IEC 61158-6-25:2019

Industrial communication networks - Fieldbus specifications - Part 6-25: Application layer protocol specification - Type 25 elements

IEC 61158-6-25:2019 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 2 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 risks failure of the applications requesting the actions, with attendant risk to equipment, plant and possibly human life.
This International Standard specifies interactions between remote applications and defines the externally visible behavior provided by the Type 2 fieldbus application layer. The purpose of this document is to define the protocol provided to
a) define the wire-representation of the service primitives defined in this document, and
b) define the externally visible behavior associated with their transfer. This document specifies the protocol of the Type 2 fieldbus application layer, in conformance with the OSI Basic Reference Model (ISO/IEC 7498-1) and the OSI application layer structure (ISO/IEC 9545).

Réseaux de communication industriels - Spécifications des bus de terrain - Partie 6-25: Spécification du protocole de la couche application - Éléments de type 25

L'IEC 61158-6-25:2019 La couche application de bus de terrain (FAL, Fieldbus Application Layer) fournit aux programmes d’utilisateur un moyen d’accéder à l’environnement de communication du bus de terrain. A cet égard, la FAL peut être vue comme une "fenêtre entre des programmes d'application correspondants".
L'IEC 61158-6-25:2019 fournit les éléments communs pour les communications de messagerie de base prioritaires et non prioritaires entre des programmes d'application dans un environnement d'automation et le matériau spécifique au bus de terrain de type 25. On utilise le terme "prioritaire" pour traduire la présence d’une fenêtre temporelle, à l’intérieur de laquelle une ou plusieurs actions spécifiées doivent être terminées avec un niveau de certitude défini. Si les actions spécifiées ne sont pas réalisées dans la fenêtre temporelle, les applications demandant les actions risquent de connaître une défaillance, avec les risques que cela comporte pour les équipements, les installations et éventuellement la vie humaine.
Le présent document définit de manière abstraite le comportement, visible par un observateur externe, assuré par les différents types de la couche application de bus de terrain, en termes
a) de syntaxe abstraite définissant les unités de données de protocole de la couche application, transmises entre les entités d'application en communication;
b) de syntaxe de transfert définissant les unités de données de protocole de la couche application, transmises entre les entités d'application en communication;
c) de diagramme d'états de contexte d'application définissant le comportement de service d'application observable entre les entités d'application en communication; et
d) de diagrammes d'états de relations d'applications définissant le comportement de communication visible entre les entités d'application en communication.

General Information

• Status: Published
• Publication Date: 19-Jun-2019
• ICS: 25.040.40 - Industrial process measurement and control
• ICS: 35.100.70 - Application layer
• ICS: 35.110 - Networking
• Technical Committee: SC 65C - Industrial networks
• Drafting Committee: WG 9 - TC 65/SC 65C/WG 9
• Current Stage: PPUB - Publication issued
• Start Date: 26-Apr-2019
• Completion Date: 20-Jun-2019

Standards Content (Sample)

IEC 61158-6-25 ®
Edition 1.0 2019-06
INTERNATIONAL
STANDARD
colour
inside
Industrial communication networks – Fieldbus specifications –
Part 6-25: Application layer protocol specification – Type 25 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
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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
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IEC 61158-6-25 ®
Edition 1.0 2019-06
INTERNATIONAL
STANDARD
colour
inside
Industrial communication networks – Fieldbus specifications –

Part 6-25: Application layer protocol specification – Type 25 elements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.040.40; 35.100.70; 35.110 ISBN 978-2-8322-7015-8

– 2 – IEC 61158-6-25:2019 © IEC 2019
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
1.1 General . 10
1.2 Specification . 11
1.3 Conformance . 11
2 Normative references . 11
3 Terms, definitions, symbols, abbreviations and conventions . 12
3.1 Reference model terms and definitions . 12
3.1.1 ISO/IEC 7498-1 terms . 12
3.1.2 ISO/IEC 8822 terms . 12
3.1.3 ISO/IEC 9545 terms . 12
3.1.4 ISO/IEC 8824-1 terms . 13
3.2 Additional Type 25 terms and definitions . 13
3.3 Symbols and abbreviations . 15
3.4 Conventions . 16
3.4.1 General conventions . 16
3.4.2 Conventions for class definitions . 16
3.4.3 Conventions for bit description in octets . 16
3.4.4 Conventions for state machine descriptions . 17
4 FAL syntax description . 18
4.1 FAL PDU type S abstract syntax . 18
4.1.1 Basic abstract syntax . 18
4.2 FAL PDU type N abstract syntax . 22
4.2.1 Basic abstract syntax . 22
4.2.2 CyclicData-PDU . 22
4.2.3 MulticastData-PDU . 23
4.2.4 PtoPData-PDU . 23
4.2.5 Aliveinfo-PDU . 23
4.2.6 Aliveinfo6-PDU . 23
4.2.7 Inq-PDU . 24
4.2.8 Ninq-PDU . 24
4.2.9 Reply-PDU . 24
4.2.10 RetransEnq-PDU . 24
4.2.11 RetransConfirm-PDU . 24
4.2.12 RetransNak-PDU . 25
4.3 Data type assignments for type S . 25
4.4 Data type assignments for type N . 25
5 FAL transfer syntax . 26
5.1 Encoding rules . 26
5.1.1 Unsigned encoding . 26
5.1.2 Octet string encoding . 27
5.1.3 SEQUENCE encoding . 27
5.2 FALPDU type S elements encoding. 27
5.2.1 RCL_header . 27
5.2.2 RHE-PDU . 28

5.2.3 LCC-PDU . 30
5.2.4 LCA-PDU . 30
5.2.5 LCN-PDU . 31
5.2.6 LNA-PDU . 32
5.2.7 SCR-PDU . 32
5.2.8 Cyclic_S-PDU . 32
5.2.9 Cyclic_header . 33
5.2.10 Control-PDU . 33
5.2.11 RMTCTL-PDU. 33
5.2.12 INFO-PDU . 34
5.3 FALPDU type N elements encoding . 35
5.3.1 General . 35
5.3.2 FALAR-N Header . 35
5.3.3 CyclicData-PDU . 49
5.3.4 MulticastData-PDU . 50
5.3.5 PtoP Data-PDU. 50
5.3.6 Aliveinfo-PDU . 50
5.3.7 Aliveinfo6-PDU . 53
5.3.8 Inq-PDU . 54
5.3.9 Ninq-PDU . 55
5.3.10 Reply-PDU . 55
5.3.11 RetransEnq-PDU . 56
5.3.12 RetransConfirm-PDU . 56
5.3.13 RetransNak-PDU . 57
6 Structure of the FAL protocol state machine . 58
7 FAL service protocol machine (FSPM) . 58
7.1 Overview. 58
7.2 FSPM type S . 58
7.2.1 Overview . 58
7.2.2 Interface of cyclic communication to FAL users . 59
7.2.3 State machine of FSPM . 61
7.3 FSPM type N . 62
7.3.1 Overview . 62
7.3.2 FSPM . 63
8 Application relationship protocol machine (ARPM) . 65
8.1 ARPM type S . 65
8.1.1 Overview . 65
8.1.2 Cyclic control . 66
8.1.3 Remote control . 70
8.1.4 RCL communication control . 75
8.1.5 RT communication control . 79
8.2 ARPM type N . 83
8.2.1 Overview . 83
8.2.2 General control . 83
8.2.3 Cyclic transmission control . 85
8.2.4 Acyclic transmission control . 90
8.2.5 RT communication control . 105
9 DLL mapping protocol machine (DMPM) . 121

– 4 – IEC 61158-6-25:2019 © IEC 2019
9.1 DMPM type S .
...

IEC 61158-6-25 ®
Edition 1.0 2019-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Industrial communication networks – Fieldbus specifications –
Part 6-25: Application layer protocol specification – Type 25 elements

Réseaux de communication industriels – Spécifications des bus de terrain –
Partie 6-25: Spécification du protocole de la couche application – Éléments
de type 25
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.

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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 Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and
once a month by email. French extracted from the Terms and Definitions clause of
IEC publications issued since 2002. Some entries have been
IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and
If you wish to give us your feedback on this publication or CISPR.

need further assistance, please contact the Customer Service

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IEC 61158-6-25 ®
Edition 1.0 2019-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Industrial communication networks – Fieldbus specifications –

Part 6-25: Application layer protocol specification – Type 25 elements

Réseaux de communication industriels – Spécifications des bus de terrain –

Partie 6-25: Spécification du protocole de la couche application – Éléments

de type 25
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040.40; 35.100.70; 35.110 ISBN 978-2-8322-9173-3

– 2 – IEC 61158-6-25:2019 © IEC 2019
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
1.1 General . 10
1.2 Specification . 11
1.3 Conformance . 11
2 Normative references . 11
3 Terms, definitions, symbols, abbreviations and conventions . 12
3.1 Reference model terms and definitions . 12
3.1.1 ISO/IEC 7498-1 terms . 12
3.1.2 ISO/IEC 8822 terms . 12
3.1.3 ISO/IEC 9545 terms . 12
3.1.4 ISO/IEC 8824-1 terms . 13
3.2 Additional Type 25 terms and definitions . 13
3.3 Symbols and abbreviations . 15
3.4 Conventions . 16
3.4.1 General conventions . 16
3.4.2 Conventions for class definitions . 16
3.4.3 Conventions for bit description in octets . 16
3.4.4 Conventions for state machine descriptions . 17
4 FAL syntax description . 18
4.1 FAL PDU type S abstract syntax . 18
4.1.1 Basic abstract syntax . 18
4.2 FAL PDU type N abstract syntax . 22
4.2.1 Basic abstract syntax . 22
4.2.2 CyclicData-PDU . 22
4.2.3 MulticastData-PDU . 23
4.2.4 PtoPData-PDU . 23
4.2.5 Aliveinfo-PDU . 23
4.2.6 Aliveinfo6-PDU . 23
4.2.7 Inq-PDU . 24
4.2.8 Ninq-PDU . 24
4.2.9 Reply-PDU . 24
4.2.10 RetransEnq-PDU . 24
4.2.11 RetransConfirm-PDU . 24
4.2.12 RetransNak-PDU . 25
4.3 Data type assignments for type S . 25
4.4 Data type assignments for type N . 25
5 FAL transfer syntax . 26
5.1 Encoding rules . 26
5.1.1 Unsigned encoding . 26
5.1.2 Octet string encoding . 27
5.1.3 SEQUENCE encoding . 27
5.2 FALPDU type S elements encoding. 27
5.2.1 RCL_header . 27
5.2.2 RHE-PDU . 28

5.2.3 LCC-PDU . 30
5.2.4 LCA-PDU . 30
5.2.5 LCN-PDU . 31
5.2.6 LNA-PDU . 32
5.2.7 SCR-PDU . 32
5.2.8 Cyclic_S-PDU . 32
5.2.9 Cyclic_header . 33
5.2.10 Control-PDU . 33
5.2.11 RMTCTL-PDU. 33
5.2.12 INFO-PDU . 34
5.3 FALPDU type N elements encoding . 35
5.3.1 General . 35
5.3.2 FALAR-N Header . 35
5.3.3 CyclicData-PDU . 49
5.3.4 MulticastData-PDU . 50
5.3.5 PtoP Data-PDU. 50
5.3.6 Aliveinfo-PDU . 50
5.3.7 Aliveinfo6-PDU . 53
5.3.8 Inq-PDU . 54
5.3.9 Ninq-PDU . 55
5.3.10 Reply-PDU . 55
5.3.11 RetransEnq-PDU . 56
5.3.12 RetransConfirm-PDU . 56
5.3.13 RetransNak-PDU . 57
6 Structure of the FAL protocol state machine .
...