EN 61158-4-12:2014

SLOVENSKI STANDARD
01-marec-2015
1DGRPHãþD
SIST EN 61158-4-12:2012
Industrijska komunikacijska omrežja - Specifikacije za procesna vodila - 4-12. del:
Specifikacija protokola na ravni podatkovnih povezav - Elementi tipa 12 (IEC 61158
-4-12:2014)
Industrial communication networks - Fieldbus specifications - Part 4-12: Data-link layer
protocol specification - Type 12 elements (IEC 61158-4-12:2014)
Industrielle Kommunikationsnetze - Feldbusse - Teil 4-12: Protokollspezifikation des
Data Link Layer (Sicherungsschicht) - Typ 12-Elemente (IEC 61158-4-12:2014)
Réseaux de communication industriels - Spécifications des bus de terrain - Partie 4-12:
Spécification du protocole de la couche liaison de données - Éléments de type 12 (CEI
61158-4-12:2014)
Ta slovenski standard je istoveten z: EN 61158-4-12:2014
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 61158-4-12

NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2014
ICS 25.040.40; 35.100.20; 35.110 Supersedes EN 61158-4-12:2012
English Version
Industrial communication networks - Fieldbus specifications -
Part 4-12: Data-link layer protocol specification - Type 12
elements
(IEC 61158-4-12:2014)
Réseaux de communication industriels - Spécifications des Industrielle Kommunikationsnetze - Feldbusse - Teil 4-12:
bus de terrain - Partie 4-12: Spécification du protocole de la Protokollspezifikation des Data Link Layer
couche liaison de données - Éléments de type 12 (Sicherungsschicht) - Typ 12-Elemente
(CEI 61158-4-12:2014) (IEC 61158-4-12:2014)
This European Standard was approved by CENELEC on 2014-09-19. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, 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: Avenue Marnix 17, B-1000 Brussels
© 2014 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 61158-4-12:2014 E
Foreword
The text of document 65C/762/FDIS, future edition 3 of IEC 61158-4-12, 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 61158-4-12:2014.

The following dates are fixed:
• latest date by which the document has (dop) 2015-06-19
to be implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2017-09-19
• latest date by which the national
standards conflicting with the
document have to be withdrawn
This document supersede EN 61158-4-12 :2012.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.
This document has been prepared under a mandate given to CENELEC by the European Commission
and the European Free Trade Association.
Endorsement notice
The text of the International Standard IEC 61158-4-12:2014 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 61131-2 NOTE Harmonised as EN 61131-2
IEC 61131-3 NOTE Harmonised as EN 61131-3
IEC 61158-1:2014 NOTE Harmonised as EN 61158-1:2014
IEC 61158-2:2014 NOTE Harmonised as EN 61158-2:2014
IEC 61158-5-12:2014 NOTE Harmonised as EN 61158-5-12:2014
IEC 61158-6-12 NOTE Harmonised as EN 61158-6-12
IEC 61784-1 NOTE Harmonised as EN 61784-1
IEC 61784-2 NOTE Harmonised as EN 61784-2

- 3 - EN 61158-4-12:2014
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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

NOTE 1 When 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 61158-3-12 -  Industrial communication networks - EN 61158-3-12 -
Fieldbus specifications
Part 3-12: Data-link layer service definition -
Type 12 elements
IEC 61588 -  Precision clock synchronization protocol for - -
networked measurement and control
systems
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 8802-3 2000 Information technology - - -
Telecommunications and information
exchange between systems - Local and
metropolitan area networks - Specific
requirements
Part 3: Carrier sense multiple access with
collision detection (CSMA/CD) access
method and physical layer specifications
ISO/IEC 9899 -  Information technology - Programming - -
languages - C
ISO/IEC 10731 -  Information technology - Open Systems - -
Interconnection - Basic Reference Model -
Conventions for the definition of OSI
services
IEEE 802.1Q -  IEEE Standard for Local and metropolitan - -
area networks - Media Access Control
(MAC) Bridges and Virtual Bridges
IETF RFC 768 -  User Datagram Protocol - -
IETF RFC 791 -  Internet Protocol - DARPA Internet Program - -
Protocol Specification
IEC 61158-4-12 ®
Edition 3.0 2014-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Industrial communication networks – Fieldbus specifications –

Part 4-12: Data-link layer protocol specification – Type 12 elements

Réseaux de communication industriels – Spécifications des bus de terrain –

Partie 4-12: Spécification du protocole de la couche liaison de données –

Éléments de type 12
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XG
ICS 25.040.40; 35.100.20; 35.110 ISBN 978-2-8322-1724-5

– 2 – IEC 61158-4-12:2014 © IEC 2014
CONTENTS
FOREWORD . 7
NTRODUCTION . 9
1 Scope . 10
1.1 General . 10
1.2 Specifications . 10
1.3 Procedures . 10
1.4 Applicability . 10
1.5 Conformance . 10
2 Normative references . 11
3 Terms, definitions, symbols, abbreviations and conventions . 11
3.1 Reference model terms and definitions . 11
3.2 Service convention terms and definitions . 12
3.3 Common terms and definitions . 13
3.4 Additional Type 12 definitions . 13
3.5 Common symbols and abbreviations . 16
3.6 Additional Type 12 symbols and abbreviations . 17
3.7 Conventions . 18
4 Overview of the DL-protocol . 23
4.1 Operating principle . 23
4.2 Topology . 23
4.3 Frame processing principles . 23
4.4 Data-link layer overview . 24
4.5 Error detection overview . 25
4.6 Node reference model . 25
4.7 Operation overview . 26
5 Frame structure . 27
5.1 Frame coding principles . 27
5.2 Data types and encoding rules . 27
5.3 DLPDU structure . 29
5.4 Type 12 DLPDU structure . 32
5.5 Network variable structure . 48
5.6 Type 12 mailbox structure . 48
6 Attributes . 50
6.1 Management . 50
6.2 Statistics . 65
6.3 Watchdogs . 68
6.4 Slave information interface . 71
6.5 Media independent interface (MII) . 75
6.6 Fieldbus memory management unit (FMMU) . 79
6.7 Sync manager . 82
6.8 Distributed clock . 89
7 DL-user memory . 93
7.1 Overview . 93
7.2 Mailbox access type . 94
7.3 Buffered access type . 96

IEC 61158-4-12:2014 © IEC 2014 – 3 –
8 Type 12: FDL protocol state machines . 97
8.1 Overview of slave DL state machines . 97
8.2 State machine description . 98
Annex A (informative) Type 12: Additional specifications on DL-Protocol state
machines . 106
A.1 DHSM . 106
A.2 SYSM . 124
A.3 RMSM . 136
Bibliography . 140

Figure 1 – Type description example . 19
Figure 2 – Common structure of specific fields . 20
Figure 3 – Frame structure. 24
Figure 4 – Mapping of data in a frame . 25
Figure 5 – Slave node reference model . 26
Figure 6 – Type 12 PDUs embedded in Ethernet frame . 27
Figure 7 – Type 12 PDUs embedded in UDP/IP . 27
Figure 8 – DL information type description . 52
Figure 9 – Address type description . 54
Figure 10 – DL control type description . 55
Figure 11 – DL status type description . 58
Figure 12 – Successful write sequence to DL-user control register . 59
Figure 13 – Successful read sequence to the DL-user status register . 60
Figure 14 – RX error counter type description . 66
Figure 15 – Lost link counter type description . 67
Figure 16 – Additional counter type description . 68
Figure 17 – Watchdog divider type description . 68
Figure 18 – DLS-user Watchdog divider type description . 69
Figure 19 – Sync manager watchdog type description . 69
Figure 20 – Sync manager watchdog status type description . 70
Figure 21 – Watchdog counter type description . 71
Figure 22 – Slave information interface access type description . 71
Figure 23 – Slave information interface control/status type description . 73
Figure 24 – Slave information interface address type description . 74
Figure 25 – Slave information interface data type description . 75
Figure 26 – MII control/status type description . 76
Figure 27 – MII address type description . 78
Figure 28 – MII data type description . 78
Figure 29 – MII access type description . 79
Figure 30 – FMMU mapping example . 80
Figure 31 – FMMU entity type description . 81
Figure 32 – SyncM mailbox interaction . 83
Figure 33 – SyncM buffer allocation . 83
Figure 34 – SyncM buffer interaction . 84

– 4 – IEC 61158-4-12:2014 © IEC 2014
Figure 35 – Handling of write/read toggle with read mailbox . 85
Figure 36 – Sync manager channel type description . 87
Figure 37 – Distributed clock local time parameter type description . 91
Figure 38 – Successful write sequence to mailbox . 94
Figure 39 – Bad write sequence to mailbox . 95
Figure 40 – Successful read sequence to mailbox . 95
Figure 41 – Bad read sequence to mailbox . 96
Figure 42 – Successful write sequence to buffer . 96
Figure 43 – Successful read sequence to buffer. 97
Figure 44 – Structuring of the protocol machines of an slave . 98
Figure 45 – Slave information interface read operation . 100
Figure 46 – Slave information interface write operation . 101
Figure 47 – Slave information interface reload operation . 102
Figure 48 – Distributed clock . 104
Figure 49 – Delay measurement sequence . 105

Table 1 – PDU element description example . 19
Table 2 – Example attribute description . 20
Table 3 – State machine description elements . 22
Table 4 – Description of state machine elements . 22
Table 5 – Conventions used in state machines . 22
Table 6 – Transfer Syntax for bit sequences . 28
Table 7 – Transfer syntax for data type Unsignedn . 28
Table 8 – Transfer syntax for data type Integern . 29
Table 9 – Type 12 frame inside an Ethernet frame . 30
Table 10 – Type 12 frame inside an UDP PDU . 30
Table 11 – Type 12 frame structure containing Type 12 PDUs . 31
Table 12 – Type 12 frame structure containing network variables . 31
Table 13 – Type 12 frame structure containing mailbox . 32
Table 14 – Auto increment physical read (APRD) . 32
Table 15 – Configured address physical read (FPRD) . 33
Table 16 – Broadcast read (BRD) . 35
Table 17 – Logical read (LRD) . 36
Table 18 – Auto Increment physical write (APWR) . 37
Table 19 – Configured address physical write (FPWR) . 38
Table 20 – Broadcast write (BWR) . 39
Table 21 – Logical write (LWR) . 40
Table 22 – Auto increment physical read write (APRW) . 41
Table 23 – Configured address physical read write (FPRW) . 42
Table 24 – Broadcast read write (BRW) . 44
Table 25 – Logical read write (LRW) . 45
Table 26 – Auto increment physical read multiple write (ARMW) . 46
Table 27 – Configured address physical read multiple write (FRMW) . 47

IEC 61158-4-12:2014 © IEC 2014 – 5 –
Table 28 – Network variable . 48
Table 29 – Mailbox . 49
Table 30 – Error Reply Service Data . 49
Table 31 – DL information . 52
Table 32 – Configured station address . 54
Table 33 – DL control . 55
Table 34 – DL status . 58
Table 35 – DLS-user specific registers . 60
Table 36 – DLS-user event . 62
Table 37 – DLS-user event mask . 63
Table 38 – External event . 64
Table 39 – External event mask . 65
Table 40 – RX error counter . 66
Table 41 – Lost link counter . 67
Table 42 – Additional counter . 68
Table 43 – Watchdog divider . 69
Table 44 – DLS-user watchdog . 69
Table 45 – Sync manager channel watchdog . 70
Table 46 – Sync manager watchdog Status . 70
Table 47 – Watchdog counter . 71
Table 48 – Slave information interface access . 71
Table 49 – Slave information interface control/status . 73
Table 50 – Actual slave information interface address . 75
Table 51 – Actual slave information interface data . 75
Table 52 – MII control/status . 76
Table 53 – Actual MII address. 78
Table 54 – Actual MII data . 78
Table 55 – MII access . 79
Table 56 – Fieldbus memory management unit (FMMU) entity . 81
Table 57 – Fieldbus memory management unit (FMMU) . 82
Table 58 – Sync manager channel . 87
Table 59 – Sync manager Structure . 89
Table 60 – Distributed clock local time parameter . 91
Table 61 – Distributed clock DLS-user parameter . 93
Table A.1 – Primitives issued by DHSM to PSM . 106
Table A.2 – Primitives issued by PSM to DHSM . 106
Table A.3 – Parameters used with primitives exchanged between DHSM and PSM . 106
Table A.4 – Identifier for the octets of a Ethernet frame . 107
Table A.5 – DHSM state table . 109
Table A.6 – DHSM function table . 124
Table A.7 – Primitives issued by SYSM to DHSM . 124
Table A.8 – Primitives issued by DHSM to SYSM . 125
Table A.9 – Primitives issued by DL-User to SYSM . 125

– 6 – IEC 61158-4-12:2014 © IEC 2014
Table A.10 – Primitives issued by SYSM to DL-User . 125
Table A.11 – Parameters used with primitives exchanged between SYSM and DHSM . 125
Table A.12 – SYSM state table . 127
Table A.13 – SYSM function table . 136
Table A.14 – Primitives issued by RMSM to SYSM . 136
Table A.15 – Primitives issued by SYSM to RMSM . 137
Table A.16 – Parameters used with primitives exchanged between RMSM and SYSM . 137
Table A.17 – RMSM state table. 138
Table A.18 – RMSM function table . 139

IEC 61158-4-12:2014 © IEC 2014 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 4-12: Data-link layer protocol specification –
Type 12 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.
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 61158-4-12 has been prepared by subcommittee 65C: Industrial
networks, of IEC technical committee 65: Industrial-process measurement, control and
automation.
This third edition cancels and replaces the second edition published in 2010. This edition
constitutes a technical revision. The main changes with respect to the previous edition are
listed below:
• bug fixes and
• editorial improvements.
– 8 – IEC 61158-4-12:2014 © IEC 2014
The text of this standard is based on the following documents:
FDIS Report on voting
65C/762/FDIS 65C/772/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.
A list of all the 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 "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.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
IEC 61158-4-12:2014 © IEC 2014 – 9 –
NTRODUCTION
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 61158-1:2013.
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 standard 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 standard is concerned, in particular, with the communication and interworking of sensors,
effectors and other automation devices. By using this standard 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 the profile parts. Use of the various protocol types in other combinations
may require permission from their respective intellectual-property-right holders.
The International Electrotechnical Commission (IEC) draws attention to the fact that it is
claimed that compliance with this document may involve the use of patents concerning
Type 12 elements and possibly other types given as follows:
EP 1 590 927 B1 [BE] Koppler für ein Netzwerk mit Ringtopologie und ein auf Ethernet basierten Netzwerk
EP 1 789 857 B1 [BE] Datenübertragungsverfahren und automatisierungssystem zum Einsatz eines
solchen Datenübertragungsverfahrens
DE 102007017835.4 [BE] Paketvermittlungsvorrichtung und lokales Kommunikationsnetz mit einer solchen
Paketvermittlungsvorrichtung
EP 1 456 722 B1 [BE] Datenübertragungsverfahren, serielles Bussystem und Anschalteinheit für einen
passiven Busteilnehmer
IEC takes no position concerning the evidence, validity and scope of these patent rights.
The holder of these patent rights has assured the IEC that he/she is willing to negotiate
licences either free of charge or under reasonable and non-discriminatory terms and
conditions with applicants throughout the world. In this respect, the statement of the holder of
these patent rights is registered with IEC. Information may be obtained from:
[BE]: Beckhoff Automation GmbH
Eiserstraße 5
33415 Verl,
Germany
Attention is drawn to the possibility that some of the elements of this document may be the
subject of patent rights other than those identified above. IEC shall not be held responsible for
identifying any or all such patent rights.
ISO (www.iso.org/patents) and IEC (http://patents.iec.ch) maintain on-line databases of
patents relevant to their standards. Users are encouraged to consult the databases for the
most up to date information concerning patents.

– 10 – IEC 61158-4-12:2014 © IEC 2014
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 4-12: Data-link layer protocol specification –
Type 12 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 all participating data-link entities
a) in a synchronously-starting cyclic manner, and
b) in a cyclic or acyclic asynchronous manner, as requested each cycle by each of those
data-link entities.
Thus this protocol can be characterized as one which provides cyclic and acyclic access
asynchronously but with a synchronous restart of each cycle.
1.2 Specifications
This standard specifies
a) procedures for the transfer of data and control information from one data-link user entity to
one or more user entity;
b) the structure of the DLPDUs used for the transfer of data and control information by the
protocol of this standard, and their representation as physical interface data units.
1.3 Procedures
The procedures are defined in terms of
a) the interactions between DL-entities (DLEs) through the exchange of 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 the MAC services of ISO/IEC 8802-3.
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 reference
model, 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.
1.5 Conformance
This standard also specifies conformance requirements for systems implementing these
procedures. This part of this standard does not contain tests to demonstrate compliance with
such requirements.
IEC 61158-4-12:2014 © IEC 2014 – 11 –
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. 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 61158-3-12, Industrial communication networks – Fieldbus specifications – Part 3-12:
Data-link layer service definition – Type 12 elements
IEC 61588, Precision clock synchronization protocol for networked measurement and control
systems
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 8802-3:2000, Information technology – Telecommunications and information
exchange between systems – Local and metropolitan area networks – Specific requirements –
Part 3: Carrier sense multiple access with collision detection (CSMA/CD) access method and
physical layer specifications
ISO/IEC 9899, Information technology – Programming Languages – C
ISO/IEC 10731, Information technology – Open Systems Interconnection – Basic Reference
Model – Conventions for the definition of OSI services
IEEE 802.1Q, IEEE Standard for Local and metropolitan Area Networks – Virtual Bridged
Local Area Networks, available at
IETF RFC 768, User Datagram Protocol (UDP), available at
IETF RFC 791, Internet protocol DARPA internet program protocol specification, available at

3 Terms, definitions, symbols, abbreviations and conventions
For the purposes
...