Method and system for remote metering the consumption of electricity, water or gas

(56) References cited:

EP-A- 1 032 238 WO-A-2007/146053

WQ-A2-2007/030826 US-A1- 2005 043 059

ΕΡ 2 085 749 Β1

Note: Within nine months ofthe publication ofthe mention ofthe grant ofthe European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall nőt be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).

Printed by Jouve, 75001 PARIS (FR)

ΕΡ 2 085 749 Β1

Description [0001] The present invention relates to a method and a system fór remote metering the consumption of Utilities distributed through a distribution network, e.g. electricity, water or gas distribution network, to a plurality ofconsumers. The present invention furthermore relates to a concentrator fór collecting consumption related data, especially regarding the consumption of Utilities, from a plurality of associated remote meters, as well as to a remote meter fór measuring the consumption of Utilities and fór providing consumption related additional data.

[0002] In a distribution network fór distributing Utilities like electricity, water or gas to a large number of consumers spread over a large geographical territory, the consumer sites are typically equipped with a meter fór measuring the consumption of the Utilities by the associated consumer. The measured consumption will then be the basis fór biliing the consumer or fór any other accounting purposes. Today, there exist public distribution networks fór Utilities like electricity, water and gas, which make these Utilities available to consumers on a nation wide scale. At present, in the majority ofthe existing distribution networks, the meters located at custorner premises require to be read by a humán operator at regular intervals, e.g. once peryear. Reading the measured consumption with the aid of humán interaction has a lót of obvious disadvantages, due to the fact that humán resources are expensive and tend to make mistakes when repeatedly performing simple tasks like reading utility meters at a larger number of custorner premises.

[0003] In orderto alleviate problems and costs associated with the reading ofthe consumption data by humán operators, systems have been envisaged fór remote metering the consumption of Utilities. In a system fór remote metering the consumption of Utilities as described in WO 03/055031 Aor WO 2005/015890, concentrator devices are provided, each of which administrating a certain numberof remote meters located at custorner premises. The remote meters report the measured consumption data to their associated concentrators. The concentrators in turn communicate with other higher level concentration nodes or directly with centralized management facilities which will further process the collected data, send out bilis to the customers and perform other high level administrative tasks relating to the operation ofthe utility distribution network.

[0004] In such a system fór remote metering the consumption of Utilities, each of the concentrators communicates with a plurality of remote meters in order to collect the measured data and perform tasks related to the administration ofthe remote meters associated with the concentrator. In order to accomplish the tasks of metering the consumption, reporting data to the concentrator, receiving commands from the concentrator and other activities, a remote meter has a hőst controller and a program mernory fór executing programs stored in the program mernory.

[0005] WO 2007/030826 A2 describes a RF meter reading system utilizing one-way and two-way communication between an endpoint and a reader. Here, in response to a specific event (such as, fór example, the passage of a certain amount of time), the endpoint enters an active operating mode, or bubbles up and transmits an initial message, which is a relatively short message. By virtue of its short duration, the initial message requires a relatively small amount of energy to be transmitted by the endpoint. The initial message includes at least a unique identifier of the endpoint, and any necessary overhead bits that identify the initial message as a transmission from an endpoint device to enable its reception by an AMR system receiver. The initial message may include a synchronization pattern (such as a string of alternating bits), a preamble that is recognizable by a reader as indicating the presence ofan AMR message, and an identification ofthe particular endpoint, orthe initial message can include additional information, such as consumption information. A decision fór whether to initiate further communication can be based on the content ofthe initial message, system configuration instructions sent from the head end or hőst processor, the time of day or day of the biliing cycle, the amount of time since the last successful consumption reading received from the particular endpoint 108, and the like. The follow-up communication is an instruction, such as a command requesting certain additional information from endpoint, and the amount of information that is exchanged in the follow-up communication may be substantially greater, fór example the reader may request a large amount of consumption data or status data.

[0006] The present invention has been made to provide further improvements to such remote metering systems, the concentrators and the remote meters of such systems as well as the methods fór remote metering employed in such systems.

[0007] Accordingly, the present invention provides a method of remote metering the consumption of Utilities distributed through a public distribution network to a plurality of consumers, each consumer being associated with at least one remote meter, wherein each of the plurality of remote meters measures a consumption of said Utilities and Stores consumption related data fór reporting such data to a concentrator associated with said plurality of remote meters, said concentrator communicates with said plurality of remote meters in orderto collect consumption related data and perform tasks concerning the administration of its associated remote meters, and each of said remote meters comprises a program mernory, a controller executing programs stored in said program mernory and a data element mernory fór storing data elements related to the consumption ofsaid Utilities and at least indicative ofthe consumption ofsaid Utilities; characterized by a remote meter transmitting an amount of consumption related data to said concentrator upon a request from said concentrator, said request indicating the amount of consumption related data, said amount being determined on the basis of status data ofsaid remote meter.

ΕΡ 2 085 749 Β1 [0008] Further, the present invention provides a system fór remote metering the consumption of Utilities distributed through a public distribution network to a plurality of consumers, the system comprising a plurality of remote meters measuring a consumption of Utilities, each of said remote meters having a controller and a program memory, said controller executing programs stored in said program memory, and a data element memory fór storing data elements related to the consumption ofsaid Utilities and at least indicative ofthe consumption ofsaid Utilities; and a concentrator communicating with said plurality of remote meters in order to collect consumption data and perform tasks related to the administration of associated remote meters; wherein said remote meters ofthe system are adapted to perform the opération of transmitting an amount of consumption related data to said concentrator upon a request from said concentrator, and wherein said concentrator said is adapted to request the amount of consumption related data and to determine said amount on the basis of status data of said remote meter.

[0009] Further, the present invention provides a concentrator fór collecting data regarding the consumption of Utilities from a plurality of remote meters, each having a controller and a program memory, said controller executing programs stored in said program memory, and a data element memory fór storing data elements related to the consumption of said Utilities and at least indicative ofthe consumption ofsaid Utilities, said concentrator comprising a communication interface fór communicating with said plurality of remote meters; a controller fór Processing data received from said remote meters through said communication interface; wherein said concentrator is adapted to perform the operations of requesting status data from a selected one ofsaid remote meters; computing an amount of consumption related data to be requested and received from said selected remote meter on the basis of said status data; and receiving said amount of consumption related data from said selected remote meter.

[0010] Still further, the present invention provides a remote meter fór measuring the consumption of Utilities, comprising a communication interface fór transmitting data concerning the measured consumption of Utilities to a concentrator; a consumption data element storage means comprising storage locations fór storing data elements at least indicating the consumption measured at the time of storing a respective one ofsaid data elements; a time value storage means fór storing a time value corresponding to the date/time of storing of said most recent data element; and a controller being arranged to controi the opération of the remote meter relating to the measuring of the consumption of Utilities such that periodically, indicated by a stored time paraméter, a data element corresponding to the measured consumption of Utilities is stored in a respective subsequent one ofsaid storage locations ofsaid circular storage means, and the time value stored in said time value storage means is updated to correspond to the date/time of storing of said most recent data element; and the transmitting of data concerning the measured consumption of Utilities to said concentrator via said communication interface such that upon a respective request from said concentrator said time value is transmitted to said concentrator, and a number of data elements stored in said storage locations is transmitted to said concentrator, said number being determined bysaid concentrator.

[0011] According to all aspects ofthe present invention described above it is possible to retrieve a specific amount of data, i.e. consumption data and/or additional data, from remote meters of a remote metering system. The retrieved data provide a data profile, fór example indicative of the consumption characteristics over time at the location of a remote meter or, in the case of a distribution network fór electric energy, indicative of a ratio of active and reactive energy consumption at the location of a remote meter over time.

[0012] The above aspects and advantages ofthe invention will be further elaborated in the following description of preferred embodiments ofthe present invention with reference to the accompanying drawings.

Figure 1 shows an example of a distribution network comprising a concentrator and remote meters according to the invention.

Figure 2 shows an embodiment of a concentrator according to the invention.

Figure 3 shows a diagram illustrating an example of a communication between a concentrator and a remote meter according to the invention.

Figure 4 shows an embodiment of a remote meter according to the invention.

Figure 5 shows a flow chart illustrating an exampleof a load procedure performed by a concentrator and the associated remote meters according to the invention.

[0013] In the following, the present invention will be explained in greater detail while reference is made frequently to a remote metering system in which the consumption of electric energy is measured and respective data are collected in remote meters and transmitted to concentrators. However, it is understood that the invention can be used in very different or relatively similar remote metering systems and with respect to various kinds of data which are collected in the remote meters ofsuch systems.

ΕΡ 2 085 749 Β1 [0014] As mentioned before, Figure 1 shows an embodiment of a system fór remote metering the consumption of electricity in an electricity distribution network which comprises a high voltage network portion HV, a médium voltage network portion MV as well as a low voltage network portion LV. PP denotes a power plánt which feeds electric power intő the high voltage network portion HV fór distribution over a large geographical area. TP denotes a primary substation which transforms the high voltage carried on the high voltage network portion intő a médium voltage in order to feed a section ofthe médium voltage network portion MV. ST denotes a secondary substation, which connects the médium voltage network portion MV with a network section 1 in the low voltage network portion LV. The secondary substation ST comprises a secondary transformer TS which transforms the médium voltage of e.g. 20 kV intő a low voltage of e.g.

220 V fór distribution to a plurality of consumer sites Η1, H2.....Hn. Each consumer site H1.....Hn comprises a remote meter RM which is connected between the low voltage network section 1 and a power line 2 which distributes the electric energy at the customer premises to a plurality of electricity consumers L1, L2.....Lk like lamps, washing machines, dish washers, television sets in case of domestic consumers or industrial facilities like machine tools in case of commercial consumers.

[0015] In the embodiment shown in Fig. 1, the secondary substation ST comprises a concentrator C located at the premises of the secondary substation ST. The concentrator C is connected to the low voltage network section fed by the secondary substation ST in orderto communicate with the remote meters RM at the customer premises Η1, H2.....

Hn via power line carrier using the low voltage network section 1 fór the transmission of communication signals between the concentrator C and its associated remote meters RM.

[0016] AMM denotes a centralized management facility fór administrating a large number of consumers connected to the electricity distribution network shown in Fig. 1. This centralized management facility AMM gathers various data, e.g. consumption data, from the large number of consumers and performs activities like biliing the consumers in accordance with the measured consumption reported by the remote meters RM at the customer premises H1, H2..... Hn to the concentrator C. The concentrator C collects the reported data, including fór example consumption data, from the remote meters, suitably processes and buffers the reported data and transmits data in a suitable formát and at a suitable timing to the centralized management facility AMM. The AMM in return transmits commands, requests and other data to the concentrators C in the network of Fig. 1 in order to control and administrate the operation of the concentrators C and the remote meters RM in the network.

[0017] In the embodiment of Fig. 1, the communication between the concentrators C and the centralized management facilities AMM takes piacé through a public telecommunication network, which is most preferably a wireless or mobile telecommunication network like the GSM network. To this end, the concentrator C comprises a GSM modem device nőt shown in Fig. 1 which is connected to an antenna A. The modem communicates in a wireless fashion with a base station B which forms a part of the public mobile telephoné network PSTN/PLMN in Fig. 1. The public telephoné network PSTN/PLMN in turn is connected with the centralized management facilities AMM. However, the communication between the concentrators C and the centralized management facilities AMM may be performed alsó in a different manner using alternative communication networks, e.g. POTS (piáin old telephoné system), the Internet or the power lines of the electricity distribution network.

[0018] Figure 2 shows an embodiment of the concentrator C located at the secondary substation ST of the network shown in Fig. 1. The concentrator C comprises a controller, e.g. a micro controller MCC which is connected with a program memory MÉM through adata bús B. In Figure 2 DBC denotes meansforstoringdata coiiected bythe concentrator C from the associated remote meters RM as well as other data. The data storing means DBC may be implemented as a random access memory (RAM), a hard disc drive (HD), network attached storage (NAS) or any other suitable data storage device, e.g. a flash memory. The data storing means DBC is connected with the micro controller MCC ofthe concentrator C and the program memory MÉM through the data bús B. In Fig. 2 M denotes a GSM modem under control ofthe micro controller MCC through the data bús B. The GSM modem M is connected with the antenna A fór wireless communication in a GSM network.

[0019] In Figure 2 CIC denotes a communication interface ofthe concentrator C. The communication interface CIC serves to enable the concentrator C to communicate with its associated remote meters RM through the power line of the low voltage network section LV to which both the concentrator and its associated remote meters are connected. The communication interface CIC receives data from the data bús B under control ofthe micro controller MCC fór transmission to one, somé or all ofthe associated remote meters either in unicast, multicast or broadeast mode depending on the content of the message to be transmitted. If data from the concentrator are intended fór transmission to a particular remote meter only (unicast mode), the data message transmitted through the communication interface CIC will contain a specific remote meter address. A message transmitted in multicast mode will contain the address of a group of remote meters which are intended to récéivé the particular multicast message. In broadeast mode, messages transmitted through the communication interface CIC will bear an identifier that they are broadeast messages intended to be received by any recipient, or they may simply nőt include a specific destination address. Of course, any kind of message protocol is suitable fór implementing the CIC which includes the possibility to transmit messages in unicast, multicast and/or broadeast transmission modes. These functions ofthe communication interface CIC are performed under control ofthe micro

ΕΡ 2 085 749 Β1 controller MCC. The communication interface CIC takes the data to be transmitted from the data bús B and converts the data intő a physical signal suitable fór transmission over the low voltage power lines. Moreover, the communication interface CIC alsó acts as a receiver interface fór receiving power line communication signals from the remote meters RM which are addressed to the concentrator C. To this end, the communication interface CIC compares the address of messages sent by remote meters on the LV network section with its own address. Ifthe communication interface CIC finds a message to be addressed to the concentrator C, it will récéivé the message from the LV network section and pass it on to the micro controller MCC and/or other components of the concentrator C fór further Processing.

[0020] While the concentrator according to the embodiment in Figure 2 has an internál GSM modem M, it is of course possible to employ an external modem instead. In this case, a separate modem interface may be provided in the concentrator fór connecting the external GSM modem, or the interface IFC may be used fór this purpose.

[0021] Other elements in Figure 2 which correspond to elements already described in connection with Figure 1, have been denoted with the same reference numerals such that in this respect reference can be made to the description of Figure 1.

[0022] When operating a utility distribution network with remote metering facilities as shown in Figure 1, the low voltage network, although advantageously used fór communication between the concentrator C and a remoter meter RM, is nőt perfectly suited fór communication purposes as somé of electric consumers L1, L2.....Lk cause disturbances of various kinds negatively influencing the communication operations and causing a need fór data to be transmitted repeatedly. Due to such negative influences the communication between the concentrator C and a remote meter RM should be limited to only such data actually required from the concentrator C orthe centralized managernent facilities ANM especially in view of the relatively high number of remote meters RM typically administered by a single concentrator C.

[0023] In fact, similar considerations apply with respect to the communication between the concentrator C and the centralized managernent facilities AMM when performed via power lines. Additionally, communication between the concentrator C and the centralized managernent facilities AMM is costly when performed via wireless communication systems, fór example mobile telephoné systems like GSM. Therefore, any reduction of the volume of communication between all levels ofthe remote metering system is generally desirable.

[0024] On the other hand, meaningful information about the status and the consumption at the remote meters should be available in the centralized managernent facilities AMM whenever required. Therefore, transmission of specific data must be carried out, while said data should be selected carefully to avoid transmission of superfluous or redundant data. [0025] According to a generál aspect ofthe invention, the concentrator C computes on the basis of status data, which the concentrator C requests and receives from a remote meter RM in a first communication process, the amount of data, fór example consumption related data, to be requested and received from a remote meter RM in a second communication process. In a preferred embodiment of this aspect ofthe invention, as described further below, samples of energy/power related data collected in a remote meter are transmitted during the second communication process to provide data equivalent to a load profile ofthe remote meter. In an eiectricity distribution network, the profile characterizes the consumption load to the network.

[0026] Figure 3 shows a diagram to illustrate by means of a preferred example the communication between the concentrator C and a remote meter RM.

[0027] In a first communication operation O1 the concentrator C sends a message to the remote meter RM requesting status data on the basis of which the concentrator C determines the kind and the amount of data to be requested in a subsequent operation. Upon receipt ofsaid message, the remote meter RM determines the status data in a Processing operation 02, preferably by reading out respective storage locations in a storage device as will be explained further below with respect to an embodiment of a remote meter according to the invention. The remote meter RM transmits to the concentrator C a message comprising the status data in a second communication operation 03.

[0028] Taking intő consideration the received status data, the concentrator C determines in a Processing operation 04 the amount L of data, fór example consumption data, to be requested from the remote meter RM.

[0029] In a preferred embodiment, the concentrator C determines the amount L of data by further referring to one or more predetermined values previously received from the centralized managementfacilities AMM and stored in a suitable storage location in the concentrator C. One of the predetermined values may be time related to define a consumption period, i.e. one week, one month, one year etc, fór which the consumption should be retrieved. Based on the predetermined values and on received status data, the amount L of data to be requested from the remote meter RM is determined by the concentrator C.

[0030] In a third communication operation 05, the concentrator C transmits a message to the remote meter RM providing the remote meter RM with the amount L of data, including especially consumption data, to be transmitted and requests the remote meter RM to transmit the amount L of consumption related data. The remote meter RM obtains the requested amount L of data, including especially consumption data, in a Processing operation 06. The remote meter RM determines the requested data, especially consumption data, preferably by reading out respective storage locations in a storage device as will be further explained with respect to an embodiment of a remote meter described below.

[0031] In a fourth communication operation 07, the remote meter RM transmits the requested data to the concentrator

ΕΡ 2 085 749 Β1

C. The concentrator C performs further processing of said received data, especially intermediate storing and error checking, and transmits data to the AMM based on the received data, in a processing operation 08. Alternatively, the concentrator C can be arranged to allow the AMM to access the data directly such that the data is retrieved by the AMM from a fiié stored in the data storage means DBC ofthe concentrator C, fór example by down loading said fiié to the AMM. [0032] According to the invention, the actual communication between the concentrator C and a specific one ofthe remote meters RM is reduced since the transmitted data is limited to such an amount of data as it is required with respect to said specific one of the remote meters administered by the concentrator C. The amount may differ from one remote meter to the other and is therefore determined by the concentrator C taking intő account the status data of each individual remote meter. However, under certain conditions, fór example when the same or similar information is required fór more than one or all remote meters RM, the amount L of data computed by the concentrator C can be identical fór said remote meters RM.

[0033] On the other hand, the concentrator C may request the remote meter RM to transmit any amount of data, fór example consumption data over one or more given periods of time, i.e. time intervals. As far electrícity distribution networks are concerned the concentrator C may request the remote meter RM to transmit data regarding active and reactive energy or positive/negative reactive energy separately.

[0034] The records maintained by the concentrator C with respect to the associated remote meters RM are preferably stored in the data storage means DBC of the concentrator C (see Fig. 2). Typically, the records are stored in one or more table which may be part of a database maintained by the concentrator C. According to an example of said table a record has the following structure.

<td> Remote Meter ID</td><td> Time Value</td><td> Indicator</td><td> Numeric Value</td><td> Measurement Values</td>

<td> RM-ID</td><td> TV</td><td> ID</td><td> NM</td><td> MV1, MV2</td>

<td></td><td></td><td></td><td></td><td> MV (L)</td>

[0035] The status data may comprise a time value TV which indicates date and time of a last measured consumption of energy/power provided that the consumption of energy/power is measured periodically in the remote meter and that the measurement results are stored in a storage location of a storage device of the remote meter. Further, the status data may comprise an indicator ID pointing at the storage location of the last measured consumption value. Still further, the status data may comprise a numeric value NM indicating the number of stored measured consumption values. Preferably, the status data comprise one or more ofthe before mentioned values, i.e. a time value TV, an indicator ID or a numeric value NM.

[0036] Preferably, the amount L of consumption data is determined further on the basis of a time interval INTERVAL fór which consumption data are required, fór example a biliing period (a week, a month etc.) or a maintenance cycle. [0037] According to a first option, the concentrator C considers the time value TV of said status data as a time value defining the end of a time period (time interval) and computes a start time value. The concentrator C transmits the start time value to the remote meter RM requesting consumption data measured and stored with respect to the period defined by said start date/time and said end date/time. The start time value defines and therefore corresponds to the amount L of consumption data MV1, MV2 ... MV(L) to be transmitted by the remote meter RM. Fór this option it is sufficient if the status data transmitted by the remote meter RM comprise the time value TV only.

[0038] According to a second option, reducing the processing ofdata atthe remote meter, the concentrator C computes a number of consumption value storage locations the content of which is to be transmitted by the remote meter RM. By transmitting the number L of storage locations the receiving remote meter RM can perform a reading out of the storage location containing the last measured consumption value and of L-1 precedent storage locations containing the previously measured consumption values, respectively. In a further refined alternative of this option, the concentrator C computes the storage locations or rangé of storage locations from which the remote meter RM should read out said consumption values, so that the status data preferably comprise an indicator pointing at the storage location of the last measured consumption value.

[0039] According to a third option, the concentrator C computes the number L of consumption value storage locations the content of which is to be transmitted by the remote meter RM bút additionally compares the number L with the numeric value of the received status data NM indicating the number of stored consumption values.

[0040] According to all options, the remote meter RM transmits a number of consumption values MV1, MV2 ... MV(L), fór example samples of energy consumption, which have been measured and stored in several periodically repeated measurements so that the consumption data transmitted by said remote meter RM may be regarded as a consumption profile since the transmitted data nőt only comprise an actual consumption value bút alsó previous consumption values.

ΕΡ 2 085 749 Β1

Still, the amount L of data transmitted from the remote meter RM to the concentrator C and consequently the amount of data transmitted from the concentrator C to the centralized management facilities AMM is reduced when compared with the entire meter RM consumption buffer, since the amount L is determined by the concentrator C according to the specific requirements/parameters and on the basis ofthe status data. The specific requirements/parameters are previously stored inside the concentrator C by the AMM.

[0041] Figure 4 shows an embodiment of a remote meter RM located inside or outside of customer premises in the network of Figure 1. In Figure 4, reference numerái 1 denotes a power line as a part ofthe low voltage network section. Power supplied through the power line 1 passes through an energy metering unit EM which counts the energy consumed by the electric loads L1, L2, ... shown in Figure 1. In Figure 4, MCM denotes a controller ofthe remote meter, forexample a micro controller. DBM denotes a data storage device, e.g. a random access memory, a hard disk drive or the like. PM denotes a program storage location fór storing a sequence of instructions to be executed by the micro controller MCM to operate the meter. The micro controller MCM, the data storage device DBM, the program memory PM and the energy metering unit EM are connected with each other through a data bús BM provided in a remote meter RM according to the invention.

[0042] In the embodiment shown in Fig. 4, CB denotes a circular buffer providing storage locations N fór storing data elements mv(x), mv (x+1) ... indicating the energy consumption measured by said energy metering unit EM. Under the control ofthe controller MCM, the measured consumption values mv(x), mv (x+1) ... are stored in respective storage locations Nx, Nx+1 etc. on a periodical basis, fór example in cycles of T minutes, wherein T can be considered a time paraméter stored in the remote meter RM. As shown in Figure 4, the storage location Nx, intő which a data element or data set corresponding tothe consumption measured during the last measurement cycle has been written bythe controller MCM, is identified by a identifier ID, which is stored in an identifier storage means IDSM, so that in a subsequent cycle the controller MCM Stores a new data element corresponding to the consumption measured during the subsequent cycle in a subsequent one Nx+1 ofsaid storage locations.

[0043] By using a circular buffer CB fór storing the consumption related data elements, the memory requirements of the remote meter are limited and impose reduced constraints on the design ofthe remote meter RM. The circular buffer CB can be embodied in various forms, fór example a random access memory, preferably ofthe non-volatile type like a NAND flash memory. The circular buffer CB needs nőt to be embodied in a separate component as it is possible fór those skilled in the art to implement the circular buffer CB in the data storage device DBM ofthe remote meter by means of software under the control of controller MCM, as indicated in Figure 4.

[0044] At the end of each of the above measurement cycles, the controller MCM updates the identifier ID to point at the next storage location so that the identifier ID indicates the storage location ofthe last stored data element, which corresponds to the consumption measured during said measurement cycle. The identifier ID is stored in said identifier storage location IDSM, preferably a memory location ofthe data storage device DBM, as shown in Figure 4. Further, a time value TV representing the date and time ofthe storing ofthe last stored data element is updated and stored in a time value storage means TVSM, preferably a memory location ofthe data storage device DBM, as alsó shown in Figure 4. According tothe invention, atthe end ofeach measurement cycle the a data element corresponding to the consumption measurement fór that cycle is stored in a storage location which is identified by said identifier ID stored in said identifier memory location IDSM and fór which date and time ofthe measurement is stored in said time value memory location TVSM.

[0045] In Figure 4, CÍM denotes a power line communication interface ofthe remote meter RM. The communication interface CÍM listens to data messages on the power line 1 and receives broadcast data messages or messages addressed to the remote meter. Such messages will be passed on bythe communication interface CÍM fór further Processing by the micro controller MCM and its associated peripherals. Data messages on the power line 1 nőt addressed to the remote meter will be ignored by the power line communication interface CÍM or at a later stage during the Processing bythe micro controller MCM. Messages generated bythe remote meter RM are converted bythe communication interface CÍM intő signals suitable fór transmission over the power line 1. To perform these tasks, the communication interface CÍM is connected to the common system bús BM ofthe remote meter RM and implements any suitable communication protocol in accordance with the communication protocol implemented in the concentrator C.

[0046] lf a message addressed to the remote meter RM is received from the concentrator C requesting the transmission ofthe identifier ID and the time value TV, i.e. of status data, the controller MCM in the remote meter RM reads out the respective data from said identifier memory location IDSM and said time value memory location TVSM. Then, the controller MCM supplies the identifier ID and the time value TV to the communication interface CÍM fór being transmitted to the requesting concentrator C.

[0047] According to a first option, if a message addressed to the remote meter RM is received from the concentrator C requesting the transmission of data elements stored in the circular buffer from a start time value to an end time value, the controller MCM determines the storage location that corresponds to the start time value, typically on the basis ofthe time value stored in the time value storage means TVSM and the cycle time period T. Then, the controller MCM reads out the data elements stored in respective storage locations of the circular buffer CB between the computed storage

ΕΡ 2 085 749 Β1 location and the storage location identified by identifier ID. Finally, the controller MCM supplies the data elements to the communication interface CÍM fór being transmitted to the requesting concentrator C.

[0048] According to a second option, if a message addressed to the remote meter RM is received from the concentrator C requesting the transmission ofa number L of data elements stored in the circular buffer CB, the controller MCM reads out the most recent data element and L-1 data elements stored in L-1 precedent storage locations ofthe circular buffer CB. Then, the controller MCM supplies the L data elements to the communication interface CÍM fór being transmitted to the requesting concentrator C.

[0049] According to a third option, if a message addressed to the remote meter RM is received from the concentrator C requesting the transmission of data elements stored in the circular buffer CB beginning with a storage location transmitted from the concentrator C, the controller MCM reads out the data elements from the storage location given in the concentrator message to the storage location ofthe last stored data element ofthe circular buffer CB. Then, the controller MCM supplies the data elements to the communication interface CÍM fór being transmitted to the requesting concentrator C.

[0050] According to a fourth option, if a message addressed to the remote meter RM is received from the concentrator C requesting the transmission of data elements stored in the circular buffer CB within a given rangé of storage locations, information regarding said rangé being transmitted from the concentrator C, the controller MCM ofthe remote meter RM reads out the data elements from the rangé of storage locations ofthe circular buffer CB as provided in the concentrator message. Then, the controller MCM supplies the data elements to the communication interface CÍM fór being transmitted to the requesting concentrator C.

[0051] Obviously, since the exact storage locations are determined by the concentrator C according to the third and fourth option above, such computations need nőt to be performed by the remote meter RM so that the requirements regarding the computation power of the controller MCM at the remote meter RM are less severe whereby the hardware costs ofa remote meter can be reduced.

[0052] Ifthe concentrator C provides information regarding the exact storage locations, the concentrator C determines this information preferably on the basis of a start time and an end time of the desired measurement period, e.g. one week, one month or one year, and the cycle time T of the repetitive measurements performed by the remote meter RM as well as the identifier ID, i.e. status data, received from the remote meter.

[0053] Figure 5 shows a flow chart according to an embodiment ofthe invention to illustrate operations performed by the concentrator C administrating several remote meters RM. The concentrator C starts the load profile procedure (operation S1) to obtain consumption data MV1, MV2 ... MV(L) from remote meters RM fór a given time interval, i.e. a consumption related data profile.

[0054] The concentrator C determines whether a selected remote meter RMn is enabled fór the load profile procedure (operation S2). Preferably, the concentrator C determines whether the remote meter RMn is enabled fór the load procedure by looking up a respective entry in a record maintained fór the respective remote meter RMn in the concentrator data storage device.

[0055] Ifthe remote meter RMn is nőt capable of taking part in the load profile procedure, the concentrator C continues with the determination whether the last ofthe remote meters RM associated with the concentrator C has been processed in the load procedure (operation S9). Ifthe last remote meter has been processed, the concentrator C stops the load profile procedure (operation S12). Ifthe last ofthe remote meters RM has nőt yet been processed, the concentrator C selects the next remote meter RMn+1 to be processed (operation S10) and returns to the beginning (operation S2) of the load profile procedure.

[0056] lf the concentrator C determines that a selected remote meter RMn is enabled fór the load profile procedure, the concentrator C reads status data from the remote meter RMn (operation S3) by transmitting a status data request to the remote meter RMn and receiving status data from the remote meter RMn (see alsó operations 01 to 03 in Fig. 3). The status data may comprise one or more of a time value TV, an identifier ID and a numeric value NV as described above as well as additional status data.

[0057] Based on the received status data, the concentrator C determines (operation S4) whether there are any data elements stored in the remote meter RMn which precede the activation date/time ofthe load profile procedure.

[0058] lf there are no data elements available, the concentrator C Stores a respective mark M1 in the record maintained in the concentrator data storage device fór the remote meter RMn and (operation S11a) and continues with the determination whether the last one ofthe remote meters RM has been processed in the load procedure (operation S9). Ifthe last remote meter RM has been processed, the concentrator C stops the load profile procedure (operation S12), bút if the last remote meter RM has nőt yet been processed, the concentrator C selects the next remote meter RMn+1 to be processed (operation S10) and returns to the beginning ofthe load profile procedure (operation S2).

[0059] lf the concentrator C determines that consumption related data elements stored in the remote meter RMn preceding the activation date/time ofthe load profile procedure are available (operation S4), the concentrator C computes the length ofthe load profile to be requested, i.e. the number L of data elements to be transmitted from the remote meter RMn, based on the time interval (operation S5). The concentrator C determines whether there are adequate data elements

EP 2 085 749 Β1 forthe predetermined time interval and whetherthe totál numberof storage locations in the storage buffer ofthe remote meter RMn is sufficient to provide data elements for the predetermined time interval (operation S6).

[0060] lf either one or both aspects are nőt confirmed, the concentrator C Stores a respective mark M2 in the records maintained in the concentrator data storage device for the remote meter RMn (operation S11 b) and continues with the détermination whetherthe last remote meter RM has been processed in the load profile procedure (operation S9) and if the last remote has been processed, the concentrator C stops the load procedure (operation S12), bút if the last remote meter has nőt yet been processed, the concentrator C selects the next remote meter RMn+1 to be processed (operation S10) and returns to the beginning (operation S2).

[0061] lf both aspects are confirmed (operation S6), the concentrator C determines the correct start storage location in the storage buffer CB ofthe remote meter RMn, based on number L and identifier ID, and obtains the data elements from the start storage location to the storage location identified by identifier ID (operation S7) by transmitting the start storage location to the remote meter RMn and requesting the transmission ofthe respective data elements. After having received the requested consumptíon related data elements MV1, MV2 ... MV(L) the concentrator C saves the data in the concentrator storage means DBC.