Abstract:
Apparatus is provided for use with a commodity consumption meter (2), of a type having a sealed housing (3, 4, 6) and including a rotating component (14) whose rate of rotation depends upon the rate of consumption of the commodity, the rotating component being visible through a wall of the sealed housing. The apparatus comprises: a casing (38) which substantially completely covers the wall of the meter (2) and includes a transparent region (62) through which the rotating component (14) can be viewed and an optical assembly (64) for monitoring rotation of the rotating component. Preferably the optical assembly (64) comprises a light source (66) which is amplitude modulated at a selected frequency and is arranged to direct light (70) through the housing onto the rotating component (14) and a light detector (68) to detect reflected light (74) from the rotating component (14), the apparatus further including a synchronous detector circuit (82) connected to the detector (68) and operated at the selected frequency and processing means (96) arranged to count the number of revolutions of the component (14) using the output signal from the synchronous detector circuit (82).
Abstract:
A commodity consumption meter in the form of a modular assembly comprising: a basic module (1) for metering the consumption of the commodity; and at least one add-on module (3,5) for providing a function ancillary to the metering of the commodity, said meter including a connection (13) consisting of a single plug (24) and socket (23) between said basic module (1) and the or an add-on module (3) by means of which the basic module (1) supplies to the add-on module (3) both power and information regarding the metering by the basic module (1).
Abstract:
A synchronous detector circuit arrangement (30) is provided for detecting a signal of interest in an input signal, in which the input signal comprises a signal at a selected frequency which is modulated by the signal of interest and by an unwanted signal. The circuit arrangement comprises signal combining means (33) for combining the input signal with a correction signal (34); a synchronous detector (14) connected to the output of the signal combining means and operated at the selected frequency for detecting the signal of interest; and means (40, 43, 44) for generating the correction signal such that in operation the correction signal is a signal at the selected frequency, is in antiphase with the input signal and has an amplitude which is selected such as to at least partially cancel the unwanted signal.
Abstract:
Apparatus is provided for use with a commodity consumption meter (2), of a type having a sealed housing (3, 4, 6) and including a rotating component (14) whose rate of rotation depends upon the rate of consumption of the commodity, the rotating component being visible through a wall of the sealed housing. The apparatus comprises: a casing (38) which substantially completely covers the wall of the meter (2) and includes a transparent region (62) through which the rotating component (14) can be viewed and an optical assembly (64) for monitoring rotation of the rotating component. Preferably the optical assembly (64) comprises a light source (66) which is amplitude modulated at a selected frequency and is arranged to direct light (70) through the housing onto the rotating component (14) and a light detector (68) to detect reflected light (74) from the rotating component (14), the apparatus further including a synchronous detector circuit (82) connected to the detector (68) and operated at the selected frequency and processing means (96) arranged to count the number of revolutions of the component (14) using the output signal from the synchronous detector circuit (82).
Abstract:
A synchronous detector circuit arrangement (30) is provided for detecting a signal of interest in an input signal, in which the input signal comprises a signal at a selected frequency which is modulated by the signal of interest and by an unwanted signal. The circuit arrangement comprises signal combining means (33) for combining the input signal with a correction signal (34); a synchronous detector (14) connected to the output of the signal combining means and operated at the selected frequency for detecting the signal of interest; and means (40, 43, 44) for generating the correction signal such that in operation the correction signal is a signal at the selected frequency, is in antiphase with the input signal and has an amplitude which is selected such as to at least partially cancel the unwanted signal.
Abstract:
An electricity metering equipment wherein, in order to reduce the possibility of fraudent consumption of electricity, there is provided in addition to the usual meter (3) for measuring the amount of electricity consumed, an independent device (5) which produces a signal corresponding to the supply of electricity. A comparison means (4) then compares the signal with the amount of electricity consumed as measured by the meter, and an output signal is produced if there is a discrepancy which may be used to disconnect the supply and/or transmit a signal to the supply authority.
Abstract:
A transmitter/receiver unit for use in a two way electrical power supply line carrier communication system. The unit includes two conductors (3, 5) for connection to the supply line, and a transmitter (1) and a receiver (7) each connected across the two conductors. A first winding (9) of a transformer is connected in series between the transmitter (1) and receiver (7) on one of the conductors (3). Switching means (13, 15, 21) is provided which is operable to control the impedance across a second winding (11) of the transformer so that the first winding (9) presents a relatively high impedance to carrier signals when the receiver (7) is operating, and a relatively low impedance to carrier signals when the transmitter is operating.
Abstract:
A commodity consumption meter in the form of a modular assembly comprising: a basic module (1) for metering the consumption of the commodity; and at least one add-on module (3,5) for providing a function ancillary to the metering of the commodity, said meter including a connection (13) consisting of a single plug (24) and socket (23) between said basic module (1) and the or an add-on module (3) by means of which the basic module (1) supplies to the add-on module (3) both power and information regarding the metering by the basic module (1).
Abstract:
A commodity consumption meter in the form of a modular assembly comprising: a basic module (1) for metering the consumption of the commodity; and at least one add-on module (3,5) for providing a function ancillary to the metering of the commodity, said basic module (1) supplying to the or an add-on module (3) a single signal indicative of both the rate of consumption of the commodity as metered by the basic module (1) and whether the passage of the commodity is to or away from the consumer.
Abstract:
A transmitter/receiver unit for use in a two way electrical power supply line carrier communication system. The unit includes two conductors (3, 5) for connection to the supply line, and a transmitter (1) and a receiver (7) each connected across the two conductors. A first winding (9) of a transformer is connected in series between the transmitter (1) and receiver (7) on one of the conductors (3). Switching means (13, 15, 21) is provided which is operable to control the impedance across a second winding (11) of the transformer so that the first winding (9) presents a relatively high impedance to carrier signals when the receiver (7) is operating, and a relatively low impedance to carrier signals when the transmitter is operating.