GB2321753A

GB2321753A - Metering system

Info

Publication number: GB2321753A
Application number: GB9702075A
Authority: GB
Inventors: William Mark Lewis
Original assignee: Landis and Gyr AG; Landis and Gyr UK Ltd
Current assignee: Landis and Gyr AG; Landis and Gyr UK Ltd
Priority date: 1997-01-31
Filing date: 1997-01-31
Publication date: 1998-08-05
Anticipated expiration: 2017-01-31
Also published as: GB9702075D0; GB2321753B; GB2321753A8; GB9709605D0

Abstract

A commodity metering system includes a pre-payment unit 1 with a slot 8 for receiving a smart card 9 loaded with a credited amount of consumption. The unit 1 also houses a switch or control valve 6. The credited amount of consumption is transmitted from the unit 1 via a communications link 2 to a meter 3. The credited amount is stored in the meter 3. The meter measures the consumption of the commodity and when the credited amount has been consumed transmits an alarm signal via the link 2 to the prepayment unit 1 which activates the switch or valve 6 to stop the flow of the commodity to the consumer. Thus for the purpose of activating the switch or valve 6, the credit amount is transmitted once to the meter 3, and the alarm signal is transmitted once to the prepayment unit 1. Thus there is avoided the need to continuously transmit consumption data from the meter 3 to the unit 1.

Description

METERING SYSTEM This invention relates to a metering system for metering consumption of a service which may be supplied by a supplier of the service to a consumer. The service may be any meterable service such as gas, electricity or water, amongst others.

In general there are two types of metering systems which are termed herein "a payment metering system", and "a non-payment metering system". For the nonpayment system, the meter is read periodically, and the consumer is billed for consumption of the service up to the last meter reading. If a bill is not paid, the supply to the consumer may be cut off. In the case of gas this is generally done by attendance at the consumer's premises to operate a manual shut-off valve, and in the case of electricity this may also be done by remote activation of a cut-off switch in the meter for example.

Payment metering systems include prepayment metering systems in which, the consumer pays in advance by loading the meter system with credit, for example by inserting coins, tokens, or, more recently, a smart card which has been loaded with credit purchased by a consumer at a remote point of sale. In such a system, a control unit stores a credit value indicative of consumption for which the consumer has paid in advance. If consumption exceeds the credit value, the system automatically cuts off the supply. In the case of a gas meter, for example, the control unit activates an associated shut-off valve, and in the case of an electricity meter, the control unit simply activates a switch to disconnect the supply. The supply is restored by deactivating the cut-off means when the meter is loaded with further credit.

Payment metering systems also include meters which allow the consumer to be in debt to the supplier in a manner similar to the 'non-payment' systems. The control unit stores a credit limit which is the maximum amount which the consumer may owe the supplier. If the consumer exceeds the credit limit the supply is cut off.

The consumer uses a smart card which is loaded with credit purchased at point of sale. The control unit reduces the debt by the amount of purchased credit.

Depending on the amount of credit purchased some debt may remain, or the debt may be reduced to zero, or a positive balance may be established. Such meters otherwise operate in the same way as prepayment meters.

Payment metering systems may allow the consumer an emergency credit to continue to use the service for a limited period or to a limited amount of consumption after their normal credit has been exceeded. This allows the consumer time to reach a point of sale in emergency situations. The consumption is deducted from the next payment loaded into the system.

Payment metering systems may also allocate credit to both consumption of the consumable service (e.g. gas) and to fixed charges which are independent of consumption. Examples of fixed charges are standing charges, and debt recovery charges.

Payment metering systems thus offer a number of advantages over nonpayment metering systems. Payment metering systems ensure that payment keeps pace with consumption within limits defined by the supplier and the consumer's account is kept up-to-date. The use of smart cards in payment systems also provides a convenient mechanism for communicating consumption data to the supplier since the meter reading can be loaded automatically to the card when inserted in the meter and then read at the point of sale when the card is presented to purchase credit.

It is also known to provide non-payment meters which are, or may be, adapted to connect to a prepayment unit: see for example GB-A-780 574 which discloses a mechanical gas meter adapted to connect to a mechanical prepayment unit by a mechanical coupling which signals the consumption of gas to the prepayment unit.

It is known to provide a prepayment unit and valve controller unit connected to an ultrasonic gas meter via an optical signalling link. The optical link allows direct communication to the prepayment unit of a variety of data produced by a control unit of the meter including meter readings and status information. Prepayment is made using for example a smart card which is plugged into the prepayment unit. The credit value indicative of the amount of consumption credited to the consumer is stored in the prepayment unit. The prepayment unit receives consumption data from the meter control unit and when the credited amount has been consumed causes a gas flow control valve to shut-off the flow of gas. The meter and its control unit are battery powered. Such an arrangement requires continuous supply of data from the meter to the prepayment unit using the energy of the battery.

The invention seeks to reduce signalling between a payment unit and a meter to reduce energy consumption of the metering system.

According to one aspect of the present invention, there is provided a metering system comprising a meter for generating consumption data indicative of consumption of a service by a consumer of the service, control means for storing for the said service a credit value indicative of an amount of consumption credited to the consumer of the said service, and cut-off means selectively operable in response to a control signal to stop supply of the service wherein the control means transmits the said credited amount to the meter, the meter stores the credited amount and transmits an alarm signal when the credited amount is consumed, and the said control signal to stop supply of the service is produced in response to the alarm signal.

"Amount of Consumption" as used herein and in the claims is generic to the amount of consumable service such as gas, water or electricity and also to the amount allocated to any standing charges and any other fixed charges if such charges are made by the supplier.

"Credited amount" as used herein and in the claims is generic to: an amount paid for in advance as used in a prepayment metering system; and an amount allowed within a credit limit.

In accordance with the invention, the monitoring of the credited amount takes place in the meter and the meter generates an alarm signal only when the credited amount is used. This reduces the signalling between the payment unit and the meter because only the credited amount is transmitted to the meter and only the alarm signal is transmitted from the meter for the purposes of controlling the supply of the service.

Thus the amount of signalling between the meter and control unit is greatly reduced, reducing energy consumption by the metering system. Where the meter is battery powered, the load on the battery is reduced.

According to another aspect of the invention there is provided a prepayment unit for use in the metering system of said one aspect, comprising means for storing, for a service, a credit value indicative of an amount of consumption credited to a consumer of the said service and means for transmitting the credited amount to a meter.

According to a further aspect of the invention, there is provided a meter for use in the metering system of said one aspect, comprising means for generating consumption data indicative of consumption of a service by a consumer of the service, means for receiving from a prepayment unit, and for storing, a credited amount indicative of an amount of consumption credited to the consumer for the service, and for producing an alarm signal when the credited amount is consumed.

For a better understanding of the present invention, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a schematic block diagram of a metering system according to the present invention; Figure 2 is a schematic block diagram of a prepayment unit useful in the system of Figure 1; and Figure 3 is a schematic block diagram of a meter useful in the system of Figure 1.

For ease of explanation the invention will be described by way of example with reference to an illustrative prepayment metering system which comprises a prepayment unit 1, linked by a communications link 2 to a meter 3. The consumer uses a smart card and purchases credit in advance. The credit purchased is transferred to the meter system using the card. A gas inlet pipe 4 passes through the prepayment unit 1 to the meter. A gas outlet pipe 5 passes from the meter to a flow control valve 6 in the prepayment unit 1. The prepayment unit 1 is battery powered.

In this example the meter is an E6 ultrasonic gas meter, having an IEC 1107 opto port 7. The link 2 includes an opto port to receive data from and send data to the opto port in the meter. The meter 3 is battery powered.

The prepayment unit 1 has a slot 8 for receiving a smart card 9 loaded with a credited amount of consumption. The unit 1 also houses the gas flow control valve 6. In accordance with the invention, in the example of Figure 1, the credited amount of consumption is transmitted from the unit 1 via the communications link 2 to the meter 3. The credited amount is stored in the meter 3. The meter measures the consumption of gas and when the credited amount has been consumed transmits an alarm signal via the link 2 to the payment unit 1 which activates the control valve 6 to stop the flow of gas to the consumer and thus also to the meter 3. Thus for the purpose of activating the control valve 6, the credited amount is transmitted once to the meter 3, and the alarm signal is transmitted once to the payment unit 1.

Accordingly there is avoided the need to continuously transmit consumption data from the meter 3 to the unit 1, thus reducing the drain of energy from the batteries of the meter 3 and unit 1.

Figure 2 shows in more detail an example of the prepayment unit 1. The unit 1 is powered by a battery 10 and comprises a smart card interface 16, connected to a prepayment controller 15, for communication of data from the smart card 9 to the controller 15 when the card is inserted in the card slot 8.

In operation, the consumer takes the smart card 9 to a point of sale and pays in advance for a desired amount of gas consumption. A credited amount indicating the gas consumption credited to the consumer is loaded onto the smart card at the point of sale, and the consumer then inserts the smart card into the card slot 8 of the prepayment unit 1 on returning to the premises. The card is read by the card interface 16 and the credited amount is supplied to the prepayment controller 15. The prepayment controller 15 stores the credited amount after adjustment, if necessary, for any unused credit left over from the previous payment. While the smart card is inserted in the card reader, other data may be read from the card, eg. settings for the prepayment controller 15, and, the prepayment controller also loads data onto the card, via the card interface 16, for communication to the supplier when the next transaction at the point of sale is made.

The prepayment controller 15 transmits a message including the net credited amount to the meter 3 via a transmitter 22 of the communications link 2 and the opto port 7 of the meter.

The meter transmits back to the controller 15 an acknowledgement that the message has been correctly received, or an error signal if the message has not been correctly received.

The prepayment controller 15 receives the alarm signal from the meter 3 via the opto port 7 and a receiver 22 of the link 2 when the credited amount of gas has been consumed. The controller 15 activates the control valve 6 in response to the alarm signal to cut off the gas flow.

The meter 3 is shown in more detail in Figure 3. The meter is powered by a battery 40 and comprises an ultrasonic measuring device 30 for producing consumption data indicating the amount of gas consumed. The consumption data is supplied to a processor 31. The processor also receives via the link 2 and the opto port 7, the credited amount of gas which the consumer may consume. The credited amount is stored in a store 32 of the processor 31. The processor effectively compares the stored credited amount with accumulated consumption. Once the credited amount is consumed the alarm signal is produced. This maybe done in various ways. For example, the stored credited amount may be decremented as gas is consumed. Once the decremented amount reaches zero, the alarm signal is produced. Alternatively the stored credited amount may be held constant and compared with a value of accumulated consumption held in an accumulator. Once the accumulated value equals the stored amount the alarm signal is produced.

The alarm signal is transmitted to the prepayment unit via the opto port 7 and the link 2.

The batteries 10 and 40 are each a long-life battery such as a Lithium Thionyl Chloride battery having a nominal voltage of 3.6V.

The cut-off valve 6 is shown housed in the prepayment unit 1. The valve could be outside the unit 1. It could be in the meter 3. It could be remote from both the unit 1 and the meter 3.

Although the alarm signal is transmitted to the prepayment unit 1 in the example given above, it may be transmitted directly to the cut-off valve 6, via suitable circuitry.

Although the invention has been described by way of example to metering gas, it may be used for metering electricity, water or another service.

In the case of electricity metering the cut off valve 6 is replaced by a switch.

In the case of water metering the cut off valve 6 is a flow control valve.

The signalling link between the meter and payment unit could be an RF link, a magnetic coupling or a wired electrical signalling link. The control signal could be transmitted to the cut-off valve or switch via an RF link or a wired electrical signalling link. An RF link would be appropriate if the cut-off valve or switch is remote from the meter 3 and/or prepayment unit 1.

The invention has been illustrated with reference to a battery powered prepayment unit 1 and a battery powered meter 3. The prepayment unit and/or the meter could be powered by a solar cell or array of solar cells optionally supplemented by a battery charged by the cell or cells. The prepayment unit and/or meter could be powered from the electrical mains supply.

A single prepayment unit could be linked to two meters, e.g. one gas meter and one electricity meter via respective signalling links.

The invention has been illustrated with reference to a metering system in which the amount of consumption allowed to the consumer is only that for which the consumer has paid in advance. To allow for situations where the consumer cannot reach a point of sale before their prepaid consumption has expired, there is an emergency credit provision allowing the consumer to exceed the amount of consumption for which they have paid in advance. This allows the consumer time to reach a point of sale if unforseen or unplanned additional consumption occurs. It also allows for closure of points of sale at weekends and holidays and unforseen circumstances such as illness.

Furthermore the payment system may allocate a credit limit to the consumer.

Provided the consumer does not exceed his credit limit, he may remain in debt to the supplier. The consumer uses his smart card to reduce or eliminate his debit as he wishes by purchasing credits.

Claims

1. A metering system comprising a meter for generating consumption data indicative of consumption of a service by a consumer of the service, control means for storing for the said service a credit value indicative of an amount of consumption credited to the consumer of the said service, and cut-off means selectively operable in response to a control signal to stop supply of the service wherein the control means transmits the said credited amount to the meter, the meter stores the credited amount and transmits an alarm signal when the credited amount is consumed, and the said control signal to stop supply of the service is produced in response to the alarm signal.

2. A system according to claim 1 wherein the alarm signal is transmitted by the meter to the cut-off means.

3. A system according to claim 1, wherein the alarm signal is transmitted by the meter to the control means which produces the said control signal in response to the alarm signal.

4. A system according to claim 3, wherein the cut-off means and the control means are housed in a payment unit.

5. A system according to claim 3 or 4, wherein the control means and the meter are linked via a signalling link which transmits the credited amount to the meter and the alarm signal to the control means.

6. A system according to claim 5, wherein the signalling link includes an optical signalling link.

7. A system according to claim 5, wherein the signalling link comprises an RF link. a wired electrical link, or a magnetic coupling.

8. A system according to any one of claims 1 to 7, wherein the cut-off means and the meter are housed in the same housing.

9. A system according to any one of claims 1 to 7, wherein the cut-off means is remote from the meter and the control means.

10. A system according to any preceding claim, wherein the said service is provision of gas and the cut-off means comprises a flow control valve.

11. A system according to any one of claims 1 to 9, wherein the said service is provision of electricity and the cut-off means comprises an electrical switch.

12. A system according to any one of claims 1 to 9, wherein the said service is provision of water and the cut-off means comprises a flow-control valve.

13. A system according to any preceding claim, wherein the said amount of consumption includes fixed charges.

14. A metering system substantially as hereinbefore described with reference to Figure 1 optionally together with Figure 2 and/or Figure 3.

15. A payment unit for use in the metering system of claim 1, comprising means for storing for a service a credit value indicative of an amount of consumption credited to a consumer of the said service and means for transmitting the credited amount to a meter.

16. A unit according to claim 15, further comprising means for receiving from a meter an alarm signal indicating the credited amount has been consumed and for producing in response to the alarm signal a control signal for operating cut-off means to stop supply to the service.

17. A unit according to claim 16, wherein the receiving means includes an optical signalling link.

18. A unit according to claim 16 wherein the receiving means includes an RF link, a wired electrical link, or a magnetic coupling.

19. A unit according to claim 16, 17 or 18, further comprising cut-off means housed in the unit and responsive to the control signal to stop supply of the service.

20. A unit according to claim 19, wherein the service is provision of gas and the cut-off means is a gas flow control valve.

21. A unit according to claim 19, wherein the said service is provision of electricity and the cut-off means comprises an electrical switch.

22. A unit according to claim 19, wherein the said service is provision of water and the cut-off means comprises a flow-control valve.

23. A unit according to any one of claims 15 to 22, wherein the said amount of consumption includes fixed charges.

24. A payment unit substantially as hereinbefore described with reference to Figure 2.

25. A meter for use in the system of claim 1, comprising means for generating consumption data indicative of consumption of a service by a consumer of the service, and means for receiving from a payment unit, and for storing, a credited amount indicative of an amount of consumption credited to the consumer for the service, and for producing an alarm signal when the credited amount is consumed.

26. A meter according to claim 25, further comprising means for transmitting the alarm signal.

27. A meter according to claim 26, wherein the transmitting means include an optical signalling link.

28. A meter according to claim 26, wherein the transmitting means includes an RF link, a wired electrical link, or a magnetic coupling.

29. A meter according to claims 25, 26, 27 or 28, further comprising cut-off means responsive to the alarm signal to stop supply of the service.

30. A meter according to claim 26, 27 or 28 wherein the transmitting means is for transmitting the alarm signal to the payment unit.

31. A meter according to any one of claims 25 to 30 for metering gas.

32. A meter according to any one of claims 25 to 30 for metering electricity.

33. A meter according to any one of claims 25 to 30 for metering water.

34. A meter substantially as hereinbefore described with reference to Figure 3.