Glossary Metering Introduction (LC)

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Glossary - metering and SMART metering

As experts in smart grid market, EBV can help you to recognise the most common terms and abbreviations in the areas of Energy storage, Metering and SMART metering, Solar Photovoltaic (PV) system, Wind power:



Availability Based Tariff. It is a performance-based tariff for the supply of electricity by state-owned generators. It is also a new system of scheduling and despatch, which requires both generators and consumers to commit to pre-defined schedules which are enforced with a system of rewards and penalties.




Alternating Current. With AC the movement (or flow) of electric charge periodically reverses its direction. It is the normal way that electricity is delivered within the electricity grid. In our homes we refer to 220 volts AC.


Active Energy


Active Energy


Advanced Metering


Technology which enables an automated bi-directional communication between the energy meter and the utility. The communication is not limited to meter data alone but also includes information about consumption, tariffs, alerts and complementary services.




Active Information Management




stands for Advanced Metering




Automated or advanced metering infrastructure. AMI is an utility infrastructure with two-way communications for metering and associated systems allowing delivery of a wide variety of services and applications for both the generators, transmission and distribution system operators and the customer.




Advanced Metering Management, systems that measure, collect and analyse energy usage.




Automated Meter Reading (AMR) collects utility meter data via radio or other networking technology. AMR is a form of Advanced Metering that uses communication devices to communicate data from the meter to the utility or to a meter data management provider. AMR may be used to transmit simple energy usage data from the meter or to transmit more complex measures of energy recorded in the meter. Moreover, it can feature advanced functionality such as outage detection or remote programming of meters by an authorised party.




American National Standards Institute.




stands for Access Point Name


Application Service Provider


A third party business that manages and distributes software-based services and solutions to customers across a wide-area network from a central data centre.


AT command


Attention command. AT commands are used to parameterise the modem correctly before making connection.




The verification of the identity of a person, object or process. In RFID, the term is used in two ways. For contactless smart cards and other payments systems, the reader must make sure the transponder is a valid device within the system. That is, someone is not using an unauthorized device to commit fraud. There is also some talk of using EPC technology to authenticate products as a way of reducing counterfeiting.




LAN components with Auto-Crossover recognise automatically whether the connected Ethernet cable is a normal patch cable or a crossover cable and adjust to this cable accordingly. This kind of connection is also called Auto-MDI/X.




Mode of operation of communication module in which IEC 62056-21 as well as dlms is automatically recognised. It is even possible to change the mode during a session.




Customer generating electricity for their own use. This is sometimes called autogeneration. Normally autoproduction includes all consumer generating equipment, regardless of size. This would include microgeneration.


Baud rate


Transmission rate


Billing cycle


Period of days in which a utility or supplier totals customer energy use and produces the customer bill.


Billing data


TOU data




stands for Current Average Demand


Calibration adjustment


A customer magnitude adjustment and/or a CT/VT correction has been made.




Challenge-Handshake Authentication Protocol. CHAP is used by Point to Point Protocol (> PPP) servers to authenticate a user to an Internet access provider.




Combined Heat and Power: CHP is the simultaneous production of utilizable heat and electricity from an integrated thermo-dynamic process.




Common Information Model, a standard developed by the electric power industry which aims to allow application software to exchange information about the configuration and status of an electrical network.




Used therm in metering when specifying meter’s accuracy. IEC defines classes as 0.2%, 0.5%, 1.0% and 2.0% max. measurement deviation; the new MID (Metering instrument directive) specifies classes A, B, C. Class C represents the highest accuracy. The term is sometimes also used for environmental, mechanical and electromagnetic conditions.




Caller Line Identification. The telephone number of the caller can be recognised in this way before the receiver is picked up or the modem accepts the call. The telephone or modem must support CLI.


Client / Server


In a Client-Server-environment, a server is an application or a computer which receives and responds to requests from a client application or computer. If data communication is referred to, it is also possible to regard the computer as a client that establishes a connection to a server (or host).




Companion Specification for Energy Metering, specifications required in addition to DLMS, which describe the interface to the meter.




Capture Period




iMEGA ComPortClient




Cyclic Redundancy Check. A CRC is a function which produces a checksum to detect errors after data transmission or storage. A CRC is computed and appended before transmission or storage, and verified afterwards by the recipient to confirm that no changes occurred on transit.




Current loop serial interface. A serial transmission method that uses a closed loop. Current loops provide a better signal-to-noise ratio (SNR) than voltage-based systems, i.e. they offer very good noise immunity.




Comma separated values. The CSV file format is a very simple data file format for the storage or exchange of tabular data that is supported by almost all spreadsheet software such as Excel, Calc,etc.




Current transformer. An alternating current device which reduces actual current flow through meter with a fixed ratio.


CT Ratio


The relationship of a current transformers' primary to secondary rating. This ratio defines the multiplication factor that has to be applied to the meter output in order to obtain the actual metered amount.




Clear To Send. A signal employed in a procedure which intends to ensure that nodes within a network refrain from sending data for a given time if a particular destination node replies with a Clear To Send frame (CTS) upon reception of a Request to Send frame (RTS).




Communication unit. A device which can be connected to a meter in order to enable automatic meter reading.


Cumulative value


Value cumulated since the beginning of the measurement.




Data Acquisition


Daily Consumption


The amount of energy a consumer uses in a 24 hour day. It is captured at a specific time each day, usually at midnight, and refers to active energy.


Data Concentrator


Data concentrator applications are an important node in the AMI which is networked with several utility meters and central utility servers and enables communication of the data between the meters and the utility servers. Data concentrators, at several points in the infrastructure, securely aggregate data from a manageable number of meters and send to the utility servers.




Data Communication Equipment. Designation of a unit which only passes on data, e.g. a modem.


Delta value


Value calculated over the billing or the capture period. After the end of the period the value is reset.


Demand billing


The demand upon which billing to a customer is based, as specified in the rate schedule or contract.


Demand interval


The interval of time over which a demand measurement is taken. Common intervals: 10, 15, 30, or 60 minutes.




The elimination of regulation from a previously regulated industry or sector of an industry.




Dynamic Host Configuration Protocol. This is a protocol used by networked devices (clients) to obtain the parameters necessary for operation in an Internet Protocol network. This protocol reduces system administration workload, allowing devices to be added to the network with little or no manual configuration.




Deutsche Industrienorm (German industrial standard)




A relay that can turn off power to a whole house or other metered electric service. In specific cases, it can be operated remotely.


Distribution utility


The regulated electric utility that constructs and maintains the distribution wires which connect the transmission grid to the final customer. This utility can also perform other services such as aggregating customers, purchasing power supply and transmission services for customers, billing customers and reimbursing suppliers, and offering other regulated or non-regulated energy services to retail customers.




Distribution Line Carrier. DLC utilizes the existing electrical distribution network in the Medium voltage (MV) – i.e., 11 kV, Low Voltage (LV) as well building voltages for data transmission. It is very similar to PLC.




Device Language Message Specification. This specification provides an environment for structured modelling and meter data exchange. Applications such as remote meter reading, remote control and value added services for metering any kind of energy (electricity, water, gas, and heat) are supported.


dlms device identification


Worldwide unique number in each dlms device to identify the device (in blue book it is named 'COSEM logical device name')


dlms UA


dlms User Association. Group of various companies interested in promoting, developing and enhancing the dlms standard.




The addressing in IP-network is performed with the use of IP-addresses. Because it is more user-friendly, the addressing with a domain address is usually preferred. Name Server (DNS) to obtain the corresponding IP-address.




Data Not Valid (flag)




Demand side management. This is a means to control energy consumption and to optimise network usage via tariff control and/or load control. Both can be controlled via ripple control signals (PLC) and radio signals. DSM encourages consumers to modify patterns of electricity usage, including the timing and level of electricity demand.




Distribution System Operator = Verteilnetzbetreiber




Data Set Ready, Signal of e.g. the RS-232-C Interface




Device Software, Firmware.




Data Terminal Equipment. This is an end instrument - e.g. PC, terminal or laptop - that converts user information into signals for transmission, or reconverts the received signals into user information. A DTE device communicates with the Data Communication Equipment (DCE).




Data Terminal Ready. An abbreviation used in RS232 serial communications. The DTR signal is sent via a dedicated wire from the transmitting computer to the transmission device to indicate that the computer is ready to receive data.




The EAN is the International Article Number (formerly European Article Number) and is a product designation for commercial articles. Generally, the EAN is printed onto the product packaging in the form of a machine-readable bar code and can be decoded by bar code scanners.




End of Interval. This bit indicates that the capture period was terminated and the profile entry was made due to an unsynchronised tariff switching.




Energy Data Identification System (energy industry standard)




Energy Data Management covers the management and calculation of energy data in the liberalised electricity and gas market




Electrically Erasable Programmable Read Only Memory. An EEPROM is a non-volatile storage chip used to store data safely even in case of a power cut.




Energy Flow Active. The energy flow signal EFA is derived from the measured quantities |+A|+|-A| and is solely used to drive the energy flow contacts.




Energy Flow Reactive. The energy flow signal EFR is derived from the measured quantities |+R|+|-R| and is solely used to drive the energy flow contacts.




Electronic Industries Alliance. The EIA publishes standards, e.g. for interfaces such as RS-232 (now EIA-232). The former designation RS stands for Radio Sector. Nowadays, it is interpreted as Recommended Standard because it encompasses standards that go beyond the actual radio sector.




Electromagnetic Compatibility is concerned with the unintentional generation, propagation and reception of electromagnetical energy and with the unwanted effects that such an energy may induce. In particular, the aim of EMC is the correct operation, in the same environment, of different equipments which involve electromagnetic phenomena in their operation.


Energy Data Acquisition


Acquisition/read-out of energy meter data via handheld-terminals, drive-by or communication technology (e.g. radio, mesh, plc, PSTN, GSM/GPRS).


Energy Data Management


Processing of energy data for billing, forecasting and other purposes, related to the operational and/or commercial processes of energy utilities.


Energy Management


Technologies or strategies that reduce, limit or shift peak loads to off-peak time periods.




Energy Register




Electrostatic discharge




Energy Service Utility




Embedded Software




Energy Total




Ethernet is a wired local data network (LAN) technology. It enables data exchange with data frames between all devices (e.g. computer, printer) connected to a local network (LAN). Usually, a LAN spans entire buildings. However, today applications which connect devices over wide distances via glass fibre or radio are also possible. Ethernet entails definitions of cables and connector types, describes the signalisation for the bit transmission layer and defines packet formats and protocols. Generally, Ethernet is standardised in the IEEE-standard 802.3. From the 1990s it became the most widely used LAN technology.


Ferraris meter


The Ferraris meter, named after Galileo Ferraris, is an electromagnetic electricity meter used to display electric energy and to record transmitted energy in single and three phase alternating current networks.




Static software that resides on a hardware device such as a meter. This software defines the meter’s functionality.


Frequency Load Control


This is a circuit fitted to electrical appliances that senses grid conditions by monitoring the frequency of the system and provides automatic demand response when needed. It relies on the fact that a disturbance of the 50-Hz frequency is a universal indicator of serious imbalance between supply and demand that, if not tackled leads to a blackout. The controller computer chip can be installed in household appliances and turn them off for a few minutes or even a few seconds to allow the grid to stabilize.




Frequency Shift Keying, a classical narrow band modulation method: the digital form of frequency modulation. A specific frequency corresponds to a digital level.




Designation for an interface in which data can be transmitted mutually independently in both directions, e.g. RS232.




The PLC G3 protocol main features: •A robust high-performance PHY layer based on OFDM modulation (AKA OFDM Modulation type 2) •A IEEE 802.15.4 MAC layer, perfectly suited to handle noisy and heavily disturbed environments •IPv6, the new generation of IP (Internet Protocol), which widely opens the range of potential applications and services •6LoWPAN adaptation sub-layer defined by the Internet Engineer Task Force (IETF)


Generation Company


A regulated or non-regulated entity that operates and maintains existing generating plants. This company may own the generation plants or interact with the short term market on behalf of plant owners.




A machine that produces electricity.




General Packet Radio Service. GPRS is a mobile data service available to users of GSM mobile phones. It is often described as "2.5G", that is, a technology between the second (2G) and third (3G) generations of mobile telephony. It provides transmission rates of up to 115.2 kbps by using unused channels in the GSM network.


Greenhouse Effect


The increasing average global surface temperature caused by gases in the atmosphere (including carbon dioxide, methane, nitrous oxide, ozone, and chlorofluorocarbon). The greenhouse effect allows solar radiation to penetrate but absorbs the infrared radiation returning to space.


Grid company


A company that manages power lines and generators to ensure generators are dispatched as needed to meet the requirements of the customers connected to the grid at various points.


Grid meters


High precision electricity meters for the highest energy quantities with several communication interfaces for e.g. GPRS/GSM or TCP/IP. These meters provide flexible communication with several central stations, making all relevant data accessible to all partners.




Global System for Mobile Communication. This is a worldwide standard for digital mobile networks. Apart from voice services (telephone), GSM also supports several data services such as Fax, SMS, CSD and GPRS. Depending on legal regulations in the various countries, the frequency bands 900 MHz, 1800 MHz or 850 MHz and 1900 MHz are used. GSM




Designation for an interface in which data can only be transmitted in one direction at a time. The data direction can, however, be subsequently changed, e.g. RS485.




Home Area Network. This is a network in the home used for communication between digital devices typically deployed in the home, usually a small number of personal computers and accessories, such as printers and mobile computing devices. With the advent of the Smart Grid, and with DR, AMR it can help consumers minimize their energy costs.




High-Level Data Link Control (HDLC) is a bit-oriented synchronous data link layer protocol specified by the International Organisation for Standardisation (ISO). The current standard for HDLC in ISO 13239: Information Processing Systems – Data Communication High-Level Data Link Control Procedure – Frame Structure




The Head End System is part of Advanced Metering Infrastructure (AMI). It typically manages the data communication between AMI meters and meter data management system (MDMS)




Handheld terminal/unit, used for automated meter readings




High Level Security. The client and the server are both mutually authenticated. The server transmits a “challenge” (typically a random number) to the client; the client processes the “challenge” in a secret way (typically by encrypting it with a secret key) and transmits the processed challenge back to the server. The server then checks if the “challenge” was processed correctly. The authentification of the server is done in reverse order.


Hourly Metering


A type of interval metering where the measurement or recording of customer usage is collected on an hourly basis.




HyperText Transfer Protocol


I&C meters


Industrial and commercial meters: Multi-tariff meters, often featuring active and reactive energy registers, for industrial or commercial usage.




Inverse Address Resolution Protocol. IARP is used within an Ethernet-IP-network to determine the IP-address of someone whose MAC-address is known. Subscriber A knows the MAC-address of subscriber B. In order to establish a TCP/IP-connection to subscriber B, subscriber A needs the IP-address of subscriber B. To find out the IP-address of subscriber B, subscriber A sends an IARP-request to the MAC-address of subscriber B. Subscriber B responds with its IP-address.




Integrated Circuit Card, also known as SIM card.




Interoperable Device Interface Specification, an association established to maintain and promote publicly available technical interoperability specifications based on open standards.




International Electrotechnical Commission, an international standards organization dealing with electrical, electronic and related technologies.


IEC readout


Billing data readout according to IEC 62056-21.




IHU - In-Home display Unit, a unit which informs end-users about their energy consumption.




Pulse emitting module (SyM²)




The International Mobile Equipment Identity is a number unique to every GSM and UMTS mobile phone as well as some satellite phones.




An International Mobile Subscriber Identity is a unique number associated with all GSM and UMTS network mobile phone users. It is stored in the SIM.


In Home Display


An in-home display or energy monitor provides prompt, convenient feedback on electrical or other energy use. Devices may also display cost of energy used, and estimates of greenhouse gas emissions. Various studies have shown a reduction in home energy use of 4-15% resulting from the greater awareness created through use of these in-home energy displays.


Industrial meter


An electricity meter used in industrial and commercial settings. These meters have an extended functionality and communication possibilities and can be integrated into systems for high data availability.


Interval meter


Interval meters measure customer energy consumption by fixed time periods or intervals (typically every 15 minutes, but this can vary depending on utility requirements). Today, interval metering is provided to commercial and industrial customers and some residential customers. In the future, in an unbundled environment, the residential market may require more frequent interval measurements. These meters produce many hundreds of sets of data and are usually read remotely due to the large amounts of data collected.




An intranet is a private IP-network whose size may vary. An IP-network of a company or several interconnected private computers might form an intranet. In contrast, the internet is a public network. Intranet and internet should only be connected via security devices such as a firewall.


IOU (investor owned utility)


A company, owned by stockholders for profit, that provides utility services. A designation used to differentiate a utility owned and operated for the benefit of shareholders from municipally owned and operated utilities and rural electric cooperatives.




Internet Protocol. This is the universal computer language that made the internet possible by breaking all content into packets to transmit it, carrying those packets to their intended destination and re-assembling them into text, documents, graphics, computer code and video at the other end. The real genius was realizing all that content could be mixed together along the networks and then sorted back out as needed for delivery and reassembly.




Each host or router in the internet / intranet has a unique IP-address (IP = Internet Protocol). The IP-address consists of 32 bits (= 4 Byte) and is written as 4 numbers (ranging from 0 to 255) separated by a dot. An IP-address has two parts: the network address and the host address. All hosts of a network have the same network address but different host addresses.




See Datagram.




Protocol according to E DIN 43863-4 for the transmission of telemetry data via IP-networks. It is optimised in such a way that only few control data are added to the user data. It enables the use of dynamically assigned IP-addresses.




Internet Protocol Telemetry




IP (above) version 4 is the protocol that was used to create the internet we've all come to know since the mid 90s and includes an addressing protocol that never imagined billions of devices would one day be connected to the internet and thus need unique addresses. IPv6 is being deployed now bit-by-bit and has a new addressing standard that allows for a much larger universe of addressable devices.




International Standardization Organisation, an international-standard-setting body.




Live wire. L1, L2, L3 are the phases 1, 2 and 3 of a three-phase network.




Last Average Demand




Local Communication mode.




Logical Link Control. Conforms to ISO/IEC 8809-2.




Low Level Security. The client authenticates itself with a “secret” known by the client and the server. The “secret” is typically a password. LLS is normally used on “secure” channels where no eavesdropper is expected.




Load management


Load (electric)


The amount of electric power delivered or required at any specific point or points on a system, as demanded by an electricity-consuming system, or systems.


Load control


Activities performed by the utility that can interrupt load at the time of peak by interrupting power supply on consumer premises. Load control is usually applied to residential consumers.


Load data


Electric power consumption (kWh), measured in specific intervals.


Load management


Utility activities designed to influence the timing and amount of electricity that customers may use.


Load profile


Hourly or sub-hourly pattern of energy use. It is stored as a list of time stamped power data and is sometimes shown as a graph depicting the power consumption over a specific period.


Load profiling


In a deregulated energy market, the public utility commission may require utilities to perform load profile reads on a certain number of customers in each customer class. This load profiling data is needed to determine rates and usage for other customers in the same customer class.


Load shedding


The process of deliberately removing (either manually or automatically) preselected customer demand from a power system in response to an abnormal condition to maintain the integrity of the system and minimise overall customer outages.


Load shifting


Demand-side management programs designed to encourage consumers to move their use of electricity from on-peak times to off-peak times.




Local Operating Network, a technology variant to implement PLC.




Load profile




Low Voltage, an electrical engineering term that broadly identifies safety considerations of an electricity supply system based on the voltage used. It is often defined as 50-1000 V AC and is the voltage used in the final distribution to users.




The M-Bus, also called Meter Bus, was produced from the necessity to interlink a large number of consumption measuring units, such as electricity, water, gas or heat meters over a long section at low cost to permit communication with a central station, i.e. to read meter data or to perform service functions (setting starting values, time/date, etc.). The central station computer (PC) together with a repeater connected to its RS232 interface forms the M-Bus master. Up to 250 meters can be connected to the repeater as M-Bus slaves. Check our EBV chip M-Bus slave transceiver - Hermes.




Medium Access Control. MAC specifies the link layer address of the device for the communication. COSEM separates the address in a lower MAC address (addressing the physical device) and an upper MAC address (addressing the logical device within the physical device).


Maximum demand


The highest demand measured over a designated period of time, e.g. one year.




Master (remote) Communication mode




Meter Data Management, a single repository for hosting data from multiple and existing metering systems and then provide, make available this data to multiple in-house or hosted applications.




Meter Data Management System




Maximum Demand Register




Multi Energy


Meter constant


The meter constant is a factor applied to the output of a meter to obtain the desired units of measure. In Ferraris-meters, it represents the number of revolutions for 1 kWh. In electronic meters, it defines how many times the Test-LED flashes per 1 kWh.


Metering Gateway


Internet Metering Gateway. iMEGA is the interface between the meter and the AMR system. It manages a list of the dynamic IP addresses of the Internet-connected meters. iMEGA is therefore a kind of telephone book for automatic meter reading. iMEGA is also an important security component in the overall system, since it does permit access to the meter without a valid code. The iMEGA software does not store any meter data.




The meter and the attached PLC-module Meter node European Measuring Instruments Directive 2004/22/EU.








Metering Point




Minimum Power Factor




Meter Test Equipment




Medium Voltage, an electrical engineering term that broadly identifies safety considerations of an electricity supply system based on the voltage used. It is often defined as 1-72 kV AC and is the voltage used in the local power lines.








Network Control


Net capacity resource


The total owned capacity, plus capacity available from independent power producers, plus the net of total capacity purchases and sales, less the sum of inoperable capacity, and less planned outages.




Network Time Protocol. NTP is an IP-Protocol for the acquisition of accurate time from a time server via an IP-network. Time servers are usually coupled to a time standard and provide the coordinated universal time (UTC) with a very high accuracy. The Network Time Protocol uses special algorithms to determine the network delay time by sending a sequence of several requests.




OBject Identification System, defines identification codes for all data in DLMS/COSEM compliant metering equipment




Orthogonal frequency-division multiplexing (OFDM) is a method of encoding digital data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital communication, whether wireless or over copper wires, used in applications such as digital television and audio broadcasting, DSL broadband internet access, wireless networks, and 4G mobile communications.




On Load Active: active energy line losses




On Load Reactive: reactive energy line losses




Original meter values




Open System Interconnection




Active power


P running


Current Average Demand


P2M and P2MP


Point to multi-point, based on a data concentrator. Today, we consider PLC as P2M technology.




Uses point to point communication. Today, this is usually GPRS and Ethernet.




Password Authentication Protocol


Peaking Capacity


Capacity of generators normally reserved for operation during the hours of maximum loads.




Power Line Automation Network, a technology variant to implement PLC.




Power Line Communication, a system for carrying data on a conductor also used for electric power transmission.




Functional box and communication interface connecting the meter to a DC over power line


Point to Point


Type of connection in which exactly two units are interconnected.


Port number


The field “Port number” is a field in UDP- and TCP-headers with 2 Bytes. The assignment of port numbers enables the identification of various data streams processed simultaneously by UDP/TCP. The complete data exchange between UDP/TCP and the applications is performed via these port numbers. The assignment of port numbers to applications is dynamic and optional. For specific, often used applications, fix port numbers are assigned.


Power Factor


The power factor of an AC electric power system is defined as the ratio of the real power to the apparent power.


Power Line Carrier


Power Line Communication, also called Mains Communication or Power Line Telecoms (PLT), is a term describing several different systems which use power distribution wires for a simultaneous distribution of data. The carrier can communicate voice and data by superimposing an analogue signal over the standard 50 or 60 Hz alternating current (AC).




Power-over-Ethernet is a technology to supply LAN components with power via wires of the Ethernet cable which are not needed for data transmission.




Point-to-Point Protocol. PPP is used to establish a direct connection between two nodes. It can connect computers using serial cable, phone line, mobile phone, radio links, or fiber optic links.




Point-to-Point Protocol over Ethernet. Based on the standards PPP and Ethernet. PPPoE is a specification with which users can be connected to the internet via Ethernet by using a common broadband medium such as DSL, Wireless LAN or cable-modem.




Power Quality Information


Prepayment meters


Prepayment meters are electric meters that allow the customer to pay a specified amount of money in advance of service to guarantee some level of minimum service while allowing low-income customers to keep within their budget.




A narrowband PLC communications technique which uses Orthogonal Frequency-Division Multiplexing as the technology at physical layer to provide data rates of up to 128 kbit/s.


Protocol, transmission protocol


Devices which communicate with each other have to use the same rules. They have to speak the “same language”. These rules and standards are called protocols or transmission protocols. Common protocols are IP, TCP, PPP, HTTP, SMTP. TCP/IP is the generic term for all IP based protocols.




Public Switched Telephone Network. This network can be used for data transmission. A modem (modulator/demodulator) must be inserted between computer and telephone network and also between the telephone network and the remote meter.


Publicly Owned Utilities (POU)


Municipal utilities (utilities owned by branches of local government) and/or co-ops (utilities owned cooperatively by customers).




In metering, an electric or optical signal that communicates a defined amount of energy consumption.








Reactive power




Reactive energy


Real Time Metering


Metering that records consumer use in the same time frame as pricing changes in the market, typically hourly or more frequently.


Real Time Pricing


The pricing of electricity based on the cost of the electricity available for use at the time the electricity is demanded by the customer. As distinguished from TOU pricing, RTP is usually applied to that power demand above a defined base usage for a given customer, and not to all power consumed by that customer.


Remote parameterisation


Possibility for parameterising certain meter parameters (all parameters contained in the service tree) from a central station.


Reverse energy


Energy that flows from the consumer back to the utility supplier, e.g. generated by solar panels on the consumer’s premises.


Ripple control receivers


Ripple control receivers (RCR) perform load management, tariff switching, lighting control, and all other switching tasks. Current switching commands can be generated and sent by a PC or the operator's station. Radio based RCR abbreviation is RRCR.




Remote Metering




Root mean square (abbreviated RMS or rms) is a statistical measure of the magnitude of a varying quantity and is normally used to calculate the power dissipated by an electrical conductor or load.


Rogowsky Coil


Named after the German physicist Walter Rogowski, the Rogowski Coil is an electrical device used for measuring alternating current (AC) such as high speed transient; pulsed currents or power frequency sinusoidal currents


Rolling demand


A method of measuring power that uses an interval with subintervals, in which the oldest subinterval is replaced by the newest subinterval number and the demand calculated. With this method, the demand is recalculated for the interval at the end of each new subinterval.




Registration period


RS 485


EIA-485 (formerly RS-485 or RS485) is an OSI Model physical layer electrical specification of a two-wire, half-duplex, multipoint serial connection. The standard specifies a differential form of signalling.




EIA-232 (formerly RS232) is a standard for serial binary data interconnection. In RS232, data is sent as a time-series of bits. Both synchronous and asynchronous transmissions are supported by the standard. Since transmit data and receive data are separate circuits, the interface can operate in a full duplex manner, supporting concurrent data flow in both directions.




Real Time Clock. Time/date is invalid




Real Time Pricing


S (VA)


Apparent power




Spread frequency shift keying. A modulation scheme which is a combination of narrow band FSK and spread-spectrum technology. The signal is transmitted on a bandwidth considerably larger than the frequency content of the original information, this increases the signal-to-noise ratio.




Service Access Point. The SAP is a device address defined in the link layer (see HDLC). Only a correctly addressed device reacts to the communication data received.




Supervisory Control And Data Acquisition. A large-scale, distributed measurement (and control) system. SCADA systems are e.g. used to monitor or to control electric power generation, transmission and distribution.




The Server-ID is the unique address of each SyM²-module. The Server-ID corresponds to the MAC-adress of a SyM²-module on the local bus. The Server-ID is determined in various ways for components without local bus connection (e.g. MDE or central station). It is, however, always unique.


Service Provider


Provider, company, institution, which offers users access to the internet or to an online service.


SIM card


Subscriber Identity Module. A chip card that is inserted in a mobile device and is used for the identification of the user in the network.




SML (Smart Message Language) is a communication protocol for applications in the area of data acquisition and parametrisation of devices.




Signal-to-Noise Ratio


Solid state meter


Digital/electronic metering device.


Solid state recorder


Device that saves data pulses in solid state memory for later analysis.




Serial Process Interface.


Start-Stop bit


Characters used with asynchronous interfaces (e.g. RS232) to find the beginning and end of the transmission frame. One start and one stop bit and 8 data bits are normally used per transmission frame.


Starting bit rate


It is specified by IEC to permit change to a higher bit rate (the maximum bit rate or communication speed) after an opening. 300 bps is normally selected for starting and 9600 bps for the maximum rate via the optical interface. As soon as communication takes place e.g. via a modem connection, however, the bit rate can no longer be changed. In this case therefore the starting bit rate is selected to be the same as the communication speed.




Serial Transmission of Original Meter Values. Acquisition of meter values with subset from IEC 870-5-102 and transmission via IEC 870 or SCTM to the central station.




A facility for switching electrical elements, transforming voltage, regulating power, or metering.




Activities conducted on the utility's side of the customer meter.




Transmission Control Protocol/Internet Protocol, the suite of communication protocols used to connect hosts on the internet.




The instantaneous transmission of metering data.




Total Harmonic Distortion of a signal is a measurement of the harmonic distortion present and is defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental.


Time window


In the communication module, a time interval can be parameterised during which the communication module can receive a call. This interval can also be repeated periodically (daily, weekly, monthly).




Total Losses of Active energy




Total Losses of Reactive energy




Time-of-Use tables facilitate load control and planning on the part of utilities. This involves dividing the day, month and year into tariff slots and with higher rates at peak load periods and low tariff rates at off-peak load periods. The TOU table can also be used for load control, signal generation, etc.


Transmission rate


The transmission rate, sometimes also called bit rate, represents the digital data quantity transmitted within a specific time. Unit: bit/s or bps. The term “baud rate” is often used for transmission rate, although it signifies the symbol changes per time unit at the interface (unit: baud = symbols/second). Depending on coding, a symbol can consist of several bits of a data stream. The transmission rate can, therefore, be several times higher than the baud rate.




The Union for the Co-ordination of Transmission of Electricity (UCTE) operates the European synchronous grid and is an association of electricity distribution network operators in Continental Europe. Its interconnected network is a single phase-locked 50 Hz mains frequency electricity grid that supplies over 400 million customers in 22 countries, including most European Union members.








User Interface UMTS Universal Mobile Telecommunications System




Uninterruptible power supply. This is a device which maintains a continuous supply of electric power to connected equipment by supplying power from a separate source, e.g. batteries, when utility power is not available.


V.250 command set


New standard for the modem command format.




Communication standard for PSTN modems, 4800 to 9600 bps full-duplex. Return to a slower mode is possible depending on the opposite station, e.g. to V.22bis.




Communication standard for PSTN modems, 4800 to 14'400 bps full-duplex. Return to a slower mode is possible depending on the opposite station, e.g. to V.22bis.


V.34, V.Fast


Communication standard for PSTN modems, 2400 to 28'800 bps full-duplex. Return to a slower mode is possible depending on the opposite station, e.g. to V.22bis.




Communication standard for PSTN modems, 2400 to 33’600 bps full-duplex. Return to a slower mode is possible depending on the opposite station, e.g. to V.22bis.




Protocol for modem error correction.




Protocol for data compression for modems by a maximum factor 4 (exact value depends on the data transmitted). Based on V.42.




Virtual Application Association. Defines the relationship (on application level) between a server (meter) and the client (central unit, hand held unit). The VAA specifies how the client “sees” the meter, i.e. it defines which of the meter objects are actually available for the specific client. In connection with the ZxD, ZxG and ZxQ meters, a VAA corresponds to a security level which is defined by parameters.




Virtual Private Network, a network that uses a public telecommunication infrastructure, such as the Internet, to provide remote offices or individual users with secure access to their organization's network




Wide Area Network. This is a computer network connecting all the buildings in a building complex to each other or all the homes and businesses in a neighborhood, town or city to the internet.


Watt (W)


A Watt is the standard unit of electrical power. 1,000 Watts is called a kilowatt (kW). A traditional incandescent light bulb might be rated at 40 Watts.


Watt hour (Wh)


1 watt hour is the amount of electrical energy consumed by a 1-watt load over a period of one hour. For example, a 100 watt light bulb (a 100-watt load) uses 100 watt-hours of energy every hour. Rather confusingly, watt-hours are sometimes used to describe "power." This is incorrect. Watt hours are a measure of energy transferred, i.e., the product of power (kW) x time (hours).




Wireless fidelity. This is an international standard for sending and receiving data -- such as in a home or small office network.




eXtended Device Language Message Specification, the application layer service element providing access to the COSEM objects




The Extensible Markup Language (XML) is a general-purpose markup language for creating special-purpose markup languages, capable of describing many different kinds of data. Its primary purpose is to facilitate the sharing of data across different systems, particularly systems connected via the Internet.




ZigBee is a low-cost, low-power, wireless mesh networking proprietary standard. The low cost allows the technology to be widely deployed in wireless control and monitoring applications, the low power-usage allows longer life with smaller batteries, and the mesh networking provides high reliability and larger range.