GB2229834A - Consumption meters and meter reading apparatus - Google Patents

Abstract

A water meter (2) is connected to a reader unit (1) which is capable of communicating by infrared pulse signals with a portable data handling unit (3). The reader unit (1) incorporates registers allotted to different time periods for recording the consumption of water during those periods, and revised tariff information appropriate to those periods can be transmitted to the reader unit (1) from the data handling unit (3). The time interval between the rising edge of one infrared pulse and the next is used as the measure of a number being communicated between the units (1, 3). The reader unit (1) also records the longest time for which there has been no water flow, in order to indicate a possible leak. <IMAGE>

Description

CONSUMPTION METERS AND METER READING APPARATUS This invention relates to consumption meters, particularly, but not exclusively, to water meters provided in or nearby domestic or commercial premises, and to apparatus adapted to read a consumption meter and to store, or transmit to another device, a meter reading.

Water meters have generally been read manually by a meter reader who has visited the metered premises and has written down the meter reading on a record sheet which is subsequently processed by the accounts department of the water authority, who then issue a bill to the consumer. Errors can arise in writing down the meter reading, or in subsequently reading the manuscript record, and in order to reduce the possibility for errors there have been various proposals for hand-holdable data collection units. Patent Specification No.

US 4133034 discloses a hand-holdable data collection unit provided with keys which the meter reader presses to input the meter reading.

This avoids the problems involved in interpreting the manuscript figures on a record sheet, but keying-in errors may still arise.

Specification No. GB 2083932A discloses a hand-holdable data collection unit provided with an associated bar-code reading probe which the meter reader employs to read the meter output which is in bar-code form. Specification No. GB 2084773A discloses a similar data collection unit provided with some sort of electronic probe which is arranged to receive meter output data transmitted from a probe receptacle connected to the meter.

All such arrangements for reading a consumption meter merely process and store a meter reading. We have appreciated the fact that there can be advantages in providing two-way communication between a hand-holdable data handling unit and a consumption meter, and a first aspect of the invention is concerned with such two-way communication.

According to the first aspect of the invention we provide a reader unit incorporated in or adapted to be connected to a consumption meter, the reader unit being arranged to provide an output signal indicative of the consumption of the metered product, and a portable data handling unit adapted to communicate with the reader unit so as to receive the output signal therefrom, the data handling unit and the reader unit being so arranged as to permit the communication of some data from the data handling unit to the reader unit.

The data which is sent on occasions from the portable data handling unit to the reader unit is preferably configuration data for altering the configuration of the data handling process performed by the reader unit. Preferably the data transmitted to the reader unit is tariff information.

The reader unit is preferably arranged to allow the application of different charge rates at different times, and the amounts of the charge rates and/or the times at which the different charge rates are applied are arranged to be alterable by the sending of appropriate instructions from the data handling unit to the reader unit.

Thus the reader unit can comprise a plurality of registers which are allotted to different time periods for recording the consumption during those time periods.

For example, a first charge rate may be applied during a daytime period whereas a lower, second charge rate may be applied at night.

Different charge rates may be set for a weekend, or even for designated public holdiays during which overall industrial consumption is reduced. Since the dates of public holidays change from year to year the invention enables the reader unit to be re-programmed as and when required.

It will be appreciated that the reader unit is provided with a suitable time clock for the purposes of applying different tariffs to different periods.

Any convenient communication system may be employed to provide two-way communication between the data handling unit and the reader unit. Although a plug and socket connection might be employed in some circumstances, this will not usually be desirable due to problems of dirt and weather protection when the meter is outside.

We prefer to use an electro-magnetic wave communication system, most preferably employing infra-red radiation, and a second aspect of the invention is concerned with a communication system employing a transmitter having a relatively low power consumption, thereby placing a relatively low drain on any power source associated with the reader unit.

According to a second aspect of the invention, we provide a communication system for providing communication between an emitter of electro-magnetic radiation and a receiver of the radiation, the emitter being arranged to emit a pulse train, and the time period between two pulses of the pulse train being arranged to be a function of a number to be communicated.

Thus, the interval between two pulses is representative in some way of a number, and since it can be arranged that substantially no power is consumed by the transmitter for the duration of that interval, the overall power consumption of the communication system, or at least that of the transmitter, can be kept to a minimum.

Preferably the interval between the rising edge of one pulse and the rising edge of the next succeeding pulse is employed as the measure of the number to be communicated, but it would be possible to use the falling edges of the pulses if desired. It is preferred not to use the length of the actual space between the pulses as the measure since that length would depend to some extent on the duration of one pulse. The duration of the pulses need only be sufficient for the pulse to be seen by the amplifiers associated with the receiver.

The receiver is arranged to measure the time period between two pulses and to compare the measured time period with predetermined reference values or reference ranges.

The use of infra-red radiation for the pulses is particularly desirable because of the availability of matched pairs of infra-red emitting diodes and infra-red receivers at low cost.

The number information is preferably transmitted as a series of hexadecimal digits, each of four bits, the spacing between the first two pulses of a group of pulses representing one digit, and the spacing between the second pulse and the third pulse representing a second digit, and so on. The order of transmission of bits can be according to a predetermined protocol.

The timing of the pulses in the receiver may be performed by logic circuitry or by a micro-processor.

A third aspect of the invention is concerned with the detection of leaks, and/or meter malfunction, by accidental failure or through tampering by the customer.

According to the third aspect of the invention a consumption meter, or a reader unit adapted to be connected to a consumption meter, comprises a store in which is recorded a measure of the longest time for which there has been no detectable consumption of the metered product.

If the currently stored amount of the longest time is, say, only a few minutes then this would indicate a possible leak. On the other hand, if it is found that the currently stored amount is particularly long, say greater than a few weeks, then this may indicate customer tampering or meter output failure.

It is preferred that the meter output is provided as, or converted to, a square wave, and that the time between adjacent pulses of the wave is stored in the longest time store. The longest time store can then be interrogated at an appropriate time, and the store value can be reset after interrogation.

It is, of couse, desirable to detect a leakage of water to avoid wastage, but when used in conjunction with a gas meter, leak detection is desirable for safety reasons.

A system in accordance with the invention for providing and analysing water meter readings will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic vertical cross-section of a water meter installation comprising a water meter housed in a weather-proof ground enclosure; Figure 2 is a vertical section, on a larger scale, of the upper part of the ground enclosure of Figure 1 and showing a probe cup in position on the lid of the enclosure for communicating with an outreader unit.

The complete system consists of three basic units, these are the outreader, hereinbefore referred to as a 'reader unit' which is connected to a water meter, a portable data-collection device, hereinbefore referred to as a 'portable data handling unit', and a standard personal computer running software to interface it to a central billing computer.

The outreader is housed in an environmentally protected package, and can be mounted either on the wall of the customer's premises if the water meter is indoors, or under the cover plate of the meter chamber in an external installation, as in Figure 1. The outreader 1 is connected to a water meter 2 which must have an electrical interface. Thus it measures the quantity of water which has flowed through the meter. It stores this figure in its memory and can communicate it (along with various other pieces of data) to a portable data-collection device.

The portable data-collection device is able to communicate with the outreader using a contact-less interface, in this embodiment infra-red light is used. It is taken into the field to gather data from a number of outreaders, guiding the operator from outreader to outreader with directions displayed on an alpha-numeric display panel. The data-collection device receives data from the outreader by means of a contact-less probe 3 (and also sends certain configuration parameters back to the outreader). The data-collection device stores the data from a number of outreaders (up to 1000 in this embodiment) and can send the data in the form of a file to a personal computer for further processing. At the same time the personal computer can send customer details and configuration parameters to the data-collection device ready for interrogation of the next batch of outreaders.

When the data is loaded onto the personal computer, proprietary software is run which processes the data received, splitting it into billing records which are sent to the billing computer via a standard computer interface, and further files which provide details of customer behaviour and diagnostic information.

The Outreader In the present embodiment the outreader is housed in the lid 4 closing the upper end of a weather-proof ground enclosure 5, and is based around a standard micro-controller. This controls the operation of the outreader and also provides the memory which is necessary for the water-use accumulators, the clock calendar registers and the parameters which are stored to configure the outreader and its tariffing scheme.There is some support circuitry around the micro-controller: this consists of the driver and receiver circuits for the infra-red interface used to communicate with the data-collection unit; signal conditioning circuitry for the interface with the water meter; an accurate stable oscillator providing a pulse every minute for the clock calendar; a 'watch-dog' circuit which resets the micro-controller if it stops running its programme properly; and power control circuitry to apply battery power to the micro-controller when it runs its programme and to maintain the memory contents.

The outreader is powered by a lithium battery which has a very long life (which is estimated at at least 10 years in this application).

The outreader monitors the use of its own battery and indicates the need for battery replacement to the data-collection unit at least 1 year before it is exhausted, hence the battery can be replaced long before it ceases to maintain the contents of the outreader memory.

The outreader memory contains, for example, 12 water-use accumulators, each 6 (decimal) digits wide, for example. It can use different accumulators at different times of year and at different times during the day, depending on the way the tariffing parameters have been set.

The micro-controller spends most of its time in an idle mode where it is merely maintaining the contents of its memory, and consuming a minimum of batter power. It is brought out of this mode at regular intervals by the clock oscillator (which is running constantly) in order that it can update the internal clock calendar. At the same time, if necessary, the water-use accumulator selection is updated and the meter is interrogated if it is of the encoded type. The micro-controller is also activated every time a pulse is detected, if the meter is of the pulsed output type.

The micro-controller is also activated if it detects a certain sequence of infra-red light pulses from the data-collection unit.

In this case the outreader responds with its frames of data sent as infra-red pulses, then waits for data back from the data-collection unit. This data if sent, is stored in the outreader memory as the configuration parameters. If none is sent the outreader slips back into its idle low-power mode.

The Portable Data-collection Device In the present embodiment the data-collection device is based around a standard bought-in hand-held computer which is fitted with a proprietary probe which enables it to communicate, using infra-red light pulses, with the outreader, In use the data-collection device is taken into the field in order to read customer meters which are fitted with outreaders. It has a display which gives the operator directions for finding the meter to be interrogated. When the meter is found, the probe on the data-collection device is placed against the outreader housing, and the outreader transmits its data to the probe; the data is captured, verified and stored in the memory in the data-collection device (or a warning signal is issued by the data-collection device if the data communication was erroneous). The data-collection device also uses its contact-less interface to send configuration parameters to the outreader.

The data from many outreaders (rcorresponding to consumption figures for many customers) can be stored in the memory in the data-collection device. When the data has been collected and stored, it can be up-loaded to a personal computer for further processing. This can be performed either by sending the data via a direct electrical connection, or the data can be sent on the telephone network using a modem.

The Interface to the Central Billing Computer This consists of a standard bought-in personal computer eg: IBM PC-AT, fitted with suitable standard interfaces to the data-collection device and the central billing computer eg: R5232.

It runs a proprietary software package which controls the data communication and analyses and formats the data.

Its operation consists of 3 phases. The first phase is when the data-collection unit is connected, the water-usage information which was captured in the field is extracted from the data-collection unit, and the unit is loaded with the customer information and configuration parameters ready for the next session of data-collection.

The second phase is where the personal computer processes the file which was received from the data-collection device and produces several output files. Amongst these is a file which contains customer billing information. There are also files containing customer statistics. These are in a format which can be further processed by standard bought-in software packages, for example Lotusl23 could be used for graphical representation of the data and as an aid for resource management. An additional file produced is one containing diagnostic information, eg: a list of installations where the outreader batteries need to be changed.

The third phase is where the correctly formatted billing file is sent to the central billing computer in order that it can print the customer bills ready for posting. At the same time the central billing computer down-loads a file to the personal computer containing records of customers to be billed in the next batch.

This data in turn is sent to the data-collection unit in phase 1.

Key features of the Outreader System Configurability: The outreader is readily configurable with parameters which are sent to it from the data-collection unit. The parameters are then stored in the outreader memory. These parameters are described below. All the parameters are sent to the data-collection unit in the course of data collection.

Meter ID: This is a 10 digit hexadecimal number which is set to a unique number (usually the unique meter serial number which is printed on the body of the meter). It is checked by the data-collection unit during the reading process to ensure that the correct meter is being read.

Tariffing Parameters: These are a set of parameters which are set to define the way in which the outreader splits the year into seasons and time zones in order that different water-use accumulators can be used to get an idea of water consumption behaviour. This can be used to implement a multi-tariff billing system, or used to provide resourcemanagement information.

The tariffing framework implemented allows up to 4 seasons to be set in each year, and up to 8 time zones in each day. In addition up to 8 special dates can be defined (eg: for Bank Holidays).

In addition, the setting of the clock-calendar which is maintained by the outreader can be set, the 'longest period without water use' record can be cleared, the tamper tell-tale can be cleared, the battery usage record can be cleared, and the accumulator contents can be set.

Compatibility with Different Meter Types: Two versions of the outreader may be provided, one type interfacing with water meters which have a pulsed output (usually provided by an internal reed switch and magnet arrangement), the other type interfacing with water meters which have an encoded output. The first type works in an event-driven way, counting pulses when they occur; the second type works in a time-driven way, interrogating the meter register at times when the tariffing scheme changes the active water-use accumulator.

Longest Period Without Pulses: The outreader contains a 'longest period without pulses' record which is stored and updated within the outreader and is interrogated by the data-collection unit. This record is as its name suggests and is a constantly updated record of the greatest time which has elapsed without any water consumption being registered. It can take a range of values from less than 1 minute up to 15 weeks (if the time becomes greater than 15 weeks the value is not increased any further). This record serves a dual purpose: it can indicate a water leak in the customer's premises if the value of the record is abnormally low, indicating a constant trickle of water through the meter. It can also indicate customer tampering (or meter output failure) if the value is abnormally high. This record can be reset by the data-collection unit.

Tamper 'Tell-Tale': The outreader contains a physical tamper 'tell-tale': this is a record maintained by the outreader, and interrogated by the data-collection unit which is set if the cable between the outreader and the meter has been violated (either by cutting, or short-circuiting) the flag remaining set even if the cable is restored to its correct state (it can be reset when the outreader is interrogated).

Battery Usage Record: According to a further aspect of the invention, the outreader contains a battery usage record, the state of the battery being ascertained by the outreader using a counter which is maintained and updated within its memory and is interrogated by the data-collection unit. The counter is constantly being incremented at a rate proportional to the rate at which the battery is supplying current.

Thus its value provides a measure of the capacity of the battery which has been used, hence the capacity of the battery which is left can be calculated by the data-collection unit.

Infra-red Communication Protocol: The data-collection unit communicates with the outreader using infra-red light pulses, the communication protocol which is used optimises the data-rate for a given amount of energy (hence in this application battery life is maximised). The data is transmitted to and from the outreader in fixed length frames, each terminated by a checksum. This ensures that errors which may occur in communication are detectable. The communication protocol is conveniently a proprietary one with sufficient error detection to make the probability of unauthorised tampering insignificant.

Claims (20)

1. A meter system comprising a consumption meter reader unit and a portable data handling unit, the reader unit being incorporated in or adapted to be connected to a consumption meter, the reader unit being arranged to provide an output signal indicative of the consumption of the metered product, the portable data handling unit being adapted to communicate with the reader unit so as to receive the output signal therefrom, and in which the data handling unit and the reader unit are so arranged as to permit the communication of some data from the data handling unit to the reader unit.

2. A system as claimed in claim 1 in which the data which is sent on occasions from the portable data handling unit to the reader unit is configuration data for altering the configuration of the data handling process performed by the reader unit.

3. A system as claimed in claim 2 in which the data transmitted to the reader unit is tariff information.

4. A system as claimed in claim 3 in which the reader unit is arranged to allow the application of different charge rates at different times, and the amounts of the charge rates and/or the times at which the different charge rates are applied are arranged to be alterat'e by the sending of appropriate instructions from the data handling unit to the reader unit.

5. A system as claimed in claim 4 in which the reader unit comprises a plurality oi registers which are allotted to different time periods for recording the consumption during those time periods.

6. A system as claimed in any of the preceding claims in which two-way communication between the reader unit and the data handling unit utilises electromagnetic waves.

7. A system as claimed in claim 6 in which the electromagnetic waves are infrared waves.

8. A system as claimed in claim 6 in which the communication is between an emitter of electro-magnetic radiation and a receiver of the radiation, the emitter being arranged to emit a pulse train, and the time period between two pulses of the pulse train being arranged to be a function of a number to be communicated.

9. A system as claimed in claim 8 in which the interval between the rising edge of one pulse and the rising edge of the next succeeding pulse is employed as the measure of the number to be communicated.

10. A system as claimed in claim 9 in which the number information is transmitted as a series of hexadecimal digits, each of four bits, the spacing between the first two pulses of a group of pulses representing one digit, and the spacing between the second pulse and the third pulse representing a second digit, and so on.

11. A meter system comprising a reader unit and a data handling unit, the units being arranged to operate substantially as described with reference to the accompanying drawings.

12. A consumption meter reader unit suitable for use in th system as claimed in any one of claims 1 to 11.

13. A data handling unit suitable for use in the system as claimed in any one of claims 7 to 11.

14. A consumption meter reader unit suitable for use in the system as claimed in any one of claims 1 to 10, and which comprises a store in which is recorded a measure of the longest time for which there has been no detectable consumption of the metered product.

15. A communication system for providing communication between an emitter of electro-magnetic radiation and a receiver of the radiation, the emitter being arranged to emit a pulse train, and the time period between two pulses of the pulse train being arranged to be a function of a number to be communicated.

16. A communication system as claimed in claim 15 in which the interval between the rising edge of one pulse and the rising edge of the next succeeding pulse is employed as the measure of the number to be communicated.

17. A communication system as claimed in claim 15 or claim 16 in which the radiation is infrared radiation.

18. A communication system as claimed in any one of claims 15 to 17 in which the number information is transmitted as a series of hexadecimal digits, each of four bits, the spacing between the first two pulses of a group of pulses representing one digit, and the spacing between the second pulse and the third pulse representing a second digit, and so on.

19. A consumption meter, or a reader unit adapted to be connected to a consumption meter, comprises a store in which is recorded a measure of the longest time for which there has been no detectable consumption of. the metered product.

20. A meter as claimed in claim 19 in which the meter output is provided as, or converted to, a square wave, and the time between adjacent pulses of the wave is stored in the longest time store.