AMR transmitter and method using multiple radio messages

The invention provides a method and several types of devices for converting meter reading signals into data messages including a first message (40) having meter data (44) representing consumption of a utility, and meter diagnostic status data (43), and a second message (60) having meter reverse flow data (63-65) and meter diagnostic data (66) particular to an electronic flow meter, and receiving said first message (40) and said second message (60) and converting first message and said second message to radio frequency signals (25) and transmitting said radio frequency signals (25) to a receiver (22, 24).

TECHNICAL FIELD

This invention relates to automatic meter reading (AMR) systems that include an electronic meter or meter register and a network for collecting utility metering data.

DESCRIPTION OF THE BACKGROUND ART

Recently, electronic meter registers have begun to appear in utility metering applications. An example of a separate electronic meter register is disclosed in Olson, U.S. Pat. No. 6,611,769. An example of an electronic meter register integrated in one housing with a mechanical meter is disclosed in Lazar et al., U.S. Pat. No. 7,412,882.

Traditionally, ultrasonic and acoustic type meters have been used for measuring industrial and wastewater flows. Examples of such meters are disclosed in Lee, U.S. Pat. No. 3,935,735; Lee et al., U.S. Pat. No. 4,052,896 and Vander Heyden et al., U.S. Pat. No. 4,633,719. Such meters depend on signals impinging upon particles in the flow stream, Doppler methods and time-of-travel characteristics to measure the flow. European Patent Publication 1 493 998 A2, published Jun. 8, 2004, discloses an ultrasonic flow meter for utility usage.

The use of some types of electronic meters, such as ultrasonic types, fluidic oscillatory types and electromagnetic sensing meters, has been limited due to elements of cost. With advances in the design and construction of these devices, it may now be possible to meet marketplace pricing constraints.

Electronic meters have not previously been in widespread use in utility applications in the United States due to cost factors. As raw material costs and manufacturing costs are rapidly increasing at this time, there is a now a cost advantage to converting mechanical-based metering systems to electronic metering systems. Also, electronic meters are well-suited for use in AMR systems. Electronic meters provide greater accuracy than some other types of known utility meters. And, electronic meters are well adapted to flows with particles included.

Electronic meters and meter registers may be able to handle certain data that is particular to electronic meters such as reverse flow data, empty pipe data and end-of-life data. This, however, requires improvements in network communication protocols to handle the additional data.

SUMMARY OF THE INVENTION

In one aspect, the invention relates to a method and circuitry for communicating metering data in a pair of related messages to a receiver. The first of two messages includes a transmitter ID number, utility consumption data, and diagnostic data for conventional conditions such as, for example, a tamper indication, a leakage indication, and a stuck meter indication. A second message is provided to add reverse flow data and diagnostic data, particular to an electronic meter, such as an empty pipe indication, and an end of life indication.

In a further aspect of the invention, status data are added to the first message to indicate the presence of reverse flow data and diagnostic data, such as empty pipe, low temperature and end-of-life in the second message.

In a further aspect of this invention, the second message can be transmitted less frequently than the first message by an order of magnitude, or the interval can be extended for the purpose of conserving the life of one or more batteries.

The invention also provides diagnostic data and profiling data for reverse flow conditions over the last seven days and the last twenty-four (24) hours.

The invention is provided in three physical embodiments, one embodiment which fully integrates a meter, a meter register and a radio transmitter in one housing, and two other embodiments in which meter data is output through a data port from the meter register to a separate transmitter assembly, which can be mounted to a pit lid.

Other objects and advantages of the invention, besides those discussed above, will be apparent to those of ordinary skill in the art from the description of the preferred embodiments which follows. In the description, reference is made to the accompanying drawings, which form a part hereof, and which illustrate examples of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIGS. 1 and 2, in this example, the invention is incorporated in a water meter assembly16,20, and a radio transmitter assembly10disposed in a subsurface pit enclosure11and connected by a cable21. The pit enclosure11is typically made of metal, concrete, plastic or other materials with a lid15which is removable to open the enclosure11for access. The pit enclosure11is located along the route of water supply pipe17. The housing assembly16,20includes a lower, tubular housing16for housing the water metering elements and for withstanding water pressure, which is connected in the water supply line17by coupling nuts18and19(FIG. 2). An upper housing20for a water meter register, and in some other embodiments, a transmitter, is positioned on top of the lower housing16. This upper housing20is preferably made of plastic, such as polystryrene, ASA Luran or an equivalent non-metallic material. A visual display of a type known in the art would be seen from the top of the upper housing20. In recent years, the meter register has included a transducer for converting: i) mechanical movements, ii) movements of a magnet or iii) electrical meter signals to electrical signals of a type known in the art for signaling units of consumption of a utility.

As further seen inFIGS. 2 and 4, in a “remote version” of the present invention, a shielded cable21connects the electronics in the meter register housing20,20″ to a transmitter assembly10,10″ which is housed in a tubular transmitter housing28,28″, preferably of a plastic material, such as polystryrene, ASA Luran or an equivalent non-metallic material. The transmitter housing28,28″ hangs down from the pit lid15and includes its own battery, as is known in the art. The transducer electronics in the meter register housing20,20″ transmits electrical signals representing units of consumption of a utility to the transmitter assembly10,10″, which incorporates meter data and other data in messages encoded for transmission through a radio network.

FIG. 2provides a version in which the meter and meter register are integrated, but where the transmitter assembly10is contained in a separate housing.FIG. 4represents the traditional configuration of a separate meter register20″ mounted on a water meter housing16″ with a separate transmitter assembly10″.

In a fully “integrated version” of the invention seen inFIG. 3, a housing20′ encloses both meter register and transmitter formed on a circuit board26with an antenna29for transmitting signals directly through the pit lid15to a radio signal receiver24. In this version, the pit lid15is made of a non-RF-interference material, for example, plastic, concrete, or other materials that will not significantly change the direction of, or attenuate, RF signals.

The transmitter assemblies10,10″,26communicate via RF signals with a receiver24which can be a mobile receiver in a vehicle27seen inFIG. 1. The transmitter assemblies10,10″,26each transmit radio frequency signals encoded with messages and meter data, as will be further described below in relation toFIGS. 8-11. The meter data is collected from various customer locations and transmitted to a central office for processing for billing purposes.

In the present invention, the transmitter assemblies10,10″,26also communicate via RF signals with a fixed receiver22installed on a utility pole23seen inFIG. 1, within a range of up to one thousand feet of the transmitter unit10. The transmitter assembly10,10″,26transmits electronic messages, including meter data, as will be further described below in relation toFIGS. 8-11.

Referring toFIG. 5, in the integrated meter, meter register and transmitter (FIG. 3version), the meter housing16is made of brass or another suitable material, preferably lead-free, to withstand water pressures. Inside the housing16is a plastic metering insert38positioned in the conduit16and supporting two mirrors32,33at minus forty-five degrees and plus forty-five degrees, respectively, relative to vertical. The assembly also includes two ultrasonic transducers30,31, a temperature sensor39, a signal processing section,50, and one or more batteries37. A first ultrasonic signal will be transmitted through one of the transducers30downward, to reflect off one of the mirrors32at ninety degrees, to travel through the flow stream35as an ultrasonic signal parallel to the flow stream and the meter housing16, which is shaped like a pipe. The signal will then reflect off the second mirror33at ninety degrees and be detected by the second ultrasonic transducer31and converted to an input to the signal processing section50inFIG. 7. A second signal is then transmitted in a reverse direction through second one of the transducers31, downward to reflect off the second one of the mirrors33at ninety degrees to travel through the flow stream35opposite the direction of flow35and parallel to the direction of flow and the conduit16. The signal will then reflect off the first-mentioned mirror32at ninety degrees and be detected by the first ultrasonic transducer30and input to the signal processing section50inFIG. 7. A temperature sensor39is also positioned with one end projecting into the flow stream35.

Referring toFIG. 7, the housing20′ inFIGS. 3 and 5, encloses an electrical signal processing section50typically formed on a circuit board26and including a microelectronic CPU51operating according to a control program of program instructions stored in a program memory52, which may be internal to the CPU51. The memory52is flash memory that can be altered with a special programming unit, which communicates with the transmitter through an optical I/O data port56, preferably utilizing the IrDa (infrared frequency) protocol. Data profiling data for reverse flow is read through this optical I/O data port56as well. This can be stored in a non-volatile memory external to the CPU51.

As further seen inFIG. 7, the CPU51receives signals from an ultrasonic transducer interface53. This section53can receive the ultrasonic signals34after conversion by the transducers30,31, to eventually produce data signals at a logic level of power, such as 3.6 dc volts, for digital circuitry. The CPU51produces metering data in messages, which are converted to radio frequency (RF) signals by an RF transmitter section54that modulates signals for transmission. These signals can then be signaled directly through an antenna29(FIGS. 6 and 7) to an RF receiver, represented generally by block24inFIG. 3, provided that the pit lid15is not made of metal so as to interfere with the radio frequency signals. The message data contained in the RF transmissions is mapped inFIGS. 8-11.

In the embodiments inFIGS. 2 and 4, a meter transducer section (not illustrated) in the meter register housing20,20″ would transmit data representing units of utility consumption through a cable output port and through the cable21, to respective transmitter assemblies10,10″ seen inFIGS. 2 and 4for conversion to RF signals and transmission to a radio receiver24seen inFIG. 1. In these embodiments, the transmitter assemblies10,10″ would include a signal processing section of a type seen inFIG. 7, including a CPU, a program memory, an RF transmitter section and an antenna to convert the meter data to radio frequency signals according to a message protocol. The information in the radio messages, as transmitted from the transmitter assemblies10,10″, would be organized as illustrated inFIGS. 8-11.

The radio signals can be transmitted from the AMR transmitter in several modes of operation in a one-way AMR network. Although the invention is disclosed in one example, in a one-way network, the invention could also be applied in a two-way communication network, where each radio transmitter described herein would be included as one portion of a transceiver. Drive-by vehicles27(FIG. 1) will be able to read the transmitter signal and collect meter readings. This type of system uses a battery for power and this mode of transmission provides long battery life using small batteries. This signal may be read by fixed receivers22provided they are not too far from the transmitter.

To reach fixed location receivers22(FIG. 1), it is desirable to provide a transmission utilizing a higher power level than the prior art low power methods used for communicating with drive-by receivers. In the present invention, this is accomplished by sending out a frequency-hopping spread-spectrum (FHSS) signal over twenty-five channels. Various time periods can be observed in sending out the two messages, and the second message may be sent out less frequently than the first message.

FIGS. 8-11show the data in the two messages referred to more generally above. The messages contain data for implementing various alarm conditions, including a reverse flow alarm, a potential leak alarm, a stuck meter condition (no usage for 30 days), a tamper alarm, an empty pipe alarm, a low temperature alarm and an end-of-life notification. The reverse flow alarm, the empty pipe condition and the end-of-life notification are conditions which are particularly related to electronic flow meters. The low temperature condition is a feature of the ultrasonic flow meter that is available and is sensed with the addition of a temperature sensor39to the meter housing assembly16,20as seen inFIG. 4.

As seen inFIG. 8, the first message40includes a header41of forty-eight (48) bits, a data field and an error code field in the form of 120 bits comprising twenty (20) hexadecimal digits. The first six hexadecimal digits, D1-D6, provide digits of a transmitter identification number. The next two hexadecimal digits, D7-D8, provide status data43seen in more detail inFIG. 9. This is followed by six hexadecimal digits, D9-D14, of meter data representing consumption of the utility by the customer. This is followed by two more hexadecimal digits, D15-D16, providing the most significant digits of a transmitter identification number. This is followed by four more hexadecimal digits, D17-D20, providing an error checking code, preferably a cyclic redundancy code (CRC).

Referring toFIG. 9, the status byte43includes status bits indicating presence of alarm data in a following message for the tamper alarm47, other alarms48such as empty pipe, low temperature (3 degrees C. or below) or end-of-life, potential leak alarm49(no usage 24 hours), reverse flow alarm57or stuck meter (no usage) alarm58. The last three bits59indicate a meter encoder type, such as RTR, ADE or gas, which are types known from the commercial products of the assignee.

As seen inFIG. 10, the second message60also includes a header61of forty-eight (48) bits, a data field and an error code field in the form of 136 bits comprising thirty-four (20) four-bit hexadecimal digits. The first eight hexadecimal digits, D1-D8, provide four bytes of a transmitter identification number. The next six hexadecimal digits, D9-D14, provide reverse flow data63. This is followed by four hexadecimal digits, D15-D18, of “Δ reverse flow” data64in the last twenty-four (24) hours. This is followed by four more hexadecimal digits, D19-D22 providing of “Δ reverse flow” data65in the last seven (7) days. This is followed by four more four more hexadecimal digits, D23-D26, providing two bytes of status data66seen in more detailFIG. 11. This is followed by two more hexadecimal digits, D27-D28, providing data for max flow rate and by four more hexadecimal digits D29-D32 (not shown inFIG. 9) providing an error checking code, preferably a cyclic redundancy code (CRC).

FIG. 11shows the details of the two status bytes66in which meter size is defined by four bits68, a unit of measure is defined by the next three bits69, units of time are defined by the next two bits70, and indicators are provided for the following alarms: tamper71, leak72, reverse flow73, stuck meter74(no usage for 30 days), end-of-life75and low temperature76.

It should be noted that the alarm status bits47-49and57-58in the first message inFIG. 8indicate the presence of actual alarm data in the second message. It should now be apparent how the first message and second message contribute to increasing the diagnostic data available in the two messages due to the capabilities of electronic flow meters, including an ultrasonic flow meter. This provides advantages in diagnosing operating conditions, which have not been known before the invention.

This has been a description of the preferred embodiments, but it will be apparent to those of ordinary skill in the art that variations may be made in the details of these specific embodiments without departing from the scope and spirit of the present invention. For example, although the preferred embodiment uses electronic signals to develop a meter reading, it will be apparent that the same messaging can be applied to other types of electronic meters as well as to conventional electromechanical meters and that such variations are intended to be encompassed by the following claims, unless specifically excluded.