WO1999065169A1 - Time synchronization of a utility meter via a wireless network - Google Patents

Time synchronization of a utility meter via a wireless network Download PDF

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Publication number
WO1999065169A1
WO1999065169A1 PCT/US1999/012976 US9912976W WO9965169A1 WO 1999065169 A1 WO1999065169 A1 WO 1999065169A1 US 9912976 W US9912976 W US 9912976W WO 9965169 A1 WO9965169 A1 WO 9965169A1
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WO
WIPO (PCT)
Prior art keywords
time
remote device
communication server
meter
communications module
Prior art date
Application number
PCT/US1999/012976
Other languages
French (fr)
Inventor
Ingemar Lars Hedvall
David F. Dunn
Hwai John Lin
Original Assignee
Abb Power T & D Company Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Abb Power T & D Company Inc. filed Critical Abb Power T & D Company Inc.
Priority to AU42325/99A priority Critical patent/AU4232599A/en
Publication of WO1999065169A1 publication Critical patent/WO1999065169A1/en

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01DMEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D4/00Tariff metering apparatus
    • G01D4/002Remote reading of utility meters
    • G01D4/004Remote reading of utility meters to a fixed location
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B90/00Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02B90/20Smart grids as enabling technology in buildings sector
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04SSYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S20/00Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
    • Y04S20/30Smart metering, e.g. specially adapted for remote reading

Definitions

  • a system for time-synchronizing a clock in a utility meter over a wireless network infrastructure includes a communication server set to a predetermined standard time, and a communications module that communicates to the network infrastructure and the utility meter.
  • the communication server comprises at least one line interface module that converts between a protocol of the communication server and a protocol of the wireless network infrastructure.
  • a communications module is also provided that communicates to the network infrastructure and the utility meter. The communication module converts between a protocol of the wireless network infrastructure and a protocol of the utility meter, and receives and responds to requests from the communication server.
  • the communications module When the communication server initiates a request to the utility meter, the communications module returns a response to the request that includes a time of the clock within the utility meter. If the time is outside of predetermined upper and lower limits, the communication server initiates a request to synchronize the meter time to the predetermined standard time using a determined offset time value.
  • Figure 3 is a functional block diagram of an exemplary communications module connected to an exemplary wide area network (WAN) option board in accordance with the present invention
  • Figure 4 is a functional block diagram illustrating the various components of the meter and WAN option board in greater detail, and the inter-connection between the meter and the WAN option board;
  • the communications module 10 enables communications over a wireless network 80, such as the ARDIS network in the United States and the BellARDIS network in Canada. Other packet switched wireless networks may be utilized as the present invention is particularly suitable for packet-based wireless transmission.
  • the communications server 70 comprises an RCS 250, available from ABB Power T&D Information Systems, Raleigh, North Carolina. Referring to Figure 2, there is illustrated a functional block diagram of the communication server 70, wireless network 80, communications module 10 and meter 30. As illustrated, the communication server 70 may be functionally divided into three main platforms.
  • Line Interface Modules are real-time interfaces that are used to communicate with remote devices (e.g., communications module 10 and meter 30).
  • the LIMs are essentially protocol converters and are responsible for converting between the Remote Server Protocol (RSP) and the protocol used at the remote device (e.g., the ABB meter protocol).
  • RSP Remote Server Protocol
  • ABB Alpha Meter the protocol used at the remote device
  • only two LIMs communicate with the ABB Alpha Meter.
  • the AlphaLIM 70G communicates with the meter either using the public switched telephone network or a leased line (direct connection).
  • the ArdisLEVI 70E communicates with the Alpha Meter through the ARDIS radio network.
  • the type of modem that is used is dependent on the network that is used.
  • the ARDIS network uses the Motorola DataTAC technology.
  • a preferred modem is the Motorola ARDIS modem, model number 505sd.
  • Another exemplary modem is an ARDIS modem from Research In Motion (REVI).
  • An energy storage device 22 may be provided, such as a battery or series of batteries that are used to power the modem 12 and allow the electronics to draw power off the meter supply.
  • capacitors may be used as an energy storage device 22.
  • the communications module can be supplied with power from any type of power source, and is not limited to the batteries or capacitors described above.
  • the meter 30 preferably contains removable a wide area network (WAN) option board 50 that connects to the communications module 10, as shown in Figure 3, and provides KYZ relays 52 (preferably two), a power supply 54, a current limiter 56, a pin header 58 (preferably having 4 pins: Tx, Rx, Power, and Ground), and a serial communications device 60.
  • the current limiter 56 prevents anything in the communication module external enclosure from consuming too much current, which would cause the meter 30 to reset.
  • the transmit (Tx) and receive (Rx) pins on the header 58 are isolated from the meter 30.
  • the communications module 10 handles the request by sending it to the meter 30 and requests the meter time (Tmeter).
  • the communications module 10 then builds a response and returns it to the LEVI 70E via the communications network 80.
  • the LEVI 70E saves the time at which it receives the response (T2) and returns the data to the RCS 70D.
  • the meter clock may be adjusted (i.e., synchronized) using the result of (Tl - Tmeter).
  • a time synchronization telegram is sent to the communications module 10 with the offset. It is noted that the offset may be positive or negative. A negative offset may be sent as a 2's complement value to the communication module 10.

Abstract

A system for time synchronization of a remote meter (30) to a communication server (70) via a wireless communication network. As the communication server (70) initiates a request to the meter (30), the time of the request is stored at the communication server (70). At the remote side, the request is received by a communication module (10) that is connected to the meter (30). The communication module (10) retrieves the meter's current time from a clock within the meter (30) and transmits the meter time to the server in a response message. When the response is received by the communication server (70), the time is stored by the communication server (70). A comparison is made between request time, response time and meter time to determine if the meter time is out of synchronization with respect to the server time and if the meter time should be corrected in a subsequent communication to the meter.

Description

TIME SYNCHRONIZATION OF A UTILITY METER VIA A WIRELESS NETWORK
FIELD OF THE INVENTION
The present invention relates in general to the field of utility meters. More particularly, the present invention relates to automatic equipment and systems for remote reading and synchronization of utility meters, such as electric, gas, or water meters, via a wireless network.
BACKGROUND OF THE INVENTION
The recent deregulation of the utility industry has created a market for products that provide a utility or its customers with their usage via a utility usage meter. Utility companies use utility usage meters to determine the utility consumption at a customer site. A periodic reading of the utility meter is necessary to determine the usage and to bill the customer for the amount used. The need to send utility company employees to customer sites to read the meters is costly, time consuming, and subject to considerable error. Thus, automated means of recording and reporting the utility usage at customer sites is rapidly replacing the manually read utility meters. Many companies provide automatic meter reading equipmentwhich is capable of reading remote meters on customer premises and transmitting the meter readings automatically, via telephone lines and a telephone modem, to a central office of the utility company. The modem shares the telephone line with the customer's normal usage, such as incoming and outgoing voice communications. Such sharing requires that the system be able to recognize when the telephone line is in use, and to delay demanding use of the telephone line until it is free. Steps must be taken to prevent the data communications system from interfering with other uses and to prevent other uses from corrupting the transmitted data.
Other methods have been used to communicate with remote meters. Such methods include wireless communication, via wireless networks such as ARDIS. However, wireless networks have uncertain transmission delays ranging from seconds to possibly an hour. Of great concern to energy providers is that the remote meter is synchronized in time with the utility company's communication server or host site, as a meter that is out-of- synchronization may not accurately record energy usage information. Inaccuracies in recordation of energy usage leads to inaccurate billing, which frustrates customers and takes time to correct. This is particularly a problem under the new deregulation rules which legislate that meters must be time-synchronized and where customers may have different billing rates associated with different times of the day, seasons of the year, etc.
Conventional systems attempt to synchronize remote meters by sending to the meter the absolute time (e.g., 17:00) and a specific date (e.g., 060198). The meter time is then set to the transmitted absolute time and date, however, because of the delays associated with wireless networks, the meter may still not be synchronized with the utility company's communication server. Accordingly, a new method and apparatus for time synchronizing a remote meter is necessary in order to ensure that billing information and recordation of energy usage by a customer's remote meter is accurate, and that customers are accurately billed for energy usage. The present invention provides a novel solution to this problem.
SUMMARY OF THE INVENTION
The present invention is directed to method and apparatus that permits remote meter reading of a utility meter via a wireless modem that communicates using data packet networks along a communications system, such as ARDIS. The apparatus comprises a communications module that is a microprocessor-based transmitter/receiver which receives data collection requests from a system server, initiates data collection from a utility meter, and reports the data back to a host computer system. Preferably, session-based communication using the meter protocol is implemented between the communications module and the meter, and packet switching is used between the communications server and the communications module through the network.
An embodiment within the scope of this invention includes a system for time- synchronizing a clock in a remote device over a network infrastructure. The system includes a communication server set to a predetermined standard time, and a communications module that communicates to the network infrastructure and the remote device. The communication module receives and responds to requests from the communication server. When the communication server initiates a request to the remote device, the communications module returns a response to the request that includes a remote device time of the clock. If the remote device time is outside of predetermined upper and lower limits, the communication server initiates a request to synchronize the remote device time to the predetermined standard time using a determined offset time value.
According to a feature of the present invention, the communication server comprises a line interface module that saves a first time at which the request is sent to the remote device and a second time at which a response is received from the communications module. The offset time value is determined based on a difference of the first time and the remote device time.
According to another feature of the present invention, the communications module reads an absolute time from the remote device, adds the offset time value to the absolute time to determine a corrected absolute time, and sets the clock to the corrected absolute time.
According to yet another feature, if an absolute value of a difference of the second time and the remote device time is greater than a difference of an absolute value of the second time and the first time, the communication server determines the offset time value based on a difference of the first time and the remote device time and sends the offset time value to the communications module to synchronize the remote device. According to still another feature, the transmitting of the remote device time is performed during the course of normal communication between the communication server and the remote device.
According to a feature of the invention, the network infrastructure comprises a wireless packet-switched network. In addition, the communications module may include a datalink feature to reduce an airlink protocol and minimize airtime.
According to a further feature, the remote device comprises a utility meter. The communication module may be connected to an option board provided within the utility meter. According to another aspect of the present invention, a method of time- synchronizing a clock in a remote device to a predetermined standard time set in a communication server over a network infrastructure is provided, to perform the method the remote device is connected to a communications module that receives and responds to requests from the communication server. The method includes sending a request from the communication server to the remote device via the network infrastructure and the communications module; returning a response to the communication server that includes a remote device time within the clock; determining an offset time value based on the remote device time and the standard time; and initiating a request to synchronize the remote device to the standard time using the determined offset time value if the device time is outside predetermined upper and lower limits.
According to a feature of the method, sending a request from the communication server to the remote device includes saving a first time at which the request is sent to the remote device; and saving a second time at which the response is received from the communications module. According to another feature, determining an offset time value is performed based on a difference of the first time and the remote device time.
According to yet another feature of the method, the synchronization includes reading an absolute time from the remote device; adding the offset time value to the absolute time to determine a corrected absolute time; and setting the clock to the corrected absolute time. According to still another feature, initiating a request to synchronize the remote device to the standard time using the determined offset time value comprises determining if an absolute value of a difference of the second time and the remote device time is greater than a difference of the second time and the first time; and determining the offset time value based on a difference of the first time and the remote device time.
According to another aspect of the present invention, there is provided a system for time-synchronizing a clock in a utility meter over a wireless network infrastructure. The system includes a communication server set to a predetermined standard time, and a communications module that communicates to the network infrastructure and the utility meter. The communication server comprises at least one line interface module that converts between a protocol of the communication server and a protocol of the wireless network infrastructure. A communications module is also provided that communicates to the network infrastructure and the utility meter. The communication module converts between a protocol of the wireless network infrastructure and a protocol of the utility meter, and receives and responds to requests from the communication server. When the communication server initiates a request to the utility meter, the communications module returns a response to the request that includes a time of the clock within the utility meter. If the time is outside of predetermined upper and lower limits, the communication server initiates a request to synchronize the meter time to the predetermined standard time using a determined offset time value.
According to a feature of the present invention, the line interface module saves a first time at which the request is sent to the utility meter and a second time at which a response is received from the communications module. The offset time value is determined based on a difference of the first time and the utility meter time. According to another feature of the present invention, the communications module reads an absolute time from the utility meter, adds the offset time value to the absolute time to determine a corrected absolute time, and sets the clock to the corrected absolute time.
According to yet another feature, if an absolute value of a difference of the second time and the utility meter time is greater than a difference of an absolute value of the second time and the first time, the communication server determines the offset time value based on a difference of the first time and the utility meter time and sends the offset time value to the communications module to synchronize the utility meter.
The foregoing and other aspects of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a overview of an exemplary system in accordance with the present invention;
Figure 2 is afunctional block diagram of an exemplary communication server, wireless network, communications module, and meter in accordance with the present invention;
Figure 3 is a functional block diagram of an exemplary communications module connected to an exemplary wide area network (WAN) option board in accordance with the present invention; Figure 4 is a functional block diagram illustrating the various components of the meter and WAN option board in greater detail, and the inter-connection between the meter and the WAN option board; and
Figure 5 is a timing diagram to demonstrate an exemplary method of calculating the time difference between a utility meter and a host.
DETAILED DESCRTPTION OF THE PREFERRED EMBODIMENTS
The present invention is directed to an apparatus and method that permits remote meter reading of a utility meter via a wireless modem and a communications system, such as ARDIS, which is a public wireless packet switching network operated by American Mobile Satellite Corp. Referring to Figure 1 , there is illustrated an overview of an exemplary network in which the present invention may be embodied. As illustrated, the network includes a communication server or host site 70, a wireless network 80, a communications module 10 and a meter 30. The communications module 10 is a microprocessor-based transmitter/ receiver which receives data collection requests from a system server or a host computer system, initiates the data collection from a utility meter 30, and reports the data back to the host site 70 residing, for example, at a central office. The communications module 10 is a bridge between a wireless packet-based network and the utility meter 30. Preferably, session- based communication using the meter protocol is implemented between the communications module 10 and the meter 30, and packet switching is used between the communications server and the communications module 10 through the wireless network.
The communications module 10 continuously monitors the connection between the module 10 and the meter 30. Whenever communications are lost with the meter 30 due to a line power outage or tamper, the module waits a predetermined length of time to allow the line to recover automatically. If the connection fails to recover, an alarm may be generated and transmitted to the communication server 70 for appropriate intervention. The communications module 10 preferably responds to all requests and constantly monitors radio- related information. Additionally, the communications module 10 preferably supports the meter protocol, commands to get and/or set the meter/communications module configuration request and response, commands to adjust and read the meter time, and responses to notify of a power failure and/or power restoration.
The meter 30 is typically read over the wireless network 80 at a predetermined time (e.g., after midnight). The communications module 10 responds with the appropriate load profile data (e.g., for the previous 24 hours), time-of-use data, as well as any other data stored in the meter 30.
A typical communications exchange over the network proceeds as follows. The communication server or host site 70 sends a request over the wireless network 80 to the communications module 10. The communications module 10 receives the request, and retrieves the requested data from within the module 10 itself and/or the utility usage meter 30 (via transmit/receive cable 15). The data is the transmitted back to the communication server 70 via the wireless network 80 for further processing.
Although the communications module 10 is shown and described as being separate from the meter 30, it is contemplated that the communications module 10 can be implemented within the meter 30, in addition to providing the flexibility to be remotely located outside of the meter 30. The utility usage meter 30 preferably comprises an Alpha
PowerPlus or Alpha meter manufactured by ABB Power T&D Company. Other meters may be used as utility usage meter 30. It is noted that the preferred Alpha Meter or Alpha PowerPlus meter utilize a standard ABB protocol as a meter protocol. The communications module 10 enables communications over a wireless network 80, such as the ARDIS network in the United States and the BellARDIS network in Canada. Other packet switched wireless networks may be utilized as the present invention is particularly suitable for packet-based wireless transmission. Preferably, the communications server 70 comprises an RCS 250, available from ABB Power T&D Information Systems, Raleigh, North Carolina. Referring to Figure 2, there is illustrated a functional block diagram of the communication server 70, wireless network 80, communications module 10 and meter 30. As illustrated, the communication server 70 may be functionally divided into three main platforms. The Applications are services and processes that in some way manipulate data in the real time database. For example, the Applications may comprise an historical database 70 A, a user interface 70B, and an export and import system 70C. Applications are not a part of the communications server 70 itself, and use a public subscriber interface to communicate with the remote communication server 70D and its real time database (not shown). The public subscriber interface is provided such that the remote communications server 70D does not need to be specifically programmed for each subscriber application, but rather can make all information collected therein publically available. The subscribing application then selects what information is needed to fulfill its particular task.
The Remote Communication Server (RCS) 70D is the main application in the communication server 70 that serves other applications . The RC S 70D is built around the real time database. The real time database stores configuration and other data without any time stamp (i.e., using last reported values). Time stamped data are sent to the subscriber and stored in a relational database 70A for long term storage.
Line Interface Modules (LEVl) are real-time interfaces that are used to communicate with remote devices (e.g., communications module 10 and meter 30). The LIMs are essentially protocol converters and are responsible for converting between the Remote Server Protocol (RSP) and the protocol used at the remote device (e.g., the ABB meter protocol). In the preferred embodiment utilizing the ABB Alpha Meter as utility meter 30, only two LIMs communicate with the ABB Alpha Meter. The AlphaLIM 70G communicates with the meter either using the public switched telephone network or a leased line (direct connection). The ArdisLEVI 70E communicates with the Alpha Meter through the ARDIS radio network. The ArdisLEVI 70E communicates with the ARDIS network 80 using an Internet connection, a leased line, or a dial-up line, and an X.25 card, available from Eicon Technology, Montreal, Quebec. RFGate software, available from Nettech Systems Inc., Princeton, NJ, is used as low-level access software to reach the X.25 line.
On the remote side, the meter 30 is connected to communications module 10. An exemplary communications module 10 is the AlphaStar, manufactured by ABB Power T&D Company. The communications module 10 comprises software that converts from the ARDIS X.25 protocol to the ABB Protocol used by the meter 30. Using the communications module 10 in combination with the ArdisLEVI 70E, the meter 30 functions similarly as if it was connected to a telephone modem.
In addition, the meter 30 has a datalink feature, which facilitates communication with the communications module 10 and supports packet-based, wireless transmission, thereby reducing the airlink protocol and minimizing airtime. The communication server 70 issues datalink requests. It is noted that the request from the communication server 70 to the meter 30 should be as small as possible for a maximum of 1 packet (240 bytes or 480 bytes, for example, depending on the protocol supported by the network at the install location). The response back from the meter 30 to the communication server 70 should minimize the data and put it into as few packets as possible (e.g., two or fewer for 2 channels of load profile data every 15 minutes for 24 hours).
Referring to Figure 3, the communications module 10 includes a radio or wireless modem 12, a microprocessor 14, an internal antenna 16, a memory 20 that is preferably non-volatile, an optional power supply 24, and an optional energy storage device 22. Also included is a header 25, preferably having 4 pins: Tx, Rx, Power, and Ground. An optional external antenna 18, can be used to improve radio coverage in fringe areas. The communications module 10 is connected to an option board 50 residing in the meter 30, which is described in further detail below. The communications module 10 further includes an outage or power failure (PF) detector 26. The communication module contains a wireless modem 12 that communicates over various data-packet networks including, but not limited to, ARDIS, BellSouth Wireless Data, Reflex, GSM, satellite, and other packet wireless data networks. The type of modem that is used is dependent on the network that is used. The ARDIS network uses the Motorola DataTAC technology. A preferred modem is the Motorola ARDIS modem, model number 505sd. Another exemplary modem is an ARDIS modem from Research In Motion (REVI). An energy storage device 22 may be provided, such as a battery or series of batteries that are used to power the modem 12 and allow the electronics to draw power off the meter supply. Optionally, capacitors may be used as an energy storage device 22. It should be noted that the communications module can be supplied with power from any type of power source, and is not limited to the batteries or capacitors described above.
A preferred microprocessor 14 is the H8 S/2350, manufactured by Hitachi. The microprocessor 14 preferably has a 16-bit or 32-bit architecture, with a preferred operating frequency of about 3.6864 MHZ and operating voltage of 3.3V. It should be noted the invention is not limited to this microprocessor and that any microprocessor can be used. The microprocessor 14 also preferably has an on-chip RAM and at least 2 universal asynchronous receiver transmitters (UARTs). One UART may be used for the connection to the meter 30, and the other for a connection to the modem 12.
The microproces sor 14 in the communications module 10 responds to requests from a server such as an Energy Axis™, CSM, C&I server, an AMR server, or RCS 250 communications server and converts these requests to modem 30 protocol requests. The microprocessor 14 listens to the radio modem 12, interprets requests, responds, preferably immediately, and/or passes those requests onto the meter 30, extracts the data, and converts it to a minimized packet response to the server request on a near-real time basis. The communications module 10 offers in-field upgradeability via flash memory 23. The communications module 10 can store host data in any optional storage device such as a RAM or EEPROM 21. An internal antenna 16 is mounted within the communications module enclosure. In areas where transmission interference is prevalent or network/host signal levels are irregular or insufficient, an external antenna 18 can be used. The communications module 10 is responsible for receiving requests from a server such as an Energy Axis™, CSM, AMR, RCS 250, or C&I server. The communications module 10 responds to these requests and retrieves data from the meter 30 and/or reports data about itself back to the host system, depending on the type of request. A protocol is defined that is used to communicate between the communications module 10 and the host system 70. The communications module 10 passes data requests to the meter 30, retrieves the data from the meter 30, and returns it to the host system. The host system is responsible for re-assembling the data packets in their correct order, interpreting the data, and loading it into a database for evaluation.
The meter 30 preferably contains removable a wide area network (WAN) option board 50 that connects to the communications module 10, as shown in Figure 3, and provides KYZ relays 52 (preferably two), a power supply 54, a current limiter 56, a pin header 58 (preferably having 4 pins: Tx, Rx, Power, and Ground), and a serial communications device 60. The current limiter 56 prevents anything in the communication module external enclosure from consuming too much current, which would cause the meter 30 to reset. Preferably the transmit (Tx) and receive (Rx) pins on the header 58 are isolated from the meter 30.
Referring to Figure 4, there is shown a functional block diagram of the interconnection of the option board 50 and the meter 30. As illustrated, the transmit/receive cable 15 connects to the pin header 58. The transmit (Tx) and receive (Rx) leads are input to the serial communication device 60. The power and ground lines are input to the power supply 54. The option board 50 is connected to an option connector 30C provided within the meter 30. The option connector 30C is connected to a serial communications line 30D, which is connected to the UART (not shown) within the microcontroller 30B. The UART preferably operates in a session-based fashion with the option board 50 to receive and transmit data and commands from the option board 50 and the communications module 10. Information and commands may be passed from the communications module 10 to the microcontroller 30B or Meter IC 30 A via the option connector 30C to affect the operation of the microcontroller 30B or Meter IC 30A and other functions controlled by the microcontroller 30B or Meter IC 30 A.
It is noted that the connection between option board 50 and the option connector 30C is illustrated in the exemplary configuration as having certain signals or leads . The connection between option board 50 and the option connector 30C is not limited to such signals, nor is the option board 50 limited to having the disclosed elements and functions, as other functionalities may be provided.
Although not shown, the meter 30 contains an internal clock that transmits its time and date information back to the communications module 10 and communication server 70 along with additional data obtained from a meter reading. In a preferred embodiment, the internal clock is controlled by the microcontroller 3 OB. The communications module 10 reads the meter clock (table 9 TD) and sends the time back to the LEVI 70E. Thus, the meter time is reported in every instance the LEVI 70E communicates to the meter 30. As noted above, the request and response time via ARDIS network may vary from 2 seconds to 1 hour. The average, however, is approximately 5 seconds.
In accordance with the present invention, the meter time is synchronized using an offset, rather than the conventional method of an absolute time and date. Such a method advantageously allows for the transmission delay to be ignored. A typical scenario will now be described with reference to Figures 2 and 5. One of the functions of the LEVIs is to ensure that the meter 30 is synchronized to the appropriate time. This synchronization is preferably accomplished during normal communications with the meter rather than using a separate process to minimize traffic. The LEVI is synchronized by a remote process to Greenwich Mean Time, while the meter normally is synchronized to its local time with or without daylight saving time correction. Depending on the requirement from the local utility, the meter time is maintained within predetermined upper and lower limits, otherwise the time value is treated as invalid or out of synchronization.
The process by which the meter 30 is synchronized is as follows. The RCS 70D launches a request for data and sends it to the LEVI 70E. The LEVI 70E converts the request (using the X.25 card and RFGate software 70F) and sends the request via the wireless network 80 to the communications module 10 and the meter 30. The LEVI 70E saves the time (Tl) at which the telegram was sent.
The communications module 10 handles the request by sending it to the meter 30 and requests the meter time (Tmeter). The communications module 10 then builds a response and returns it to the LEVI 70E via the communications network 80. The LEVI 70E saves the time at which it receives the response (T2) and returns the data to the RCS 70D. If abs(T2-Tl) < abs(T2 - Tmeter), the meter clock may be adjusted (i.e., synchronized) using the result of (Tl - Tmeter). If the offset is more than a predetermined limit (e.g., 2 seconds), a time synchronization telegram is sent to the communications module 10 with the offset. It is noted that the offset may be positive or negative. A negative offset may be sent as a 2's complement value to the communication module 10.
If a time synchronizing telegram is sent, when the communications module 10 receives the message, the meter clock is read, and the offset is added to the clock to synchronize the meter 30. It is noted that the meter 30 utilizes an absolute time, therefore the communications module 10 first reads the clock from the meter 30, adds the offset to the time, and then sets the clock in the meter 30.
If the meter cannot be synchronized for any reason, an alarm is generated to indicate such a failure. It is also noted that it is preferable to make only one synchronization attempt in order to minimize the network traffic.
To perform the above-described meter time synchronization, messages are passed at various times. At time Tresp, the communications module 10 builds a response message containing the following information that is transmitted to the communication server 70.
1 T j LEN I SEARAT | DOYl | DOY2 | TDYR | TDMON | TODAY | TDHR | TDMIN | TDSEC
Where:
T: Character 'T' ; hex value 0x54
LEN: Length of data bytes; 0x09
SEARAT: Season and rate flags
DOY 1 : First byte for day of year (B CD Coded Value)
DOY2: Second byte for day of year (BCD Coded Value)
TDYR: Last two digits of year; 00 to 99 (BCD Coded Value)
TDMON: Month number; 01 to 12 (BCD Coded Value)
TDD AY: Day of month; 01 to 31 (BCD Coded Value)
TDHR: Hour; 00 to 23 (BCD Coded Value) TDMIN: Minute; 00 to 59 (BCD Coded Value)
TDSEC: Seconds; 00 to 59 (BCD Coded Value)
After time T2, and if a time synchronization telegram is necessary, the following command is returned by the communications server 70 to the communications module 10 to adjust the meter time clock.
LENl HA MA SA
Where:
T: Character 'T', hex value 0x54
LENl: Length of data bytes; 0x03
HA: Hour adjustment; 2's compliment value if negative adjustment
MA: Minute adjustment; 2's compliment value if negative adjustment
SA: Second adjustment; 2's compliment value if negative adjustment
It is noted that the communications wireless network 80 can be any network such as ARDIS, BellSouth Wireless Data, EDACS, and Reflex, and other networks. However, ARDIS advantageously utilizes DataTAC technology, which is a public network using an open protocol standard used by Motorola and other manufacturers' modems . ARDIS has implemented this network protocol and is available across the United States with about 90% coverage of all commercial facilities. This network protocol is available in most other countries as well. ARDIS connectivity to the meter is a cabled serial interface utilizing the existing meter protocol to the external enclosure containing the communications module 10.
BellSouth Wireless Data is another network that could be used. This network uses the Mobitex network technology. REVI manufactures a modem that communicates on the BellSouth Wireless Data network. This modem has the same form factor as the REVI ARDIS modem and communicates with its host using the same protocol (RAPI). The BellSouth Wireless Data network is a multi-frequency reuse system.
The EDACS network is a private network that some of the larger companies in the United States have invested in. This network is primarily used to dispatch workers or for communication between workers and the dispatcher. This network could also be used to read meters. Preferably, a 120V outlet is wired up next to the modem. It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the invention has been described with reference to preferred embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitations. Further, although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein; rather, the invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. Those skilled in the art, having the benefit of the teachings of this specification, may effect numerous modifications thereto and changes may be made without departing from the scope and spirit of the invention in its aspects.

Claims

WHAT IS CLAIMED:
1. A system for time-synchronizing a clock in a remote device over a network infrastructure, said system comprising: a communication server set to a predetermined standard time; and a communications module that communicates to said network infrastructure and said remote device, said communication module receiving and responding to requests from said communication server, wherein when said communication server initiates a request to said remote device, said communications module returns a response to said request that includes a remote device time of said clock, and wherein if said remote device time is outside of predetermined upper and lower limits, said communication server initiates a request to synchronize said remote device time to said predetermined standard time using a determined offset time value.
2. The system as recited in claim 1, said communication server comprising a line interface module, wherein said line interface module saves a first time at which said request is sent to said remote device and a second time at which a response is received from said communications module.
3. The system as recited in claim 2, wherein said offset time value is determined based on a difference of said first time and said remote device time.
4. The system as recited in claim 3, wherein said communications module reads an absolute time from said remote device, adds said offset time value to said absolute time to determine a corrected absolute time, and sets said clock to said corrected absolute time.
5. The system as recited in claim 2, wherein if an absolute value of a difference of said second time and said remote device time is greater than a difference of an absolute value of said second time and said first time, said communication server determines said offset time value based on a difference of said first time and said remote device time and sends said offset time value to said communications module to synchronize said remote device.
6. The system as recited in claim 1, wherein said transmitting of said remote device time is performed during the course of normal communication between said communication server and said remote device.
7. The system as recited in claim 1, wherein said network infrastructure comprises a wireless packet-switched network.
8. The system as recited in claim 7, wherein said communications module comprises a datalink feature to reduce an airlink protocol and minimize airtime.
9. The system as recited in claim 1, wherein said remote device comprises a utility meter.
10. The system as recited in claim 9, wherein said communication module is connected to an option board provided within said utility meter.
11. A method of time-synchronizing a clock in a remote device to a predetermined standard time set in a communication server over anetworkinfrastructure, said remote device being connected to a communications module that receives and responds to requests from said communication server, said method comprising: sending a request from said communication server to said remote device via said network infrastructure and said communications module; returning a response to said communication server that includes a remote device time within said clock; determining an offset time value based on said remote device time and said standard time; and initiating a request to synchronize said remote device to said standard time using said determined offset time value if said device time is outside predetermined upper and lower limits.
12. The method as recited in claim 11, wherein said sending a request from said communication server to said remote device comprises: saving a first time at which said request is sent to said remote device; and saving a second time at which said response is received from said communications module.
13. The method as recited in claim 12, wherein said determining an offset time value is determined based on a difference of said first time and said remote device time.
14. The method as recited in claim 13, further comprising: reading an absolute time from said remote device; adding said offset time value to said absolute time to determine a corrected absolute time; and setting said clock to said corrected absolute time.
15. The method as recited in claim 12, wherein said initiating a request to synchronize said remote device to said standard time using said determined offset time value comprises: determining if an absolute value of a difference of said second time and said remote device time is greater than a difference of said second time and said first time; and determining said offset time value based on a difference of said first time and said remote device time.
16. A system for time-synchronizing a clock within a utility meter over a wireless network infrastructure, said system comprising: a communication server set to a predetermined standard time, said communication server comprising at least one line interface module that converts between a protocol of said communication server and said wireless network infrastructure; and a communications module that communicates to said network infrastructure and said remote device, said communication module converting between a protocol of said wireless network infrastructure and said utility meter, and said communications module receiving and responding to requests from said communication server, wherein when said communication server initiates a request to said utility meter, said communications module returns a response to said request that includes a current time of said clock, and wherein if said current time is outside of predetermined upper and lower limits, said communication server initiates a request to synchronize said current time to said predetermined standard time using a determined offset time value.
17. The system as recited in claim 16, wherein said line interface module saves a first time at which said request is sent to said remote device and a second time at which a response is received from said communications module.
18. The system as recited in claim 17, wherein said offset time value is determined based on a difference of said first time and said current time.
19. The system as recited in claim 18, wherein said communications module reads an absolute time from said meter, adds said offset time value to said absolute time to determine a corrected absolute time, and sets said clock to said corrected absolute time.
20. The system as recited in claim 17, wherein if an absolute value of a difference of said second time and said remote device time is greater than a difference of an absolute value of said second time and said first time, said communication server determines said offset time value based on a difference of said first time and said remote device time and sends said offset time value to said communications module to synchronize said meter.
PCT/US1999/012976 1998-06-09 1999-06-09 Time synchronization of a utility meter via a wireless network WO1999065169A1 (en)

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Cited By (15)

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EP1244083A1 (en) * 2001-03-21 2002-09-25 Metrix Systems AG Method for collecting consumption data
EP1515579A2 (en) * 2003-09-05 2005-03-16 Itron, Inc. Automatic meter reading system utilizing a countdown timer
US7372372B2 (en) 2003-09-05 2008-05-13 Itron, Inc. Sequence inversion keyed countdown timer utilized within a utility meter system
EP1515579A3 (en) * 2003-09-05 2007-08-15 Itron, Inc. Automatic meter reading system utilizing a countdown timer
DE102004018734A1 (en) * 2004-04-17 2005-11-03 EMH Elektrizitätszähler GmbH & Co. KG Electronic electricity meter has satellite position determination receivers providing input to microcomputer with filter to extract time signal for tariff control
WO2007080310A1 (en) * 2006-01-10 2007-07-19 Suez Environnement Device for remote reading of fluid meters
WO2007080309A1 (en) * 2006-01-10 2007-07-19 Suez Environnement France Device for bidirectional remote water-meter reading by means of radio, for invoicing in accordance with consumption time bands
FR2896069A1 (en) * 2006-01-10 2007-07-13 Lyonnaise Des Eaux France Sa TELE-DISPLAY DEVICE OF FLUID METERS.
FR2896067A1 (en) * 2006-01-10 2007-07-13 Lyonnaise Des Eaux France Sa RADIO WATER METER BI-DIRECTIONAL TELE-STREAM DEVICE FOR INVOICING ACCORDING TO CONSUMPTION SCHEDULES.
AU2007204296B2 (en) * 2006-01-10 2012-03-01 Suez International Device for bidirectional remote water-meter reading by means of radio, for invoicing in accordance with consumption time bands
US8212686B2 (en) 2006-01-10 2012-07-03 Suez Environnement Device for bidirectional remote water-meter reading by means of radio, for invoicing in a accordance with consumption time bands
US8082367B2 (en) * 2009-07-23 2011-12-20 Schneider Electric USA, Inc. Differential time synchronization of intelligent electronic devices
WO2017102885A1 (en) * 2015-12-18 2017-06-22 Stark Software International Ltd. Meter reader and meter reading system
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AU2016372364B2 (en) * 2015-12-18 2021-12-16 Stark Software International Ltd. Meter reader and meter reading system

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