HK1085009B - Communications and features protocol for a measuring water meter - Google Patents

Description

Communication and feature protocol for a metered water meter

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to a provisional application No. 60/423,598 entitled "electronic self-powered water meter" filed on 11/4/2002.

Technical Field

The present invention relates to a meter. More particularly, the present invention relates to communications and data protocols for data loggers for meters.

Background

Meters that meter the use of materials according to flow are widely used to track the consumption of end users. For example, utility companies that supply water to their customers typically charge for their products based on usage. The amount of water is typically metered by means of a meter mounted on the water supply line of each customer. Employees of the utility company manually collect readings from the meter on a regular basis, typically once a month. These readings are typically cumulative readings, and therefore, the usage for this cycle is calculated by subtracting the readings from the previous cycle. Once the usage is calculated, the customer is billed for the amount of water used in the cycle.

Manual reading of the usage meters is labor and material intensive and can produce human error, particularly for residential customers, due to the relatively small usage monitored by each meter as compared to larger commercial customers. As a result, electronic meters are used so that usage data can be collected more quickly, efficiently, and accurately. Electronic meters meter usage by monitoring flow through conventional mechanical meters. The usage readings are stored electronically and then transmitted via radio signals to a local transmitter/receiver operated by the utility company.

However, electronic meters require a power source. Typically, such meters rely on batteries as a power source. The batteries must be replaced manually, which is another time consuming and expensive process. Furthermore, if the battery fails, the utility company cannot determine the correct usage at the meter, resulting in a low customer charge.

Disclosure of Invention

In some aspects, the present invention relates to an apparatus for monitoring a meter, comprising: a meter to monitor usage of the dispensing system; an electronic data logger for processing data from the meter; an external unit for controlling data processing in the electronic data recorder using a communication protocol; and wherein the communication protocol includes an initialization signal, a time interval identification signal, and a clock signal.

In other aspects, the invention relates to a device for use with a monitoring meter, comprising: a meter to monitor usage of the dispensing system; means for receiving data from the meter; means for processing data from the meter; and means for detecting a leak in the distribution system.

In other aspects, the invention relates to a method of calculating a utility usage model, comprising: receiving usage data from a monitoring distribution system; processing the usage data to calculate a utility usage model; and wherein the utility usage model identifies predetermined conditions in the distribution system.

In other aspects, the invention relates to a method of calculating a utility usage model, comprising: receiving usage data of a distribution system; a step of processing the usage data to calculate a utility usage model; and identifying a predetermined condition in the distribution system based on the utility usage model.

Other aspects and advantages of the invention will become apparent from the following description and appended claims.

Drawings

It should be noted that the same reference numerals are used in different figures to denote the same features.

Fig. 1 shows a schematic diagram of an electronic water meter monitoring system according to an embodiment of the invention.

Figure 2 illustrates a perspective view of a self-powered water meter according to one embodiment of the present invention.

Fig. 3 shows a schematic view of a display of an electronic data recorder according to an embodiment of the invention.

Fig. 4 shows a block diagram of an ASIC circuit of an electronic data recorder according to an embodiment of the invention.

FIG. 5 shows a timing diagram of clock signals operating at 1200Hz according to one embodiment of the present invention.

FIG. 6 shows a timing diagram of an initialization signal followed by a clock signal operating at 1200Hz in accordance with one embodiment of the present invention.

FIG. 7 shows a timing diagram of a cycle identification signal and an initialization signal followed by a clock signal operating at 1200Hz in accordance with one embodiment of the present invention;

FIG. 8 shows a timing diagram of an optional cycle identification signal and an initialization signal followed by a clock signal operating at 1200Hz in accordance with one embodiment of the present invention;

FIG. 9 shows a timing diagram of an optional cycle identification signal and an initialization signal followed by a clock signal operating at 1200Hz in accordance with one embodiment of the present invention;

FIG. 10a shows a timing diagram of an optional cycle identification signal and an initialization signal followed by a clock signal operating at 1200Hz in accordance with one embodiment of the present invention;

FIG. 10b shows a timing diagram of an initialization signal followed by an optional cycle identification signal and a clock signal operating at 1200Hz in accordance with one embodiment of the present invention;

FIG. 11 shows a chart of bit values for a leak detection (current) feature in accordance with one embodiment of the invention;

FIG. 12 shows a chart of bit values for a leak detection (of epoch) feature, according to one embodiment of the invention;

FIG. 13a shows a chart of bit values and LCD display of a flow/direction feature in accordance with one embodiment of the present invention;

FIG. 13b shows a chart of bit values (3-bits) for a non-traffic feature in accordance with one embodiment of the invention;

FIG. 13c shows a chart of bit values (2-bits) for a non-flow feature in accordance with one embodiment of the invention;

FIG. 14 shows a chart of bit values for a peak continuous backflow feature in accordance with one embodiment of the present invention; and

fig. 15 shows a graph of bit values of a peak backflow feature according to one embodiment of the invention.

Detailed Description

Metering meters with communications and feature protocols have been developed that allow for monitoring of customer usage data. The metering device measures and records the volumetric usage of material flowing through the device. The meter may be used to measure water, gas, or electricity usage in utility applications. Furthermore, such meters are commonly used in industrial applications to measure the flow of various components. In this section, a self-powered water meter in a utility application is used to illustrate various embodiments of the present invention. It will be appreciated, however, that the invention described may be applied to many different types of meters in a wide range of applications.

Fig. 1 shows a schematic diagram of an electronic water meter monitoring system 10 according to one embodiment of the present invention. The system 10 includes an electronic water meter 12a or 12b for an individual customer. The meter is typically located at a point on the customer's personal supply line between the customer and the utility's main supply line. A Meter Interface Unit (MIU)14a or 14b is connected to the corresponding meter 12a or 12 b. The MIR 14a or 14b is an electronic device that collects meter usage data from an electronic register on its corresponding meter and transmits the data via radio signals to the local transmitter/receiver 16a or 16 b. In alternative embodiments, other external devices may be used, such as a laptop computer, a data logger, or other suitable device as known in the art. In other embodiments, an MIU or similar device may be integrated as one internal component of the meter. Two alternative embodiments of an electronic water meter are shown. The first embodiment includes meter 12a and MIU14a disposed in an underground or "meter well" unit. Another embodiment includes a meter 12b and MIU14 b positioned on the ground. Two alternative types of transmitter/receivers 16a and 16b are also shown. A first transmitter/receiver 16a is mounted in the vehicle and the other transmitter/receiver is a handheld unit 16 b. An additional type of transmitter/receiver may be permanently installed in a central location of the plurality of meters and MIUs. Each of these transmitters/receivers allows utility personnel to receive usage data without having to manually read each individual meter. Alternatively, when each transmitter/receiver 16a and 16b is within range of a meter 12a or 12b, data from the meter is sent to the transmitter/receiver, which in turn sends it to the computer system 18 of the utility. Computer system 18 then calculates the usage of each customer based on the data. The utility then generates the appropriate bill for each customer.

The electronic water meter of the system is self-powered by an internal "Wiegand Wire". A Wiegand wire is a device that generates an electrical signal when it is exposed to a magnetic field having a changing magnetic flux polarity. The wire may also be used to induce a voltage across the coil near the wire. The polarity of the magnetic field changes depending on the kinetic energy of the fluid flowing through the meter. In some embodiments, as fluid flows through the meter, the fluid turns an internal water wheel, which in turn turns an attached shaft. A plurality of magnets are arranged on a disc attached to the rotating shaft. As the disc rotates with the shaft, the movement of the magnet induces an alternating magnetic flux field in the Wiegand wire in close proximity to the disc. The signal generated by the wire due to the change in magnetic flux is used to power the electronic circuitry of the monitoring meter. By analyzing the number and rate of signals generated by the wires, the rate, volume, and direction of fluid flow through the meter may also be determined.

Figure 2 illustrates a perspective view of a self-powered electronic water meter 20 according to one embodiment of the present invention. In this embodiment, the electronic water meter 20 is connected to a water supply line by a meter inflow connector 22. Water flows from the supply line through the connector 22 into the meter body 26 and out to the customer through the outflow connector 24. As water flows through the meter body 26, it forces the inner water wheel 28 to rotate. The rotating water wheel 28 in turn rotates a circular magnetic disk 30 connected to the water wheel 28 by a shaft (not shown). In the present embodiment, the circular magnetic disk 30 is shown as having four separate magnetic regions (the polarity direction of each region is labeled "N" and "S") that constitute a quadrupole magnet. In other embodiments, different magnet configurations may be used.

As the disk 30 rotates, it changes the magnetic flux polarity of the Wiegand wire sensor 32 disposed adjacent the disk 30. As described above, the change in polarity induces a signal generated by the sensor 32. These signals represent data about the water flowing through the meter 20 and also provide power to the electronic circuitry of the meter. More specifically, the signal flow corresponds to the velocity and direction of the water flowing through the meter. The flow rate of water through the meter 20 is calibrated to the rotational rate of the water wheel 28, the magnetic disk 30, and the signal stream generated by the sensor 32. In fig. 2, only one Wiegand wire sensor 32 is shown for use with the meter 20. It should be appreciated that in alternative embodiments of the invention, multiple sensors may be used in the meter. In other embodiments, a secondary magnet assembly is provided at the EDR. The secondary magnet is coupled to the disk so that it rotates with the rotation of the disk. When the secondary magnet rotates, it changes the magnetic flux polarity of the Wiegand wire sensor.

The data is processed and stored in an electronic data logger 34 attached to the meter 20. The recorder 34 contains an ASIC (application specific integrated circuit) chip that processes the signal stream from the Wiegand wire sensor 32 with the energy contained within the signal stream. In other embodiments, additional processing may be performed by an external device that may also provide power to the system. In some embodiments, the non-volatile memory is disposed within the ASIC. This memory is used to store data. Fig. 3 shows a view of the display on top of the electronic data recorder 34. The recorder 34 has a cover 36 (shown in the open position) for protecting the display 38 from dirt, debris, etc. The display 38 itself is a series of LCDs (liquid crystal displays) that display data. In this embodiment, the LCD may display nine numbers. In alternative embodiments, other types and numbers of display schemes may be used. The display is powered by a row of solar cells 40 that are exposed to sunlight or other light sources when the cover 36 is open. The display may be conveniently used by the property owner or utility in situations where manual reading of the meter is required due to failure of the MIU or other system component.

Fig. 4 shows a block diagram of an ASIC circuit of the Electronic Data Recorder (EDR). In this embodiment, two Wiegand wire sensors 32 are used to provide two independent data streams to the ASIC 41. Other connections to the ASIC include a POWER supply (EXT POWER) external to the ASIC and a Ground (GND) connection. The main processor (not shown) is an electronic circuit within the EDR with a microprocessor powered by the solar cell 40, or MIU14a or 14 b. The host processor uses external power lines to access data stored in non-volatile memory embedded in the ASIC. Other connections to the ASIC include: an ENABLE signal (ENABLE); a DATA signal (DATA); a CLOCK signal (CLOCK); read/write signal (R/W); an output signal (PULSEOUTPUT); and a DIRECTION signal (PULSE DIRECTION). Each of these connections goes through a host processor interface (not shown) to the rest of the data logger. Although the EDR is illustrated herein as a separate element from the meter, it should be appreciated that in alternative embodiments, the EDR may be integrated as a part of the meter.

The EDR clock signal is a steady stream of time signals that synchronize the communication operations of the data stream. The frequency of the clock signal is typically on the order of thousands of cycles per second. The units of measurement are hertz (Hz) per one second. Another optional unit of measurement is kilohertz (kHz) at one thousand cycles per second.

In one embodiment, the electronic meter communicates with a clock signal at a frequency of 1200Hz or 1.2 kHz. Such EDR clock signals are typically sent from the MIU to each electronic meter over wires. In other embodiments where multiple meters are operated in network mode, the EDR clock signal may operate at 19.2 kHz. In this embodiment, the electronic data logger calculates usage data over a 15 minute time interval or "read-out period" resulting in 96 data readings per 24 hour period. Usage data is typically stored in system memory and used to transmit to the utility.

Fig. 5 shows a timing diagram of a clock signal at 1200 Hz. An initialization signal is sent when an external device, such as the MIU14a or 14b, is ready to read data from the EDR 34. Fig. 6 shows a timing diagram of the initialization signal 44 followed by the clock signal 42 operating at 1200 Hz. In the present embodiment, the initialization signal 44 is a single long initial signal of 50 milliseconds (mSec) duration. However, in alternative embodiments, the duration of the signal may be as short as 25 milliseconds, or as long as 100 milliseconds. The initialization signal is used to enable the host processor to receive, process and store data from the meter. After the initialization signal 44, the signal transitions back to a 1200Hz clock signal.

In one embodiment of the invention, a communications protocol is used to start up the electronic data recorder with its ASIC and data read out is performed at regular intervals of a prescribed period. The communication protocol comprises: initializing a signal; a time interval identification signal; and a clock signal. In this example, the specified period is one hour with four separate readings at 15 minute intervals. These readings are referred to as: "0 minute reading"; "15 minute reading); "30 minute reading"; and "45 minute reading".

An initialization signal 44 is sent with the clock signal at the beginning of each 15 minute time interval. Immediately following this is a time interval identification signal 46 identifying which 15 minute cycle is to be recorded. Fig. 7 shows a timing diagram of the initialization signal 44 followed by a time interval identification signal 46 and a clock signal 42 operating at 1200 Hz. In the illustrated embodiment, the duration of the time interval identification signal 46 is two 1200Hz signal widths. The term "signal width" should be understood as half the duration of a complete signal cycle comprising one high phase and one low phase. This signal 46 identifies the first 15 minute cycle reading of a specified period. The first reading is referred to as the "0 minute reading". Fig. 8 shows a timing diagram of a second 15 minute cycle reading, referred to as a "15 minute reading". As shown in fig. 7, the initialization signal 44 is followed by a time interval identification signal 46, and a clock signal 42 operating at 1200 Hz. However, the identification signal 46 is three 1200Hz signal widths. Fig. 9 shows a time chart of the third 15 minute cycle reading, referred to as the "30 minute reading". As shown in fig. 7 and 8, the initialization signal 44 is followed by a time interval identification signal 46, and a clock signal 42 operating at 1200 Hz. However, the identification signal 46 is four 1200Hx signal widths. Fig. 10a shows a timing diagram of the fourth 15 minute cycle reading, referred to as the "45 minute reading". As shown in fig. 7-9, the initialization signal 44 is followed by a time interval identification signal 46, and a clock signal 42 operating at 1200 Hz. However, the identification signal 46 is five 1200Hz signal widths. In some instances, a specified reading outside of the 15 minute time interval may be required. A specific identification signal may be used to identify the specified cycle reading, for example, six 1200Hz signal widths or any other unique width. Fig. 10b shows a timing diagram of the initialization signal 44 followed by an interval identification signal 46 and a clock signal 42 operating at 1200 Hz. In this example, the time interval identification signal 46 is six 1200Hz signal widths. This signal allows a read to be made without incrementing the internal 15 minute clock or updating any time related calculations. It is important to recognize that a key feature of the time signal is the "time interval identification signal". The time interval identification signal is used to identify the passage of a time period, or a request for non-timed time interval information.

A 15 minute read interval is used to ensure proper read sequence. If one read interval is received in the proper order, the data is stored. But if, for example, a read-out time interval is received in the wrong order, all stored time-dependent data are reset to the initial value. The data is stored provided that the read intervals are received each time in the proper order. This enables the system to compensate for situations where the meter is disconnected from the EDR and later reconnected.

In an alternative embodiment, during a cycle read error, the system will automatically expect the next scheduled identification signal for the next read cycle. For example, if for some reason a "15 minute reading" (three 1200Hz signal width identification signals) is not received, the system will automatically expect the next reading identified as a "30 minute reading" (four 1200Hz signal width identification signals). This prevents an error in one reading cycle from permanently persisting in subsequent reading cycles and corrupting all subsequent data.

One advantage of the present invention is that the identification signal of each cycle reading is based on the width of a plurality of individual clock signals. However, in an alternative embodiment, the sensing may be performed at different time intervals and may be performed for different time periods. For example, four independent readouts may be performed at 30 minute intervals over a 2 hour time period. In addition, other widths and frequencies of initialization signals, interval identification signals, and clock signals may be used in alternative embodiments.

Once the system is initialized and the correct read interval is identified, the host processor processes the data from the meter and stores it in non-volatile memory embedded in the ASIC. In addition to basic information such as water usage, the present invention may also monitor other data to provide other characteristics to the utility regarding customer usage. These features include: leak detection in the current time period; leak detection on a date; a flow/direction indication; a period of time of day; and reflux detection. The data of these features is stored as "bits" or binary digits in designated sectors or "registers" of the memory. Each register typically comprises 2 or 3 bits, depending on the number of potential values required for the data of the respective feature. However, in alternative embodiments, more bits may be used.

The leak detection feature includes first establishing a minimum volume (V) for a prescribed time period_min). V for a particular meter_minBased on its size and capacity, and it is generally provided by the manufacturer of the meter. In this example, V is a 15 minute time period_minIs 0.1 gallon. If the volume flowing through the meter exceeds V continuously during each 15 minute interval in the previous 24 hour cycle_minThen since during "off-peak" hours, the water usage should be below V_minSo there may be leakage. An example of an off-peak hour is between midnight and early morning.

During normal operation, the system monitors each 15 minute cycle to determine if the flow volume exceeds V_min. When this occurs, the calculation exceeds V_minThe number of cycles of (c). Giving a defined number of exceedances V in a 24-hour period_minEstablishes a predetermined threshold. If this is exceededA threshold value, then indicating that a leak may exist. In this embodiment, the threshold for 96 separate 15 minute read cycles per 24 hour period is 50. This means that if V is exceeded in 50 of the previous 96 cycles_minThen the system will indicate that a leak may be present. In alternative embodiments, multiple thresholds may be used to indicate the persistence of the leak. For example, a first 50 threshold may be set to indicate intermittent leaks, while a second 50 threshold may be set to indicate continuous system leaks.

Fig. 11 shows a graph indicating bit values indicating the presence of a leak. As described above, the illustrated embodiment uses two thresholds to indicate the persistence of the leak. A "00" bit value indicates that the first threshold of 50-95 read cycles has not been exceeded, but that the flow-through volume exceeds V_min. This is the initial value of the system and it indicates that there is no leak. A "01" bit value indicates that the first threshold of 50-95 read cycles has been reached, but has not been exceeded. This indicates that there may be intermittent leaks in the system. The "10" bit value indicates that a second threshold of 96 has been reached. This is an indication that there may be a continuous leak in the system. The "11" bit value indicates that the leak detection feature is not usable with this embodiment of the invention.

If a leak is indicated by a "01" or "10" bit value, a system alarm is activated to notify the utility. The alarm may take the form of an LCD indication on a meter display and/or a signal relayed to a utility computer system. Personnel may then be dispatched to confirm the presence of the leak and to perform any necessary repairs. In other embodiments, different thresholds may be used. Further, more bit values may be used to accommodate the use of more than two thresholds.

Another feature that is performed in conjunction with leak detection is to determine the total number of days a leak is detected. In this embodiment, the system monitors the number of days of indicated intermittent and/or continuous leaks. Fig. 12 shows a chart of bit values indicating the number of days a continuous leak has been detected. In this embodiment, a 3-bit value is used in order to improve the accuracy and range of the feature. The "000" bit value indicates that a leak has not been detected. This is the initial value of the system. A "001" bit value indicates that a 1-2 day leak has been detected. "010" indicates that a leak has been detected for 3-7 days. A "011" bit value indicates that a leak has been detected for 8-14 days. A "100" bit value indicates that a leak has been detected for 15-21 days. A "101" bit value indicates that a leak has been detected for 22-34 days. A "110" bit value indicates that a leak has been detected for more than 35 days. A "111" bit value indicates that the feature is not usable in this embodiment of the system. In alternative embodiments, different ranges of days may be used for different bit values. Further, more bit values may be used to increase the total number of possible leak days that may be recorded. An alternative embodiment uses the bit values in fig. 12 to indicate the number of days an intermittent or continuous leak has been detected.

Another feature that may be used in this embodiment is the flow/direction indicator of the meter. This feature shows the relative flow and direction of water through the meter at any given LCD update cycle. In this embodiment, the main processor updates the LCD every 1/2 seconds when the solar cell provides sufficient power. This feature also shows the direction of flow through the meter (i.e., forward or backward). The flow rate and direction of water flow is valuable information as a way to detect system malfunctions and/or fraud. The type of fraud discovered includes the customer physically disconnecting the meter from the supply line in order to receive water without recording usage. Another form of fraud involves the customer reversing the direction of the meter, thereby "spinning it back". In this case, the actual water usage by the customer causes the system to record a negative usage or "back flow". In effect, the customer subtracts the amount of water used from his usage record.

FIG. 13a shows a chart of bit values and LCD icon states for a flow/direction feature used by an embodiment of the present invention. Several different relative flows are predetermined for the meter. "Zero" indicates no flow through the meter. "Q_START"indicates the normal usage traffic established for the system. "1/2 Max Flow (Max)Flow) "indicates that the flow has reached half the maximum flow for that particular meter. The LCD icon is used to display the status of the meter's flow/direction to the utility upon visual inspection. For no flow, the flow icon is turned off on the LCD display. If the flow satisfies "Q_START"horizontal" then a single arrow icon is displayed. If the Flow satisfies the "1/2 Max Flow" level, a single arrow icon with a striped icon at the end is displayed. Further, the arrow icons with "+" marks indicate positive flow direction, and "-" indicates negative or backflow. A "00" bit value indicates that the meter has not detected flow. The "01" bit value indicates that a "Q" has been detected at the meter since the last LCD update cycle_START"is measured. The "10" bit value indicates that a "1/2 MaxFlow" traffic has been detected. The "11" bit value indicates that the flow/direction feature is not available for this embodiment of the system.

Another feature that works in conjunction with the flow/direction feature is the ability to monitor consecutive days in which no water flows through the meter. This feature is useful in detecting possible fraud because most customers are unlikely to have been through days without water flowing through their meters. If the monitoring system detects that no water has flowed for a predetermined number of days, personnel may be dispatched from the utility to check whether the meter has been cheated or malfunctioned.

This feature functions in the same manner as previously shown in fig. 12 for monitoring consecutive days of leakage. Figure 13b shows a chart of 3-bit values for one embodiment of this feature. The "000" bit value indicates a consecutive day during the previous 35 day period when no water was flowing through the meter. This is the initial value of the system. A "001" bit value indicates that no water flow has been detected for 1-2 days. A "010" bit value indicates that no water flow has been detected for 3-7 days. A "011" bit value indicates that no water flow has been detected for 8-14 days.

A "100" bit value indicates that no water flow through for 15-21 days was detected. The "101" bit value indicates that no water flow through for 22-34 days was detected. The "110" bit value indicates that no water flow has been detected for more than 35 days. A "111" bit value indicates that the feature is not available for this embodiment of the system. In alternative embodiments, different ranges of days may be used for different bit values. Furthermore, more bit values may be used to increase the total number of possible days of no water flow that may be recorded.

Figure 13c shows a graph with a 2-bit value in an alternative embodiment of this feature. This feature functions in the same manner as the leakage monitoring with several thresholds described above in connection with fig. 11. However, in this embodiment, two thresholds are established for a particular number of days that no water has flowed. The first threshold was 7 days without water flow. The second threshold is 14 days without water flowing. The "00" bit value indicates that the first threshold of 7 days has not been exceeded. This is the initial value of the system. A "01" bit value indicates that the first threshold of no water flow has been reached for but not exceeded for 7-14 days. This is also an indication that there may be fraud or malfunction in the system. The "10" bit value indicates that the second threshold of 14 days of no water flow has been reached. This is also an indication that there may be an active fraud activity or failure in the system. The "11" bit value indicates that this feature is not usable with this embodiment of the invention.

Another embodiment of the invention is a feature to detect backflow through a meter. "reflux" is the reverse flow through the meter. This is an indication that fraud may exist, in which case the customer runs the meter backwards and removes the water usage from the meter. In some systems, a "backflow preventer" is installed in the system to prevent reverse flow. These are generally a type of one-way value known in the art. Detection of backflow by means of this feature may indicate malfunction or malfunction of the backflow preventer if the backflow preventer is installed in the system.

Fig. 14 shows a graph of the bit values of the Peak Continuous Backflow Volume (PCBV) feature. This embodiment of the feature measures continuous reflux volume over successive 15 minute periods. In the illustrated embodiment, the system monitors the meter for continuous flow back during the previous 35 day period. Each system typically has some level of backflow if no backflow preventer is installed. Any measured backflow volume would be an indication of a possible problem if a backflow preventer was installed. This normal level of backflow is taken into account by establishing a "Min Value" threshold for the system with the backflow preventer. In this example, the value is 0.1 gallons. A "Max Value" is also established for systems without a backflow preventer to indicate an abnormal level of backflow. In this example, this value is 10.0 gallons. As shown in the graph, a "00" bit Value indicates that the PCBV for the last 35 day period was below the Min Value level. This is an indication of the normal condition of any system with or without a backflow preventer. This is also the initial value of the system. A "01" bit Value indicates that the PCBV for the last 35 day period was above the Min Value level, but below the Max Value level. This is indicative of an abnormal condition (fraud or malfunction) of the system with the backflow preventer. It indicates the normal condition of the system without the backflow preventer. The "10" bit Value indicates that the PCBV level for the last 35 day period was above the Max Value level. This is an abnormal condition (fraud or malfunction) indicative of any system with or without a backflow preventer. The "11" bit value indicates that this feature is not usable with this embodiment of the invention. In other embodiments, different thresholds may be used depending on the characteristics of the system. Further, more thresholds may be used to accommodate the use of more than two thresholds.

An alternative embodiment for detecting backflow involves monitoring the Peak Backflow Volume (PBV) instead of the peak continuous backflow volume described above. This technique measures one surge or "peak" backflow through the meter at any time interval. As noted above, each system typically has some level of backflow. As with the previous embodiment, the normal level of backflow is taken into account by establishing a "Min Value" threshold for the system with the backflow preventer. A "Max Value" is also established for systems without a backflow preventer to indicate an abnormal backflow level. FIG. 15 shows a chart of bit values for a PBV monitoring feature. In the illustrated embodiment, the system monitors the peak reflux volume of the meter during any 15 minute cycle of the previous 35 day period. As shown in the graph, a "00" bit value indicates that the PBV of the last 35 day period was below the MinValue level. This indicates a normal condition for any system with or without a backflow preventer. This is also the initial value of the system. A "01" bit Value indicates that the PBV for the last 35 day period was above the Min Value level, but below the Max Value level. This indicates an abnormal condition (fraud or malfunction) of the system with the backflow preventer. It indicates normal conditions of the system without the backflow preventer. The "10" bit Value indicates that the PBV level for the last 35 day period was above the Max Value level. This indicates an abnormal condition (fraud or malfunction) for any system with or without a backflow preventer. The "11" bit value indicates that this feature is not usable with this embodiment of the invention. In other embodiments, different thresholds may be used depending on the characteristics of the system. Further, more bit values may be used to accommodate the use of more than two thresholds.

In describing the various communication protocols and features that may be used with the present invention, it is noted in particular that various embodiments may use some, different, or all of the features and protocols. Individual utilities may decide what aspects and features to use based on their system needs and capabilities. Further, each value displayed for the communication protocol and feature may vary according to the needs of the utility. Thus, the present invention provides great flexibility for monitoring automated systems including leak detection and fraud detection for electronic instrumentation systems that are self-powered through Wiegand wires.

While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention is to be limited only by the following claims.

Claims (40)

1. An apparatus for monitoring a meter, comprising:

a meter to monitor usage of the dispensing system;

an electronic data logger for processing data from the meter;

an external unit for controlling processing of data in the electronic data recorder using a communication protocol;

wherein the communication protocol comprises an initialization signal, a time interval identification signal and a clock signal,

wherein the time interval identification signal identifies the current cycle reading of data from the meter using a characteristic signal width of the time interval identification signal, the characteristic signal width comprising a multiple of the signal cycle width.

2. The apparatus of claim 1, wherein the meter is a utility meter.

3. The apparatus of claim 2, wherein the utility meter is a water meter.

4. The apparatus of claim 3, wherein the water meter is self-powered.

5. The apparatus of claim 4, wherein the power is provided to the water meter by a Wiegand wire.

6. The device of claim 5, wherein the Wiegand wire provides power to the electronic data recorder.

7. The apparatus of claim 1, wherein the external unit is a meter interface unit.

8. The apparatus of claim 1, wherein the duration of the initialization signal is between 25 and 100 milliseconds.

9. The apparatus of claim 1, wherein the clock signal operates at a frequency of 1200 hertz.

10. The apparatus of claim 1, wherein the clock signal operates at a frequency of 19.2 kilohertz.

11. The device of claim 1, wherein the electronic data recorder is activated by a communication protocol at 15 minute intervals.

12. The apparatus of claim 11, wherein the time interval identification signal identifies a time interval of every 15 minutes in the one hour time period.

13. The apparatus of claim 1 wherein the electronic data logger processes data from the meter to detect leaks in the distribution system.

14. The apparatus of claim 13, wherein the leak is continuous.

15. The apparatus of claim 13, wherein the leak is intermittent.

16. The apparatus of claim 13, wherein the electronic data logger further processes data from the meter to determine how long a leak exists.

17. The apparatus of claim 1 wherein the electronic data recorder processes data from the meter to determine flow in the distribution system.

18. The apparatus of claim 1 wherein the electronic data recorder processes data from the meter to determine the direction of flow in the distribution system.

19. The apparatus of claim 1 wherein the electronic data recorder processes data from the meter to detect the absence of flow in the dispensing system.

20. An apparatus for monitoring a meter, comprising:

a meter to monitor usage of the dispensing system;

an electronic data logger for processing data from the meter to detect the absence of flow in the distribution system and to determine how long the absence of flow has lasted;

an external unit for controlling processing of data in the electronic data recorder using a communication protocol;

wherein the communication protocol includes an initialization signal, a time interval identification signal, and a clock signal, wherein the time interval identification signal identifies a current cycle reading of data from the meter using a characteristic signal width of the time interval identification signal, the characteristic signal width comprising a multiple of a signal cycle width.

21. The apparatus of claim 1 wherein the electronic data logger processes data from the meter to detect backflow in the dispensing system.

22. The apparatus of claim 21, wherein the backflow is continuous.

23. An apparatus for monitoring meter usage, comprising:

a meter to monitor usage of the dispensing system;

means for receiving data from the meter;

means for processing data from a meter, wherein the means for processing data from a meter is controlled by an external unit using a communication protocol, the communication protocol comprising an initialization signal, a time interval identification signal, and a clock signal, wherein the time interval identification signal identifies a current cycle reading of data from the meter using a characteristic signal width of the time interval identification signal, the characteristic signal width comprising a multiple of a signal cycle width; and

apparatus for detecting leaks in a dispensing system.

24. The apparatus of claim 23, further comprising:

means for determining a flow rate in the dispensing system.

25. The apparatus of claim 23, further comprising:

means for determining the direction of flow in the distribution system.

26. The apparatus of claim 23, further comprising:

means for detecting the absence of a flow in the distribution system.

27. The apparatus of claim 23, further comprising:

means for detecting backflow in the dispensing system.

28. A method of calculating a utility usage model, comprising:

receiving usage data from a meter monitoring usage of the dispensing system;

processing the usage data to compute a utility usage model, wherein the usage data is processed by the external unit using a communication protocol, the communication protocol including an initialization signal, a time interval identification signal, and a clock signal, wherein the time interval identification signal identifies a current cycle reading of the usage data using a characteristic signal width of the time interval identification signal, the characteristic signal width including a multiple of a signal cycle width; and

the utility usage model identifies predefined conditions in the distribution system.

29. The method of claim 28, wherein the predefined condition is indicated by a level of size.

30. The method of claim 29, wherein the predefined condition is indicated by at least 3 levels of size.

31. The method of claim 28, wherein the utility usage model is determined on a motion time scale.

32. The method of claim 28, wherein the predefined condition comprises a leak in the distribution system.

33. The method of claim 28, wherein the predefined condition comprises a flow rate in the distribution system.

34. The method of claim 28, wherein the predefined condition comprises a direction of flow in the distribution system.

35. The method of claim 28, wherein the predefined condition comprises an absence of a flow in the distribution system.

36. The method of claim 28, wherein the predefined condition comprises a backflow in the distribution system.

37. The method of claim 28, wherein the meter is a water meter.

38. The method of claim 37, wherein the water meter is self-powered.

39. The method of claim 38, wherein the water meter is powered by a Wiegand wire.

40. A method of calculating a utility usage model, comprising:

receiving usage data of a distribution system;

a step of processing usage data to calculate a utility usage model, wherein the step of processing usage data is controlled by an external unit using a communication protocol, wherein the communication protocol comprises an initialization signal, a time interval identification signal and a clock signal, wherein the time interval identification signal identifies a current cycle reading of the usage data with a characteristic signal width of the time interval identification signal, the characteristic signal width comprising a multiple of a signal cycle width; and

a step of identifying predefined conditions in the distribution system according to the utility usage model.