907-A (GB)
Title: Improvements in systems of electrical remote indication
IPC: H03M1/00
Filed: 1951-04-27
Abstract: 694,907. Electric selective signalling. GENERAL ELECTRIC CO., Ltd., and FIELD, R. W. G. Feb. 12, 1952 [April 27, 1951], No. 9940/51. Class 40 (i). In a telemetering system, the meter-movement torque is opposed by a counter-torque which is increased by additative but successively diminishing steps by a storage device responsive to the degree of balance. Any increment of torque which produces overbalance is removed before application of the next reduced increment. The retained values which represent the meter reading in coded form, are then. transmitted electrically. The binary. code is preferably used. As shown, the torque produced by the meter OM, whose reading is to be transmitted, tends to close a contact MC in opposition to the counter torque produced thereon by a balance movement BM. The two coils OM, BM may alternatively be mounted on a single core and act as a differential relay. When a reading is to be transmitted a start relay ST is momentarily energized to energize successively the relays A, B, ... G of a counting relay chain under the time control of a pair of alternately operated slow-torelease relays X, Y. When relay A operates a direct current corresponding to ¢ the maximum torque:exerted by the originating meter OM is fed from-+ ve at G5 through the balancing movement over resistor Rl. If contact MC remains closed the relay AA of a storage relay chain AA, BA, ... GA is operated and locks at AA1 so that when relay B operates the ¢ maximum torque current flow through the balance movement is maintained over contacts AA2. Relay B feeds a “ maximum torque current through the balance movement over resistor R2 and if the counter torque is still not sufficient to open contact MC, relay BA operates to maintain the current flow when relay C operates. In this way the operation of the counting chain relays successively add counter torque currents corresponding to ¢, “, #, ... 1/128 of maximum torque to the balance movement. If overbalance is achieved at any step in the chain, the relay in the storage chain corresponding to the operative counter chain relay is not operated as the contacts MC are open, so that at the next step of the counter chain the counter current added by the preceding step is removed. In this way a 'combination of the relays in the storage relay chain is operated corresponding to the binary value of the meter reading. After the last relay G of the counting chain has operated, release of relay X operates a relay RL which locks, releases all the relays A ... G of the counting chain and applies + ve to a line 24 which causes potentials, direct or alternating, to be applied to lines 1 ... 7 so that the digits of the binary value are transmitted successively or simultaneously over contacts of the storage relays and lines 8 ... 21 to the remote point. Release of the counting relay chain re-energizes relay X which releases RL. The setting of the storage relays is maintained until the start relay ST is again energized to open the locking circuits of the energized storage relays. The, counting relay chain may be replaced by a stepping switch. Specification 644,041 is referred to.