EN 62056-62:2007

SLOVENSKI STANDARD
01-september-2007
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Electricity metering - Data exchange for meter reading, tariff and load control -- Part 62:
Interface classes
Messung der elektrischen Energie - Zählerstandsübertragung, Tarif- und Laststeuerung -
- Teil 62: Interface-Klassen
Equipements de mesure de l'énergie électrique - Echange des données pour la lecture
des compteurs, le contrôle des tarifs et de la charge -- Partie 62: Classes d'interface
Ta slovenski standard je istoveten z: EN 62056-62:2007
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
35.200 Vmesniška in povezovalna Interface and interconnection
oprema equipment
91.140.50 Sistemi za oskrbo z elektriko Electricity supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 62056-62
NORME EUROPÉENNE
February 2007
EUROPÄISCHE NORM
ICS 91.140.50; 35.200 Supersedes EN 62056-62:2002

English version
Electricity metering -
Data exchange for meter reading, tariff and load control -
Part 62: Interface classes
(IEC 62056-62:2006)
Equipements de mesure  Messung der elektrischen Energie -
de l'énergie électrique - Zählerstandsübertragung,
Echange des données Tarif- und Laststeuerung -
pour la lecture des compteurs, Teil 62: Interface-Klassen
le contrôle des tarifs et de la charge - (IEC 62056-62:2006)
Partie 62: Classes d'interface
(CEI 62056-62:2006)
This European Standard was approved by CENELEC on 2006-12-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62056-62:2007 E
Foreword
The text of document 13/1389/FDIS, future edition 2 of IEC 62056-62, prepared by IEC TC 13, Equipment
for electrical energy measurement and load control, was submitted to the IEC-CENELEC parallel vote
and was approved by CENELEC as EN 62056-62 on 2006-12-01.
This European Standard supersedes EN 62056-62:2002.
It includes the following significant technical changes with respect to EN 62056-62:2002:
– the list of common data types has been amended, some new types have been added;
– formatting for floating point numbers has been added;
– new HLS mechanisms have been added;
– instance specific data types have been replaced with a well-defined set of applicable data types;
– new units have been added;
– encoding of application_context_name and authentication_mechanism_name attributes of the
Association LN class has has been clarified;
– new interface classes “Register table” and “Status mapping” have been added;
– a new version of the “IEC local port setup”, “Modem configuration”, “Auto connect” and “HDLC setup”
interface classes have been added;
– new interface classes for setting up a TCP/IP based communication profile have been added.
References to related IETF RFCs and standards, as well as related definitions have been added;
– several amendments in Annex D “Relation to OBIS” have been made.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
(dop) 2007-09-01
national standard or by endorsement
– latest date by which the national standards conflicting
(dow) 2009-12-01
with the EN have to be withdrawn
The International Electrotechnical Commission (IEC) and CENELEC draw attention to the fact that it is
claimed that compliance with this International Standard / European Standard may involve the use of a
maintenance service concerning the stack of protocols on which the present standard IEC 62056-62 /
EN 62056-62 is based.
The IEC and CENELEC take no position concerning the evidence, validity and scope of this maintenance
service.
The provider of the maintenance service has assured the IEC that he is willing to provide services under
reasonable and non-discriminatory terms and conditions with applicants throughout the world. In this
respect, the statement of the provider of the maintenance service is registered with the IEC. Information
(see also 4.6.2 and Annex E) may be obtained from:

1)
DLMS User Association
Geneva / Switzerland
www.dlms.ch
1)
Device Language Message Specification

- 3 - EN 62056-62:2007
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 62056-62:2006 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
IEC 61334-6 NOTE  Harmonized as EN 61334-6:2000 (not modified).
__________
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

IEC 60050-300 2001 International Electrotechnical Vocabulary - - -
Electrical and electronic measurements and
measuring instruments -
Part 311: General terms relating to
measurements -
Part 312: General terms relating to electrical
measurements -
Part 313: Types of electrical measuring
instruments -
Part 314: Specific terms according to the type
of instrument
IEC 60559 1989 Binary floating-point arithmetic for HD 592 S1 1991
microprocessor systems
IEC 61334-4-41 1996 Distribution automation using distribution line EN 61334-4-41 1996
carrier systems -
Part 4: Data communication protocols -
Section 41: Application protocols -
Distribution line message specification

IEC/TR 62051 1999 Electricity metering - Glossary of terms - -

IEC/TR 62051-1 2004 Electricity metering - Data exchange for meter - -
reading, tariff and load control - Glossary of
terms -
Part 1: Terms related to data exchange with
metering using DLMS/COSEM
IEC 62056-21 2002 Electricity metering - Data exchange EN 62056-21 2002
for meter reading, tariff and load control -
Part 21: Direct local data exchange

IEC 62056-31 1999 Electricity metering - Data exchange EN 62056-31 2000
for meter reading, tariff and load control -
Part 31: Use of local area networks on twisted
pair with carrier signalling
IEC 62056-46 2002 Electricity metering - Data exchange EN 62056-46 2002
A1 2006 for meter reading, tariff and load control - A1 2007
Part 46: Data link layer using HDLC protocol

IEC 62056-47 2006 Electricity metering - Data exchange EN 62056-47 2007
for meter reading, tariff and load control -
Part 47: COSEM transport layers for IPv4
networks
- 5 - EN 62056-62:2007
Publication Year Title EN/HD Year
IEC 62056-53 2006 Electricity metering - Data exchange EN 62056-53 2007
for meter reading, tariff and load control -
Part 53: COSEM application layer

IEC 62056-61 2006 Electricity metering - Data exchange EN 62056-61 2007
for meter reading, tariff and load control -
Part 61: Object identification system (OBIS)

ANSI C12.19:1997/ 1997 Utility Industry End Device Data Tables - -
IEEE 1377
STD 0005 1981 Internet Protocol - -

STD 0051 1994 The Point-to-Point Protocol (PPP) - -

INTERNATIONAL IEC
STANDARD 62056-62
Second edition
2006-11
Electricity metering –
Data exchange for meter
reading, tariff and load control –
Part 62:
Interface classes
© IEC 2006 ⎯ Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale XF
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue

– 2 – 62056-62 © IEC:2006(E)
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references .7
3 Terms, definitions and abbreviations .8
4 Basic principles .9
4.1 General .9
4.2 Class description notation .10
4.3 Common data types .12
4.4 Data formats .13
4.5 The COSEM server model .17
4.6 COSEM logical device.18
4.7 Authentication procedures.19
5 The interface classes .20
5.1 Data (class_id: 1) .22
5.2 Register (class_id: 3) .22
5.3 Extended register (class_id: 4) .26
5.4 Demand register (class_id: 5).27
5.5 Register activation (class_id: 6).30
5.6 Profile generic (class_id: 7) .32
5.7 Clock (class_id: 8).37
5.8 Script table (class_id: 9).40
5.9 Schedule (class_id: 10) .41
5.10 Special days table (class_id: 11) .44
5.11 Activity calendar (class_id: 20) .45
5.12 Association LN (class_id: 15) .48
5.13 Association SN (class_id: 12) .53
5.14 SAP assignment (class_id: 17) .56
5.15 Register monitor (class_id: 21) .56
5.16 Utility tables (class_id: 26) .57
5.17 Single action schedule (class_id: 22).59
5.18 Register table (class_id: 61) .60
5.19 Status mapping (class_id: 63) .62
6 Maintenance of the interface classes.63
6.1 New interface classes .63
6.2 New versions of interface classes.63
6.3 Removal of interface classes.63

Annex A (normative) Protocol related interface classes.64
Annex B (normative) Data model and protocol .84
Annex C (normative) Using short names for accessing attributes and methods .85
Annex D (normative) Relation to OBIS .94
Annex E (informative) Previous versions of interface classes.116

Bibliography.122

62056-62 © IEC:2006(E) – 3 –
Index .123

Figure 1 – An interface class and its instances .10
Figure 2 – The COSEM server model.17
Figure 3 – Combined metering device.17
Figure 4 – Overview of the interface classes.21
Figure 5 – The attributes when measuring sliding demand .27
Figure 6 – The attributes when measuring current_average_value if number of periods
is 1 .27
Figure 7 – The attributes if the number of periods is 3 .28
Figure 8 – The generalized time concept .38
Figure B.1 – The three step approach of COSEM.84

Table 1 – Common data types .12

– 4 – 62056-62 © IEC:2006(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICITY METERING – DATA EXCHANGE
FOR METER READING, TARIFF AND LOAD CONTROL –

Part 62: Interface classes
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
The International Electrotechnical Commission (IEC) draws attention to the fact that it is claimed that compliance
with this International Standard may involve the use of a maintenance service concerning the stack of protocols on
which the present standard IEC 62056-62 is based.
The IEC takes no position concerning the evidence, validity and scope of this maintenance service.
The provider of the maintenance service has assured the IEC that he is willing to provide services under
reasonable and non-discriminatory terms and conditions with applicants throughout the world. In this respect, the
statement of the provider of the maintenance service is registered with the IEC. Information (see also 4.6.2 and
Annex E) may be obtained from:
DLMS User Association
Geneva / Switzerland
www.dlms.ch
———————
Device Language Message Specification.

62056-62 © IEC:2006(E) – 5 –
International Standard IEC 62056-62 Ed. 2 has been prepared by IEC technical committee 13:
Equipment for electrical energy measurement and load control.
This second edition cancels and replaces the first edition published in 2002 and constitutes a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
• the list of common data types has been amended, some new types have been added;
• formatting for floating point numbers has been added;
• new HLS mechanisms have been added;
• instance specific data types have been replaced with a well-defined set of applicable data
types;
• new units have been added;
• encoding of application_context_name and authentication_mechanism_name attributes of
the Association LN class has has been clarified;
• new interface classes “Register table” and “Status mapping” have been added;
• a new version of the “IEC local port setup”, “Modem configuration”, “Auto connect” and
“HDLC setup” interface classes have been added;
• new interface classes for setting up a TCP/IP based communication profile have been
added. References to related IETF RFCs and standards, as well as related definitions
have been added;
• several amendments in Annex D “Relation to OBIS” have been made.
The text of this standard is based on the following documents:
FDIS Report on voting
13/1389/FDIS 13/1400/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of the publication may be issued at a later date.

– 6 – 62056-62 © IEC:2006(E)
INTRODUCTION
Driven by the need of the utilities to optimize their business processes, the meter becomes
more and more part of an integrated metering and billing system. Whereas in the past the
commercial value of a meter was mainly generated by its data acquisition and processing
capabilities, nowadays the critical issues are system integration and interoperability.
The Companion Specification for Energy Metering (COSEM) addresses these challenges by
looking at the meter as an integrated part of a commercial process, which starts with the
measurement of the delivered product (energy) and ends with the revenue collection.
The meter is specified by its “behaviour” as seen from the utility's business processes. The
formal specification of the behaviour is based on object modelling techniques (interface
classes and objects). The specification of these objects forms a major part of COSEM.
The COSEM server model (see 4.5) represents only the externally visible elements of the
meter. The client applications that support the business processes of the utilities, customers
and meter manufacturers make use of this server model. The meter offers means to retrieve
its structural model (the list of objects visible through the interface), and provides access to
the attributes and specific methods of these objects.
The set of different interface classes form a standardized library from which the manufacturer
can assemble (model) its individual products. The elements are designed so that with them
the entire range of products (from residential to commercial and industrial applications) can
be covered. The choice of the subset of interface classes used to build a meter, their
instantiation, and their implementation are part of the product design and therefore left to the
manufacturer. The concept of the standardized metering interface class library provides the
different users and manufacturers with a maximum of diversity without having to sacrifice
interoperability.
62056-62 © IEC:2006(E) – 7 –
ELECTRICITY METERING – DATA EXCHANGE
FOR METER READING, TARIFF AND LOAD CONTROL –

Part 62: Interface classes
1 Scope
This part of IEC 62056 specifies a model of a meter as it is seen through its communication
interface(s). Generic building blocks are defined using object-oriented methods, in the form of
interface classes to model meters from simple up to very complex functionality.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60050-300:2001, International Electrotechnical Vocabulary – Electrical and electronic
measurements and measuring instruments – Chapter 311: General terms relating to
measurements – Chapter 312: General terms relating to electrical measurements – Chapter
313: Types of electrical measuring instruments – Chapter 314: Specific terms according to the
type of instrument
IEC 60559:1989, Binary floating-point arithmetic for microprocessor systems
IEC 61334-4-41:1996, Distribution automation using distribution line carrier systems – Part 4:
Data communication protocols – Section 41: Application protocols – Distribution line message
specification
IEC 62051:1999, Electricity metering – Glossary of terms
IEC 62051-1:2004, Electricity metering – Data exchange for meter reading, tariff and load
control – Glossary of terms – Part 1: Terms related to data exchange with metering
equipment using DLMS/COSEM
IEC 62056-21:2002, Electricity metering – Data exchange for meter reading, tariff and load
control – Part 21: Direct local data exchange
IEC 62056-31:1999, Electricity metering – Data exchange for meter reading, tariff and load
control – Part 31: Using local area networks on twisted pair with carrier signalling
IEC 62056-46:2002, Electricity metering – Data exchange for meter reading, tariff and load
control – Part 46: Data link layer using HDLC-protocol
Amendment 1
IEC 62056-47:2006, Electricity metering – Data exchange for meter reading, tariff and load
control – Part 47: COSEM transport layers for IPv4 networks
IEC 62056-53:2006, Electricity metering – Data exchange for meter reading, tariff and load

control – Part 53: COSEM Application layer
———————
To be published.
– 8 – 62056-62 © IEC:2006(E)
IEC 62056-61:2006, Electricity metering – Data exchange for meter reading, tariff and load
control – Part 61: Object identification system(OBIS)
ANSI C12.19:1997 / IEEE 1377:1997, Utility Industry End Device Data Tables
STD 0005: 1981, Internet Protocol (Also: IETF RFC 0791, RFC 0792, RFC 0919, RFC 0922,
RFC 0950, RFC 1112)
STD 0051: 1994, The Point-to-Point Protocol (PPP) (Also: IETF RFC 1661, RFC 1662)
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-300,
IEC 62051, and IEC 62051-1 apply.
3.2 Abbreviations
AARE Application Association Response
AARQ Application Association ReQuest
ACSE Application Control Service Element
APDU Application Protocol Data Unit
ASE Application Service Element
A-XDR Adapted eXtended Data Representation
CHAP Challenge Handshake Authentication Protocol
COSEM Companion Specificationfor Energy Metering
CtoS Client to Server Challenge
DHCP Dynamic Host Control Protocol
DLMS Device Language Message Specification
DNS Domain Name Server
EAP Extensible Authentication Protocol
GMT Greenwich Mean Time
GPS Global Positioning System
HLS High Level Security
IANA Internet Assigned Numbers Authority
IC Interface Class
IETF Internet Engineering Task Force
IP Internet Protocol
IPCP Internet Protocol Control Protocol
LCP Link Control Protocol
LLS Low Level Security
LN Logical Name
LSB Least Significant Bit
m mandatory
MD5 Message Digest Algorithm 5
MSB Most Significant Bit
o Optional
62056-62 © IEC:2006(E) – 9 –
OBIS OBject Identification System
PAP Password Authentication Protocol
PDU Protocol Data Unit
PLMN Public Land Mobile Network
PPP Point-to-Point Protocol
PSTN Public Switched Telephone Network
ROHC Robust Header Compression
SAP Service Access Point
SHA-1 Secure Hash Algorithm
SMS Short Message Service
SMTP Simple Mail Transfer Protocol
SN Short Name
StoC Server to Client Challenge
4 Basic principles
4.1 General
This subclause describes the basic principles on which the COSEM interface classes are
built. It also gives a short overview on how interface objects (instantiations of the interface
classes) are used for communication purposes. Data collection systems and metering
equipment from different vendors, following these specifications can exchange data in an
interoperable way.
Object modelling: for specification purposes this standard uses the technique of object
modelling. An object is a collection of attributes and methods.
The information of an object is organized in attributes. They represent the characteristics of
an object by means of attribute values. The value of an attribute may affect the behaviour of
an object. The first attribute in any object is the “logical_name”. It is one part of the
identification of the object. An object may offer a number of methods to either examine or
modify the values of the attributes.
Objects that share common characteristics are generalized as an interface class with a
class_id. Within a specific class, the common characteristics (attributes and methods) are
described once for all objects. Instantiations of an interface class are called COSEM objects.
Manufacturers may add proprietary methods or attributes to any object, using negative
numbers.
Figure 1 illustrates these terms by means of an example:

– 10 – 62056-62 © IEC:2006(E)
Methods
Class Object      Attribute Values

Attributes  Instantiation
class identifier
Total Positive
Register  class_id=3
Active Energy: Register
logical_name: octet-string
logical_name = [1 1 1 8 0 255]
value: instance specific
... value = 1483
…
reset
Total Positive
Reactive Energy: Register
logical_name = [1 1 3 8 0 255]
value = 57
…
IEC  305/02
Figure 1 – An interface class and its instances
The interface class “Register” is formed by combining the features necessary to model the
behaviour of a generic register (containing measured or static information) as seen from the
client (central unit, hand-held terminal). The contents of the register are identified by the
attribute “logical_name”. The logical_name contains an OBIS identifier (see IEC 62056-61).
The actual (dynamic) content of the register is carried by its “value” attribute.
Defining a specific meter means defining several specific registers. In the example of
Figure 1, the meter contains two registers, i.e. two specific COSEM objects of the class
“Register” are instantiated. This means that specific values are assigned to the different
attributes. Through the instantiation, one COSEM object becomes a “total, positive, active
energy register” whereas the other becomes a “total, positive, reactive energy register”.
REMARK The COSEM objects (instances of interface classes) represent the behaviour of the meter as seen from
the “outside”. Therefore, modifying the value of an attribute must always be initiated from the outside (e.g.
resetting the value of a register). Internally initiated changes of the attributes are not described in this model (e.g.
updating the value of a register).
4.2 Class description notation
This subclause describes the notation used to define the interface classes.
A short text describes the functionality and application of the class. A table gives an overview
of the class including the class name, the attributes, and the methods (class description
template).
Class name Cardinality class_id, version
Attribute(s) Data type Min. Max. Def.
1. logical_name (static) octet-string
2. … (…) …
3. … (.) …
Specific method(s) (if required) m/o
1. … …
…
2. …
Each attribute and method must be described in detail.

62056-62 © IEC:2006(E) – 11 –
Class name
Describes the class (e.g. “Register”, “Clock”, “Profile generic”,.)
Cardinality Specifies the number of instances of the class within a logical device (see
4. 6 ) .
value The class shall be instantiated exactly “value”
times.
min.max. The class shall be instantiated at least “min.” times
and at most “max.” times. If min. is zero (0) then the
class is optional, otherwise (min. > 0) "min."
instantiations of the class are mandatory.
class_id Identification code of the class (range 0 to 65 535). The class_id of each
object is retrieved together with the logical name by reading the object_list
attribute of an “Association LN” / ”Association SN” object.

The class_id-s from 0 to 8 191 are reserved to be specified by the DLMS
UA. Class_id-s from 8 192 to 32 767 are reserved for manufacturer
specific interface classes. Class_id-s from 32 768 to 65 535 are reserved
for user group specific interface classes. DLMS UA reserves the right to
assign ranges to individual manufacturers or user groups.
Version Identification code of the version of the class. The version of each object
is retrieved together with the logical name and the class_id by reading the
object_list attribute of an “Association LN” / ”Association SN” object.

Within one logical device, all instances of a certain class must be of
the same version.
Attribute(s) Specifies the attribute(s) that belong to the class.

(dyn.) Classifies an attribute that carries a process value,
which is updated by the meter itself.

(static)
Classifies an attribute, which is not updated by the
meter itself (e.g. configuration data).
logical_name octet-string The logical name is always the first attribute of a class.
It identifies the instantiation (COSEM object) of this
class. The value of the logical_name conforms to
OBIS (see IEC 62056-61).
Data type Defines the data type of an attribute (see 4.3).

Min. Specifies if the attribute has a minimum value.

x The attribute has a minimum value.

The attribute has no minimum value.

Max. Defines if the attribute has a maximum value.

x
The attribute has a maximum value.

The attribute has no maximum value.

Def. Specifies if the attribute has a default value. This is the value of the
attribute after reset.
x The attribute has a default value.

The default value is not defined by the class definition.

– 12 – 62056-62 © IEC:2006(E)
Specific Provides a list of the specific methods that belong to the object.
method(s)
Method Name () The method has to be described in the subsection
"Method description".
m/o Defines if the method is mandatory or optional.

m (mandatory) The method is mandatory.

o (optional) The method is optional.

Attribute description
Describes each attribute with its data type (if the data type is not simple), its data format and
its properties (minimum, maximum and default values).
Method description
Describes each method and the invoked behaviour of the instantiated COSEM object(s).
NOTE Services for accessing attributes or methods by the protocol are described in IEC 62056-53.
Selective access
The xDLMS services Read, Write, UnconfirmedWrite (used with SN referencing) and GET,
SET (used with LN referencing) typically reference the entire attribute. However, for certain
attributes selective access to just a part of the attribute may be provided. The part of the
attribute is identified by specific selective access parameters. These are defined as part of the
attribute specification.
4.3 Common data types
The following table contains the list of data types usable for attributes of COSEM objects.
Table 1 – Common data types
a
Type description Tag Definition Value range
--simple data types
null-data [0]
boolean [3] boolean TRUE or FALSE
bit-string [4] An ordered sequence of boolean values
double-long [5] Integer32 -2 147 483 648…
2 147 483 647
double-long-unsigned [6] Unsigned32 0…4 294 967 295
octet-string [9] An ordered sequence of octets (8 bit bytes)
visible-string [10] An ordered sequence of ASCII characters
bcd [13] binary coded decimal
integer [15] Integer8 -128…127
long [16] Integer16 -32 768…32 767
unsigned [17] Unsigned8 0…255
long-unsigned [18] Unsigned16 0…65 535
63 63
long64 [20] Integer64 - 2 …2 -1
long64-unsigned [21] Unsigned64 0…2 -1

62056-62 © IEC:2006(E) – 13 –
Table 1 (continued)
Type description aDefinition Value range
Tag
enum [22] The elements of the enumeration type are

defined in the “Attribute description” section
of a COSEM interface class specification.
float32 [23] OCTET STRING (SIZE(4)) For formatting, see 4.4.2.
float64 [24] OCTET STRING (SIZE(8))
date_time [25] OCTET STRING (SIZE(12)) For formatting, see 4.4.1.
date [26] OCTET STRING (SIZE(5))
time [27] OCTET STRING (SIZE(4))
--complex data types
array [1] The elements of the array are defined in the
“Attribute description” section of a COSEM
interface class specification.
structure [2] The elements of the structure are defined in
the “Attribute description” section of a
COSEM interface class specification.
compact array [19] The elements of the compact array are
defined in the “Attribute description” section
of a COSEM interface class specification.
--CHOICE For some attributes of some COSEM inter-
face objects, the data type may be chosen at
COSEM object instantiation, in the
implementation phase of the COSEM server.
The Server always shall send back the data
type and the value of each attribute, so that
together with the logical name, an
unambiguous interpretation is ensured. The
list of possible data types is defined in the
“Attribute description” section of a COSEM
interface class specification.
a
The tags are as defined in IEC 62056-53, 8.3.

4.4 Data formats
4.4.1 Date and time formats
Date and time information may be represented with data type octet-string, or using the data
types date, time and date_time, as defined in the relevant interface class definition.
NOTE 1 In future versions of interface classes and in newly defined interface classes, only the data types date,
time and date_time will be used.
NOTE 2 The (SIZE( )) specifications do not apply if date, time or date_time are represented by data type octet-
string.
date OCTET STRING (SIZE(5))
{
year highbyte,
year lowbyte,
month,
day of month,
day of week
}
year: interpreted as long-unsigned
range 0…big
0xFFFF = not specified
year highbyte and year lowbyte reference the 2 bytes of the

– 14 – 62056-62 © IEC:2006(E)
long-unsigned
month: interpreted as unsigned
range 1…12, 0xFD, 0xFE, 0xFF
1 is January
0xFD = daylight_savings_end
0xFE = daylight_savings_begin
0xFF = not specified
dayOfMonth: interpreted as unsigned
range 1…31, 0xFD, 0xFE, 0xFF
nd
0xFD = 2 last day of month
0xFE = last day of month
0xE0 to 0xFC = reserved
0xFF = not specified
dayOfWeek: interpreted as unsigned
range 1…7, 0xFF
1 is Monday
0xFF = not specified
For repetitive dates, the unused parts must be set to “not
specified”.
The elements dayOfMonth and dayOfWeek have to be
interpreted together:
- if last day of month is specified (0xFE) and day of week
is wildcard, this specifies the last calendar day of the
month;
- if last day of month is specified (0xFE) and an explicit
day of week is specified (e.g. 7, Sunday) then it is the
last occurrence of the weekday specified in the month,
i.e. the last Sunday;
- if the dayOfMonth and dayOfWeek elements are both
explicitly defined and they are not consistent, (for
th
example 24 of the month is not Wednesday in the
given year and month) it shall be considered as an
error.
time OCTET STRING (SIZE(4))
{
hour,
minute,
second,
hundredths
}
hour: interpreted as unsigned
range 0…23, 0xFF
0xFF = not specified,
minute: interpreted as unsigned
range 0…59, 0xFF
0xFF = not specified,
second: interpreted as unsigned
range 0…59, 0xFF
0xFF = not specified,
hundredths: interpreted as unsigned
range 0…99, 0xFF
0xFF = not specified
For repetitive times the unused parts must be set to “not
specified”.
62056-62 © IEC:2006(E) – 15 –
deviation long –720…720:
in minutes of local time to GMT
0x8000 = not specified
clock_status unsigned interpreted as 8 bit string

The status bits are defined as follows:
a
bit 0 (LSB): invalid value,
b
bit 1: doubtful value,
c
bit 2: different clock base ,
d
bit 3: invalid clock status ,
bit 4: reserved,
bit 5: reserved,
bit 6: reserved,
e
bit 7 (MSB): daylight saving active

date_time OCTET STRING (SIZE(12))
{
year highbyte,
year lowbyte,
month,
day of month,
day of week,
hour,
minute,
second,
hundredths of second,
deviation highbyte,
deviation lowbyte,
clock status
}
Individual fields of date_time are encoded as defined above.
Some may be set to “not specified“ as described above in date
and time.
a
Time could not be recovered after an incident. Detailed conditions are manufacturer specific (e.g. after the
power to the clock has been interrupted).
b
Time could be recovered after an incident but the value cannot be guaranteed. Detailed conditions are
manufacturer specific.
c
Bit is set if the basic timing information for the clock is at the actual moment taken from a timing source
different from the source specified in clock_base.
d
This bit indicates that at least one bit of the clock status is invalid. Some bits may be correct. The exact
meaning shall be explained in the manufacturer’s documentation.
e
Flag set to true: the transmitted time contains the daylight saving deviation (summer time), Flag set to false:
the transmitted time does not contain daylight saving deviation (normal time).

4.4.2 Floating point number formats
...