WO2006024854A2

WO2006024854A2 - Automated meter reader

Info

Publication number: WO2006024854A2
Application number: PCT/GB2005/003379
Authority: WO
Inventors: Eric Beattie
Original assignee: Iskraemeco Ecl Limited
Priority date: 2004-09-01
Filing date: 2005-09-01
Publication date: 2006-03-09
Also published as: WO2006024854A3; GB0419343D0

Abstract

An automated meter reader and method are provided suitable for monitoring and recording the data output of 4 a utility meter, such as a gas, water or electricity meter. The meter reader comprises a data logger, an isolation barrier, a regeneration unit a communication controller. The isolation barrier can be an optical isolator, providing electrical isolation greater than 10kV (rms). The invention removes the requirement for a separate isolation component, such as a chatterbox, to be placed between the data logger and the utility meter and provides a reader that is efficient and cost effective to install and maintain.

Description

Automated Meter Reader

The present invention relates to the field of utility meters employed to monitor the volume of electricity, gas or water consumed by a user. In particular the present invention relates to an automated meter reader for use in conjunction with such a utility meter.

Utilities provide both industrial and domestic users with commercial electricity, gas and water. From a business stance it is clearly very important that the volume of the supplied commodity is correctly measured so as to provide a means for accurately billing the user or for carry out load analysis. In the UK alone it is estimated that there are approximately V₄ million water meters, 18 million gas meters and 22 million electricity meters. Therefore, it can be appreciated that the monitoring of these meters involves a large scale, labour intensive process especially if each of the meters requires manual retrieval of the output data.

Attempts have been made to automate the reading of the large-scale utility consumers (referred to as Automated Meter Reading or AMR) . Two different methods of automation are known in the art. The first method involves the employment of so-called "intelligent meters" 1 i.e. a meter with data-logging functionality that is coupled to a controlled off of the shelf modem 2, see Figure 1. The major drawback of such systems would be the major expense involved in replacing all the existing utility meters as well as the fact that such meters are not particularly suited for use as gas meters for reasons discussed below.

Alternatively, purpose built modem/interface units 3 have been designed and thereafter installed with existing utility meters 4, see Figure 2. The modem/interface unit 3, commonly referred to as a data logger, is in fact the preferred option, as they tend to be more cost effective than intelligent meters. A data logger 3 effectively acts as a data capture and storage unit that employs a separately powered modem to transfer data to a remote processing site on a daily, weekly or monthly basis.

The data for capture, referred to above, results from the utility meter 4 generating contact closures commensurate with the volume of flow. Thus, as the utility meter 4 operates or passes the product to the end user it causes mechanics within the utility meter 4 to update the reading dials while simultaneously opening and closing internal switches that are normally accessed from the bottom of the utility meter 4. It is these switch closures, referred to as pulses, which are actually monitored and counted by the data logger 3. It is known to those skilled in the art that the switch closures suffer from the effects of bouncing. Bouncing acts to add extra data pulses that appear as noise on an electrical output signal from the utility meter 4. This is a problematic feature that increases as the switches deteriorate with time. Therefore, AMR systems are required to incorporate signal processing in order to compensate for the addition of noise through bouncing.

A significant advantage of data loggers 3 is that they can be calibrated for a particular utility meter 4 by simply programming the pulses to a supplied commodity ratio, i.e. typically 600 pulses per kilowatt/hour for an electricity meter or 100 pulses per cubic meter of gas for a gas meter. Therefore, the same data logger 3 can be employed with different utility meters 4 provided that the conversion ratio is known.

Within the gas utility market an additional isolation component 5 is required to be installed between the utility meter 4 and any data logger 3. This isolation component 5 is required since if a faulty data logger 3 were to be installed with a faulty gas meter 4 then there would be a significant risk of a gas explosion. Consequently, gas suppliers are required to operate under strict guidelines that require any equipment proposed to be connected directly to a gas meter 4, to undergo extensive testing.

Under these guidelines the isolation component 5 must demonstrate isolation levels greater than lOkV(rms) . Any connection to the associated utility meter 4 must not be capable of carrying power greater than a few milliwatts. In accordance with such requirements isolation components 5 are designed that employ relays to provide the necessary electrical isolation. A voltage free pulse from the gas meter 4 acts to operate a transistor within the isolation component 5 that in turn operates a relay. In practice the data pulse is transferred to the safe side of the isolation component 5 by having the data logger 3 read the data pulse generated by the relay. During periods of high consumption pulses flow through the isolation component 5 fairly rapidly causing a number of relays to quickly open and close. A chattering noise emanating from the isolation component 5 results and as such the devices are commonly referred to in the art as chatterboxes.

Such chatterbox isolation components 5 suffer from several inherent limitations. In the first instance relay devices require power to operate. Consequently it is necessary to replace the battery power sources within a chatterbox isolation component 5 every six months or so. Typically each device employs six such battery power sources.

It is also known in the art that relay switches can suffer from mechanical failure causing them to jam. With the systems taught in the prior art such a jam can result in the associated battery being permanently electrically connected such that it quickly drains of power and so requires to be replaced more frequently than expected.

As with the utility meter 4, chatterbox isolation components 5 suffer from the effects of bouncing. As these effects increase with age, regular on site maintenance is required in order to re-synchronise the data logger 3 to the utility meter 4.

Working guidelines for chatterbox isolation components 5 specify that single gas utility meters outputs should be capable of being regenerated to two or more outputs. However, the chatterbox isolation devices taught of in the art are incapable of easily producing more than two regenerated signals.

A further disadvantage of chatterbox isolation component 5 is that they are expensive to produce, install and maintain. Therefore, a more cost effective alternative would certainly be of financial benefit to utility suppliers .

It is an object of aspects of the present invention to provide an automated meter reader suitable for use with a standard gas utility meter that removes the requirement for a separate isolation component to be placed between the data logger and the gas utility meter.

It is a further object of aspects of the present invention to provide an automated meter reader suitable for use with a standard utility meter that is efficient and cost effective to install and maintain.

According to a first aspect of the present invention there is provided a solid-state automatic meter reader suitable for monitoring and recording the data output of a utility meter comprising a data logger, an isolation barrier, a regeneration unit and a communication controller.

Most preferably the isolation barrier is located so as to electrically isolate the data logger from the regeneration unit.

Preferably, the isolation barrier is located so as to electrically isolate the communications controller from the regeneration unit.

Alternatively, the isolation barrier is located so as to electrically isolate the data logger from the communications controller.

Preferably the data logger comprises one or more electrical inputs, a computer processor, a memory unit and a power source.

Most preferably the computer processor provides a means for signal processing the data output of the utility meter.

Preferably the power source comprises a battery.

Most preferably the isolation barrier comprises an optical isolator.

Alternatively the isolation barrier comprises two or more optical isolators wherein at least one optical isolator communicates with the regeneration unit and at least one optical isolator communicates with the communication controller. Preferably each optical isolator provides electrical isolation to a level greater than approximately 10 kV (rms) .

Preferably the regeneration unit comprises one or more outputs suitable for providing a regenerated data utility meter output signal.

Most preferably, the communications controller comprises a modem and a radio transceiver.

Typically the radio transceiver is a GSM transceiver.

Optionally, the communications controller comprises a modulator and a radio transmitter.

Alternatively, the communication controller comprises a computer processor, a modem and a telephone line wherein the telephone supplies the required power for the computer processor and the modem.

Alternatively the communication controller comprises a computer processor, a modem, a battery and a telephone line.

Typically the solid state automatic meter reader further comprises an optically isolated communications interface connected to said data logger.

Preferably, said optically isolated communications interface comprises a light source and a photo receptor. Preferably, said optically isolated communications interface comprises an IEC1107 interface.

Typically the solid state automatic meter reader further comprises an electrically isolated communications interface connected to said data logger and said communications controller.

Preferably, said electrically isolated communications interface comprises an RS485 interface.

According to a second aspect of the present invention there is provided a method for automating the monitoring and recording of a utility meter comprising the steps of: 1) Electrically connecting a solid state data logger to the utility meter; 2) Employing an isolation barrier to electrically isolate the solid state data logger; 3) Reading and recording output data from the utility meter; 4) Creating output signals representative of the output data from the utility meter; 5) Employing an optoelectronic means for transferring the output signals across the isolation barrier.

Most preferably a computer processor is employed to read the output data from the utility meter. A memory unit then records the output data read by the computer processor.

Preferably the computer processor carries out signal processing on the output data from the utility meter before generating two or more output signals. Preferably the signal processing comprises the removal of noise on the output data from the utility meter caused by switch bouncing.

Most preferably at least one output signal is transferred to a communication controller such that it may be relayed to a remote site in order to allow a customer's account to be updated.

Optionally, said at least one output signal is transferred across the isolation barrier to said communication controller.

Preferably said at least one output signal is relayed to the remote site on a daily basis.

Optionally utility load analysis is carried out at the remote site on the output signal.

Preferably at least one output signal is transferred across the isolation barrier to a regeneration unit so as to be available for use by a third party.

Preferably the computer processor provides a means for multiplexing the output data from the utility meter and one or more output signals transferred to the regenerated unit.

Embodiments of the present invention will now be described, by way of example only and with reference to the accompanying Figures, in which: 1 Figure 1 presents a schematic presentation of an

2 intelligent meter as described in the

3 Prior Art;

4 Figure 2 presents a schematic presentation of a

5 purpose built modem interface unit as

6 described in the Prior Art;

7 Figure 3 presents a schematic presentation of an

Q

O automated meter reader having a GSM

9 communications controller, in situ with a 0 standard gas meter, in accordance with a 1 preferred embodiment of the present 2 invention; 3 Figure 4 presents a schematic presentation of an 4 automated meter reader having a line 5 powered modem communications controller, 6 in situ with a standard gas meter, in 7 accordance with an embodiment of the 8 present invention; 9 Figure 5 presents a circuit diagram of the input 0 ports; 1 Figure 6 presents a circuit diagram of the 2 regeneration and isolation units; 3 Figure 7 presents a circuit diagram of the 4 processor; 5 Figure 8 presents a circuit diagram of the 6 control, clocking and memory of the 7 processor support hardware; 8 Figure 9 presents a circuit diagram of the GSM 9 communications controller; 0 Figure 10 presents a circuit diagram of the IEC1107 1 interface; 2 Figure 11 presents a circuit diagram of the RS845 3 interface; Figure 12 presents a circuit diagram of the logger to line powered modem isolation circuit; and Figure 13 presents a circuit diagram of the line powered modem.

A schematic representation of an automated meter reader 6 in accordance with a preferred embodiment of the present invention is presented in Figure 3.

The automated meter reader 6 is a solid state device comprising a data logger 7, an isolation barrier 8, a communications controller 9 and a regeneration unit 10. Locating the data logger 7 on the meter side of the isolation barrier 8 provides the required electrical isolation necessary for employment of the automated meter reader 6 with the gas meter 4.

The data logger 7 comprises input ports 11, a computer processing unit (CPU) 12 (e.g. a Hitachi HD 3664 processor) , an on-board memory unit in the control, clocking and memory support hardware 13, a battery 14 and optical isolators 15. By connecting the data logger 7 to the utility meter 4 data output is transmitted to the CPU 12 via the input ports 11.

The CPU 12 then carries out signal processing of the utility meter output data. Initially this involves detecting the closing of a relay on the utility meter 4. This allows for erroneous data produced as the result of relay bouncing removed and for output pulses to be generated that are characterised by being both short and of a constant width regardless of the length of the input pulses. These pulses are then transmitted for storage purposes to the on-board memory unit of 13 while separate signals are transmitted to the regeneration unit for use by third parties. The described signal processing techniques allow for greater accuracy to be obtained in recording the output data while avoiding the problematic feature of battery drainage through mechanical failure of the relays .

Optical isolators 15 are employed to pass information across the isolation barrier 8 to the regeneration unit 10, while simultaneously providing the required electrical isolation. These are well known devices in the field of optoelectronics and basically comprise of a light emitting diode (LED) and a semiconductor detector separated by a short optical transmission path. The optical transmission path may be air or a dielectric waveguide and it is this optical transmission path that provides the required electrical isolation between the elements in the circuit.

The battery 14 provides the power for the data logger 7. Although the battery 14 will eventually be required to be replaced, its lifetime is significantly increased by employing the de-bouncing signal processing techniques within the CPU 12. It is estimated that a single battery will be capable of providing power for a minimum period of four years.

In a preferred embodiment of the present invention the communication controller 9 is a GSM (Global System for Mobile communications) modem. Data stored within the memory unit of 13 is then transferred to the communication controller 9 that has a modem and transceiver that transmits the data to a remote site via the GSM telecommunications network.

Although the above preferred embodiment comprises a GSM communication controller 9 it would be obvious to one skilled in the art that any radio based communication controller could also be used, for example, GPRS (General Packet Radio Service) , WiFi Wireless Local Area Network, or Bluetooth. Rather than connecting directly to the GSM telephone network, the radio connection would then be to another network.

The automated meter reader also includes an RS485 communication port on the data logger side of the isolation barrier that allows data to be transferred through the on-board GSM modem for connection to external equipment. The port is voltage and current limited in order to comply with the guidelines for connection to a gas meter.

In an alternative embodiment presented in Figure 4 the communication controller 18 comprises a CPU 19 (e.g. a Hitachi HD 3664 processor) and a modem 20 that are both powered via a current carried by a telephone line 21, employing a technique as taught by the present author within PCT Application WO 0237824. Data stored within the memory unit of 13 is then transferred across the isolation barrier 8 to the CPU 19 via the optical isolators 22. Thereafter, the modem 20 retrieves the data from the CPU before transmitting it to a remote site via the telephone line 21. Although the above alternative embodiment comprises a communication controller 18 that employs a telephone line power supply technique it would be obvious to one skilled in the art that a standard communication controller could also be used. Typically such a communication controller (not shown) comprises a CPU a standard modem and a designated battery power source. However, the employment of such a standard communication controller would increase both the installation and maintenance costs of the automatic meter reader.

Figure 5 presents a circuit diagram of the input port circuitry 11 which connects to (up to 4) gas meters. These inputs are current limited to comply with approval standards, and also have components fitted which help with the debouncing of the gas output relays.

Figure 6 presents a circuit diagram of the regeneration 10 and isolation 15 units, the opto-isolators replace the function of the conventional chatterbox.

Figure 7 presents a circuit diagram of the processor (CPU) 12.

Figure 8 presents a circuit diagram of the control and clocking support hardware 13 for the processor. Also included in this section is the memory and temperature measuring circuits.

Figure 9 presents a circuit diagram of the GSM communication controller 9 (including modem) of the preferred embodiment of the present invention. Figure 10 presents a circuit diagram of the IEC1107 interface 16. This includes the infrared diodes which allow data to be input/output from the logger locally.

Figure 11 presents a circuit diagram of the RS485 interface 17.

Figure 12 presents a circuit diagram of the logger to line powered modem isolation circuit 22 of the alternative embodiment of the present invention. This provides the isolation between the conventional line powered modem communications controller 18 and the logger section 7.

Figure 13 presents a circuit diagram of the line powered modem 20.

In general the CPU on the data logger monitors and counts the data produced by the meter in thirty minute cycles before transferring this data to the memory unit. At the end of the day the data is then transferred to the remote location such that a customers bill may be updated. In addition the data may be used to calculate a user's load profile. If all the customer load profiles for a particular day are collated then this information may be used to make accurate predictions regarding the total volume requirement of the utility for the next day, inclusive of peak and off peak periods.

The automated meter reader 6 is based on solid state electronics that permit for communication functionality to be included. Therefore, the automated meter reader 6 may by supplied and installed with a gas meter at substantially lower costs than the three component unit systems presently provided i.e. those that comprise the chatterbox, data logger and modem.

By adapting the signal processing carried out by the CPU 12 the automated meter reader 6 also provides a means for converting data from old fashioned styled utility meters into that produced by the new meter types e.g. IEC 1107 meters. This functionality allows for a cost effective means for updating the technology of presently installed meters while at the same time producing a common interface standard for all the meters, namely the IEC 1107 European Standard.

In addition to being more cost effective to install than those systems taught in the prior art the automatic meter reader 6 is also cheaper to maintain as there are no mechanical parts and generally fewer batteries that require to be replaced. In addition, when employed with a gas meter the requirement for a separate chatterbox is removed along with the need to systematically re- calibrate this component and to filter out additional noise cased as a result of relay bouncing.

An advantage of aspects of the present invention is that the optical isolators provide a simplified means for electrically isolating a gas meter to the standards required the regulatory bodies.

A yet further advantage of aspects of the present invention is that the employment of the CPU allows for accurate de-bouncing of the incoming data. This allows for output pulses to be generated that are both short and of a constant width regardless of the length of the input pulses. Such features act to considerably reduce battery consumption. On average the battery lifetime will be extended to have a minimum lifetime of four years. In addition, as the CPU is programmable multiplexing may take place, wherein any of the input data lines may be transferred to any one of or combination of the outputs on the regeneration unit.

The above embodiments have been described primarily for use with a gas meter. However, it will be obvious to those skilled in the art that the same automated meter reader may readily be employed in systems for automating both water and electricity meters, even although there is no requirement to provide the same levels of electrical isolation within these systems.

The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed. The described embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilise the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Therefore, further modifications or improvements may be incorporated without departing from the scope of the invention herein intended.

Claims

1. A solid-state automatic meter reader suitable for monitoring and recording the data output of a utility meter, the solid-state automatic meter reader comprising a data logger, an isolation barrier, a regeneration unit and a communication controller.

2. The solid-state automatic meter reader of Claim 1, wherein the isolation barrier is located so as to electrically isolate the data logger from the regeneration unit.

3. The solid-state automatic meter reader of any previous claim, wherein the isolation barrier is located so as to electrically isolate the communications controller from the regeneration unit.

4. The solid-state automatic meter reader of any of Claims 1 to 2 , wherein the isolation barrier is located so as to electrically isolate the data logger from the communications controller.

5. The solid-state automatic meter reader of any previous claim, wherein the data logger comprises one or more electrical inputs, a computer processor, a memory unit and a power source.

6. The solid-state automatic meter reader of Claim 5, wherein the computer processor provides a means for signal processing the data output of the utility meter.

7. The solid-state automatic meter reader of any of Claims 5 to 6, wherein the power source comprises a battery.

8. The solid-state automatic meter reader of any previous claim, wherein the isolation barrier comprises an optical isolator.

9. The solid-state automatic meter reader of any previous claim, wherein the isolation barrier comprises two or more optical isolators wherein at least one optical isolator communicates with the regeneration unit and at least one optical isolator communicates with the communication controller.

10. The solid-state automatic meter reader of any of Claims 8 to 9 , wherein each optical isolator provides electrical isolation to a level greater than approximately 10 kV (rms) .

11. The solid-state automatic meter reader of any previous claim, wherein the regeneration unit comprises one or more outputs suitable for providing a regenerated data utility meter output signal.

12. The solid-state automatic meter reader of any previous claim, wherein the communications controller comprises a modem and a radio transceiver.

13. The solid-state automatic meter reader of Claim 12, wherein the radio transceiver is a GSM transceiver.

14. The solid-state automatic meter reader of any previous claim, wherein the communications controller comprises a modulator and a radio transmitter.

15. The solid-state automatic meter reader of any of Claims 1 to 13, wherein the communication controller comprises a computer processor, a modem and a telephone line wherein the telephone supplies the required power for the computer processor and the modem.

16. The solid-state automatic meter reader of any of Claims 1 to 13, wherein the communication controller comprises a computer processor, a modem, a battery and a telephone line.

17. The solid-state automatic meter reader of any previous claim, further comprising an optically isolated communications interface connected to said data logger.

18. The solid-state automatic meter reader of Claim 17, wherein said optically isolated communications interface comprises a light source and a photo receptor.

19. The solid-state automatic meter reader of any of Claims 17 to 18, wherein said optically isolated communications interface comprises an IEC1107 interface.

20. The solid-state automatic meter reader of any previous claim, further comprising an electrically isolated communications interface connected to said data logger and said communications controller.

21. The solid-state automatic meter reader of Claim 20, wherein said electrically isolated communications interface comprises an RS485 interface.

22. A method for automating the monitoring and recording of a utility meter comprising the steps of: 1) electrically connecting a solid state data logger to the utility meter; 2) employing an isolation barrier to electrically isolate the solid state data logger; 3) reading and recording output data from the utility meter; 4) creating output signals representative of the output data from the utility meter; and 5) employing an optoelectronic means for transferring the output signals across the isolation barrier.

23. The method of Claim 22, wherein a computer processor is employed to read the output data from the utility meter, and a memory unit then records the output data read by the computer processor.

24. The method of Claim 23, wherein the computer processor carries out signal processing on the output data from the utility meter before generating two or more output signals.

25. The method of Claim 24, wherein the signal processing comprises the removal of noise on the output data from the utility meter caused by switch bouncing.

26. The method of any of Claims 22 to 25, wherein at least one output signal is transferred to a communication controller such that it may be relayed to a remote site in order to allow a customer's account to be updated.

27. The method of Claim 26, wherein said at least one output signal is transferred across the isolation barrier to said communication controller.

28. The method of any of Claims 26 to 27, wherein said at least one output signal is relayed to the remote site on a daily basis.

29. The method of any of Claims 26 to 28, wherein utility load analysis is carried out at the remote site on the output signal.

30. The method of any of Claims 22 to 29, wherein at least one output signal is transferred across the isolation barrier to a regeneration unit so as to be available for use by a third party.

31. The method of any of Claims 23 to 30, wherein the computer processor provides a means for multiplexing the output data from the utility meter and one or more output signals transferred to the regenerated unit.