CA2264913C - Electronic electric meter for networked meter reading - Google Patents

Abstract

An electronic electric meter for use in a networked automatic meter reading environment. The electric meter retrofits into existing meter sockets and is available for new meter installations for both single phase and three phase electric power connections. The meter utilizes an all electronic design including a meter microcontroller, a measurement microcontroller, a communication microcontroller and spread spectrum processor, and a plurality of other communication interface modules for communicating commodity utilization and power quality data to a utility. The electric meter utilizes a modular design which allows the interface modules to be changed depending upon the desired communication network interface. The meter measures electricity usage and monitors power quality parameters for transmission to the utility. over a two-way 900 MHz spread spectrum local area network (LAN) to a remotely located gateway node. The gateway node transmits this data to the utility over a commercially available fixed wide area network (WAN).
The meter also provides direct communication to the utility over a commercially available network interface that plugs into the meter's backplane or bus system bypassing the local area network communication link and gateway node.

Description

101520253035CA 02264913 1999-03-03wo 9s/10299 PCT/US97/15728ELECTRONIC ELECTRIC METER FOR NETWORKED METER READINGBACKGROUND OF THE INVENTIONThe present invention relates to apparatus for measuringusage of a commodity. More particularly, the invention relates toan electronic electric meter for measuring consumption of electric-ity and communicating that usage data and other power informationto a utility over a two—way wireless local area network (LAN) to aremotely located gateway node that transmits the data over a two-way fixed common carrier wide area network (WAN), or communicatingthat data directly to the utility over a commercially availabletwo~way data communication network.Commodity usage is conventionally determined by utilityTheutility service provider typically’ determines the subscriber'scompanies using meters that monitor subscriber consumption.consumption by sending a service person to each meter location toThemanual reading is then entered into a computer which processes themanually record the information displayed on the meter dial.information and outputs a billing statement for the subscriber.However, it is often difficult for the service person to access themeter for reading, inspection and maintenance. When access to ameter is not possible, billings are made on the basis of estimatedThese often lead to customerreadings. estimated billingscomplaints.Currently available electric meters such as watt—hourbut they must beThis makes it difficult to cost effectively measuremeters work well for their intended purpose,manually read.electricity usage for each user to promote fair billing andencourage conservation. Manual reading of electric meter is highlylabor intensive, inefficient and very expensive. Therefore, therehas been a strong interest on the part of utility companies to takeadvantage of modern technology to reduce operating costs andincrease necessity for manualefficiency by eliminating thereadings.Many attempts have been made in recent years to developan automatic meter reading system for electric meters which avoidmost of thesethe high costs of manual meter reading. However,prior art systems have achieved little success. For automatic orremote meter reading, a transducer unit must be used with the. .. V.t¥.| .. .. .........,.................»........m...\....., ..101520253035CA 02264913 1999-03-03W0 98/10299 PCT/US97/15728meters to detect the output of such meters and transmit thatinformation back to the utility.Various types of devices have been attached to utilitymeters in an effort to simplify meter reading. These devices weredeveloped to transfer commodity usage data over a communicationlink to a centrally located service center or utility. Thesecommunication links included telephone lines,(RF) link.The use of existing telephone lines and power lines topower lines, or aradio frequencycommunicate commodity usage data to a utility have encounteredsignificant technical difficulties. In a telephone line system,the meter data may interfere with the subscriber's normal phoneline operation, and would require cooperation between the telephonecompany and the utility company for shared use of the telephonelines. A telephone line communication link would also require ahard wire connection between the meter and the main telephone line,increasing installation costs. The use of a power line carrier(PLC)require a hard wire connection between the meter and the main powercommunication link over existing power lines would againline. Another disadvantage of the PLC system is the possibility oflosing data from interference on the power line.Meters have been developed which can be read remotely.Such meters are configured as transducers and include a radiotransmitter for transmitting data to the utility. These prior artsystems required the meter to be polled on a regular basis by adata interrogator. The data interrogator may be nmunted to amobile unit traveling around the neighborhood, incorporated withina portable hand—held unit carried by a service person, or mountedat a centrally located site. when the meter is interrogated by anRF signal from the data interrogator, the meter responds bytransmitting a signal encoded with the meter reading and any otherinformation requested. The meter does not initiate the communica-tion.ThemeterHowever, such prior art systems have disadvantages.first disadvantage is that the device mounted to thegenerally has a small transceiver having a very low power outputand thus a very short range. This would require that the interro-gation unit be in close proximity to the meters. Another disadvan-tage is that the device attached to the meter must be polled on a-2-101520253035CA 02264913 1999-03-03W0 98/10299 PCTIUS97ll5728The device attached to theThe mobile andhand—held data interrogators are of limited value since it is stillregular basis by the data interrogator.meter is not able to initiate a communication.necessary for utility service personnel to travel around neighbor-hoods and businesses to remotely read the meters. It only avoidsthe necessity of entering a residence or other building to read themeters. interrogator at fixedThe systems utilizing a datalocations still have the disadvantages of low power output from thedevices attached to the meters, and requiring polling by the datainterrogator to initiate communication.Therefore, although automatic meter reading systems areknown in the prior art, the currently available automatic meterreading systems suffer from several disadvantages, such as lowThus, it would bedesirable to provide an electronic electric meter to retrofit intooperating range and communication reliability.existing meter sockets or for new installations that enables costIt wouldalso be desirable to have an electric meter that is capable ofeffective measurement of electricity usage by a consumer.providing automatic networked meter reading.SUMMARY OF THE INVENTIONAn object of the present invention is to provide anintegrated fully electronic electric meter that retrofits intoexisting meter sockets and is compatible with current utilityoperations.Another theelectronic electric meter that communicates commodity utilizationobject of invention is to provide andata and power quality information to a utility over a two-waywireless spread spectrum local area network to a gateway node thattransmits the data over a two-way fixed common carrier wide areanetwork, or communicates the data directly to the utility over acommercially available two-way data communication network.A further object of the invention is to provide a gatewaynode for receiving commodity utilization data and power qualityinformation from the electric meter and transmitting that data toa utility service provider over a commercially available fixedcommon carrier wide area network.Yet another object of the invention is to provide anelectronic electric meter that communicates commodity utilization-3-101520253035CA 02264913 1999-03-03W0 98/ 10299 PCT/US97/ 15728datacommunication node,and power quality information upon interrogation by aat preprogrammed scheduled reading times, andby spontaneous reporting of tamper or power outage conditions.Yet another object of the invention is to provide anelectronic electric meter that is of a modular construction toeasily allow an operator to change circuit boards or modulesdepending upon the desired data communication network.The present invention ii; a fully electronic electricmeter for collecting, processing and transmitting commodityutilization and power quality data to a utility service provider.The electronic electric meter is of a nmdular designallowing for the removal and interchangeability of circuit boardsand modules within the meter. All of the circuit boards andmodules plug into a common backplane or busing system.The electric meter is able to communicate commodityutilization data and power quality information to a utility over a(LAN) (WAN).transceiver located within the meter creates a LANlocal area network or a wide area network A radio(RF)link between the meter and a gateway node located remotely from thefrequencymeter. This LAN utilizes a 900MHz spread spectrum communicationtechnique for transmitting comodity utilization data and powerquality information from the meter to the gateway node, and forreceiving interrogation signals from the gateway node.The electric meter is also able to communicate directlywith the utility through the variety of commercially availablecommunication network interface modules that plug into the meter’sfor example, these modules might include(PCS)For these modules, a gateway nodebackplane or bus system.a narrowband personal communication services module or apower line carrier (PLC) module.is not necessary to complete the communication link between themeter and the utility.The gateway node is located remotely from the meter tocomplete the local area network. The gateway node is also made upof four major components. These components include a wide areanetwork interface module, an initialization. microcontroller, aspread spectrum processor and an RF transceiver. The gateway nodeis responsible for providing interrogation signals to the meter andcommodity utilization data from the interfacefor receivingmanagement unit for the local area network. However, the gateway-4-1015202530CA 02264913 2002-04-02node also provides the link to the utility serviceprovider over a commercially available fixed two—waycommon carrier wide area network.The RF transceiver of the gateway node transmitsinterrogationsignals from the utility or preprogrammedsignals for scheduled readings to the electric meter, andreceives commodity utilization data in return from themeter for transmission to the utility over the wide areanetwork. The spread spectrum processor is coupled to theRF transceiver and enables the gateway node to transmitand receive data utilizing the spread spectrumcommunication technique. The WAN interface module iscoupled to the spread spectrum processor and transmitsdata to and from the utility service provider over anycommercially available wide area network that is desired.A different WAN interface module can be used for eachdifferent commercially available wide area networkdesired. The initialization microcontroller is interposedbetween the interface module and the spread spectrumprocessor for controlling operation of the spread spectrumprocessor and for controlling communication within thegateway node.Meter reading, meter information management andnetwork communications are all controlled by two—waysystent software that is preprogrammed into the electricmeter's memory during manufacture and installation. Thesoftware enables an operator to program utilityidentification numbers, meter settings and readings, unitsof measure and alarm set points.Accordingly, in one aspect, the presentinvention provides an electronic electric metercomprising: an electronic transducer for measuringl015202530CA 02264913 2002-04-02commodity utilization and monitoring power quality; ameter microcontroller coupled to said electronictransducer for interpreting said commodity utilizationdata and said power quality information; a measurementmicrocontroller coupled to said meter microcontroller forprocessing said commodity utilization data and said powerquality information: a two-way wireless transceivercoupled to said measurement microcontroller forselectively transmitting commodity utilization data andpower quality information from the meter to a remotegateway node over a local area network (LAN), and forreceiving data requests from said remote gateway node overthe local area network (LAN); and at least onecommunication network module coupled to said measurementmicrocontroller for selectively transmitting commodityutilization data and power quality information fronl themeter to a utility service provider over a wide areanetwork (WAN), and for receiving data requests from saidutility service provider over the wide area network (WAN),such that the electric meter can selectively transmitcommodity utilization data and power quality informationover either the WAN or the LAN.In a further aspect, the present inventionprovides An electronic electric meter comprising: anelectronic transducer for measuring commodity utilizationand monitoring power quality; a measurementmicrocontroller coupled to said electronic transducer forprocessing said commodity utilization data and powerquality information for communication to a utility serviceprovider; a two-way wireless transceiver coupled to saidmeasurement microcontroller for selectively transmittingcommodity utilization data from. the meter over a local_5a._1015202530CA 02264913 2002-04-02area network (LAN), and for receiving data requests from aremote communication node over the local area network(LAN); and at least one network interface module coupledto said measurement microcontroller for selectivelytransmitting commodity utilization data and power qualityinformation from the meter to the utility service providerover a wide area network (WAN), and for receiving datarequests from said utility service provider over the widearea network (WAN), such that the electric meter canselectively transmit commodity utilization data and powerquality information over either the WAN or the LAN.In a still further aspect, the present inventionprovides An electronic electric meter comprising: anelectronic transducer for measuring commodity utilizationand monitoring power quality; a meter microcontrollercoupled to said electronic transducer for interpretingsaid commodity utilization data and said power qualityinformation; a measurement microcontroller coupled to saidmeter microcontroller for processing said commodityutilization data and said power quality information; atwo—way wireless transceiver coupled to said measurementmicrocontroller for transmitting commodity utilizationdata and power quality information fronl the meter to autility service provider over a local area network (LAN),and for receiving data requests from said utility serviceprovider over the local area network (LAN); wherein themeasurement microcontroller is operable to receive a shut—off signal from the utility service provider such that thewireless transceiver generates an alarm signal upondetection of measured commodity utilization after thereceipt of the shut—off signal._ 5b..10CA 02264913 2002-04-02BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGSFig. 1 is a perspective view of an electronicelectric meter in accordance with the present invention;Fig. 2 is a cross—sectional View of the internalstructure of the electric meter shown in Fig. 1;Fig. 3 is a block diagram of the electric metercircuitry;Fig. 4 is a front elevational View of a gatewaynode;Fig. 5 is a schematic view of the electric meterinterfacing with a remote gateway node and a utilityservice provider, creating a networked automatic meterreading data communication system;_5C...101520253035CA 02264913 1999-03-03W0 98/10299 PCT/US97/15728Fig. 6 is a flow diagram of the automatic meter readingdata communication system shown in Fig. 5;Fig. 7 is a block diagram of the gateway node circuitry;Fig. 8 is a functional block diagram of the automaticmeter reading data communication system of Figs. 5 and 6;Fig. 9A is a flow diagram of the WAN handler portion ofthe data communication system of Fig. 8;Fig. 9B is a flow ciiagrann of the message dispatcherportion of the data communication system of Fig. 8;Fig. 9C is a flow diagram of the RF handler portion ofthe data communication system of Fig. 8;Fig. 9D is a flow diagram of the scheduler portion of thedata communication system of Fig. 8; andFig. 9E is a flow diagram of the data stores portion ofthe data communication system of Fig. 8.DETAILED DESCRIPTION OF THE INVENTIONElectronic Electric MeterFigs. 1 and 2 show a fully integrated, self-containedelectronic electric meter 10 for measuring electricity usage andThe meter 10 is operable for both singleThe meter 10monitoring power quality.phase and three phase electric power installations.includes a top cover 12 attached to a meter base 14. Extendingoutwardly from the meter base 14 is a mounting frame 16 and a pairof terminals 18, 20. The meter 10 easily retrofits into existingmeter sockets by insertion of terminals 18, 20 into the sockets andTheterminals 18, 20 complete the connection between the electric powerinterlocking the mounting frame to secure the meter in place.line and the meter 10. The meter 10 further includes a liquidcrystal display 22 for displaying meter readings and settings,units of measure and status conditions. The top cover 12 includesa rectangular opening 24 for the LCD 22. A rectangularly shapedtransparent piece of glass or plastic covers the rectangularopening 24 for viewing LCD 22.As shown in Fig. 2, the fully electronic, self—contained,modular electric meter 10 includes several electronic sub—assem-The sub—assembliesblies. include a power transformer 32, acurrent transformer 34, a power/meter circuit board 36, aninterface management unit circuit board 38, an RF transceiver sub--5-101520253035CA 02264913 1999-03-03WO 98/10299 PCT/US97/15728assembly 40, an LCD sub—assembly 42, and a variety of commerciallyavailable plug in network modules, such as a narrowband personalcommunication services (PCS) module 41 and a power line carrier(PLC) module 43.All of the circuit boards and modules plug into a commonbackplane or busing system (not shown) providing a modularconstruction allowing for interchangeability of circuit boards andmodules depending on the data communication network desired.Circuitry of Electronic Electric MeterFig. 3 shows a block diagram of the electric meter’sinternal circuitry. The meter 10 is powered directly from theelectric power line coming through terminals 18, 20 and into powertransformer 32 to provide the DC power required of the metercircuitry. Back up battery power 44 is provided. in case ofelectrical power outages.The electrical power flowing through terminals 18 and 20is sensed by voltage interface transducer 46 and current interfacetransducer 48. The accumulated pulse totalization from transducers46 and 48 is input into meter microcontroller 50 which interpretsthe electrical signal data received from transducers 46 and 48.The processed electrical signal data is then sent through a leveltranslator 52 to condition the signals for the required input intomeasurement microcontroller 54. Measurement microcontroller 54performs additional calculations on the electrical signals receivedfrom meter microcontroller SO and prepares them for output to theLCD 22 or an appropriate communication network. Meter microcontro-ller 50 may comprise the integrated circuit sold by SAMES of SouthAfrica under the designation SA9603B. The measurement microcontro-ller S4 is an SMOS chip available under the designation SMCAA316F03.The measurement microcontroller 54 also monitors inputsfrom tamper switch 56 and disconnect relay 57 for disconnecting themeter from the electrical line. The progrant ROM 59 containscustomer specific and site specific variables that may be importantfor calculating electricity usage. The meter 10 has an accuracy ofapproximately 0.2% for a power input current range of 0-200 amps.Other features that the measurement microcontroller 54 is able tomeasure are kilowatt hour usage, voltage and frequency measure-101520253035CA 02264913 1999-03-03W0 98/10299 PCT/US97/15728ments, energy direction, time and date reporting, load profilingand failure reporting. The power/meter circuit board includesmeasurement microcontroller 54, level translator 52, metermicrocontroller 50, backup battery 44, and primary power supply 32.Electric meter 10 is able to communicate commodityutilization data and power quality information to a utility over a(LAN) (WAN).communication section within the electric meter 10local area network or a wide area network A radio(RF)is comprised by a communication microcontroller and a spreadAn antenna 62is coupled to the RF transceiver 60 for transmitting and receivingfrequencyspectrum processor chip 58 and an RF transceiver 60.RF spread spectrum signals.The communication microcontroller portion of chip 58 isresponsible for all aspects of radio frequency (RF) communicationmanagement in electric meter 10 including determining the presenceof a valid interrogating signal from a remotely located gatewayThe chip 58provides control information to spread spectrum processor portionnode. communication microcontroller portion ofof chip 58 and RF transceiver 60 to control spread spectrumprotocol and RF channelization. Communication microcontroller andspread spectrunl processor chip 58 may comprise the integratedcircuit sold by Siliconians of California,SSlO5.under the designationThe spread spectrum communication technique makes use ofa sequential noise—like signal structure, for example, pseudo-noise(PN) codes to spread a normally narrowband information signal overa relatively’ wide band of frequencies. This spread spectrumcommunication technique may be further understood by reference toU.S. Patent 5,166,952 and the numerous publications cited therein.The use of the spread spectrum communication technique,when used in conjunction with the direct sequence modulationtechnique, hereinafter described, gives the LAN data communicationsystem a measure of security. This communication technique alsoavoids the need to obtain licensure from governmental authoritiescontrolling radio communication.The chip 58functions to perform spread spectrum encoding of the data fromspread spectrum processor portion ofcommunication microcontroller provided to RF transceiver 60 and-8-l0l520253035CA 02264913 1999-03-03W0 98/10299 PCT/US97/15728decoding of the spread spectrum data from the RF transceiver. Abetter understanding of the spread spectrum communication techniquecan be obtained by reading the subject matter under the subheadingentitled "Circuitry of Gateway Node". The RF transceiver 60 andcommunication microcontroller and spread spectrum processor chip 58are part of the circuitry on interface management unit board 38 andRF module 40 of Fig. 2.The meter 10 also includes plugin interface modules whichcorrespond to a variety of different commercially available LAN orWAN communication devices. These communication devices provide acommunication link directly from the electric meter 10 to a utilityshown in Fig. 3, is a narrow band(PCS)interface module 66 powered by a PLCservice provider. For example,personal communication services interface module 64, and a(PLC)interface power supply 68.power line carrierThese communication interface modulesare easily interchangable within electric meter 10. These moduleswith theinterface microcontroller 70 along a common backplane or busingcommunicate measurement microcontroller 54 and ansystem (not shown).Networked Automatic Meter Reading Data Communication SystemIn a preferred embodiment of the invention, Figs. 5 and6, the electric meter 10 communicates over a local area network(LAN)from the electric meter 10 to a utility 76 over a fixed common(WAN) 78.the end to end communication links from the meter 10 to the utility74 to a gateway node 72 which transmits the commodity datacarrier wide area network The gateway node 72 provides76. A first link in the data communication system is a two—way 900MHz spread spectrum LAN 74. The second link within the datacommunication system is designed to be any commercially availableIn this embodiment,72 must be within the communication range of the electric meter 10two—way common carrier WAN 78. a gateway nodewhich is approximately one mile.In an alternate embodiment, the electric meter 10provides direct local area and wide area network access throughprinted circuit board sub—assemblies installed in meter 10described above.A more detailed representation of the preferred embodi-ment is shown in Figs. 8 and 9A-9E. Fig. 8 shows a functional flow-9-101520253035CA 02264913 1999-03-03W0 98/ 10299 PCT/US97/15728diagram of the networked automatic meter reading data communicationinvention in which the componentssystem of the present aredescribed as functional blocks. The flow diagram, Fig. 8, includesthe main functional components of the gateway note 72 which includea message dispatcher 80, an RF handler 82, a WAN handler 84, a datastores component 86 and a scheduler component 88. The data storesand scheduler components comprise data that is preprogrammed intothe gateway node's memory. The gateway node 72 interfaces with theelectric meter 10 over the two-way wireless LAN 74. The gatewaynode 72 also interfaces with the utility service provider 76 overthe fixed common carrier WAN 78.Fig. 9A is a «detailed functional diagranx of the WANhandler 84 of Fig. 8. theutility 76 may initiate a request for data from the electric meterThe WAN handler 84 ofthe gateway node 72 receives the WAN data stream,In a typical communication episode,10 by sending a data stream over the WAN 78.creates a WANmessage, verifies the utility ID of the sender from the data stores86 and routes the WAN message to the message dispatcher 80 in thegateway node.Referring’ now to Fig. 9B, the message dispatcher 80receives the WAN message from the WAN handler 84 and determines theThe message dispatcher 80 determinesThemessage dispatcher 80 then verifies the meter ID from the datarequest from the utility 76.that the end recipient or target is the electronic meter 10.stores 86,RF handler 82.Referring now to Fig. 9C, the RF handler 82 receives thecreates an RF message and routes the RF message to theRF message from the message dispatcher 80, selects a proper RFchannel, converts the RF message to an RF data stream, sends the RFdata stream to the electric meter 10 over the LAN 74 and waits fora response. The electric meter 10 then responds by sending an RFdata stream over the LAN 74 to the RF handler 82 of the gatewaynode 72.RF message from the RF data stream and routes the RF message to theThe RF handler 82 receives the RF data stream, creates anmessage dispatcher 80. As shown in Fig. 15B, the message dispatch-er 80 receives the RF message, determines the target utility forresponse from the data stores 86, creates a WAN message and routesthe WAN message to the WAN handler 84. The WAN handler 84 receivesthe WAN message from the message dispatcher 80, converts the WAN-10..l01520253035CA 02264913 1999-03-03WO 98/10299 PCT/US97/15728message to a WAN data stream and sends the WAN data stream to theutility 76 over the fixed common carrier WAN 78, as shown in Fig.15A to complete the communication episode.A communication episode can also be initiated byscheduled readings preprogrammed into the scheduler‘ 88 of thegateway node as shown in Fig. 9D. A list of scheduled readingThescheduler 88 runs periodically when a scheduled reading is due.times is preprogrammed into memory within the gateway node 72.When it is time for a scheduled reading, the scheduler 88 retrievesmeter 10 information from the data stores 86, creates an RF messageand routes the RF message to the RF handler 82, receives the RFmessage, selects a proper RF channel, converts the RF message to anRF data stream, sends the RF data stream to the electric meter 10The meter then responds with an RF dataThe RF handler 82 receives the RFcreates an RF message from the RF data stream andand waits for a response.stream to the RF handler 82.data stream,routes the RF message to the message dispatcher 82. The messagedispatcher 80 receives the RF message, determines the targetutility for response from the data stores 86, creates a WAN messageand routes the WAN message to the WAN handler 84. The WAN handler84 receives the WAN message, converts the WAN message to a WAN datastream and sends the WAN data stream to the utility 76.Occasionally, the utility 76 may request data that isstored within the gateway node's memory. In this case, the utility76 initiates the communication episode by sending a WAN data streamto the WAN handler 84. The WAN handler 84 receives the WAN datacreates a WAN message, verifies the utility ID of thesender in the data stores 86 and routes the WAN message to thestream,message dispatcher 80. As shown in Fig. 15B, the message dispatch-er 80 receives the WAN message and determines the request from theutility 76. The message dispatcher 80 then determines the targetof the message.node memory, then the gateway node 72 performs the requested task,If the data requested is stored in the gatewaydetermines that the requesting utility is the target utility for aresponse, creates a WAN message and routes the WAN message to theWAN handler 84.converts the WAN message to a WAN data stream and sends the WANThe WAN handler 84 receives the WAN message,data stream to the utility 76.-11-101520253035CA 02264913 1999-03-03WO 98110299 PCTIUS97/15728The last type of communication episode is one which isinitiated by the electric meter 10. In this case, the meterdetects an alarm outage or tamper condition and sends an RF dataThe RF handlercreates an RF message from the RFstream to the RF handler 82 of the gateway node 72.82 receives the RF data stream,data stream and routes the RF message to the message dispatcher 80.The message dispatcher 80 receives the RF message, determines thetarget utility for response from the data stores 86, creates a WANThe WANconverts the WAN message to amessage and routes the WAN message to the WAN handler 84.handler 84 receives the WAN message,WAN data stream and sends the WAN data stream to the utility 76.There are thus three different types of communicationthatreading data communication system shown in Figs.can be accomplished within the automatic meter8 and 9A—E. Theautomatic meter reading functions incorporated into electric meterepisodes10 include monthly usage readings, demanmd usage readings, outageloadand virtual shutoffdetection and reporting, tamper detection and notification,profiling, first and final meter readings,capability.Fig. 9D represents information or data that is prepro-grammed into the gateway node's memory. Included within the memoryis a list of scheduled reading times to be performed by theinterface management unit. These reading times may correspond tomonthly or weekly usage readings, etc.Fig. 9E represents data or information stored in thegateway node's memory dealing with registered utility informationand registered interface management unit information. This dataincludes the utility identification numbers of registered utili-ties, interface management unit identification numbers of regis-tered interface management units, and other information forspecific utilities and specific interface management units, so thatthe gateway node may communicate directly with the desired utilityor correct electric meter.Electronic Electric Meter Virtual shut-off FunctionThe virtual shut-off function of the electric meter 10 isused for situations such as a change of ownership where a utilityservice is to be temporarily inactive. When a residence is vacatedthere should not be any significant consumption of electricity at-12-101520253035CA 02264913 1999-03-03WO 98/10299 PCT/US97/15728that location. If there is any meter movement, indicatingunauthorized usage, the utility needs to be notified. The tamperswitch 56 of the electric meter 10 provides a means of flagging andreporting meter movement beyond a preset threshold value.Activation of the virtual shut—off mode is accomplishedthrough the "set virtual threshold"count which the electric meter is not to exceed.message, defined as a meterIn order to knowwhere to set the threshold it is necessary to know the presentmeter count. The gateway node reads the meter count, adds whateveroffset is deemed appropriate, sends the result to the electricmeter as a "set virtual shut-off" message. The electric meter willthen enable the virtual shut—off function. The electric meter thenaccumulates the meter counts. If the meter count is greater thanthe preset threshold value then the electric meter sends a "send"clear error code"if themeter count is less than the preset threshold value then thealarm" message to the gateway node until amessage is issued in response by the gateway node. However,electric meter continues to monitor the meter count. The virtualshut—off function may be canceled at any time by a "clear errorcode" message from the gateway node.If the meter count in the meter does not exceed thepreset threshold value at any given sampling time, then the metercontinues to count until the preset threshold count is attained oruntil operation in the virtual shut—off mode is canceled.Gateway NodeThe gateway node 72 is shown in Fig. 4. The gateway node72 is typically located on top of a power pole or other elevatedlocation so that it may act as a communication node between LAN 74and WAN 78.receiving and transmitting data over the RF communication links,The gateway’ node 72 includes an antenna 90 forand a power line carrier connector 92 for connecting a power lineto power the gateway node 72. The gateway node 72 may also beThe compact design allows for easy placement on anyThegateway node 72 provides end to end communications from the metersolar powered.existing utility pole or similarly situated elevated location.10 to the utility 76. The wireless gateway node 72 interfaces withthe electric meter 10 over‘ a two-way’ wireless 900 MHz spreadspectrum LAN 74. Also, the gateway node 72 will interface and be-13-101520253035CA 02264913 1999-03-03W0 98/10299 PCT/US97/15728compatible with any commercially available WAN 78 for communicatingcommodity usage and power quality information with the utility.The gateway node 72 is field programmable to meet a variety of datareporting needs.The gateway node 72 receives data requests from theutility, interrogates the meter and forwards commodity usageover the WAN 78The gateway node 72 exchanges data withinformation, as well as power quality information,to the utility 76.meters for which it is responsible, andcertain, predetermined,"listens" for signals from those meters. The gateway node 72 doesnot store data for extended periods, thus minimizing securityrisks. The gateway node's RF communication range is typically onemile.A wide variety of fixed wide area network (WAN) communi-cation systems such as those employed with two-way pagers, cellulartelephones, conventional telephones, narrowband.personal communica-(PCS), (CDPD)and satellites may be used to communicate data between the gatewaytion services cellular digital packet data systems,nodes and the utility. The data communication system utilizeschannelized direct sequence 900 MHz spread spectrum transmissionsfor communicating between the meters and gateway nodes.Circuitry of Gateway NodeFig. 7 shows a block diagram of the gateway nodecircuitry. The RF transceiver section 94 of gateway node 72 is thesame as the RF transceiver section 60 of electric meter 10 andcertain portions thereof, such as the spread spectrum processor andTheincludes a WAN interface module 96 which mayfrequency synthesizer, are shown in greater detail in Fig. 7.gateway node 72incorporate electronic circuitry for a two-way pager, power linecarrier (PLC), satellite, cellular telephone, fiber optics,cellular digital packet data (CDPD) system, personal communicationservices (PCS), or other commercially available fixed wide areanetwork (WAN) system. The construction of WAN interface module 96and initialization microcontroller 98 may change depending on thedesired. WAN RF channelthrough an RF channel select bus 100 which interfaces directly withinterface. selection is accomplishedthe initialization microcontroller 98.-14-101520253035CA 02264913 1999-03-03W0 98/10299 PCT/US97/15728Initialization microcontroller 98 controls all nodefunctions including programming spread spectrum processor 102, RFchannel selection in frequency synthesizer 104 of RF transceiver94, transmit/receive switching, and detecting failures in WANinterface module 96.Upon power up, initialization microcontroller 98 willprogram the internal registers of spread spectrum processor 102,read the RF channel selection from the electric meter 10, and setthe system for communication at the frequency corresponding to thechannel selected by the meter 10.Selection of the RF channel used for transmission andreception is accomplished via the RF channel select bus 100 toinitialization microcontroller 98. Valid channel numbers rangefrom O to 23.input to initialization microcontroller 98 causing false channeltheChannel selection data must be present and stable on the inputs toIn order to minimize a possibility of noise on theswitching, inputs have been debounced through software.initialization microcontroller 98 for approximately 250 us beforethe initialization microcontroller will accept it and initiate achannel change. After the channel change has been initiated, ittakes about 600 us for frequency synthesizer 104 of RF transceiver94 to receive the programming data and for the oscillators in thefrequency synthesizer to settle to the changed frequency. Channelselection may only be completed while gateway node 72 is in thereceive mode. If the RF channel select lines are changed duringthe transmit mode the change will not take effect until after thegateway node has been returned to the receive mode.Once initial parameters are established, initializationmicrocontroller 98 begins its monitoring functions. When gatewaynode 72 is in the receive mode, the initialization microcontroller98 continuously monitors RF channel select bus 100 to determine ifa channel change is to be implemented.For receiving data, gateway node 72 monitors the electricmeter‘ 10 to determine the presence of data. Some additionalhandshaking hardware may be required to sense the presence of aspread spectrum signal.An alarm message is sent automatically by electric meter10 in the event of a tamper or alarm condition, such as a poweroutage. The message is sent periodically until the error has-15- 4......x..m.........,»...,. V4 ...101520253035CA 02264913 1999-03-03W0 98/ 10299 PCT/US97/15728cleared. Gateway node 72 must know how many bytes of data it isexpecting to see and count them as they come in. When the propernumber of bytes is received, reception is deemed complete and themessage is processed. Any deviation from the anticipated number ofreceived bytes may be assumed to be an erroneous message.During the transmit mode of gateway node 72, initializa-tion microcontroller 98 monitors the data line to detect idleconditions, start bits,node 24information in the event a failure of WAN interface module 96and stop bits. This is done to preventgateway from continuously transmitting meaninglessoccurs and also to prevent erroneous trailing edge data from beingTheinitialization microcontroller 98 will not enable RF transmittersent which cannot terminate transmissions in a timely fashion.106 of RF transceiver 94 unless the data line is in the invalididle state when communication is initiated.A second watchdog function of initialization micro-controller 98 when gateway node 72 is in the transmit mode is totest for valid start and stop bits in the serial data stream beingtransmitted. This ensures that data is read correctly. The firststart bit is defined as the first falling edge of serial data afterit has entered the idle stage. All further timing during thatcommunication episode is referenced from that start bit. Timingfor the location of a stop bit is measured from the leading edge ofa start bit for that particular byte of data. Initializationmicrocontroller 98 measures an interval which is 9.5 bit times fromthat start bit edge and then looks for a stop bit. Similarly, atimer of 1 bit interval is started from the 9.5 bit point to lookfor the next start bit. If the following start bit does not assertitself within 1 bit time of a 9.5 bit time marker a failure isdeclared. The response to a failure condition is to disable RFtransmitter 106.Communication to and from electric meter 10 may becarried out in one of a preselected number, for example 24 channelsfor example 902-928 MHz. Themeter 10 receives data and transmits a response on a single RFin a preselected frequency band,channel which is the same for both transmit and receive operation.As hereinafter described, the specific RF channel used forcommunication is chosen during commissioning and installation ofthe unit and loaded into memory. The RF channel is chosen to be-16-101520253035CA 02264913 1999-03-03WO 98/10299 PCT/US97/15728different from the operating channels of other, adjacent interfacemanagement units, thereby to prevent two or more interfacemanagement units from responding to the same interrogation signal.Frequency synthesizer 104 performs the modulation anddemodulation of the spread spectrum data provided by spreadspectrum processor 60 onto a carrier signal and demodulation ofsuch data from the carrier signal. The RF transceiver has separatetransmitter 106 and receiver 108 sections fed from frequencysynthesizer 104.The output of the spread spectrum processor to frequencysynthesizer comprises a 2.4576 MHz reference frequency signal inbandcomprise aconductor and a PN encoded base signal in conductor.Frequency synthesizer National SemiconductorLMX2332A Dual Frequency Synthesizer.The direct sequence modulation technique employed by(PN code) toThe resulting spread signal is usedmayfrequency synthesizer uses a high rate binary codemodulate the base band signal.to modulate the transmitter’s RF carrier signal. The spreadingcode is a fixed length PN sequence of bits, called chips, which isThe pseudo-random nature of theand the fixedsequence allows the code to be replicated in the receiver forthe baseband signal is modulated with the PN code spreading function, andconstantly being recycled.sequence achieves the desired signal spreading,recovery of the signal. Therefore, in direct sequence,the carrier is modulated to produce the wide band signal.Minimum shift keying (MSK) modulation is used in order toallow reliable communications, efficient use of the radio spectrum,Themodulation performed by frequency synthesizer 72 is minimum shiftand to keep the component count and power consumption low.keying (MSK) at a chip rate of 819.2 Kchips per second, yielding atransmission with a 6 dB instantaneous bandwidth of 670.5 KHz.The receiver bandwidth of this spread spectrum communica-tion technique is nominally 1 MHz, with a minimum bandwidth of 900KHZ.MHz,spaced a minimum of 1.024 MHz apart.Frequency resolution of the frequency synthesizer is 0.2048which will be used to channelize the band into 24 channelsThis frequency channelizationis used to minimize interference between interface management unitswithin a common communication range as well as providing growth for-17-1015CA 02264913 1999-03-03W0 98l10299 PCT/US97l15728future, advanced features associated with the data communicationsystem.Frequency control of the RF related oscillators in thesystem is provided by dual phase locked loop (PLL) circuitry withinfrequency synthesizer. The phase locked loops are controlled andprogrammed by initialization microcontroller via a serial program-Fig. 7.RF signals which are mixed together in various combinations toming control bus, The frequency synthesizer produces twoproduce a transmission carrier and to demodulate incoming RFsignals. The transmission carrier is based on frequencies in the782-807 MHz range and the demodulation signal is based on frequen-cies in the 792-817 MHz range. These signals may be referred to asRF transmit and RF receive local oscillation signals.Table I below is a summary of the transmission channelfrequencies and associated frequency synthesizer transmit/receiveoutputs. The signals in the table are provided by the two PLLsections in the dual frequency synthesizer.-13-101520253035CA 02264913 1999-03-03W0 98/102953 PCT/US97/15728Table IChannel Channel Transmit Local Receive LocalNumber Frequency (MHz) Oscillation (MHz) Oscillation (MHz)0 902.7584 782.3360 792.16641 903.7824 783.3600 793.19042 904.8064 784.3840 794.21443 905.8304 785.4080 795.23844 906.8544 786.4320 796.26245 907.8784 787.4560 797.28646 908.9024 788.4800 798.31047 910.1312 789.7088 799.53928 911.1552 790.7328 800.56329 912.1792 791.7568 801.587210 913.2032 792.7808 802.611211 914.2272 793.8048 803.635212 915.2512 794.8288 804.659213 916.2752 795.8528 805.683214 917.2992 796.8768 806.707215 918.3232 797.9008 807.731216 919.9616 799.5392 809.369617 920.9856 800.5632 810.393618 922.0096 801.5872 811.417619 923.2384 802.8160 812.646420 924.2624 803.8400 813.670421 925.2864 804.8640 814.694422 926.3104 805.8880 815.718423 927.3344 806.9120 816.7424A third signal, which is fixed at 120.4224 MHZ, is alsosupplied by the dual frequency synthesizer. This signal isreferred to as the intermediate frequency (IF) local oscillationsignal.In transmission mode, frequency synthesizer 104 providesa signal having a frequency in the 782-807 MHz range, modulatedwith the data to be transmitted. RF transmitter section 106 mixesthe signal with the fixed frequency IF local oscillator signal.This results in an RF signal which ranges between 902 MHZ and 928MHz. The signal is filtered to reduce harmonics and out of band-19.. CA 02264913 1999-03-03W0 98/ 10299 PCT/US97/15728signals, amplified and supplied to antenna switch 110 and antenna112.It is recognized that other equivalents, alternatives,and modifications aside from those expressly stated, are possibleand within the scope of the appended claims.-20-

Claims (20)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An electronic electric meter comprising:
an electronic transducer for measuring commodity utilization and monitoring power quality;
a meter microcontroller coupled to said electronic transducer for interpreting said commodity utilization data and said power quality information;
a measurement microcontroller coupled to said meter microcontroller for processing said commodity utilization data and said power quality information;
a two-way wireless transceiver coupled to said measurement microcontroller for selectively transmitting commodity utilization data and power quality information from the meter to a remote gateway node over a local area network (LAN), and for receiving data requests from said remote gateway node over the local area network (LAN); and at least one communication network module coupled to said measurement microcontroller for selectively transmitting commodity utilization data and power quality information from the meter to a utility service provider over a wide area network (WAN), and for receiving data requests from said utility service provider over the wide area network (WAN), such that the electric meter can selectively transmit commodity utilization data and power quality information over either the WAN or the LAN.

2. The electric meter according to claim 1 wherein the communication network module is removable from said meter and interchangeable with other communication network modules.

3. The electric meter according to claim 2 wherein the communication network module is a narrowband personal communication services (PCS) module.

4. The electric meter according to claim 2 wherein the communication network module is a power line carrier (PLC) module.

5. An electronic electric meter comprising:
an electronic transducer for measuring commodity utilization and monitoring power quality;
a measurement microcontroller coupled to said electronic transducer for processing said commodity utilization data and power quality information for communication to a utility service provider;
a two-way wireless transceiver coupled to said measurement microcontroller for selectively transmitting commodity utilization data from the meter over a local area network (LAN), and for receiving data requests from a remote communication node over the local area network (LAN); and at least one network interface module coupled to said measurement microcontroller for selectively transmitting commodity utilization data and power quality information from the meter to the utility service provider over a wide area network (WAN), and for receiving data requests from said utility service provider over the wide area network (WAN), such that the electric meter can selectively transmit commodity utilization data and power quality information over either the WAN or the LAN.

6. The electric meter according to claim 5 wherein the communication network module is removable from said meter and interchangeable with other communication network modules.

7. The electric meter according to claim 6 wherein the communication network module is a narrowband personal communication services (PCS) module.

8. The electric meter according to claim 5 wherein the communication network module is a power line carrier (PLC) module.

9. The electric meter according to claim 1 wherein the two-way wireless transceiver selectively receives commodity utilization data from other meters including wireless transceivers such that the electric meter communicates commodity utilization data to the utility service provider from multiple meters.

10. The electric meter of claim 9 wherein the electric meter communicates commodity utilization data to the utility service provider over the wide area network (WAN).

11. The electric meter according to claim 1 wherein the measurement microcontroller is operable to selectively transmit the commodity utilization data and the power quality information over either the local area network (LAN) or the wide area network (WAN).

12. The electric meter according to claim 5 wherein the two-way wireless transceiver selectively receives commodity utilization data from other meters including wireless transceivers such that the electric meter can communicate commodity utilization data to the utility service provider from multiple meters.

13. The electric meter of claim 12 wherein the electric meter communicates commodity utilization data to the utility service provider over the wide area network (WAN).

14. The electric meter according to claim 5 wherein the measurement microcontroller is operable to selectively transmit the commodity utilization data and the power quality information over either the local area network (LAN) or the wide area network (WAN).

15. An electronic electric meter comprising:
an electronic transducer for measuring commodity utilization and monitoring power quality;
a meter microcontroller coupled to said electronic transducer for interpreting said commodity utilization data and said power quality information;
a measurement microcontroller coupled to said meter microcontroller for processing said commodity utilization data and said power quality information;
a two-way wireless transceiver coupled to said measurement microcontroller for transmitting commodity utilization data and power quality information from the meter to a utility service provider over a local area network (LAN), and for receiving data requests from said utility service provider over the local area network (LAN);

wherein the measurement microcontroller is operable to receive a shut-off signal from the utility service provider such that the wireless transceiver generates an alarm signal upon detection of measured commodity utilization after the receipt of the shut-off signal.

16. The electric meter according to claim 15 further comprising at least one communication network module coupled to the measurement microcontroller for selectively transmitting the commodity utilization data and the power quality information from the meter to the utility service provider over a wide area network (WAN). and for receiving data requests from the utility service provider over the wide area network (WAN), wherein the communication network module transmits the alarm signal to the utility service provider.

17. The electric meter of claim 15 further comprising a disconnect relay operatively positioned between the electric meter and a supply of electricity, the disconnect relay being operable between an open position and a closed position, wherein the disconnect relay disconnects the electric meter from the supply of electricity line in the open position, wherein the disconnect relay is moved to the open position upon generation of the alarm signal after receipt of the shut-off signal.

18. The electric meter according to claim 15 wherein the electronic transducer includes a current transducer and a voltage transducer for sensing commodity usage.

19. The electric meter according to claim 15 wherein said two-way wireless transceiver includes a spread spectrum processor coupled to said communications microcontroller for enabling said electric meter to transmit and receive data utilizing a spread spectrum communication technique, and an RF transceiver coupled to said spread spectrum processor and said communication microcontroller for transmitting commodity utilization data from the meter and for receiving interrogation signals from the gateway node.

20. The electric meter according to claim 15 wherein said electric meter is programmable.