GB2144220A - Pick-up device for a meter and a metering system - Google Patents

Abstract

A pick-up device 20 for detecting the rotations of the disc 13 of a meter 10, comprises a bifurcated member 24 mounted on an adjustable bracket 21, an optical source (26, 26', Figs. 2,4 and 7 not shown) being mounted on one arm of member 24 and an optical detector 28, being mounted on the other arm, a hole or slot in the disc periodically intercepting the straight line between source and detector. Capacitative or inductive detectors may alternatively be employed. The output of the detector 28, is supplied to a timeswitch and register circuit (150, Figs. 8 to 10 not shown) which has a tariff selection circuit for selecting a particular charging rate in dependence on the time. <IMAGE>

Description

SPECIFICATION Pick-up device for a meter and a metering system The present invention relates to a pick-up device for a meter and more particularly to a device for detecting the rotations of a disc in an electricity meter. Further the invention relates to a system for ascertaining data concerning the amount of, say, electricity supplied to a user. In addition, the present invention relates to a module for receiving and storing data in such a system.

Existing electricity meters are read by visual inspection of dials with rotating hands or numbers appearing on a plurality of adjacent rotating drums.

The present invention seeks to provide a device which automatically supplies a signal representing the amount of electricity or other quantity consumed as detected by a meter. The invention also seeks to provide an improved metering system for ascertaining the amount of, for example, electricity supplied to a consumer.

According to a first aspect of the present invention there is provided a device for detecting the rotations of the rotation disc of a meter, comprising electromagnetic wave source means and detector means to receive the output thereof and to produce a corresponding outout signal, the disc of the meter having a through aperture which coincides with the straight line between the source means and the detector means.

The detection is preferably effected optically and the detecting means may comprise an infra-red sensorwhich is arranged to detect the output of an infra-red source, such as a gallium arsenide LED.

In a preferred arrangement the rotating disc of a meter, e.g. an electricity meter, is interposed between the source and the sensor cutting the straight line between the two perpendicularly. At least one through hole or slot in the disc is arranged to coincide with the straight line upon each rotation of the disc, so that the radiation from the source reaches the sensor.

The output signal from the detecting means is preferably electrical, e.g. a pulsed signal.

The device may comprise a bracket which is attached to an otherwise conventional meter. In a preferred arrangement a bifurcated member is attached to the bracket with the source arranged on one tine and the sensor arranged on the other tine, with the disc arranged to lie between the tines.

The detection may alternatively be effected inductively or capacitatively instead of optically.

The disc referred to above may be the existing disc of a conventional meter. If desired a separate disc may be employed, parallel to the existing disc on the same spindle.

The device may be employed as an interface unit between a meter and a supply metering system.

According to a second aspect of the present invention there is provided a device comprising means for detecting the rotations of a rotating member of a meter and producing an output signal representative thereof.

According to a third aspect of the present invention there is provided a supply metering system comprising a meter having means providing a signal representing the amount of a metered quantity, a module connected to the meter, and a monitoring unit with means for connecting it to the module. The module is preferably a timeswitch and register module which includes a plurality of stores corresponding to different charging (tariff) rates of said quantity. The quantity is preferably electricity.

According to a fourth aspect of the present invention there is provided a module comprising an adaptor and an electronics unit which interfits therewith, the adaptor having means for electrical connection to a meter, the adaptor being arranged to effect a tapping from an electrical supply to the meter to provide a power supply for the electronics unit. In a preferred arrangement, the adaptor has terminals for receiving power supply conductors, the electronics unit constituting a cover for said terminals. The electronics unit is preferably a timeswitch and register unit. The adaptor may have means for making further connections with the meter.

According to a fifth aspect of the present invention there is provided a timeswitch and register circuit comprising clock means, means for storing predetermined switching times, means for selecting a parti culartariff in dependence on the outputs of the clock means and the storing means, means for supplying pulses representative of a quantity to be charged, and further storing means comprising a plurality of register, the pulses (or signals representative thereof) being routed to one of the registers in dependence on the output of the tariff selection means.

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings of which: Figure 1 shows a bottom perspective view of an electricity meter having a device according to the present invention; Figure 2 shows a side view of the device of Figure 1; Figure 3 shows a view perpendicular to the view of Figure 2; Figure 4 shows a side view of a modification of the device of Figure 2; Figure 5 shows a view perpendicular to the view of Figure 4; Figure 6 shows part of a device in accordance with a further modification; Figure 7shows a side of a device in accordance with a further modification of the present invention; Figure 8 shows a supply metering system in accordance with the present invention;; Figure 9 shows a perspective view of the meter and an exploded view of the timeswitch and register module of the system of Figure 8; Figure 10 shows the module of Figure 9 when assembled; Figure ii shows an enlarged view of part of the module in the direction of arrow A in Figure 9; and Figure 12 shows a block circuit diagram of the module of Figures 9 and 10.

Referring now to the drawings Figure 1 shows the interior of a conventional electricity meter 10 with terminals 11, a display window 12 and a rotating disc 13. Disc 13 usually has graduated markings around its circumference. As electricity is consumed the disc rotates and drives drums visible through window 12 to indicate the total amount of electrical power consumed. Disc 13 has a through hole (not shown) at one part thereof.

A detector device 20 is attached to the meter by means of a universally adjustable bracket 21, which is arranged to be attached by a securing member 25 to one of the main fixing bolts of any of the more commonly used single phase kilowatt-hour meters.

Mounted on a crank-shaped arm 22 of the bracket is a bifurcated member 24 which somewhat ressembles a tuning-fork.

On one arm or tine 25 of the member 24 there is mounted a gallium arsenide light emitting diode 26 which emits radiation in the infra-red range. The diode is supplied with pulses with a mark/space ratio of 1:10 from the pulse generating section of a register unit as disclosed below. Alternatively, the diode can be driven from a suitable D.C supply.

On the other arm or tine 27 of the member 24 there is mounted an infra-red sensor 28 in the form of a photo-transistor. The straight line between the diode 26 and sensor 28 coincides with the radial position of the hole through the disc.

Electrical connections to device 20 are by way of a multicore screened cable which passes out of the meter housing through one of the existing auxiliary connection ports 11'. This may be wired directly into an adaptor of the register unit.

Normally there is no output from the phototransistor 28 but when the hole in the disc coincides with the detector optical path, a train of pulses is emitted. These pulses are processed by pulse shaping circuitry in the timeswitch and register unit to indicate the rotation of the meter disc 13. The pulses are then further processed to obtain information concerning the electricity consumed.

Members 24, 25 may be adjusted to any desired rotational position and may be also moved longitudinally relative to arm 22. They are locked in their finally adjusted position by means of screws 27.

The above-described device is compact and may befitted internally to a meter without any disturbance to the meter mechanism.

Since the device employs a transmissive detection system, several of the common associated with the reflective type of detectors are avoided. Scratch marks on the surface of the disc 13 have no effect, and the hole in the disc has relatively sharp edges elininating the effects produced by indefinite edges of reference marks on reflective systems. It also minltnises the effects of disc chattering at slow speeds. Another advantage is the high immunity to changes in ambient light levels, since the ambient light strikes the meter disc at an oblique angle and very little light is scattered into the detector 28.

The use of pulsed power to drive the LED 26 and also the fact that the increased transfer efficiency of a transmissive system allows the LED to be run at a much lower current means that the lift of the system is much extended when compared with a d.c. driven reflective system. It is expected that the life would be in excess of 15 years.

Figures 4 and 5 shows a modification of the arrangement of Figures 1 to 3, in which both members 24, 25 are secured to the same straight portion of arm 22. This is more convenientforfitting in certain existing meters. Again both members are rotationally and longitudinally adjustable.

Figure 6 shows another modification in which arm 22 is J-shaped. One of the members 24,25 is mounted on portion 22a and the other on portion 22b.

Figure 7 shows a further modification in which on one arm or tine of the member 24 there is mounted one end of an optical fibre 26', the other end of which is connected to a gallium arsenide light emitting diode. On the other arm or tine ofthe member 24 there is mounted one end of a second optical fibre 28', the other end of which is connected to an infra-red sensor in the form of a photo transistor. The straight line between the two fibres coincides with the radial position of the hole through the disc. The optical fibres mounted on the member 24 may be routed out of the meter casing through one of the auxiliary connection parts, enabling the sensor and emitter to be mounted remotely from the meter thus reducing the possibility of electrical interference between the mains power supply and the detection circuit.Alternatively the emitter (diode) and the detector may be mounted elsewhere within the meter casing. Termination of the fibre at the emitter and detector may be by any suitable commercially available fibre optic termination, and the diode and detector may be mounted on a printed circuit board.

The optical connections are also secure against tampering by consumers, since it is not possible to interfere with the optical data transmission.

Various modifications may be made to the abovedescribed devices for example instead of the existing disc 13 of a conventional meter an auxiliary disc may be used to produce the output signals. The auxiliary disc may be conveniently mounted on the same spindle as the existing disc and parallel thereto.

More than one through hole may be provided in disc 13. Moreover instead of one or more through holes, one or more slots in the edge of the disc may be employed. A plurality of devices 20 may be used; such a multiple pick-up arrangement makes it possible to determine the direction of rotation of the disc.

Alternatively, device 20 may incorporate more than one sensor 28 or diode 26 to allow the direction of rotation to be determined. The two diodes or sensors may be mounted at an angle to the centre line of member 24 to allow for easier manufacture or installation. They may conveniently to mounted on individual printed circuit boards fixed to member 24.

Instead of optical detection, inductive or capacitative detection may be employed; in this case disc 13, or where appropriate the auxiliary disc, is preferably fabricated from metal.

The device can be alternatively employed with meters in gas, water and other supply systems.

Referring now to Figure 8 there is shown an electricity metering system comprising a single rate kilowatt-hour meter 110, an interface unit 120, a timeswitch and register module 150, a hand held monitor unit 130 and a master programming unit 140.

The meter 110 contains a rotating disc, each rotation of which causes the interface unit 120 to supply one or more pulses to the module 150. The unit 120 is preferably a pick-up device as described above.

The pulses supplied to the module are then converted to represent the energy used and stored by the module 150 in an appropriate tariff register.

The hand held unit 130 is used to programme, read and check the module 150. The unit 130 itself is programmed by a master unit 140 which can be at a central location within the area of the electricity generating authority.

Referring now to Figures 9 and 10, the module 150 comprises a terminal adaptor 151 and an electronics unit 152. The adaptor is arranged to be located between the meter 110 and the conductors electrically connected therewith.

Generally a kilowatt-hour meter has four conductors connected to terminals at the bottom of the meter; two conductors are inputs from outside the user's premises, and two are outputs connected to the consumer's internal supply circuits, generally via a fuse-box. Accordingly the adaptor comprises four conductive pins 153 which are arranged to electrically contact the terminals at the bottom of meter 110.

Each pin 153 is in electrical communication with a respective socket terminal 155 in the opposite face of the adaptor. Each socket terminal is arranged to receive a respective power conductor which is retained by means of terminal screws 156, Figure 11.

In addition adaptor 151 comprises electrical connectors 158 connected to either the input or output power circuit to tap off a power supply for the electronics unit 152. The tapping is usually taken across the user's side of the meter so that the tapped power will be metered and charge. Furtherconnec- tors are connected to the cable from interface unit 120 to supply power to the LED and to feed the output pulses from the detector to the electronics unit 152 ofthetimeswitch and register module.

The internal circuitry of the electronics unit 152 is shown in Figure 12. Timekeeping is underthe control of a microprocessor real time clock and 99 year calendar 161 which derives its time-base from a quartz crystal oscillator 162. The timing circuit of the microprocessor also provides pulses from a pulse generator 166 for the LED in the optical interface unit 120 on the meter 110; the return pulses are fed into a pulse shaping and processing circuit 167 before beiiig divided down at divider 168 to give one pulse per kilowatt-hour registered on the meter 110. This pulse is then taken by the tariff selection circuit 164 and stored in the appropriate tariff register 155 to give a cumulative indication of the total kilowatthours used.The tariff selection circuit is under the control of the real time clock 161, and compares actual time with the time points stored in a time point RAM memory 163. Up to 40 time points may be stored in the memory 163. From this comparison the real time clock 161 sets the tariff selection circuit 164 to the correct kilowatt hour register for that particular time of day, day and season of the year.

Indication of which tariff is in operation is given by a series of LED's 172 on the front of the unit 152. To ensure that there is no loss of information from the kilowatt-hour registers 165, they are made up of an electrically eraseable programmable read only memory (EEPROM).

Information is fed into and out of the electronics unit 152 of the module 150 using the handset interface connector 174 which is connected to the data exchange control unit 170 via an opto-isolator 169.

To connect module 150, the terminal screws (not shown) at the bottom of meter 110 are unscrewed and the four conductors removed from the terminals. The four pins 153 are then inserted in the terminals of the meter and clamped there using the existing meter terminal screws. The meter terminals are then sealed. The previously disconnected power conductors are then connected into terminals 155 of the adaptor 151 and secured there by screws 156.

The electronics unit 152 is then plugged into the adaptor (see Figures 9 and 10) and is secured thereto by means of a screw 180 engaging a threaded recess 181. This effectively covers the terminal screws 156; the module may then be sealed to prevent unauthorised interference.

An advantage of the above-described module 150 is that it permits charging for electricity at varying rates with only a conventional single rate meter. The complete module is firmly attached to the meter and can be installed without replacing or modifying the meter mechanism. If required, the electronics unit 152 can be changed without disturbing the meter or its wiring. When in position the unit 152 constitutes a terminal cover for adaptors 151. The adaptor contains all the required connections for the unit 152, connections from the pulse interface 120 being terminated in screw terminals 185 in the adaptor.

In addition the electronics unit provides a display 172 of the current tariff; display 172 is parallel to and below the display window 111 of meter 110.

Although an optical interface unit 120 has been mentioned, this can alternatively operate capacitatively or inductively.

In addition display 172 may be modified. For example this may be an LCD display associated with a push-button 187. The display may normally indicate the time of day according to the timeswitch and the tariff in operation. Upon actuation of the pushbutton 187 by the consumer, the contents of each of the kilowatt-hour registers 165 may be read successively.

The hand held monitoring unit 130 is connected to module 150 by means of an umbilical cord (not shown) plugged into connector 174. The unit 130 is used to: a. read data into the timepoint memory RAM 163; b. set the real time clock and calendar (annualiy if necessary); c. set the division ratio of the pulse dividing circuit 168; d. read out the contents of the kilowatt-hour registers 165; and e. check the remaining life of a back-up battery of the electronic unit.

An advantage of the above-described system is that both the tariff rates and the time points at which they change may be updated as required. In addition it permits the recording and supply of detailed information of the use by the consumer of electricity charged at the various rates.

Instead of the umbilical cord the stored data could be transmitted in a contactless manner, e.g. electromagnetically or acoustically. Remote reading is also possible and the information could be superimposed on the power conductors to be transferred to the electricity generating authority. Instead of or in addition to a timeswitch and register arrangement in unit 152 there may alternatively be provided a radio teleswitch, a ripple-control receiver and/or a maximum demand control device.

Although the described system monitors the supply of electricity, it can instead monitor the supply of gas, water or other medium.

Claims (24)

1. A device for detecting the rotations of the rotating disc of a meter comprising electromagnetic wave source means and detector means to receive the output thereof and to produce a corresponding output signal, the disc of the meter having a through aperture which coincides with the straight line between the source means and the detector means.

2. A device according to claim 1, wherein the source means comprises an infra-red source.

3. A device according to claim 2, wherein the source is a gallium arsenide light-emitting diode.

4. A device according to any preceding claim wherein the source means and the detector means are mounted on respective tines of a bifurcated member.

5. A device according to claim 4 wherein the source means comprises a source optically coupled to one end of a first optical fibre and the detector means comprises a detector optically coupled to one end of a second optical fibre, and the other ends of the optical fibres are mounted on said respective tines of the bifurcated member.

6. A device according to claim 4 or 5, wherein the bifurcated member is mounted on a universally adjustable bracket.

7. A device comprising means for detecting the rotations of a rotating member of a meter and producing an output signal representative thereof.

8. A device according to claim 7, wherein the detecting means is an optical detector.

9. A device according to claim 7, wherein the detecting means is an inductive detector.

10. A device according to claim 7, wherein the detecting means is a capacitative detector.

11. A device substantially as herein described with reference to each of Figures 1 to 7 of the accompanying drawings.

12. A meter comprising a device according to any preceding claim.

13. A supply metering system comprising a meter as claimed in claim 12 and having means providing a signal representing the amount of a metered quantity, a module connected to the meter, and a monitoring unit with means for connecting it to the module.

14. A system according to claim 13, wherein the module is a timeswitch and register module including a plurality of stores corresponding to different charging rates for said quantity.

15. A system according to claim 14, wherein the timeswitch and register module has a circuit com- prising clock means, means for storing predetermined switching times, means for selecting a particular tariff in dependence on the outputs of the clock means and the storing means, means for supplying pulses representative of a quantity to be charged, and further storing means comprising a plurality of registers, the pulses (or signals representative thereof) being routed to one of the registers in dependence on the output of the tariff selection means.

16. A system according to any of claims 13 to 15, wherein the module comprises an adaptor and an electronics unit which interfits therewith, the adaptor having means for electrical connection to a meter, the adaptor being arranged to effect a tapping from an electrical supply to the meter to provide a power supply for the electronics unit.

17. A system according to claim 16, wherein the adaptor has terminals for receiving power supply conductors and the electronics unit constitutes a cover for said terminals.

18. Asupply metering system substantially as herein described with reference to the accompanying drawings.

19. As an independent invention the additional feature of any of claims 2to 10 or claims 13to 15.

20. A supply metering system comprising a meter having means providing a signal representing the amount of a metered quantity, a module connected to the meter, and a monitoring unit with means for connecting it to the module.

21. A module comprising an adaptor and an electronics unit which interfits therewith, the adaptor having means for electrical connection to a meter, the adaptor being arranged to effect a tapping from an electrical supply to the meter to provide a power supply for the electronics unit.

22. A module substantially as herein described.

23. A timeswitch and register circuit comprising a clock means, means for storing predetermined switching times, means for selecting a particular tariff in dependence on the outputs of the clock means and the storing means, means for supplying pulses representative of a quantity to be charged, and further storing means comprising plurality of registers, the pulses (or signals representative thereof) being routed to one of the registers in dependence on the output of the tariff selection means.

24. A timeswitch and register circuit substantially as herein described.