Patent GB-644041-A (GB)
Title: Improvements in electrical impulse counting devices
IPC: H03K23/74
Filed: 1948-03-10
Abstract: 644,041. Telemetering. GENERAL ELECTRIC CO., Ltd., and SMART, N. C. March 10, 1948, No. 18099/47. [Class 40 (i)] [Also in Group XIX] In a device for periodically summating and transmitting the impulses of a rotary contact making wattmeter or the like, which summation may be of either " export " or " import " sense, the impulses are counted by a relay chain operating on the " radix 2 " system and counting forwards or backwards. A timing device periodically transfers the indications of the relays operated in the counting chain to a second group of register relays and releases the operated relays in the counting chain, the register group operating to transmit each impulse total through known coding and transmitting equipment to a remote display. In Figs. 1 and 2, the export and import impulses to be counted are respectively applied as +ve signals over leads EX and IM. The initial impulse on EX operates relay EA; contact EA1 disconnects relay IA and connects lead IM to relay SU ; EA2 operates relay AD from the impulse. EA4 indicates the export sense to the coding equipment ; contact AD1 operates relay A of the " radix 2 " counting chain through contact B1. Contact A1 prepares to operate relay B, A2 prepares to release relay A, A3 holds relay EA through already closed EA3. At end of first impulse, +ve is removed from EX and AD releases. AD1 removes +ve from the join of upper coils of A and B, and B operates in series with A from +ve on T1. B1 transfers operating path from the A-B relay combination to the C-D combination and prepares to release the A-B combination, while B3 prepares to operate relay U. Relay EA remains locked while the counting chain is adding export impulses, and the next impulse operates and releases AD. AD1 operates relay C via B1, AD2, D1, and energizes the lower coil of A through A2 in opposition to the current in the upper coil, so releasing the relay, while B is held on its lower coil whose current reinforces that in the upper coil. C1 prepares to operate relay D at the end of the impulse, and C3 holds EA operated when A3 opens. At the end of the second impulse AD1 opens, releases B, and D operates in series with C. Thus initially all relays of the chain are released, after one impulse relays A, B are operated, after two, relays C, D, and subsequent impulses similarly set up specific relay combinations, e.g. third, ABCD ; fourth, EF; fifth, ABEF, &c. The relay chain may be indefinitely extended, each additional pair doubling the counting capacity. After a predetermined time interval, a relay T is momentarily impulsed by a timer over lead TE, and applies +ve to contact B3, D3, &c. to operate the relays in the U ... X register chain corresponding to the associated operated pairs of relays in the counting chain. After e.g. five impulses, the operated counter relays ABEF would operate the register relays U, W. T1 releases the operated counter relays ABEF, and the operated register relays U, W lock over their right-hand windings. U2 operates relay Z from positive on T1 while latter is operated, U3 marks the coding equipment (not shown) to send a code corresponding to operation of U, and Z1 starts the coding equipment. Relay W operates similarly to U. On release of relay T at the end of the timing impulse, further impulses on EX are added in the counting chain, while the coding apparatus transmits an indication to the main station of the number and position of the register relays operated by the counting chain. At the main station, the received code is translated into an impulse total displayed by a lamp group or meter pointer. The display, which may be that described in Specification 354,459, [Group XXXIX], remains unaltered for the succeeding time interval during which T is released. A pilot display may be provided at the substation. Import impulses on line IM operate the counting relay chain to cancel any already counted export impulses, and when the latter are all cancelled import impulses are counted as export impulses, and operation of contact IA4 causes the impulse total to be transmitted by the coding equipment to the main station as an import. If the added impulses in two successive time intervals are the same, no transmission is made to the main station at the end of the second interval.