Abstract:
A method and apparatus is disclosed for providing a metering site transceiver ( 12  or  15 ) with the ability to operate in a mobile back-up network ( 26 ) to signal utility consumption data that would otherwise be transmitted to a fixed receiver ( 30 ) in a fixed network AMR system. A mobile collection back-up capability allows a vehicle collection system ( 26, 27 ) to be used to read the remote meters ( 11, 14 ) in the fixed network, when a gateway ( 30 ) is detected as not communicating with the site transceiver ( 12  or  15 ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation-in-part of U.S. patent application Ser. No. 12/635,079, filed Dec. 10, 2009, now abandoned and the benefit of its earlier filing date is claimed herein. This application also incorporates subject matter from U.S. patent application Ser. No. 12/792,128, filed Jun. 2, 2010 and the benefit of its earlier filing date is claimed herein. 
    
    
     TECHNICAL FIELD 
     This invention relates to automatic meter reading systems, including “AMR” and “AMI” systems, and in particular to utility meters using apparatus for transmitting metering data signals to a fixed or mobile radio receiver in a wireless network for collecting utility metering data. 
     DESCRIPTION OF THE BACKGROUND ART 
     A typical fixed network meter reading system comprises metering sites, gateways, and a backhaul network. The metering sites include radio frequency transmitters or transceivers located at utility meter sites, which are contemplated as including either a water meter or a gas meter, or both. Typically, these utility meters are not connected to a source of AC power and they are operated on battery power. The metering sites communicate with receivers via a wireless radio frequency communication link. If these receivers communicate with a large number of metering sites either directly or through relay devices known as repeaters, and also interface to a backhaul network, they are known as gateways. Gateways collect the data from a plurality of metering sites and pass the information via a wired or wireless network (local or wide area network), sometimes called a backhaul technology, to a central data collection system, where the data is processed for billing purposes. This backhaul network may include various public or private systems such as the WIFI (a wireless LAN), GPRS (a second generation cellular network), POE (Power over Internet), or CDMA (code division multiple access) or many others known in the art. 
     Cerny et al., U.S. Pat. No. 5,298,894, discloses an early example of a mobile automatic meter reading (AMR) system in which a utility meter transmitter transmits radio frequency (RF) metering data signals to an RF collection unit in a drive-by vehicle. 
     Gastouniotis et al., U.S. Pat. No. 4,940,976, discloses an early example of a fixed network for transmitting data from a plurality of utility meters to a central station through a plurality of fixed receiving stations. In fixed receiver network systems today, the receiver units can be mounted on utility poles, or on water storage tank towers, or inside of electric meters or in utility pedestals. In fixed network systems, it is not necessary to provide people and equipment to travel through the areas where readings are to be collected. Fixed meter reading networks are currently referred to in some literature in the technical field as Advanced Metering Infrastructure (AMI). 
     A fixed network system is currently preferred in many situations where a large amount of data from metering sites must be processed. On the other hand, there are sometimes periods when scheduled communications are not successful in such systems for various reasons. 
     Petite et al., Pat. Pub. No. US2005/0195775 discloses a fixed two-way network. Petite does not describe, however, that a gateway or transceiver is carried by a vehicle for collecting utility metering data along a geographical route. In Petite et al., there are two transmitters at each endpoint and two receivers that are each transmitting exclusively either in narrow band communication or in spread spectrum communication, depending on the detected single mode of communication used by the receivers. When a mode is selected for a transmitter, it is based on programmed sensing of the one mode of communication from the receivers using two-way communication. 
     Osterloh et al., U.S. Pat. Pub. No. US2005/0237959, FIG. 7, shows a method of switching an endpoint between a mobile network and a fixed network according to commands received by the endpoint from the mobile data collector and the fixed data collector, respectively. This is a receiver-command-driven method for a two-way network. This is an either-or selection of the fixed mode or mobile mode, and not a conditional mode of operation for a fixed network. 
     SUMMARY OF THE INVENTION 
     The invention provides a metering site transmitter/receiver, also known as a transceiver, with the ability to operate in a mobile back-up network to signal utility consumption data when a back-up condition is detected in a fixed network meter reading system. A mobile collection back-up capability allows a vehicle collection system to be used to read the meter data of the fixed network system, when a fixed network communications are not available. 
     Such non-availability can occur during initial installation and startup, or after installation and startup. 
     A method of the invention comprises a metering site transceiver receiving metering signals from a metering device that has been installed and has started up metering consumption of a utility. The metering site transceiver is responsive to the metering signals for transmitting a first plurality of radio frequency metering data signals in a condition for reception by a fixed network receiver within a reporting interval, such as every eight (8) hours within each 24-hour period. The metering site transceiver then checks for a back-up condition, and upon detection of the back-up condition, the metering site transceiver transmits a second plurality of radio frequency metering data signals in a condition for reception by a mobile receiver. 
     The invention also relates to a utility meter interface circuit for use in an automatic meter reading network, wherein the utility meter interface circuit is adapted for installation at a metering site, wherein the utility meter interface circuit is configured to transmit a first plurality of radio frequency signals during a reporting interval within each 24-hour period, wherein said first plurality of radio frequency signals are transmitted in a condition for reception by a fixed network receiver, the utility meter interface circuit also being configured to transmit a second plurality of radio frequency signals in a condition for reception by a mobile network receiver; and wherein the utility meter interface circuit is configured to check for a back-up condition, and upon occurrence of the back-up condition, the utility meter interface circuit repeatedly transmits the second plurality of radio frequency signals in a condition for reception by the mobile network receiver until a next scheduled attempt to transmit the first plurality of radio frequency signals to the fixed network receiver. 
     The invention is particularly applicable to sites associated with water meters and gas meters, where the metering sites also include transceivers that operate on battery power. 
     This invention allows data to be collected via a mobile radio receiver, but only when the data cannot be acquired via the fixed network. This allows the most efficient use of the battery associated with the site transceiver and the most efficient use of the RF channel between the site transceiver and the gateway. 
     In a further aspect of the invention, the circuitry further comprises a CPU operating according a stored control program. The control program is stored in a tangible, non-transitory medium, such as a semiconductor memory circuit, and includes a program routine that when executed, senses that the site transceiver has not communicated with the gateway for a defined time period. It then arranges for transmissions to a mobile network within another specified time period. 
     Other features 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. Such examples are illustrative, but for the scope of the invention, reference is made to the claims which follow the description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a meter reading system with a fixed receiver for receiving transmissions from a transmitter associated with a utility meter; 
         FIG. 2  is a schematic view of a meter reading system with a mobile receiver for receiving transmissions from a transmitter associated with a utility meter; 
         FIG. 3  is a block diagram of a metering site transmitter associated with a utility meter; and 
         FIG. 4  is a flow chart of the operation of the metering site transmitter in switching communication between the receiver in  FIG. 1  and the receiver in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a fixed automatic meter reading system includes a meter and meter register assembly  11  connected in a water line (shown schematically as a dashed line in  FIG. 1 ) serving a residential building  10  through a basement  16  or a foundation crawl space. For buildings built on a concrete slab foundation, water line entry can be made through the slab or through a side wall. The assembly  11  includes a meter register for transmitting pulses to a transceiver assembly  12  mounted somewhere within or on the building  10 . Alternatively, a meter and meter register assembly  14  can be connected in a water line (shown schematically as a dashed line in  FIG. 1 ) and disposed in a subsurface pit enclosure  13  adjacent the building  10 . The meter register in the assembly  14  includes a device for transmitting signals, representing units of utility consumption, to a transceiver assembly  15  mounted to a pit lid. Examples of meter registers with signal transmitters are disclosed in Cerny et al., U.S. Pat. No. 5,298,894 and Bloss Jr. et al., U.S. Pat. No. 5,825,303 and other known well known prior art. 
     The meter register in the assembly  11 ,  14  can be one that is commercially distributed by Badger Meter, Inc., the assignee of the present invention, under the trade designation “Recordall” Transmitter Register (RTR). Besides displaying units of consumption, this device uses a pulse transmitter that is described in Strobel et al., U.S. Pat. No. 4,868,566, entitled “Flexible Piezoelectric Switch Activated Metering Pulse Generators,” to convert the mechanical movements of the meter to electrical signals. Other metering transducers known in the art, such as the absolute digital encoder (ADE) circuit offered by the assignee of the present invention can also be used as the meter register and these also produce electrical signals representing units of utility consumption. In addition, other magnetic sensing circuits are known in the art for converting movements of magnetic devices moved by a metering element, to electrical pulses representing units of metering consumption as described in Olson et al., U.S. Pat. No. 6,611,769. 
     Typically, the site transceiver assemblies  12 ,  15  are not connected to a source of AC or DC power and are operated on battery power. The site transceiver assemblies  12 ,  15  communicate with network transceiver assemblies  20 ,  30  via a wireless radio frequency communication link. The network is a fixed network, which is characterized by fixed network transceiver assemblies  30 , as opposed to mobile transceivers carried in a vehicle or carried by a human employed to collect meter data. The transceiver assemblies  20 ,  30  can communicate with the site transceiver assemblies  12 ,  15 , either directly, or through intermediate fixed transceiver assemblies  20  known as repeaters. The repeaters  20  receive messages from the site transceiver assemblies  12 ,  15  and relay the data in further radio frequency messages to the gateway transceiver assemblies  30 . Or, the repeaters  20  can communicate in an opposite direction by receiving radio frequency messages from the gateway transceiver assemblies  30  and relaying the data content in further radio frequency messages to the site transceiver assemblies,  12 ,  15 . 
     If these transceiver assemblies  30  communicate with a backhaul network, such as network  40 , they are known as gateways (to the network). These transceiver units or gateways  30  can be mounted on utility poles, streetlight poles, or on other high structures such as buildings or water storage tank towers, or can be placed inside of electric meters or in utility pedestals. Gateways typically have a source of AC power, which can be converted to DC power for operating circuitry in the gateway. Gateways collect the data that is received from a plurality of transceivers  12 ,  15  at the utility meter data origination sites and pass the data via a second network, sometimes called a backhaul network to a central data collection system shown as a control center  50  in  FIG. 1 . In this example, the backhaul network is a wireless network  40 . This wireless network  40  can include various public or private wireless systems operating according to at least one of the following protocols; WIFI (a wireless local area network connected to the Internet), GPRS (a second generation cellular network), POE (Power over Ethernet to the Internet) or CDMA (code division multiple access) and others known in the art. 
     The site transceiver assemblies  12 ,  15  transmit an electronic message that generally includes an identification code, current meter reading data, historical consumption data, status information, and an error code for checking the data at the receiving end. In addition, the site transceiver assemblies  12 ,  15  are described herein as transmitting special messages on installation and startup referred to as a “discovery” message and a “status” message. The meter data is eventually collected at the data collection center  50  for billing purposes. This data collection center  50  includes one or more computers  51  for communicating with the backhaul network  40  and processing the utility metering data into customer billing statements. The data collection center  50  also includes a network reader computer program  52 , running on a computer  51  for managing communications with the meter data collection network. This computer program is further described in U.S. Pat. Pub. No. US2009/021678, entitled “Method and System for Providing a Self-Populating Database for the Network Collection of Meter Data” published Aug. 27, 2009 and assigned to the assignee herein. 
     Referring to  FIG. 2 , under certain circumstances, described as a back-up condition, the site transceiver assemblies  12 ,  15  communicate with a mobile network receiver  26  carried by a vehicle  27 . The vehicle  27  can be driven over a predetermined route or can be driven through a general area, such as a neighborhood, to receive meter reading data and transmitter identification data associated with the meter reading data. The site transceiver assemblies transmit signals in the mobile network on a relatively short repetitive interval rather than at the longer interval applicable to the fixed network. 
     Referring to  FIG. 3 , the transceiver assembly  12 ,  15  more particularly includes an electrical circuit typically formed on a circuit board and including a microelectronic CPU  60  operating according to a control program stored in a program memory  60   a . The program memory  60   a  is a tangible, non-transitory medium, in the form of a semiconductor circuit in this example. The program memory  60   a  is preferably nonvolatile, but it can be receive data and commands from a special programming unit, which communicates with the transceiver through an optical I/O port  62 . The CPU  60  typically also utilizes a memory  61  for data storage, and this may also be located on-board the CPU  60 . 
     As further seen in  FIG. 3 , the CPU  60  receives pulses from a pulse encoder (not shown) through a meter pulse input section  63 . This input section can receive a pulse input or an input from an absolute digital encoder (ADE) circuit of a type known in the art. The meter pulse input section transmits these signals in the form of metering signals to the CPU  60 , which processes them as metering data. The CPU  60  then transmits metering data in a message protocol, which is converted to radio frequency (RF) signals by an RF modulation section  64 . The radio signals are transmitted through an antenna  66  to a receiver  22  in the fixed network ( FIG. 1 ), or under certain circumstances to a receiver  26  in the vehicle  27  ( FIG. 2 ). Radio signals can also be received through antenna  66  from the receivers or gateways  30  and these signals are demodulated by a demodulation section  65  to extract data for processing by the CPU  60 . This data can include commands and configuration data for operation of the transceiver assembly  12 ,  15 . 
     The site transceiver assemblies  12 ,  15  each have two modes of operation, one mode for communicating with the receiver  20 ,  30  in the fixed network and another mode for communicating with the receiver  26  in the mobile network. Both the mobile transmissions and the fixed channel transmission will use the same fifty channels within the 902-928 MHz frequency band. The power level of operation is programmable in a range of from 1-30 dBm, which is applied to the antenna gain to determine the power level. The fixed network RF transmission from the transceivers will be near 18-20 dBm for gas and about 30 dBm for water metering applications. Mobile network transceiver transmissions are made at a power of 8 dBm or greater. The maximum power level of the transmission is limited by FCC regulations and to one (1) Watt maximum for frequency hopping spread spectrum (FHSS) communication with the fixed network receiver over fifty (50) channels. 
     The site transceiver  12  or  15  is powered by one or more on-board batteries (not shown). It should be understood that in single family residences only one of the two site transceivers  12  or  15  that are shown in  FIGS. 1 and 2  would be utilized for a single utility such as water. In order to extend battery life, communication between a site transceiver assembly  12  or  15 , and a gateway  30  is preferably initiated by the site transceiver assembly  12 ,  15 . The site transceiver assembly  12 ,  15  is battery-powered while the gateway  30  is typically powered from an available AC source. As part of the network operation, each site transceiver assembly  12  or  15 , has a respective identification number that is included in any communication to and from the assigned gateway  30 . Due to the limitations on battery life and RF traffic of multiple endpoint transceivers and gateways, the site transceiver assembly  12  or  15  attempts to communicate with the assigned gateway only a few times per day and at least once per day. 
     All RF communication sequences between the site transceiver assembly  12  or  15 , and the gateway  30  are initiated by the site transceiver assembly  12  or  15 . The site transceiver assembly,  12  or  15 , transmits a message on one or more of the fifty (50) radio communication channels having respective different frequencies. The site transceiver assembly  12 ,  15 , then listens for a response on the same frequency communication channel that it sent the information. At a minimum, this response from the gateway  30  consists of an acknowledgment that the message was received. The gateway  30  can request that additional data be sent as part of this acknowledgement. If additional data are requested, the site transceiver assembly  12 ,  15  will transmit the data on the same frequency channel. 
     If the site transceiver assembly  12 ,  15  has received the acknowledgement and transmits the requested information, then the sequence is completed. If the site transceiver assembly  12 ,  15  does not receive an acknowledgement to a transmission of utility consumption data to an assigned gateway receiver  30 , it will attempt to communicate with the gateway  30 , through up to eight more attempts in short succession, as more particularly described in U.S. patent application Ser. No. 12/792,198, cited above, and this description is incorporated herein by reference. The number of these immediate retries is not essential to the present invention. The essential concept is that after a selected number of retries without an acknowledgement, the communication will be deemed unsuccessful with respect to reporting to the fixed network at that particular reporting interval. 
     Before a gateway receiver  30  is assigned, messages including a discover message and a status message are transmitted. The discover message includes the address “FFFFFFFF” which is a global address allowing reception by any gateway. If an acknowledgement to these messages is not received, there are no retries, until the transmission at the next reporting interval such as eight (8) hours. 
     Gateways  30  will only reply to RF messages from the site transceivers  12 ,  15  to which they have been assigned. However, the gateway receiver  30  will store the identification numbers for all site transceivers from which messages are received. There is also a passive mode which allows a gateway to store all the interval information from site transceivers  12 ,  15 , even though it will not respond via radio frequency signals to the site transceivers  12 ,  15  if the gateway has not been assigned to them. 
     The default scheduled communication from the site transceiver  12  or  15  to the gateway  30  is every eight (8) hours in the preferred example. The data packet for the initial message includes eight interval readings beginning with the top of the hour (:00). If interval data is required at shorter intervals, then the RF communication rate will increase but the initial data packet still contains eight meter readings. For 15-minute intervals, eight readings can be provided to the gateway  30  at 2-hour intervals. For 5-minute data intervals, eight readings could be provided to the gateway every 40 minutes. The gateway has 9600 time slots available. 
     A condition of the activation of the back-up mode is that communication from the site transceiver  12  or  15  to the gateway  30  must have been unavailable for a period greater than twenty-four (24) hours, which period is selected here to be two days (48 hours). If a site transceiver  12  or  15  has not heard an acknowledgement signal from the gateway receiver  30  for at least two days prior to a scheduled mobile back-up period, the site transceiver  12  or  15 , will transmit a mobile network message during a mobile network transmission interval. This message will be transmitted in a format for containing minimal data in comparison to a format of the normal fixed network message. This allows billing data, alarm data and metering data to be collected for the time period in which the gateway  30  is not in communication with the site transceiver  12  or  15 . 
     A gateway  30  will store the received information but will only send an RF acknowledgement signal to the site transceiver  12 ,  15 , if a message has been received from the computer  51  in the data collection center  50  via the backhaul network  40  in the previous two days (48 hours). This will force the site transceiver  12  or  15 , into the mobile back-up transmission (at the scheduled time) if the gateway  30  is functioning, but the data cannot be forwarded to the data collection center  50 . When network communication is re-established, the saved information can be retrieved from the gateway  30  by the data collection center  50 . 
     Referring to  FIG. 4 , a computer program routine is diagrammed. In this routine the blocks represent groups of instructions in a control program stored in the program memory  60   a  and executed by the CPU  60 . As represented by start block  70 , when a water meter assembly  11  or  14  is placed in the field, its transceiver  12  or  15  will start up upon receiving a pulse from its meter register as water begins to flow through the meter  11  or  14 . For a gas meter and register assembly, operation would start by the input of a signal through optical IR interface  62  by a technician as represented by start block  71 . 
     Once the site transceiver  12 ,  15  is started up, it will transmit a “discovery” message in a format to be received by any gateway receiver in the fixed network. A gateway address in the message is set to the global address, “FFFFFFFF.” This message will be transmitted at the highest power level and this is represented by I/O block  72 . The purpose of the “discovery” message is for the site transceiver  12 ,  15  to search for any gateways that can respond. If an acknowledgement is received from the gateway  30  as represented by the “Yes” result from decision block  73 , then the site transceiver will send a status message at the communication interval, such as every eight (8) hours, until an assigned gateway responds, as represented by I/O block  74 . If the discovery message does not result in a reply, as represented by the “No” result from decision block  73 , then the CPU  60  proceeds to execute instructions represented by decision block  80  to send mobile network messages and then block  79  to determine if eight (8) hours has passed at which time it will attempt to transmit the status message as represented by I/O block  74 . When an assigned gateway responds, as represented by the “Yes” result from decision block  77 , the site transceiver  12 ,  15  will be in a fixed network mode where it is reporting on its scheduled reporting interval and it is not transmitting data for reception in the mobile network. Until an assigned gateway responds, as represented by the “No” result from decision block  77 , the site transceiver  12  or  15  continues to send mobile network messages as represented by I/O block  78 , and then a fixed network message with status data at the communication interval, such as every eight (8) hours, as represented by decision block  79  and I/O block  74 . 
     Until a gateway is assigned, the site transceiver  12  or  15  will also transmit in mobile mode (every few seconds) while it is transmitting the discovery message every eight hours to obtain a reply from the assigned gateway. The site transceiver  12  or  15  can function in this type of operation for its entire service life. It will be transmitting mobile network data, while it is also searching to determine if a fixed network is installed. 
     When a gateway has been assigned, as represented by process block  80 , the site transceiver  12  or  15  it will begin making transmissions of messages on a reporting schedule as represented by I/O block  81 . This schedule is variable under the direction of the gateway receiver  30  and data collection center  50 . 
     The site transceivers  12 ,  15  are assigned time slots to communicate to specific gateways  30  in specific programmed time slots. An individual gateway  30  has three (3) seconds between scheduled transmissions from various metering sites. The data collection center  50  will assign the time slots in 6-second intervals first. The schedule for adjacent gateways will be offset in time so the six gateways in closest proximity will be offset by one (1) second from each other. 
     Based on the three-second interval, a gateway will have 9600 available time slots in an 8-hour period for active listening. The 8-hour time slot is the most basic system RF reporting interval for the metering sites. More frequent reporting intervals will use a plurality of these time slots for each gateway. A site transceiver with a two-hour RF reporting interval will use four (4) of the 9600 slots, while a site transceiver with a 40-minute reporting interval will use twelve (12) of the 9600 time slots. There can also be 400 passive time slots added to the 9600 time slots just described, bringing the total number of time slots assigned to a gateway to ten thousand. 
     If communication is lost for a preset number of days, such as two days, as represented by the “Yes” result from decision block  82 , the site transceiver  12  or  15  will initiate the mobile network transmissions, as represented by I/O block  84 , while continuing to attempt to send the messages according to the last known schedule to the fixed network receiver  30  as represented by the “Yes” result from decision block  85 . As long as the preset number of days has not passed, messages will be transmitted from a site transceiver according to the schedule for the fixed network, as represented by the “No” result from decision block  82 , and this additional time is represented by the “Wait” process block  83 . When communication is re-established with the gateway  30 , as represented by an acknowledgement signal, then the mobile transmissions would again cease as represented by the loop through blocks  82  and  83 . 
     This configuration allows the site transceivers  12 ,  15 , to be installed for communication in a fixed or mobile network. The site transceiver  12 ,  15 , will switch between fixed or mobile network transmissions without interaction from a user and without commands from the gateway  30  or data collection center  50 . 
     The mobile network is a limited two-way network in which the site transceivers  12 ,  15  signal the receiver  26  in the vehicle  27 , and in which is it is possible receive acknowledgement signals or commands from the mobile receiver  26 . The fixed network is a limited two-way network in which some data is sent from the data collection computer  50  to the site transceivers  12 ,  15  in response to data sent from the site transceivers  12 ,  15  to data collection computer through the gateways  30 . 
     One advantage of the invention is that it requires only a single transceiver per metering site per utility and provides both fixed and mobile modes of operation with common circuitry. Another advantage of the invention is that it conserves battery life. 
     Another advantage of the invention is that by selecting certain time periods, it maximizes communication and minimizes interference between communications. 
     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, and that such variations are intended to be encompassed by the following claims.