IEC 61158-5-28:2023

IEC 61158-5-28 ®
Edition 1.0 2023-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial communication networks –Fieldbus specifications –
Part 5-28: Application layer service definition – Type 28 elements

Réseaux de communication industriels – Spécifications des bus de terrain –
Partie 5-28: Définition des services de la couche application –
Éléments de type 28
All rights reserved. Unless otherwise specified, 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
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni
utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et
les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Secretariat Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always have
committee, …). It also gives information on projects, replaced access to up to date content tailored to your needs.
and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 300 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc
If you wish to give us your feedback on this publication or need
further assistance, please contact the Customer Service
Centre: sales@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Recherche de publications IEC - Découvrez notre puissant moteur de recherche et consultez
webstore.iec.ch/advsearchform gratuitement tous les aperçus des publications. Avec un
La recherche avancée permet de trouver des publications IEC abonnement, vous aurez toujours accès à un contenu à jour
en utilisant différents critères (numéro de référence, texte, adapté à vos besoins.
comité d’études, …). Elle donne aussi des informations sur les
projets et les publications remplacées ou retirées. Electropedia - www.electropedia.org

Le premier dictionnaire d'électrotechnologie en ligne au monde,
IEC Just Published - webstore.iec.ch/justpublished
avec plus de 22 300 articles terminologiques en anglais et en
Restez informé sur les nouvelles publications IEC. Just
français, ainsi que les termes équivalents dans 19 langues
Published détaille les nouvelles publications parues.
additionnelles. Egalement appelé Vocabulaire
Disponible en ligne et une fois par mois par email.
Electrotechnique International (IEV) en ligne.

Service Clients - webstore.iec.ch/csc
Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
sales@iec.ch.
IEC Products & Services Portal - products.iec.ch

IEC 61158-5-28 ®
Edition 1.0 2023-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial communication networks –Fieldbus specifications –

Part 5-28: Application layer service definition – Type 28 elements

Réseaux de communication industriels – Spécifications des bus de terrain –

Partie 5-28: Définition des services de la couche application –

Éléments de type 28
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040 ISBN 978-2-8322-6583-3

– 2 – IEC 61158-5-28:2023 © IEC 2023
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
1.1 Overview. 8
1.2 Specifications . 9
1.3 Conformance . 9
2 Normative references . 9
3 Terms, definitions, symbols, abbreviated terms and conventions . 10
3.1 Referenced terms and definitions . 10
3.1.1 ISO/IEC 7498-1 terms . 10
3.1.2 ISO/IEC 8822 terms . 10
3.1.3 ISO/IEC 9545 terms . 11
3.1.4 ISO/IEC 8824 terms . 11
3.2 Additional terms and definitions for this IEC 61158-5-28 . 11
3.3 Abbreviations and symbols . 12
3.4 Conventions . 13
3.4.1 Overview . 13
3.4.2 Conventions for class definitions . 13
3.4.3 Conventions for service definitions . 14
4 Concepts . 15
5 Data type ASE . 15
5.1 General . 15
5.1.1 Overview . 15
5.1.2 Overview of basic types . 16
5.1.3 Overview of fixed-length types . 16
5.1.4 Overview of constructed types . 17
5.2 AL defined data types . 17
5.2.1 Fixed length types . 17
5.2.2 String type . 19
5.2.3 Structure type . 20
6 Type 28 communication model specification . 25
6.1 General . 25
6.2 Protocol stack for Type 28 fieldbus . 26
6.3 Data mapping modelling. 27
6.4 Overview of Type 28 communication model . 29
6.4.1 General . 29
6.4.2 P/S . 29
6.4.3 C/S . 30
6.5 AL related management information table . 30
6.5.1 General . 30
6.5.2 Time management information table . 31
6.5.3 Network management information table . 32
6.6 ASEs . 33
6.6.1 Overview . 33
6.6.2 RT data ASE. 34
6.6.3 nRT data ASE . 36

6.6.4 Time ASE . 38
6.6.5 Resource ASE . 41
6.6.6 Addressing ASE . 43
6.6.7 Management ASE . 48
6.6.8 Virtualization ASE . 55
6.7 Application service . 58
6.7.1 Overview . 58
6.7.2 Read service . 58
6.7.3 Write service . 58
Annex A (informative)  Example of service data mapping DTU message . 60
Annex B (informative)  Example of OPC UA data model and Type 28 data model
mapping . 61
Annex C (informative)  Example of RTA service processing . 62
Annex D (informative)  Type 28 virtualization solution example . 63
Bibliography . 66

Figure 1 – Data type class hierarchy example . 16
Figure 2 – BITMAP data type . 20
Figure 3 – AL in fieldbus protocol stack architecture . 26
Figure 4 – Type 28 AL protocol architecture . 26
Figure 5 – Data mapping modelling object structure . 27
Figure 6 – Diagram of mapping data buffers and service data variables . 28
Figure 7 – Diagram of P/S model . 29
Figure 8 – P/S model of PUSH mode . 30
Figure 9 – P/S model of PULL mode . 30
Figure 10 – Diagram of C/S communication model . 30
Figure 11 – RT data transmission model . 35
Figure 12 – Diagram of nRT data request response model . 37
Figure 13 – Diagram of nRT data AP interaction based on C/S communication model . 38
Figure 14 – Diagram of nRT data AP interaction based on P/S communication model . 38
Figure 15 – Time synchronization application interaction process . 40
Figure 16 – Time query process . 41
Figure 17 – Resource AP interaction based on C/S communication model . 43
Figure 18 – Resource ASE local service function diagram . 43
Figure 19 – NETWORKID identification field structure . 44
Figure 20 – NETWORKID interaction process diagram . 46
Figure 21 – Diagram of MAC mapping table service function. 46
Figure 22 – IP mapping table service function diagram . 47
Figure 23 – Type 28 AL data message mapped to IP payload data payload . 47
Figure 24 – Type 28 AL protocol header and IP protocol header mapping . 48
Figure 25 – IP data message is mapped to valid data of Type 28 AL data message . 48
Figure 26 – Static configuration initialization process . 51
Figure 27 – Join the network interaction process . 52
Figure 28 – Passively exit the network interaction process . 53

– 4 – IEC 61158-5-28:2023 © IEC 2023
Figure 29 – Actively exit network interaction process . 54
Figure 30 – Diagram of diagnostic object mapping . 54
Figure 31 – Diagram of the logging process . 55
Figure 32 – A physical bus divided into two virtual bus domain diagrams . 56
Figure 33 – Diagram of virtualized AP interaction based on C/S communication model . 57
Figure 34 – Virtualization ASE local implementation diagram . 58
Figure A.1 – Data transmission unit message content example . 60
Figure B.1 – OPC UA data model and mapping of Type 28 data model . 61
Figure C.1 – Example of RTA service processing . 62
Figure D.1 – Diagram of Type 28 industrial bus service deployment . 63
Figure D.2 – Diagram of networking topology based on the virtualized bus . 63
Figure D.3 – Virtual network topology based on logical business function RT1 . 64

Table 1 – TIMEV type data coding . 17
Table 2 – TIMEDATE type coding . 18
Table 3 – TIMEOFDAY type coding . 18
Table 4 – TIMEDIFFER type coding . 19
Table 5 – VISIBLESTRING type data coding . 19
Table 6 – Description of time information structure TIMEINFO_S . 20
Table 7 – Description of clock option information structure CLOCK_OPTION_INFO_S . 21
Table 8 – Description of network configuration parameter structure
NETWORK_CFG_PARA_S . 22
Table 9 – Description of MAC mapping table NETWORKID_MAC_MAP_TABLE_S . 23
Table 10 – Description of IP mapping table structure IP_MAP_TABLE_S . 24
Table 11 – Service data mapping table parameter list . 29
Table 12 – Time management information table . 31
Table 13 – Network management information table . 32
Table 14 – Communication models supported by Type 28 AL ASEs . 33
Table 15 – Application service interface return value list . 33
Table 16 – RT data service interface parameters . 34
Table 17 – nRT data service interface parameters . 36
Table 18 – Timing service interface parameters . 39
Table 19 – Resource service interface parameters . 42
Table 20 – Addressing service interface parameters . 45
Table 21 – Management service interface parameters . 49
Table 22 – Virtual service interface parameters . 56
Table 23 – Read service parameters . 58
Table 24 – Write service parameters . 59
Table 25 – Application service errcode . 59
Table D.1 – Virtual bus environment node NETWORKID list . 65

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 5-28: Application layer service definition –
Type 28 elements
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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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.
Attention is drawn to the fact that the use of the associated protocol type is restricted by its
intellectual-property-right holders. In all cases, the commitment to limited release of intellectual-
property-rights made by the holders of those rights permits a layer protocol type to be used with
other layer protocols of the same type, or in other type combinations explicitly
authorized by its intellectual-property-right holders.
NOTE Combinations of protocol types are specified in the IEC 61784-1 series and the IEC 61784-2 series.
IEC 61158-5-28 has been prepared by subcommittee 65C: Industrial networks, of IEC technical
committee 65: Industrial-process measurement, control and automation. It is an International
Standard.
– 6 – IEC 61158-5-28:2023 © IEC 2023
The text of this International Standard is based on the following documents:
Draft Report on voting
65C/1206/FDIS 65C/1235/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts of the IEC 61158 series, published under the general title Industrial
communication networks – Fieldbus specifications, can be found on the IEC web site.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
INTRODUCTION
This document is one of a series produced to facilitate the interconnection of automation system
components. It is related to other standards in the set as defined by the "three-layer" fieldbus
reference model described in IEC 61158-1.
The application service is provided by the application protocol making use of the services
available from the data-link or other immediately lower layer. This document defines the
application service characteristics that fieldbus applications and/or system management can
exploit.
Throughout the set of fieldbus standards, the term "service" refers to the abstract capability
provided by one layer of the OSI Basic Reference Model to the layer immediately above. Thus,
the application layer service defined in this document is a conceptual architectural service,
independent of administrative and implementation divisions.

– 8 – IEC 61158-5-28:2023 © IEC 2023
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 5-28: Application layer service definition –
Type 28 elements
1 Scope
1.1 Overview
The fieldbus Application Layer (FAL) provides user programs with a means to access the
fieldbus communication environment. In this respect, the FAL can be considered as a window
between corresponding application programs.
This part of IEC 61158 provides common elements for basic time-critical and non-time-critical
messaging communications between application programs in an automation environment and
material specific to Type 28 fieldbus. The term "time-critical" is used to represent the presence
of a time-window, in which one or more specified actions are required to be completed with
some defined level of certainty.
This document defines in an abstract way the externally visible service provided by the different
Types of the fieldbus Application Layer in terms of
• an abstract model for defining application resources (objects) capable of being manipulated
by users via the use of the FAL service,
• the primitive actions and events of the service,
• the parameters associated with each primitive action and event, and the form which they
take, and
• the interrelationship between these actions and events, and their valid sequences.
The purpose of this document is to define the services provided to
• the FAL user at the boundary between the user and the Application Layer of the Fieldbus
Reference Model, and
• Systems Management at the boundary between the Application Layer and Systems
Management of the Fieldbus Reference Model.
This document specifies the structure and services of the IEC fieldbus Application Layer, in
conformance with the OSI Basic Reference Model (ISO/IEC 7498-1) and the OSI Application
Layer Structure (ISO/IEC 9545).
FAL services and protocols are provided by FAL application-entities (AE) contained within the
application processes. The FAL AE is composed of a set of object-oriented Application Service
Elements (ASEs) and a Layer Management Entity (LME) that manages the AE. The ASEs
provide communication services that operate on a set of related application process object
(APO) classes. One of the FAL ASEs is a management ASE that provides a common set of
services for the management of the instances of FAL classes.
Although these services specify, from the perspective of applications, how to request and
response are issued and delivered, they do not include a specification of what the requesting
and responding applications are to do with them. That is, the behavioural aspects of the
applications are not specified; only a definition of what requests and responses they can
send/receive is specified. This permits greater flexibility to the FAL users in standardizing such

object behaviour. In addition to these services, some supporting services are also defined in
this document to provide access to the FAL to control certain aspects of its operation.
1.2 Specifications
The principal objective of this document is to specify the characteristics of conceptual
application layer services suitable for time-critical communications, and thus supplement the
OSI Basic Reference Model in guiding the development of application layer protocols for time-
critical communications.
A secondary objective is to provide migration paths from previously existing industrial
communications protocols. It is this latter objective which gives rise to the diversity of services
standardized as the various types of IEC 61158, and the corresponding protocols standardized
in the IEC 61158-6 series.
This document can be used as the basis for formal application programming-interfaces.
Nevertheless, it is not a formal programming interface, and any such interface will address
implementation issues not covered by this document, including
• the sizes and octet ordering of various multi-octet service parameters, and
• the correlation of paired request and confirm, or indication and response, primitives.
1.3 Conformance
This document does not specify individual implementations or products, nor does it constrain
the implementations of application layer entities within industrial automation systems.
There is no conformance of equipment to this application layer service definition standard.
Instead, conformance is achieved through implementation of conforming application layer
protocols that fulfils the Type 28 application layer services as defined in this document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 All parts of the IEC 61158 series, as well as the IEC 61784-1 series and the IEC 61784-2 series are
maintained simultaneously. Cross -references to these documents within the text therefore refer to the editions as
dated in this list of normative references.
IEC 61158-1:2023, Industrial communication networks – Fieldbus specifications – Part 1:
Overview and guidance for the IEC 61158 and IEC 61784 series
IEC 61158-4-28:2023, Industrial communication networks – Fieldbus specifications – Part 4-28:
Data-link layer protocol specification – Type 28 elements
IEC 61158-6-28:2023, Industrial communication networks – Fieldbus specifications – Part 6-28:
Application layer protocol specification – Type 28 elements
ISO/IEC 7498-1:1994, Information technology – Open Systems Interconnection – Basic
Reference Model: The Basic Model
ISO/IEC 7498-3:1997, Information technology – Open Systems Interconnection – Basic
Reference Model: Naming and addressing

– 10 – IEC 61158-5-28:2023 © IEC 2023
ISO/IEC 8822, Information technology – Open Systems Interconnection – Presentation service
definition
ISO/IEC 8824-1, Information technology – Abstract Syntax Notation One (ASN.1) – Part 1:
Specification of basic notation
ISO/IEC 9545, Information technology – Open Systems Interconnection – Application Layer
structure
ISO/IEC 10731:1994, Information technology – Open Systems Interconnection – Basic
Reference Model – Conventions for the definition of OSI services
ISO/IEC/IEEE 8802-3:2021, Information technology – Telecommunications and information
exchange between systems – Local and metropolitan area networks – Specific requirements –
Part 3: Standard for Ethernet
IETF RFC 791, J. Postel, Internet Protocol, September 1981, available at https://www.rfc-
editor.org/info/rfc791 [viewed 2022-02-18]
IETF RFC 2460, S. Deering and R. Hinden, “Internet Protocol, Version 6 (IPv6) Specification”,
December 1998, available at https://www.rfc-editor.org/info/rfc2460 [viewed 2022-02-18]
3 Terms, definitions, symbols, abbreviated terms and conventions
For the purposes of this document, the following terms, definitions, symbols, abbreviated terms
and conventions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1 Referenced terms and definitions
3.1.1 ISO/IEC 7498-1 terms
For the purposes of this document, the following terms given in ISO/IEC 7498-1 apply:
• application entity
• application process
• application protocol data unit
• application service element
• application entity invocation
• application process invocation
• application transaction
• real open system
• transfer syntax
3.1.2 ISO/IEC 8822 terms
For the purposes of this document, the following terms given in ISO/IEC 8822 apply:
• abstract syntax
• presentation context
3.1.3 ISO/IEC 9545 terms
For the purposes of this document, the following terms given in ISO/IEC 9545 apply:
• application-entity-invocation
• application-entity-type
• application-process-invocation
• application-process-type
• application-service-element
3.1.4 ISO/IEC 8824 terms
For the purposes of this document, the following terms given in ISO/IEC 8824 apply:
• object identifier
• type
3.2 Additional terms and definitions for this IEC 61158-5-28
The following terms and definitions apply to this document.
3.2.1
clock query
get clock information from the management node or terminal node device
3.2.2
clock synchronization
clock calibration of the terminal node device
3.2.3
control device
device that controls all field devices for logical operations, timing, calculations, etc.
3.2.4
cyclic
events which repeat in a regular and repetitive manner
3.2.5
cyclic time
time of cyclic processing of a device or module
3.2.6
field device
physical entity that is connected to the process or to factory equipment and has at least one
signalling element that communicates with other signalling element(s) via a cable
3.2.7
management node
device for allocating and managing Type 28 network physical communication resources
3.2.8
non-RT Data
data insensitive to time deterministic requirements

– 12 – IEC 61158-5-28:2023 © IEC 2023
3.2.9
RT Data
data sensitive to time deterministic requirements
3.2.10
terminal node
device in Type 28 network that communicates based on allocated physical communication
resources
3.3 Abbreviations and symbols
AL Application layer
ALCE Application layer clock entity
ALDE Application layer data entity
ALME Application layer management entity
ALS Application layer service
AE Application entity
AP Application process
APO AP object
AR Application relationship
ASE Application service elements
C/S Client/Server
DL- Data-link layer (as a prefix)
DLCE Data-link clock entity
DLDE Data-link data entity
DLE Data-link entity
DLL Data-link layer
DLS Data-link service
DLP Data-link protocol
DLS-user Data-link service user
DTC Data transmission channel
DTS Data transmission service
DTU Data transmission unit
DLSDU Data-link service data unit
DLPDU Data-link protocol data unit
MAC Medium access control
MN Management node
NodeID Node identifier
nRT non-Real-Time
PhL Physical layer
RT Real-Time
RTA Real-Time acyclic
RTC Real-Time cyclic
TN Terminal node
3.4 Conventions
3.4.1 Overview
The FAL is defined as a set of object-oriented ASEs. Each ASE is specified in a separate
subclause. Each ASE specification is composed of two parts, including its class specification
and its service specification.
The class specification defines the attributes of the class. The service specification defines the
services that are provided by the ASE.
3.4.2 Conventions for class definitions
Class definitions are described using templates. Each template consists of a list of attributes
for the class. The general form of the template is shown below:
FAL ASE:  ASE Name
CLASS: Class Name
CLASS ID  #
PARENT CLASS: Parent Class Name
ATTRIBUTES:
1 (o) Key Attribute: numeric identifier
2 (o) Key Attribute: Name
3 (m) Attribute: attribute name(values)
4 (m) Attribute: attribute name(values)
4.1 (s) Attribute: attribute name(values)
4.2 (s) Attribute: attribute name(values)
4.3 (s) Attribute: attribute name(values)
5 (c) Constraint: constraint expression
5.1 (m) Attribute: attribute name(values)
5.2 (o) Attribute: attribute name(values)
6 (m) Attribute: attribute name(values)
6.1 (s) Attribute: attribute name(values)
6.2 (s) Attribute: attribute name(values)
SERVICES:
1 (o) OpsService service name
2 (c) Constraint: constraint expression
3.1 (o) OpsService service name
3 (m) MgtService: service name

(1) The "FAL ASE:" entry is the name of the FAL ASE that provides the services for the class
being specified.
(2) The "CLASS:" entry is the name of the class being specified. All objects defined using this
template will be an instance of this class. The class may be specified by this document, or
by a user of this document.
(3) The "CLASS ID:" entry is a number that identifies the class being specified. This number is
unique within the FAL ASE that will provide the services for this class. When qualified by
the identity of its FAL ASE, it unambiguously identifies the class within the scope of the FAL.
The value "NULL" indicates that the class cannot be instantiated. Class IDs between 1 and
99, 240 and 767 are reserved by this document to identify standardized classes. CLASS IDs
between 100 and 199, 768 and 1 279 are allocated for identifying user defined classes.

– 14 – IEC 61158-5-28:2023 © IEC 2023
(4) The "PARENT CLASS:" entry is the name of the parent class for the class being specified.
All attributes defined for the parent class and inherited by it are inherited for the class being
defined, and therefore do not have to be redefined in the template for this class.
NOTE The parent-class "TOP" indicates that the class being defined is an initial class definition. The parent class
TOP is used as a starting point from which all other classes are defined. The use of TOP is reserved for classes
defined by this document.
(5) The "ATTRIBUTES" label indicate that the following entries are attributes defined for the
class.
a) Each of the attribute entries contains a line number in column 1; a mandatory (m) /
optional (o) / conditional (c) / selector (s) indicator in column 2; an attribute type label in
column 3; a name or a conditional expression in column 4; and optionally a list of
enumerated values in column 5. In the column following the list of values, the default
value for the attribute may be specified.
b) Objects are normally identified by a numeric identifier or by an object name, or by both.
In the class templates, these key attributes are defined under the key attribute.
c) The line number defines the sequence and the level of nesting of the line. Each nesting
level is identified by period. Nesting is used to specify:
i) fields of a structured attribute (4.1, 4.2, 4.3),
ii) attributes conditional on a constraint statement (5). Attributes may be mandatory
(5.1) or optional (5.2) if the constraint is true. Not all optional attributes require
constraint statements as does the attribute defined in (5.2),
iii) the selection fields of a choice type attribute (6.1 and 6.2).
(6) The "SERVICES" label indicates that the following entries are services defined for the class.
a) An (m) in column 2 indicates that the service is mandatory for the class, while an (o)
indicates that it is optional. A (c) in this column indicates that the service is conditional.
When all services defined for a class are defined as optional, at least one has to be
selected when an instance of the class is defined.
b) The label "OpsService" designates an operational service (1).
c) The label "MgtService" designates a management service (2).
d) The line number defines the sequence and the level of nesting of the line. Each nesting
level is identified by period. Nesting within the list of services is used to specify services
conditional on a constraint statement.
3.4.3 Conventions for service definitions
3.4.3.1 General
The service model, service primitives and time-sequence diagrams used are entirely abstract
descriptions; they do not represent a specification for implementation.
3.4.3.2 Service parameters
Service primitives are used to represent service user or service provider interactions
(ISO/IEC 10731). They convey parameters which indicate information available in the user or
provider interaction. In any particular interface, not all parameters shall be explicitly stated.
The service specifications of this document use a tabular format to describe the component
parameters of the ASE service primitives. The parameters which apply to each group of service
primitives are set out in tables. Each table consists of up to five columns for the
a) parameter name,
b) request primitive,
c) indication primitive,
d) response primitive, and
e) confirm primitive.
One parameter (or component of it) is listed in each row of each table. Under the appropriate
service primitive columns, a code is used to specify the type of usage of the parameter on the
primitive specified in the column:
M parameter is mandatory for the primitive
U parameter is a user
...