IEC 61158-4-21:2023
(Main)Industrial communication networks - Fieldbus specifications - Part 4-21: Data-link layer protocol specification - Type 21 elements
Industrial communication networks - Fieldbus specifications - Part 4-21: Data-link layer protocol specification - Type 21 elements
IEC 61158-4-21:2023 describes:
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;
procedures for giving communication opportunities based on ISO/IEC/IEEE 8802‑3 MAC, with provisions for nodes to be added or removed during normal operation;
structure of the fieldbus data link protocol data units (DLPDUs) used for the transfer of data and control information by the protocol of this document, and their representation as physical interface data units.
Réseaux de communication industriels - Spécifications des bus de terrain - Partie 4-21: Spécification du protocole de la couche liaison de données - Éléments de type 21
L'IEC 61158-4-21:2023 décrit:
des procédures de transfert en temps opportun de données et d’informations de commande d’une entité utilisateur de liaison de données à une entité utilisateur homologue ainsi qu’entre entités de liaison de données qui constituent le fournisseur de services distribués de la liaison;
des procédures offrant des moyens de communication fondées sur la commande d’accès au support (MAC) de l’ISO/IEC/IEEE 8802‑3, ainsi que des dispositions permettant d’ajouter et de retirer des nœuds au cours du fonctionnement normal;
la structure des unités de données de protocole de liaison de données (DLPDU) de bus de terrain utilisées pour le transfert des données et les informations de commande par le protocole objet du présent document, ainsi que leur représentation en tant qu’unités de données d’interface de couche physique.
General Information
Relations
Standards Content (Sample)
IEC 61158-4-21 ®
Edition 3.0 2023-03
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –
Part 4-21: Data-link layer protocol specification – Type 21 elements
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.
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.
IEC 61158-4-21 ®
Edition 3.0 2023-03
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –
Part 4-21: Data-link layer protocol specification – Type 21 elements
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.040.40; 35.100.20; 35.110 ISBN 978-2-8322-6555-0
– 2 – IEC 61158-4-21:2023 © IEC 2023
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 . 10
2 Normative references . 11
3 Terms, definitions, symbols and abbreviated terms . 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 21 definitions . 17
3.5 Common symbols and abbreviations . 17
3.6 Additional Type 21 symbols and abbreviations . 18
4 Overview of the data-link protocol . 18
4.1 General . 18
4.2 Overview of medium access control . 19
4.3 Service assumed from the physical layer . 19
4.4 DLL architecture . 20
4.4.1 General . 20
4.4.2 DLL management (DLM) interface support function . 21
4.5 Data type . 22
4.5.1 General . 22
4.5.2 Boolean . 22
4.5.3 Unsigned integer . 22
4.5.4 Signed integer . 22
4.5.5 Octet String . 23
4.5.6 Visible String . 23
4.5.7 Time of day . 23
4.6 Local parameters and variables . 24
4.6.1 General . 24
4.6.2 DLE configuration parameters . 24
4.6.3 Queues to support data transfer . 25
4.6.4 Variables to support SAP management . 25
4.6.5 Variables to support local device information management . 27
4.6.6 Variables and counter to support network information management . 31
4.6.7 Variables and counter to support a device path information
management . 35
4.6.8 Variables, counters, timers, and queues to support path table
management . 39
5 General structure and encoding . 39
5.1 Overview. 39
5.2 MAPDU structure and encoding . 39
5.3 Common MAC frame structure, encoding and elements of procedure . 40
5.3.1 MAC frame structure . 40
5.3.2 Elements of the MAC frame . 40
5.3.3 Elements of the Type 21 DLPDU . 41
5.4 Order of bit transmission . 49
5.5 Invalid DLPDU . 49
6 DLPDU structure and procedure . 49
6.1 General . 49
6.2 Common DLPDU Field . 49
6.2.1 General . 49
6.2.2 Version . 50
6.2.3 Length . 50
6.3 DL-DATA Transfer . 50
6.3.1 DT DLPDU . 50
6.4 DL-SPDATA Transfer . 53
6.4.1 SPDT DLPDU . 53
6.5 Network control messages . 55
6.5.1 General . 55
6.5.2 NCM_LA DLPDU . 55
6.5.3 NCM_AT DLPDU . 56
6.5.4 NCM_LS DLPDU . 58
6.5.5 NCM_RS DLPDU . 59
6.5.6 NCM_AR_DLPDU . 60
6.5.7 NCM_AR DLPDU structure . 60
7 DLE elements of procedure . 61
7.1 Overall structure . 61
7.2 DL-protocol machine (DLPM) . 61
7.2.1 Overview . 61
7.2.2 Primitive definitions . 61
7.2.3 DLPM state table . 65
7.2.4 DLPM functions . 68
7.3 DLL management Protocol . 70
7.3.1 Overview . 70
7.3.2 Primitive definitions . 70
7.3.3 DLM state table . 73
7.3.4 DLM functions . 97
8 Constants and error codes . 106
8.1 General . 106
8.2 Constants . 106
8.3 Data-link layer error codes . 108
Bibliography . 109
Figure 1 – Interaction of PhS primitives with DLE . 19
Figure 2 – Data-link layer architecture . 21
Figure 3 – Relationships of DLSAPs, DLSAP-addresses, and group DL-addresses . 26
Figure 4 – Common MAC frame format for Type 21 DLPDU . 40
Figure 5 – MAC frame format for other protocols . 40
Figure 6 – Version and Length field . 41
Figure 7 – DST_addr field . 42
– 4 – IEC 61158-4-21:2023 © IEC 2023
Figure 8 – SRC_addr field . 43
Figure 9 – Frame Control Field . 43
Figure 10 – Extension field .
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.