EN IEC 61158-4-3:2019

SLOVENSKI STANDARD
01-november-2019
Nadomešča:
SIST EN 61158-4-3:2015
Industrijska komunikacijska omrežja - Specifikacije za procesna vodila - 4-3. del:
Specifikacija protokola na ravni podatkovnih povezav - Elementi tipa 3 (IEC 61158-
4-3:2019)
Industrial communication networks - Fieldbus specifications - Part 4-3: Data-link layer
protocol specification - Type 3 elements (IEC 61158-4-3:2019)
Industrielle Kommunikationsnetze - Feldbusse - Teil 4-3: Protokollspezifikation des Data
Link Layer (Sicherungsschicht) - Typ 3-Elemente (IEC 61158-4-3:2019)
Réseaux de communication industriels - Spécifications des bus de terrain - Partie 4-3 :
Spécification du protocole de la couche liaison de données - Éléments de Type 3
(IEC 61158-4-3:2019)
Ta slovenski standard je istoveten z: EN IEC 61158-4-3:2019
ICS:
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
35.100.20 Podatkovni povezovalni sloj Data link layer
35.110 Omreževanje Networking
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61158-4-3

NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2019
Supersedes EN 61158-4-3:2014
ICS 25.040.40; 35.100.20; 35.110
English Version
Industrial communication networks - Fieldbus specifications -
Part 4-3: Data-link layer protocol specification - Type 3 elements
(IEC 61158-4-3:2019)
Réseaux de communication industriels - Spécifications des Industrielle Kommunikationsnetze - Feldbusse - Teil 4-3:
bus de terrain - Partie 4-3 : Spécification du protocole de la Protokollspezifikation des Data Link Layer
couche liaison de données - Éléments de Type 3 (Sicherungsschicht) - Typ 3-Elemente
(IEC 61158-4-3:2019) (IEC 61158-4-3:2019)
This European Standard was approved by CENELEC on 2019-05-23. 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,
Turkey 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
© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61158-4-3:2019 E

European foreword
The text of document 65C/946/FDIS, future edition 4 of IEC 61158-4-3, 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 EN IEC 61158-4-3:2019.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2020-02-23
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2022-05-23
document have to be withdrawn
This document supersedes EN 61158-4-3:2014.
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.
Endorsement notice
The text of the International Standard IEC 61158-4-3:2019 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 standards
indicated:
IEC 60870-5-1 NOTE Harmonized as EN 60870-5-1
IEC 61158-1 NOTE Harmonized as EN 61158-1
IEC 61158-5-3 NOTE Harmonized as EN 61158-5-3
IEC 61158-6-3 NOTE Harmonized as EN 61158-6-3
IEC 61784-1 NOTE Harmonized as EN 61784-1
IEC 61784-2 NOTE Harmonized as EN 61784-2

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.cenelec.eu.
Publication Year Title EN/HD Year
IEC 61131-3 -  Programmable controllers - Part 3: EN 61131-3 -
Programming languages
IEC 61158-2 2014 Industrial communication networks - EN 61158-2 2014
Fieldbus specifications - Part 2: Physical
layer specification and service definition
IEC 61158-3-3 2014 Industrial communication networks - EN 61158-3-3 2014
Fieldbus specifications - Part 3-3: Data-link
layer service definition - Type 3 elements
ISO 1177 -  Information processing - Character - -
structure for start/stop and synchronous
character oriented transmission
ISO/IEC 646 -  Information technology - ISO 7-bit coded - -
character set for information interchange
ISO/IEC 2022 -  Information technology - Character code - -
structure and extension techniques
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 10731 -  Information technology - Open Systems - -
Interconnection - Basic Reference Model -
Conventions for the definition of OSI
services
IEC 61158-4-3 ®
Edition 4.0 2019-04
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –

Part 4-3: Data-link layer protocol specification – Type 3 elements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.040.40; 35.100.20; 35.110 ISBN 978-2-8322-6773-8

– 2 – IEC 61158-4-3:2019 © IEC 2019
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
1.1 General . 10
1.2 Specifications . 10
1.3 Procedures . 10
1.4 Applicability . 10
1.5 Conformance . 11
2 Normative references . 11
3 Terms, definitions, symbols and abbreviations . 11
3.1 Reference model terms and definitions . 11
3.2 Service convention terms and definitions . 13
3.3 Common terms and definitions . 14
3.4 Additional Type 3 definitions . 16
3.5 Common symbols and abbreviations . 18
3.5.1 Data units . 18
3.5.2 Miscellaneous . 18
3.6 Type 3 symbols and abbreviations . 19
4 Common DL-protocol elements . 23
4.1 Frame check sequence . 23
4.1.1 General . 23
4.1.2 At the sending DLE . 24
4.1.3 At the receiving DLE . 25
5 Overview of the DL-protocol . 26
5.1 General . 26
5.2 Overview of the medium access control and transmission protocol . 26
5.3 Transmission modes and DL-entity . 27
5.3.1 Overview . 27
5.3.2 Token procedures . 28
5.3.3 Send or send/request mode . 32
5.4 Service assumed from the PhL . 32
5.4.1 Asynchronous transmission . 32
5.4.2 Synchronous transmission . 33
5.5 Operational elements . 36
5.5.1 Overview . 36
5.5.2 Bit time t . 36
BIT
5.5.3 Asynchronous transmission . 36
5.5.4 Synchronous transmission . 42
5.5.5 Timers and counters . 47
5.6 Cycle and system reaction times . 51
5.6.1 Asynchronous transmission . 51
5.6.2 Synchronous transmission . 53
6 General structure and encoding of DLPDUs, and related elements of procedure . 54
6.1 DLPDU granularity . 54
6.1.1 Asynchronous transmission – UART character . 54
6.1.2 Synchronous transmission . 55

IEC 61158-4-3:2019 © IEC 2019 – 3 –
6.2 Length octet (LE, LEr) . 55
6.3 Address octet . 56
6.3.1 Destination and source station address (DA and SA) . 56
6.3.2 Address extension (EXT) . 56
6.3.3 Address check . 57
6.3.4 DL-service-access-point (DLSAP) . 58
6.4 Control octet (FC) . 58
6.4.1 General . 58
6.4.2 Frame count bit . 60
6.5 DLPDU content error detection . 62
6.5.1 Asynchronous transmission – frame checksum (FCS) . 62
6.5.2 Synchronous transmission – frame check sequence (FCS) . 62
6.6 DATA_UNIT . 63
6.6.1 General . 63
6.6.2 Ident user data . 63
6.7 Error control procedures . 64
6.7.1 Asynchronous transmission . 64
6.7.2 Synchronous transmission . 64
7 DLPDU-specific structure, encoding and elements of procedure . 64
7.1 DLPDUs of fixed length with no data field . 64
7.1.1 Asynchronous transmission . 64
7.1.2 Synchronous transmission . 66
7.2 DLPDUs of fixed length with data field . 66
7.2.1 Asynchronous transmission . 66
7.2.2 Synchronous transmission . 67
7.3 DLPDUs with variable data field length . 68
7.3.1 Asynchronous transmission . 68
7.3.2 Synchronous transmission . 68
7.4 Token DLPDU . 69
7.4.1 Asynchronous transmission . 69
7.4.2 Synchronous transmission . 70
7.5 ASP DLPDU . 70
7.6 SYNCH DLPDU . 70
7.7 Time Event (TE) DLPDU . 70
7.8 Clock Value (CV) DLPDU . 70
7.9 Transmission procedures . 71
7.9.1 Asynchronous transmission . 71
7.9.2 Synchronous transmission . 72
8 Other DLE elements of procedure . 73
8.1 DL-entity initialization. 73
8.2 States of the media access control of the DL-entity . 74
8.2.1 General . 74
8.2.2 Offline . 75
8.2.3 Passive_Idle . 76
8.2.4 Listen_Token . 76
8.2.5 Active_Idle. 76
8.2.6 Claim_Token . 77
8.2.7 Wait_TCT . 77

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8.2.8 Use_Token . 78
8.2.9 Await_Data_Response . 78
8.2.10 Check_Access_Time . 78
8.2.11 Pass_Token . 79
8.2.12 Check_Token_Pass . 79
8.2.13 Await_Status_Response . 80
8.3 Clock synchronization protocol . 80
8.3.1 Overview . 80
8.3.2 State machine time master . 80
8.3.3 State machine time receiver . 82
Annex A (normative) DL-Protocol state machines . 85
A.1 Overall structure . 85
A.2 Variation of state machines in different devices . 86
A.3 DL Data Resource . 87
A.4 FLC / DLM . 91
A.4.1 Primitive definitions . 91
A.4.2 State machine description . 96
A.5 MAC . 115
A.5.1 Primitive definitions . 115
A.5.2 State machine description . 116
A.6 SRU . 142
A.6.1 Overview . 142
A.6.2 Character send SM(CTX) . 143
A.6.3 Character receive SM (CRX) . 143
A.6.4 Timer-SM (TIM) . 144
A.6.5 Primitive definition of SRC . 144
A.6.6 State machine description . 146
Annex B (informative) Type 3 (synchronous): exemplary FCS implementations . 160
Annex C (informative) Type 3: Exemplary token procedure and message transfer
periods . 162
C.1 Procedure of token passing. 162
C.2 Examples for token passing procedure . 163
C.3 Examples for message transfer periods – asynchronous transmission . 168
Bibliography . 170

Figure 1 – Relationships of DLSAPs, DLSAP-addresses and group DL-addresses . 15
Figure 2 – Logical token-passing ring . 29
Figure 3 – PhL data service for asynchronous transmission . 33
Figure 4 – Idle time T . 38
ID1
Figure 5 – Idle time T (SDN, CS) . 39
ID2
Figure 6 – Idle time T (MSRD) . 39
ID2
Figure 7 – Slot time T . 40
SL1
Figure 8 – Slot time T . 40
SL2
Figure 9 – Slot time T . 45
SL1
Figure 10 – Slot time T . 45
SL2
Figure 11 – Token transfer period . 51
Figure 12 – Message transfer period . 52

IEC 61158-4-3:2019 © IEC 2019 – 5 –
Figure 13 – UART character . 54
Figure 14 – Octet structure . 55
Figure 15 – Length octet coding . 55
Figure 16 – Address octet coding . 56
Figure 17 – DAE/SAE octet in the DLPDU . 57
Figure 18 – Address extension octet . 57
Figure 19 – FC octet coding for send/request DLPDUs . 58
Figure 20 – FC octet coding for acknowledgement or response DLPDUs . 59
Figure 21 – FCS octet coding. 62
Figure 22 – Data field . 63
Figure 23 – Ident user data . 63
Figure 24 – DLPDUs of fixed length with no data field . 65
Figure 25 – DLPDUs of fixed length with no data field . 66
Figure 26 – DLPDUs of fixed length with data field . 67
Figure 27 – DLPDUs of fixed length with data field . 67
Figure 28 – DLPDUs with variable data field length . 68
Figure 29 – DLPDUs with variable data field length . 69
Figure 30 – Token DLPDU . 69
Figure 31 – Token DLPDU . 70
Figure 32 – Send/request DLPDU of fixed length with no data . 71
Figure 33 – Token DLPDU and send/request DLPDU of fixed length with data . 71
Figure 34 – Send/request DLPDU with variable data field length . 72
Figure 35 – Send/request DLPDU of fixed length with no data . 72
Figure 36 – Token DLPDU and send/request DLPDU of fixed length with data . 73
Figure 37 – Send/request DLPDU with variable data field length . 73
Figure 38 – DL-state-diagram . 75
Figure 39 – Overview of clock synchronization . 81
Figure 40 – Time master state machine . 82
Figure 41 – Time receiver state machine . 83
Figure 42 – Clock synchronization . 84
Figure A.1 – Structuring of the protocol machines . 86
Figure A.2 – Structure of the SRU Machine . 143
Figure B.1 – Example of FCS generation for Type 3 (synchronous) . 160
Figure B.2 – Example of FCS syndrome checking on reception for Type 3
(synchronous) . 160
Figure C.1 – Derivation of the token holding time (T ) . 163
TH
Figure C.2 – No usage of token holding time (T ) . 164
TH
Figure C.3 – Usage of token holding time (T ) for message transfer (equivalence
TH
between T of each Master station) . 165
TH
Figure C.4 – Usage of token holding time (T ) in different working load situations . 167
TH
Table 1 – FCS length, polynomials and constants by Type 3 synchronous . 24
Table 2 – Characteristic features of the fieldbus data-link protocol . 26

– 6 – IEC 61158-4-3:2019 © IEC 2019
Table 3 – Transmission function code . 60
Table 4 – FCB, FCV in responder . 62
Table 5 – Operating parameters . 74
Table A.1 – Assignment of state machines . 87
Table A.2 – Data resource . 88
Table A.3 – Primitives issued by DL-User to FLC . 92
Table A.4 – Primitives issued by FLC to DL-User . 92
Table A.5 – Primitives issued by DL-User to DLM . 94
Table A.6 – Primitives issued by DLM to DL-User . 94
Table A.7 – Parameters used with primitives exchanged between DL-User and FLC . 95
Table A.8 – Parameters used with primitives exchanged between DL-User and DLM . 95
Table A.9 – FLC/DLM state table . 96
Table A.10 – FLC / DLM function table . 108
Table A.11 – Primitives issued by DLM to MAC. 115
Table A.12 – Primitives issued by MAC to DLM. 115
Table A.13 – Parameters used with primitives exchanged between DLM and MAC . 115
Table A.14 – Local MAC variables . 116
Table A.15 – MAC state table . 117
Table A.16 – MAC function table . 138
Table A.17 – Primitives issued by DLM to SRC . 144
Table A.18 – Primitives issued by SRC to DLM . 145
Table A.19 – Primitives issued by MAC to SRC. 145
Table A.20 – Primitives issued by SRC to MAC. 145
Table A.21 – Parameters used with primitives exchanged between MAC and SRC . 146
Table A.22 – FC structure . 146
Table A.23 – Local variables of SRC . 146
Table A.24 – SRC state table . 147
Table A.25 – SRC functions . 159

IEC 61158-4-3:2019 © IEC 2019 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 4-3: Data-link layer protocol specification –
Type 3 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 IEC 61784-1 and IEC 61784-2.
International Standard IEC 61158-4-3 has been prepared by subcommittee 65C: Industrial
networks, of IEC technical committee 65: Industrial-process measurement, control and
automation.
This fourth edition cancels and replaces the third edition published in 2014. This edition
constitutes a technical revision.

– 8 – IEC 61158-4-3:2019 © IEC 2019
This edition includes the following significant technical changes with respect to the previous
edition:
• corrections in Table 3;
• corrections in Table A.15;
• spelling and grammar.
The text of this International Standard is based on the following documents:
FDIS Report on voting
65C/946/FDIS 65C/955/RVD
Full information on the voting for the approval of this International 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.
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 publication will remain unchanged until
the stability date indicated on the IEC web site under 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 this publication may be issued at a later date.

IEC 61158-4-3:2019 © IEC 2019 – 9 –
INTRODUCTION
This part of IEC 61158 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 data-link protocol provides the data-link service by making use of the services available
from the physical 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 data-link
entities (DLEs) 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:
a) as a guide for implementors and designers;
b) for use in the testing and procurement of equipment;
c) as part of an agreement for the admittance of systems into the open systems environment;
d) 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 may work together in any combination.
NOTE Use of some of the associated protocol types is restricted by their 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 particular data-link layer protocol type to be used with physical layer and application layer protocols in Type
combinations as specified explicitly in its profile parts. Use of the various protocol types in other combinations may
require permission from their respective intellectual-property-right holders.

– 10 – IEC 61158-4-3:2019 © IEC 2019
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 4-3: Data-link layer protocol specification –
Type 3 elements
1 Scope
1.1 General
The data-link layer provides basic time-critical messaging communications between devices in
an automation environment.
This protocol provides communication opportunities to a pre-selected “master” subset of data-
link entities in a cyclic asynchronous manner, sequentially to each of those data-link entities.
Other data-link entities communicate only as permitted and delegated by those master data-
link entities.
For a given master, its communications with other data-link entities can be cyclic, or acyclic
with prioritized access, or a combination of the two.
This protocol provides a means of sharing the available communication resources in a fair
manner. There are provisions for time synchronization and for isochronous operation.
1.2 Specifications
This document specifies
a) procedures for the timely transfer of data and control information from one data-link user
entity to a peer user entity, and among the data-link entities forming the distributed data-
link service provider;
b) the structure of the fieldbus DLPDUs used for the transfer of data and control information
by the protocol of this document, and their representation as physical interface data units.
1.3 Procedures
The procedures are defined in terms of
a) the interactions between peer DL-entities (DLEs) through the exchange of fieldbus
DLPDUs;
b) the interactions between a DL-service (DLS) provider and a DLS-user in the same system
through the exchange of DLS primitives;
c) the interactions between a DLS-provider and a Ph-service provider in the same system
through the exchange of Ph-service primitives.
1.4 Applicability
These procedures are applicable to instances of communication between systems which
support time-critical communications services within the data-link layer of the OSI or fieldbus
reference models, and which require the ability to interconnect in an open systems
interconnection environment.
Profiles provide a simple multi-attribute means of summarizing an implementation’s
capabilities, and thus its applicability to various time-critical communications needs.

IEC 61158-4-3:2019 © IEC 2019 – 11 –
1.5 Conformance
This document also specifies conformance requirements for systems implementing these
procedures. This document does not contain tests to demonstrate compliance with such
requirements.
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 IEC 61784-1 and IEC 61784-2 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 61131-3, Programmable controllers – Part 3: Programming languages
IEC 61158-2:2014, Industrial communication networks – Fieldbus specifications – Part 2:
Physical layer specification and service definition
IEC 61158-3-3:2014, Industrial communication networks – Fieldbus specifications – Part 3-3:
Data link service definition – Type 3 elements
ISO/IEC 646, Information technology – ISO 7-bit coded character set for information
interchange
ISO/IEC 2022, Information technology – Character code structure and extension techniques
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
...