EN IEC 61158-6-28:2023

SLOVENSKI STANDARD
01-november-2023
Industrijska komunikacijska omrežja - Specifikacije za procesna vodila - 6-28. del:
Specifikacija protokola na aplikacijski ravni - Elementi tipa 28 (IEC 61158-6-
28:2023)
Industrial communication networks - Fieldbus specifications - Part 6-28: Application layer
protocol specification - Type 28 elements (IEC 61158-6-28:2023)
Industrielle Kommunikationsnetze - Feldbusse - Teil 6-28: Protokollspezifikation des
Application Layer (Anwendungsschicht) - Typ 28-Elemente (IEC 61158-6-28:2023)
Réseaux de communication industriels - Spécifications des bus de terrain - Partie 6-28:
Spécification du protocole de la couche application - Éléments de type 28 (IEC 61158-6-
28:2023)
Ta slovenski standard je istoveten z: EN IEC 61158-6-28:2023
ICS:
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
35.100.70 Uporabniški sloj Application layer
35.110 Omreževanje Networking
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61158-6-28

NORME EUROPÉENNE
EUROPÄISCHE NORM May 2023
ICS 25.040
English Version
Industrial communication networks - Fieldbus specifications -
Part 6-28: Application layer protocol specification - Type 28
elements
(IEC 61158-6-28:2023)
Réseaux de communication industriels - Spécifications des Industrielle Kommunikationsnetze - Feldbusse - Teil 6-28:
bus de terrain - Partie 6-28: Spécification du protocole de la Protokollspezifikation des Application Layer
couche application - Éléments de type 28 (Anwendungsschicht) - Typ 28-Elemente
(IEC 61158-6-28:2023) (IEC 61158-6-28:2023)
This European Standard was approved by CENELEC on 2023-04-28. 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 CEN-CENELEC
Management Centre 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 CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61158-6-28:2023 E

European foreword
The text of document 65C/1206/FDIS, future edition 1 of IEC 61158-6-28, prepared by SC 65C
"Industrial networks" of IEC/TC 65 "Industrial-process measurement, control and automation" was
submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2024-01-28
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2026-04-28
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 61158-6-28:2023 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 61158-2 NOTE Approved as EN 61158-2
IEC 61158-3-28 NOTE Approved as EN IEC 61158-3-28
IEC 61158-4-28 NOTE Approved as EN IEC 61158-4-28
IEC 61158-5 (series) NOTE Approved as EN 61158-5 (series)
IEC 61158-6 (series) NOTE Approved as EN 61158-6 (series)
IEC 61784-1 (series) NOTE Approved as EN IEC 61784-1 (series)
IEC 61784-2 (series) NOTE Approved as EN IEC 61784-2 (series)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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 1  Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 61158-1 2023 Industrial communication networks - Fieldbus - -
specifications - Part 1: Overview and guidance
for the IEC 61158 and IEC 61784 series
IEC 61158-5-28 2023 Industrial communication networks - Fieldbus - -
specifications - Part 5-28: Application layer
service definition - Type 28 elements
ISO/IEC 7498-1 - Information technology - Open Systems - -
Interconnection - Basic reference model: The
basic model
ISO/IEC 7498-3 - Information technology - Open Systems - -
Interconnection - Basic reference model:
Naming and addressing
ISO/IEC 8824-1 - Information technology - Abstract Syntax - -
Notation One (ASN.1) - Part 1: Specification of
basic notation
ISO/IEC 8825-7 2021 nformation technology - ASN.1 encoding rules - - -
Part 7: Specification of Octet Encoding Rules
(OER)
ISO/IEC 9545 - Information technology - Open Systems - -
Interconnection - Application layer structure
ISO/IEC/IEEE 8802-3 2021 Telecommunications and exchange between - -
information technology systems - Requirements
for local and metropolitan area networks -
Part 3: Standard for Ethernet
IETF RFC 791 - Internet Protocol - DARPA Internet Program - -
Protocol Specification
IETF RFC 2460 - Internet Protocol - Version 6 (IPv6) - - -
Specification
IEC 61158-6-28 ®
Edition 1.0 2023-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial communication networks – Fieldbus specifications –
Part 6-28: Application layer protocol specification – Type 28 elements
Réseaux de communication industriels – Spécifications des bus de terrain –
Partie 6-28: Spécification du protocole de la couche application – Éléments de
type 28
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040 ISBN 978-2-8322-6621-2
– 2 – IEC 61158-6-28:2023 © IEC 2023
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
1.1 Overview. 7
1.2 Specifications . 7
1.3 Conformance . 8
2 Normative references . 8
3 Terms, definitions, symbols, abbreviated terms and conventions . 9
3.1 Terms and definitions from other ISO/IEC standards . 9
3.1.1 Terms and definitions from ISO/IEC 7498-1 . 9
3.1.2 Terms and definitions from ISO/IEC 9545 . 9
3.1.3 Terms and definitions from ISO/IEC 8824-1 . 9
3.1.4 Terms and definitions from ISO/IEC 8825-7 . 9
3.1.5 Terms and definitions from IEC 61158-5 . 10
3.2 Type 28 fieldbus application-layer specific definitions . 10
3.3 Abbreviations and symbols . 10
3.4 Conventions . 11
3.4.1 General concept . 11
3.4.2 Conventions for class definitions . 11
3.4.3 Abstract syntax conventions . 11
3.5 Conventions used in state machines . 11
3.5.1 State machine conventions for Type 28 . 11
4 APDU structure . 12
4.1 APDU header . 12
4.2 DTU APDU . 14
4.3 Time service notification APDU . 15
4.4 System management APDU . 16
5 State machine . 17
5.1 Publisher state machine . 17
5.2 Subscriber state machine . 19
5.3 Client state machine . 20
5.4 Server state machine . 21
5.5 ALCE state machine . 22
5.6 ALDE state machine . 22
5.7 ALME state machine . 23
Bibliography . 25

Figure 1 – APDU header structure . 12
Figure 2 – APDU structure of multiple DTUs . 14
Figure 3 – Transmission unit APDU structure . 14
Figure 4 – Time service notification APDU structure . 15
Figure 5 – System management data APDU structure . 17
Figure 6 – Diagram of state transition of publisher state machine . 18
Figure 7 – Diagram of state transition of subscriber state machine . 20
Figure 8 – Diagram of state transition of client state machine . 21

IEC 61158-6-28:2023 © IEC 2023 – 3 –
Figure 9 – Diagram of transition state of server state machine . 21
Figure 10 – Diagram of transition state of ALCE state machine . 22
Figure 11 – Diagram of transition state of ALDE state machine . 23
Figure 12 – Diagram of state transition for ALME state machine . 24

Table 1 – State machine description elements . 11
Table 2 – AL service type flag encoding . 12
Table 3 – State transition table of publisher state machine . 18
Table 4 – State transition table of subscriber state machine . 19
Table 5 – State transition table of client state machine . 20
Table 6 – State transition table of server state machine . 21
Table 7 – State transition table of ALCE state machine . 22
Table 8 – State transition table of ALDE state machine . 23
Table 9 – State transition table of ALME state machine . 24

– 4 – IEC 61158-6-28:2023 © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 6-28: Application layer protocol specification –
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 61158-6-28 has been prepared by subcommittee 65C: Industrial networks, of IEC technical
committee 65: Industrial-process measurement, control and automation. It is an International
Standard.
IEC 61158-6-28:2023 © IEC 2023 – 5 –
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.
– 6 – IEC 61158-6-28:2023 © IEC 2023
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 protocol provides the application service by making use of the services
available from the data-link or other immediately lower layer. The primary aim of this document
is to provide a set of rules for communication expressed in terms of the procedures to be carried
out by peer application entities (AEs) at the time of communication. These rules for
communication are intended to provide a sound basis for development in order to serve a variety
of purposes:
• as a guide for implementers and designers;
• for use in the testing and procurement of equipment;
• as part of an agreement for the admittance of systems into the open systems environment;
• as a refinement to the understanding of time-critical communications within OSI.
This document is concerned, in particular, with the communication and interworking of sensors,
effectors and other automation devices. By using this document together with other standards
positioned within the OSI or fieldbus reference models, otherwise incompatible systems can
work together in any combination.

IEC 61158-6-28:2023 © IEC 2023 – 7 –
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 6-28: Application layer protocol specification –
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, within which one or more specified actions are required to be completed with
some defined level of certainty. Failure to complete specified actions within the time window
can cause failure of the applications requesting the actions, with attendant risk to equipment,
plant and possibly human life.
This document defines in an abstract way the externally visible behavior provided by the
Type 28 of the fieldbus Application Layer in terms of:
• the abstract syntax defining the application layer protocol data units conveyed between
communicating application entities,
• the transfer syntax defining the application layer protocol data units conveyed between
communicating application entities,
• the application context state machine defining the application service behavior visible
between communicating application entities; and
• the application relationship state machines defining the communication behavior visible
between communicating application entities.
The purpose of this document is to define the protocol provided to:
• the wire-representation of the service primitives defined in IEC 61158-5-28, and
• the externally visible behavior associated with their transfer.
This document specifies the protocol of the Type 28 IEC fieldbus application layer, in
conformance with the OSI Basic Reference Model (ISO/IEC 7498) and the OSI Application
Layer Structure (ISO/IEC 9545).
1.2 Specifications
The principal objective of this document is to specify the syntax and behavior of the application
layer protocol that conveys the application layer services defined in IEC 61158-5-28.
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 protocols
standardized in IEC 61158-6 series.

– 8 – IEC 61158-6-28:2023 © IEC 2023
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.
Conformance is achieved through implementation of this application layer protocol specification.
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 61158-5-28:2023, Industrial communication networks – Fieldbus specifications – Part 5-28:
Application layer service definition – Type 28 elements
ISO/IEC 7498-1, Information technology – Open Systems Interconnection – Basic Reference
Model – Basic Reference Model: The Basic Model
ISO/IEC 7498-3, Information technology – Open Systems Interconnection – Basic Reference
Model: Naming and addressing
ISO/IEC 8824-1, Information technology – Abstract Syntax Notation One (ASN.1) – Partie 1:
Specification of basic notation
ISO/IEC 8825-7:2021, Information technology - ASN.1 encoding rules − Part 7: Specification of
Octet Encoding Rules (OER)
ISO/IEC 9545, Information technology – Open Systems Interconnection – Application Layer
structure
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 2022-09-14]
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 2022-09-14]

IEC 61158-6-28:2023 © IEC 2023 – 9 –
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 Terms and definitions from other ISO/IEC standards
3.1.1 Terms and definitions from ISO/IEC 7498-1
a) abstract syntax
b) application entity
c) application process
d) application protocol data unit
e) application service element
f) application transaction
g) presentation context
h) transfer syntax
3.1.2 Terms and definitions from ISO/IEC 9545
a) application-association
b) application-process-type
c) application-service-element
d) application control service element
3.1.3 Terms and definitions from ISO/IEC 8824-1
a) object identifier
b) type
c) value
d) simple type
e) structured type
f) integer type
g) octet string type
h) null type
i) tagged type
j) any type
k) module
l) production
3.1.4 Terms and definitions from ISO/IEC 8825-7
a) encoding (of a data value)
b) data value
c) identifier octets (the singular form is used in this document)
d) length octet(s) (both singular and plural forms are used in this document)
e) contents octets
– 10 – IEC 61158-6-28:2023 © IEC 2023
3.1.5 Terms and definitions from IEC 61158-5
a) cyclic
b) field device
c) clock synchronization
3.2 Type 28 fieldbus application-layer specific definitions
3.2.1
control device
device that controls all field devices for logical operations, timing, calculations, etc.
3.2.2
management node
device for allocating and managin
...