EUROPEAN UTILITY WEEK

COMMERCIAL FEATURE

20 YEARS OF
application layer. The resulting messages can
be transported over virtually any media.

DLMS/COSEM –
Object modelling is a powerful tool to formally
represent simple or complex data. Each aspect
of the data is modelled with an attribute.
Objects may have several attributes and
also methods to perform operations on the

WHAT NEXT?
attributes. Objects can interact to support
use cases that may be simple such as register
reading or more complex such as tariff and
billing schemes or load management.

OBIS specifies the object naming system

that standardizes the meaning of each data
Born in 1997, the DLMS User Association has set ambitious objectives to create the element. It allows classifying the characteristics
standard for smart meter data exchange. Have these objectives been met? of the data e.g. electrical energy – active power
– time integral – tariff – billing period.
Growth comes from the roots It had to be versatile with foundational
extensibility to allow addressing specific The potential for modelling applications with
First news about the Association appeared future needs, absorbing state of the art COSEM is huge: with the 85 interface classes
in Metering International exactly 20 years technologies and meeting new requirements specified today, a vast range of functions
ago, written by the then Chairman, Paul in areas like security, efficiency and is already covered. However, up to 65 535
Fuchs, the ‘father’ of the first meter reading manageability. A tall order for a standard interface classes are possible. OBIS also
standard IEC 1107 (aka ‘FLAG protocol’, IEC that was to be robust, certifiable and provides an enormous code space: 281 474
62056-21:1996). The subject was the first DLMS recognised globally! billion OBIS codes are possible.
UA general meeting held in October 1997 in
Amsterdam at Metering Europe (ME). The power of object modelling Evolution in all directions
Founded in March 1997, the Association DLMS/COSEM stems from IEC 61334-4-41:1996, Let’s see now how object modelling and
produced spectacular growth in just six part of the distribution automation using flexibility allows DLMS/COSEM to evolve.
months: by October, membership almost distribution line carrier systems suite.
tripled, from three to eight. A modest start of New use cases and functions are addressed
an exciting journey towards smart metering The crucial step in designing DLMS/COSEM with new objects. An example is payment
as we see it today: large rollouts putting tens is the specification of application-related metering with the account, credit, charge and
of millions of meters on the wall, a DLMS UA interface objects that can be readily used for token gateway objects. New data elements are
with 300+ members and 850+ DLMS/COSEM modelling the metering use cases, yet general identified by new OBIS codes. For example,
compliant meter types. enough to model any applications. recently a code space for renewable energy
has been added. To support new media,
Since then we have travelled together: ME The DLMS application layer services are the communication profiles are developed
evolved to EUW, the annual landmark utility same for each object; this allows adding new specifying the ‘glue’ between media-specific
event and DLMS/COSEM evolved to be the objects to the model without affecting the lower protocol layers and the DLMS/COSEM
unchallenged standard for smart metering
and energy management (IEC 62056), ready to
dlms-tree Standardization
conquer new fields. mandates Directives
• The clouds show market and Project requirements /

More than a protocol, more than

use cases
regulatory drivers;
smart metering
• The fruits are main functions Monitoring M2M and H2M I/F
The goal was ambitious: to design a standard modelled that can be picked by
companion specifications; Recording
that brings interoperability to meter data Sensing Power quality
exchange for all energy kinds, all media.
• In the trunk some important Delivery & Control
Measuring
Moreover, the standard had to be evolutive so Accounting &
elements of DLMS/COSEM are Payment Metering
that it could meet yet undefined requirements shown; Scheduling
and applications.
Composable messages • Push operation • Image transfer

• The roots illustrate key

Compact data • ACCESS service • General Block Transfer

Access rights / Security policies • Data protection

This has been achieved by specifying three key properties of DLMS/COSEM;

Communication profiles • Function manager

components: COSEM (Companion Specification Pick your own!

for Energy Metering), the object model capable • In the soil, state-of-the art
of describing virtually any application, OBIS, technologies absorbed by DLMS/
giving the name of each data and DLMS COSEM are shown. Companion Companion Companion
specification specification specification
(Device Language Message Specification), Obje
rability
the application layer protocol that turns Interope ct m
odeli
ng
information to messages.
OFDM PLC
y
ity ienc
cur Effic ibil ity
It was evident that no single communication Se Flex Manageability
media can suit all scenarios. Therefore, DLMS/ TCP/IP LTE IEEE 802.15.4 6LoWPAN
XML
COSEM was designed to be media independent. NSA Suite B GPRS M-Bus S-FSK PLC

54 METERING INTERNATIONAL ISSUE – 4 | 2017

 EUROPEAN UTILITY WEEK

COMMERCIAL FEATURE

application layer, and specifying COSEM objects home and building automation, each with DLMS/COSEM application layer (Green Book) is
to manage the medium. Examples are the their specific data models. To facilitate data standardised as IEC 62056-5-3 and referenced
OFDM PLC, high-speed PLC, M-Bus and mesh exchange across these domains, the DLMS UA from EN 13757-1. The IEC 62056 DLMS/COSEM
networks profiles. works with IEC TC13, IEC TC57 and CEN TC205 to suite is part of the IEC smart grids core
specify mapping to and from COSEM. standards portfolio.
Security and efficiency gained such an
importance recently that they deserve The quest for interoperability The DLMS UA takes care to maintain coherence
special attention. between the Books and the standards.
Interoperability is a key requirement for Therefore, compliance to the Books gives rise
Data security first communicating systems to keep integration to presumption of conformity to IEC 62056.
costs low. Such requirements are underpinned
When automatic meter reading started in the by three constituents: standards, companion DLMS/COSEM: why so successful?
1990’s using cryptography for civil purposes specifications and testing. Standards facilitate
was not yet allowed. Protection was ensured reaching interoperability on the network, The DLMS UA is keen to understand if and
by using passwords. As the utilisation of data messaging and data level. On the network how member’s requirements are met by
escalated, strong cryptographic protection level the DLMS/COSEM communication using DLMS/COSEM. From our discussions,
became imperative. profiles use IEC, ISO, CEN, ITU-T, ETSI, IEEE or the following has transpired: business
IETF standards. Messaging level (syntactical) requirements are as important or perhaps
DLMS/COSEM has foreseen this trend: the interoperability is the domain of the DLMS/ even more important than technical ones.
concepts of authentication, access rights COSEM application layer specifying services Functionality, interoperability, performance,
and ciphering were present from the to reach the COSEM objects. Data level efficiency and security are minimum
beginning. As cryptography advanced and (semantic) interoperability is the domain of requirements. Beyond that what counts is
their implementation in resource constrained the COSEM objects that ensure that all data openness, meeting regulatory requirements,
devices became feasible, a flexible and exchanged can be correctly interpreted. maturity, proven track record, stability and
powerful security architecture using symmetric future potential.
and public key algorithms has been developed Companion specifications address functional
to protect not only the messages but also and process level interoperability. They specify As suggested by the number of projects,
data carried by them. This concept provides the use cases, make selections and take utilities, governments and members using
end-to-end application level protection options from DLMS/COSEM and specify project DLMS/COSEM, we are probably on the
between market participants and devices specific elements where needed. Examples are right track.
across all network segments to meet a diverse the DSMR, GBCS, IDIS, Linky and PRIME DLMS/
range of use cases. COSEM profiles. Promises delivered – you are
invited to the DLMS UA!
Every byte counts: efficiency The DLMS UA conformance testing scheme
allows ascertaining if an implementation At this milestone, it can be concluded that
DLMS/COSEM is at home in constrained devices is compliant to the standard. Tests can be the goals have been achieved: DLMS/COSEM
and networks. performed either by manufacturers or by third is a powerful and future-proof standard for
parties. Results are verified by the DLMS UA. To data exchange between intelligent devices,
To ensure efficiency DLMS/COSEM separates date, 850+ Certifications have been issued to implemented worldwide in projects large and
data (e.g. values) from metadata (e.g. units), 150+ manufacturers. small, by many utilities and manufacturers,
provides selective access mechanisms to ready to conquer applications beyond smart
large data and encoding methods to keep Testing on the functional and process level is metering. It started in substations and
overhead low. the scope of testing against the companion factories, moved to the doorstep of homes,
specifications. and makes inroads to new fields. For many
Efficiency of DLMS/COSEM has been members, DLMS/COSEM systems constitute
greatly increased over the years by adding DLMS/COSEM coloured Books core business.
mechanisms like push operation, pre- and International standards
established and persistent application This success was made possible by the
associations, the ACCESS service handling Standardisation is key to the DLMS UA dedicated work of the members of the DLMS
lists of requests/responses in a single strategy. Through liaisons with IEC, CENELEC UA from Scandinavia to South Africa, from
exchange, block transfer with streaming and CEN the results of the standardisation Australia to the USA.
and lost block recovery, “Compact data” work are brought to those bodies. COSEM
objects with pre-defined templates, and and OBIS (Blue Book) are standardised as Not yet a member? Join us to participate in,
compression. With these, both the number IEC 62056-6-2/62056-6-1. Non-electricity OBIS to influence and drive DLMS/COSEM to new
of messages exchanged and the number of codes are standardised in EN 13757-1. The successes! MI
bytes could be minimized.
ABOUT THE AUTHOR
DLMS/COSEM is successfully deployed now in Győző Kmethy – gyozo.kmethy@dlms.com – is the President of the DLMS UA. He is also
large quantities on low throughput wireless Secretary of IEC TC13, Electrical energy measurement and control.
networks in battery operated devices, such as
in residential gas metering. ABOUT THE DLMS USER ASSOCIATION
The DLMS UA – registered in Zug, Switzerland – was established in 1997. It develops,
Smart metering in the smart grid promotes and supports DLMS/COSEM. See www.dlms.com.

context
Smart metering is part of the larger smart grid
Speak to the DLMS UA representatives at booth 2A21 during European Utility Week:
scenery, with distinct domains like distribution
3–5 October, 2017, RAI Amsterdam
management/automation, utility automation,

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