Patent Publication Number: US-9417093-B2

Title: AMR transmitter and method using multiple radio messages

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation, and claims the benefit of U.S. application Ser. No. 12/489,530, filed Jun. 23, 2009, the entirety of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present 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. 4,633,713. 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 1493998A2, 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 advance 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 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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an AMR system, illustrating a mobile receiver in a drive-by vehicle and a fixed receiver for receiving transmissions from a transmitter associated with a utility meter; 
         FIG. 2  is a side view in elevation of a meter assembly and a separate transmitter assembly installed in a subsurface pit enclosure; 
         FIG. 3  is a side view in elevation of an integrated meter, meter transducer and transmitter assembly installed in a subsurface pit enclosure; 
         FIG. 4  is a side view in elevation of a conventional water meter with a meter register and a transmitter assembly of the present, invention installed in a subsurface pit enclosure; 
         FIG. 5  is a sectional view of the meter assembly of the present invention of  FIG. 2 ; 
         FIG. 6  is an end view of the meter assembly of  FIG. 2  with parts of the housing broken away for a view of the interior; 
         FIG. 7  is a block diagram of a signal processing section within the meter of the present invention of  FIG. 4 ; 
         FIGS. 8-9  are data maps of a first message transmitted by the transmitter portion of  FIGS. 2-4  to a receiver; and 
         FIGS. 10-11  are data maps of a second message transmitted by the transmitter portion of  FIGS. 2-4  to a receiver. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1 and 2 , in this example, the invention is incorporated in a water meter assembly  16 ,  20 , and a radio transmitter assembly  10  disposed in a subsurface pit enclosure  11  and connected by a cable  21 . The pit enclosure  11  is typically made of metal, concrete, plastic or other materials with a lid  15  which is removable to open the enclosure  11  for access. The pit enclosure  11  is located along the route of water supply pipe  17 . The housing assembly  16 ,  20  includes a lower, tubular housing  16  for housing the water metering elements and for withstanding water pressure, which is connected in the water supply line  17  by coupling nuts  18  and  19  ( FIG. 2 ). An upper housing  20  for a water meter register, and in some other embodiments, a transmitter, is positioned on top of the lower housing  16 . This upper housing  20  is preferably made of plastic, such as polystryrene, ASA Luran or an equivalent non-metallic material. A visual display of a types known in the art would be seen from the top of the upper housing  20 . 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 in  FIGS. 2 and 4 , in a “remote version” of the present, invention, a shielded cable  21  connects the electronics in the meter register housing  20 ,  20 ″ to a transmitter assembly  10 ,  10 ″, which is housed in a tubular transmitter housing  28 ,  28 ″, preferably of a plastic material, such as polystryrene, ASA Luran or an equivalent non-metallic material. The transmitter housing  28 ,  28 ″ hangs down from the pit lid  15  and includes its own battery, as is known in the art. The transducer electronics in the meter register housing  20 ,  20 ″ transmits electrical signals representing units of consumption of a utility to the transmitter assembly  10 ,  10 ″, which incorporates meter data and other data in messages encoded for transmission through a radio network. 
       FIG. 2  provides a version in which the meter and meter-register are integrated, but where the transmitter assembly  10  is contained in a separate housing.  FIG. 4  represents the traditional configuration of a separate meter register  20 ″ mounted on a water meter housing  16 ″ with a separate transmitter assembly  10 ″. 
     In a fully “integrated version” of the invention seen in  FIG. 3 , a housing  20 ′ encloses both meter register and transmitter formed on a circuit board  26  and an antenna  29  for transmitting signals directly through the pit lid  15  to a radio signal receiver  24 . In this version, the pit lid  15  is 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 assemblies  10 ,  10 ″,  26  communicate via RF signals with a receiver  24  which can be a mobile receiver in a vehicle  27  seen in  FIG. 1 . The transmitter assemblies  10 ,  10 ″  26  each transmit radio frequency signals encoded with messages and meter data, as will be further described below in relation to  FIGS. 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 assemblies  10 ,  10 ″,  26  also communicate, via RF signals with a fixed receiver  22  installed on a utility pole  23  seen in  FIG. 1 , within a range of up to one thousand feet of the transmitter unit  10 . The transmitter assembly  10 ,  10 ″,  26  transmits electronic messages, including meter data, as will be further described below in relation to  FIGS. 8-11 . 
     Referring to  FIG. 5 , in the integrated meter, meter register and transmitter ( FIG. 3  version), the meter housing  16  is made of brass or another suitable material, preferably lead-free, to withstand water pressures. Inside the housing  16  is a plastic metering insert  38  positioned in the conduit  16  and supporting two mirrors  32 ,  33  at minus forty-five degrees and plus forty-five degrees, respectively, relative to vertical. The assembly also includes two ultrasonic transducers  30 ,  31 , a temperature sensor  39 , a signal processing section,  50 , and one or more batteries  37 . A first ultrasonic signal will be transmitted through one of the transducers  30  downward, to reflect off one of the mirrors  32  at ninety degrees, to travel through the flow stream  35  as an ultrasonic signal parallel to the flow stream and the meter housing  16 , which is shaped like a pipe. The signal will then reflect off the second mirror  33  at ninety degrees and be detected by the second ultrasonic transducer  31  and converted to an input to the signal processing section  50  in  FIG. 7 . A second signal is then transmitted in a reverse direction through second one of the transducers  31 , downward to reflect off the second one of the mirrors  33  at ninety degrees to travel through the flow stream  35  opposite the direction of flow  35  and parallel to the direction of flow and the conduit  16 . The signal will then reflect off the first-mentioned mirror  32  at ninety degrees and be detected by the first ultrasonic transducer  30  and input to the signal processing section  50  in  FIG. 7 . A temperature sensor  39  is also positioned with one end projecting into the flow stream  35 . 
     Referring to  FIG. 7 , the housing  20 ′ in  FIGS. 3 and 5 , encloses an electrical signal processing section  50  typically formed on a circuit board  26  and including a microelectronic CPU  51  operating according to a control program, of program instructions stored in a program memory  52 , which may be internal to the CPU  51 . The memory  52  is flash memory that can be altered with a special programming unit, which communicates with the transmitter through an optical I/O data port  56 , preferably utilizing the IrDa (infrared frequency) protocol. Data profiling data for reverse flow is read through this optical I/O data port  56  as well. This can be stored in a non-volatile memory external to the CPU  51 . 
     As further seen in  FIG. 7 , the CPU  51  receives signals from an ultrasonic transducer interface  53 . This section  53  can receive the ultrasonic signals  34  after conversion by the transducers  30 ,  31 , to eventually produce data signals at a logic level of power, such as 3.6 dc volts, for digital circuitry. The CPU  51  produces metering data in messages, which are converted to radio frequency (RF) signals by an RF transmitter section  54  that modulates signals for transmission. These signals can then be signaled directly through an antenna  29  ( FIGS. 6 and 7 ) to an RF receiver, represented generally by block  24  in  FIG. 3 , provided that the pit lid  15  is not made of metal so as to interfere with the radio frequency signals. The message data contained in the RF transmissions is mapped in  FIGS. 8-11 . 
     In the embodiments in  FIGS. 2 and 4 , a meter transducer section (not illustrated) in the meter register housing  20 ,  20 ″ would transmit data representing units of utility consumption through a cable output port and through the cable  21 , to respective transmitter assemblies  10 ,  10 ″ seen in  FIGS. 2 and 4  for conversion to RF signals and transmission to a radio receiver  24  seen in  FIG. 1 . In these embodiments, the transmitter assemblies  10 ,  10 ″ would include a signal processing section of a type seen in  FIG. 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 assemblies  10 ,  10 ″, would be organized as illustrated in  FIGS. 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 vehicles  27  ( 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 receivers  22  provided they are not too far from the transmitter. 
     To reach fixed location receivers  22  ( 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. 8-11  show 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 sensor  39  to the meter housing assembly  16 ,  20  as seen in  FIG. 4 . 
     As seen in  FIG. 8 , the first message  40  includes a header  41  of 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, D 1 -D 6 , provide digits of a transmitter identification number. The next two hexadecimal digits, D 7 -D 8 , provide status data  43  seen in more detail in  FIG. 9 . This is followed by six hexadecimal digits, D 9 -D 14 , of meter data representing consumption of the utility by the customer. This is followed by two more hexadecimal digits, D 15 -D 16 , providing the most significant digits of a transmitter identification number. This is followed by four more hexadecimal digits, D 17 -D 20 , providing an error checking code, preferably a cyclic redundancy code (CRC). 
     Referring to  FIG. 9 , the status byte  43  includes status bits indicating presence of alarm data in a following message for the tamper alarm  47 , other alarms  48  such as empty pipe, low temperature (3 degrees C. or below) or end-of-life, potential leak alarm  49  (no usage 24 hours), reverse flow alarm  57  or stuck meter (no usage) alarm  58 . The last three bits  59  indicate a meter encoder type, such as RTR, ADE or gas, which are types known from the commercial products of the assignee. 
     As seen in  FIG. 10 , the second message  60  also includes a header  61  of 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, D 1 -D 8 , provide four bytes of a transmitter identification number. The next six hexadecimal digits, D 9 -D 14 , provide reverse flow data  63 . This is followed by four hexadecimal digits, D 15 -D 18 , of “Δ reverse flow” data  64  in the last twenty-four (24) hours. This is followed by four more hexadecimal digits, D 19 -D 22  providing of “Δ reverse flow” data  65  in the last seven (7) days. This is followed by four more four more hexadecimal digits, D 23 -D 26 , providing two bytes of status data  66  seen in more detail  FIG. 11 . This is followed by two more hexadecimal digits, D 27 -D 28 , providing data for max flow rate and by four more hexadecimal digits D 29 -D 32  (not shown in  FIG. 9 ) providing an error checking-code, preferably a cyclic redundancy code (CRC). 
       FIG. 11  shows the details of the two status bytes  66  in which meter size is defined by four bits  68 , a unit of measure is defined by the next three bits  69 , units of time are defined by the next two bits  70 , and indicators are provided, for the following alarms: tamper  71 , leak  72 , reverse flow  73 , stuck meter  74  (no usage for 30 days), end-of-life  75  and low temperature  76 . 
     It should noted that the alarm status bits  47 - 49  and  57 - 58  in the first message in  FIG. 8  indicate 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 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 ultrasonic signals to develop a meter reading, it will be apparent that the same messaging can be applied to fluidic oscillator type or electromagnetic type meters and that such variations are intended to be encompassed by the following claims, unless specifically excluded.