device for determining the difference between the number of electrical signals of a first type, and the number of electrical signals of a second type are received by the device.

摘要

1186351 Metering ENGLISH ELECTRIC CO Ltd 30 June 1967 [14 July 1966] 31570/66 Headings G4D D6Y D1D9E and D6C1 Apparatus for summing electrical signals occurring at a plurality of sources comprises stores 16A, 16B, 16C, 16D, Fig. 1, transmitters 14A, 14B, 14C, 14D for transmitting signals from the sources to the associated stores, each transmitted signal being transmitted as a.D.C. level. A scanner 22 sequentially reads-out the stores so that the signals stored therein are accumulated in a counter 12. In the embodiment described for transmitting signals from electricity meters, two toothed wheels on the shaft of each meter rotate in the gaps of two transformers (T2, T3), Fig. 4B (not shown) so that when a tooth enters the gap of a transformer the amplitude of oscillation of an associated oscillator (68, 70) is altered to switch a bi-stable circuit (72) from its one stable state to its opposite stable state so that as each unit of electricity is used a negative signal is induced on the associated transmission lines 34A, 34B, 34C or 34D, Fig. 1. At the associated store, Fig. 2 each negative signal on line 34A cuts-off transistor TR 1 and so renders transistor TR2 conducting to produce a positive-going signal across resistor R8 which is transmitted via capacitor C4 and diode D1A to an associated register 18A, Fig. 1. As the shaft of the electricity meter rotates the negative level is removed from line 34A so that when a scanning pulse is received on line 24, Fig. 2 transistor TR1 is rendered conducting and transistor TR2 cut-off so that a signal is transmitted via capacitor C2 and diode D2A to the counter 12, Fig. 1. The scanner 22 comprises a ring counter incorporating two bi-stable circuits. If one of the meters requires to measure twice as much energy as the other before giving a negative output signal its output line e.g. the output line 34A may be connected through an inverter 41, Fig. 1 to a further store 16A' to which is also connected an output of scanner. Pulses are then accumulated in the counter 12 from the first store 16A when a negative signal exists on line 34A and from the second store 16A' when a positive signal exists on line 34A.