SIST EN 61158-6-20:2015

Industrial communication networks - Fieldbus specifications - Part 6-20: Application layer protocol specification - Type 20 elements (IEC 61158-6-20:2014)

IEC 61158-6-20:2014 defines the protocol provided to define the wire-representation of the service primitives defined in IEC 61158-5-20, and define the externally visible behavior associated with their transfer. This standard specifies the protocol of the Type 20 fieldbus application layer, in conformance with the OSI Basic Reference Model (ISO/IEC 7498-1) and the OSI application layer structure (ISO/IEC 9545). This third edition cancels and replaces the second edition published in 2010 and constitutes a technical revision. The main changes are:
- added protocol for new services that are added to IEC 61158-5-20;
- added normative annexes;
- updated then references, terms, definitions, symbols, abbreviations;
- corrected the editorial errors and the text.

Industrielle Kommunikationsnetze - Feldbusse - Teil 6-20: Protokollspezifikation des Application Layer (Anwendungsschicht) - Typ 20-Elemente (IEC 61158-6-20:2014)

Réseaux de communication industriels - Spécifications des bus de terrain - Partie 6-20: Spécification du protocole de la couche application - Eléments de type 20 (CEI 61158-6-20:2014)

L'IEC 61158-6-20:2014 décrit le protocole mis en place pour définir la représentation filaire des primitives de service définies dans la CEI 61158-5-20 et définir le comportement visible de l'extérieur associé à leur transfert. La présente norme spécifie le protocole de la couche application de bus de terrain de Type 20, en conformité avec le modèle de référence de base OSI (ISO/CEI 7498-1) et la structure de la couche application OSI (ISO/CEI 9545). Cette troisième édition annule et remplace la deuxième édition parue en 2010. Elle constitue une révision technique. Les principales modifications sont:
- ajout d'un protocole pour les nouveaux services ajoutés à la CEI 61158-5-20;
- ajout d'annexes normatives;
- mise à jour des références normatives, termes, définitions, symboles, abréviations;
- correction des erreurs rédactionnelles et syntaxiques.

Industrijska komunikacijska omrežja - Specifikacije za procesna vodila - 6-20. del: Specifikacija protokola na aplikacijski ravni - Elementi tipa 20 (IEC 61158-6-20:2014)

Namen standarda IEC 61158-6-20:2014 je opredeliti protokol za določitev žične predstavitve primitivov opravil iz standarda IEC 61158-5-20 in določitev zunanje vidnega vedenja, povezanega z njihovim prenosom. Ta standard določa protokol aplikacijskega nivoja procesnih vodil tipa 20 v skladu z osnovnim referenčnim modelom OSI (ISO/IEC 7498-1) in strukturo aplikacijskega nivoja OSI (ISO/IEC 9545). Ta tretja izdaja razveljavlja in nadomešča drugo izdajo, objavljeno leta 2010, in predstavlja tehnično popravljeno izdajo. Glavne spremembe so:
– dodan protokol za nova opravila, dodana v IEC 61158-5-20;
– dodane normativne priloge;
– posodobljene reference, izrazi, definicije, simboli, kratice;
– popravljene redakcijske napake in besedilo.

General Information

• Status: Published
• Publication Date: 19-Jan-2015
• ICS: 25.040.40 - Industrial process measurement and control
• ICS: 35.100.70 - Application layer
• ICS: 35.110 - Networking
• Technical Committee: MOV - Measuring equipment for electromagnetic quantities
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 11-Nov-2014
• Due Date: 16-Jan-2015
• Completion Date: 20-Jan-2015
• Mandate: M/490 - Standardisation mandate to the European Standardisation Organisations (ESOs) to support European Smart Grid deployment
• Ref Project: EN 61158-6-20:2014 - Industrial communication networks - Fieldbus specifications - Part 6-20: Application layer protocol specification - Type 20 elements

Relations

• Replaces: SIST EN 61158-6-20:2012 - Industrial communication networks - Fieldbus specifications - Part 6-20: Application layer protocol specification - Type 20 elements (IEC 61158-6-20:2010)
• Effective Date: 01-Feb-2015
• Parent: SIST EN 61158-6-2:2015 - Industrial communication networks - Fieldbus specifications - Part 6-2: Application layer protocol specification - Type 2 elements (IEC 61158-6-2:2014)
• Effective Date: 07-Jun-2022
• Parent: SIST EN 61158-6-2:2015 - Industrial communication networks - Fieldbus specifications - Part 6-2: Application layer protocol specification - Type 2 elements (IEC 61158-6-2:2014)
• Effective Date: 24-Mar-2020
• Parent: SIST EN 61158-6-2:2015 - Industrial communication networks - Fieldbus specifications - Part 6-2: Application layer protocol specification - Type 2 elements (IEC 61158-6-2:2014)
• Effective Date: 23-Jun-2020

Overview - SIST EN 61158-6-20:2015 (IEC 61158-6-20:2014)

SIST EN 61158-6-20:2015 specifies the application layer protocol for Type 20 fieldbus elements within the IEC 61158 family. Aligned with the OSI Basic Reference Model (ISO/IEC 7498-1) and the OSI application layer structure (ISO/IEC 9545), this edition defines the wire-level representation and externally visible behavior of service primitives described in IEC 61158-5-20. This third edition replaces the 2010 version and adds protocol support for new services, introduces normative annexes, updates references/definitions, and corrects editorial errors.

Key topics and technical requirements

• Application layer protocol (FAL): Defines the Fieldbus Application Layer (FAL) protocol for Type 20, mapping service primitives to on‑the‑wire messages.
• Abstract and transfer syntax: APDU (Application Protocol Data Unit) structures, common APDU fields, and device application service–specific APDUs.
• Data coding rules: Encoding for integers, unsigned types, single/double precision floats, dates and structured data as used by Type 20.
• Common procedures: Publish mode procedures, delayed responses and other application-level behaviors.
• Protocol state machines: Client and server ARPM/FAL state machines and their transitions, including error and recovery behavior.
• Device and variable models: Definitions for device variables, dynamic/primary variables, status reporting and device families (normative annexes).
• Command and error handling: Stateless and multi-transaction commands, read/write/action/indexed commands and standardized response codes.
• Normative annexes and tables: Status codes, publish trigger modes, device family/classification codes and other standardized tables required for interoperable implementations.

Practical applications and who uses this standard

• Fieldbus device manufacturers implementing Type 20 application-layer behavior and APDU encodings.
• Automation and control system vendors integrating Type 20 fieldbus devices into process measurement and control systems.
• Protocol stack developers and embedded software engineers building conformance-compliant firmware.
• System integrators and testers validating interoperability, state-machine behavior and publish/subscribe procedures.
• Standards bodies and certification labs referencing normative tables and annexes for conformance testing.

Related standards (normative references)

• IEC 61158-5-20 - Application layer service definition (Type 20)
• IEC 61158-1 - Overview and guidance for IEC 61158 / IEC 61784
• ISO/IEC 7498-1 - OSI Basic Reference Model
• ISO/IEC 9545 - OSI application layer structure
• IEC 62591 (WirelessHART), IEC 61784 series, IEEE 802.15.4 (referenced in bibliography)

By following SIST EN 61158-6-20:2015 / IEC 61158-6-20:2014, implementers achieve consistent, interoperable application‑layer behavior for Type 20 fieldbus devices - essential for reliable industrial communication in process control and automation systems.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Industrijska komunikacijska omrežja - Specifikacije za procesna vodila - 6-20. del: Specifikacija protokola na aplikacijski ravni - Elementi tipa 20 (IEC 61158-6-20:2014)Industrielle Kommunikationsnetze - Feldbusse - Teil 6-20: Protokollspezifikation des Application Layer (Anwendungsschicht) - Typ 20-Elemente (IEC 61158-6-20:2014)Réseaux de communication industriels -
Spécifications des bus de terrain - Partie 6-20: Spécification du protocole de la couche application - Eléments de type 20 (CEI 61158-6-20:2014)Industrial communication networks - Fieldbus specifications - Part 6-20: Application layer protocol specification - Type 20 elements (IEC 61158-6-20:2014)35.110OmreževanjeNetworking35.100.70Uporabniški slojApplication layer25.040.40Merjenje in krmiljenje industrijskih postopkovIndustrial process measurement and controlICS:Ta slovenski standard je istoveten z:EN 61158-6-20:2014SIST EN 61158-6-20:2015en,fr,de01-marec-2015SIST EN 61158-6-20:2015SLOVENSKI
STANDARDSIST EN 61158-6-20:20121DGRPHãþD

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 61158-6-20
October 2014 ICS 25.040.40; 35.100.70; 35.110
Supersedes
EN 61158-6-20:2012
English Version
Industrial communication networks - Fieldbus specifications - Part 6-20: Application layer protocol specification - Type 20 elements (IEC 61158-6-20:2014)
Réseaux de communication industriels -
Spécifications des bus de terrain - Partie 6-20: Spécification du protocole de la couche application - Eléments de type 20 (CEI 61158-6-20:2014)
Industrielle Kommunikationsnetze - Feldbusse - Teil 6-20: Protokollspezifikation des Application Layer (Anwendungsschicht) - Typ 20-Elemente (IEC 61158-6-20:2014) This European Standard was approved by CENELEC on 2014-09-23. 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, 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 61158-6-20:2014 E SIST EN 61158-6-20:2015

This document supersedes EN 61158-6-20:2012.
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 61158-6-20:2014 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 61784-1 NOTE Harmonized as EN 61784-1. IEC 61784-2 NOTE Harmonized as EN 61784-2. SIST EN 61158-6-20:2015

- 3 - EN 61158-6-20:2014 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 61158-1 2014
Industrial communication networks - Fieldbus specifications - Part 1: Overview and guidance for the IEC 61158 and IEC 61784 series EN 61158-1 2014
IEC 61158-5-20 2014
Industrial communication networks - Fieldbus specifications - Part 5-20: Application layer service definition - Type 20 elements EN 61158-5-20 2014 IEC 62591 2010
Industrial communication networks - Wireless communication network and communication profiles - WirelessHART™ EN 62591 2010
ISO/IEC 7498-1 -
Information technology - Open Systems Interconnection - Basic reference model: The basic model - -
ISO/IEC 8824-1 -
Information technology - Abstract Syntax Notation One (ASN.1): Specification of basic notation - -
ISO/IEC 8859-1 -
Information technology - 8-bit single-byte coded graphic character sets - Part-1: Latin alphabet No. 1 - -
ISO/IEC 9545 -
Information technology - Open Systems Interconnection - Application layer structure - -
ISO/IEC/IEEE 60559 -
Information technology - Microprocessor Systems - Floating-Point arithmetic - -
IEEE 802.15.4 -
IEEE Standard for Local and metropolitan area networks - Part 15.4: Low-Rate Wireless Personal Area Networks (LR-WPANs) - -
IEC 61158-6-20 Edition 3.0 2014-08 INTERNATIONAL STANDARD NORME INTERNATIONALE Industrial communication networks – Fieldbus specifications –
Part 6-20: Application layer protocol specification – Type 20 elements
Réseaux de communication industriels – Spécifications des bus de terrain –
Partie 6-20: Spécification du protocole de la couche application – Eléments
de type 20
INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE XC ICS 25.040.40; 35.100.70; 35.110 PRICE CODE CODE PRIX ISBN 978-2-8322-1766-5
– 2 – IEC 61158-6-20:2014 © IEC 2014 CONTENTS FOREWORD . 7 INTRODUCTION . 9 1 Scope . 10 2 Normative references . 10 3 Terms, definitions, symbols, abbreviations and conventions . 11 3.1 Terms and definitions from other ISO/IEC standards . 11 3.2 IEC 61158-1 terms . 12 3.3 Type 20 fieldbus application-layer specific definitions . 14 3.4 Abbreviations and symbols . 17 3.5 Conventions . 18 3.6 Conventions used in state machines . 18 4 Abstract syntax . 20 5 Transfer syntax . 20 5.1 Common APDU fields . 20 5.2 Common APDU structure . 22 5.3 Device application service-specific APDU structures . 24 5.4 Data coding rules . 51 6 Common procedures . 56 6.1 Delayed response . 56 6.2 Publish mode procedure . 56 7 FAL protocol state machines . 56 7.1 General . 56 7.2 AREP mapping to data link layer . 57 7.3 Client ARPM . 58 7.4 Server ARPM . 60 7.5 Functions used by FAL state machines . 61 Annex A (normative)
Application process status . 63 A.1 General . 63 A.2 Device malfunction . 63 A.3 Configuration changed . 63 A.4 Cold start . 64 A.5 More status available . 64 A.6 Loop current fixed . 64 A.7 Loop current saturated . 64 A.8 Non-primary variable out of limits . 65 A.9 Primary variable out of limits . 65 Annex B (normative)
Device and dynamic variable . 66 B.1 Device variable . 66 B.2 Dynamic variable . 66 B.3 Primary variable . 67 B.4 Device variable classification . 68 B.5 Device families . 68 B.6 Device variable status . 68 Annex C (normative)
Common tables . 70 C.1 Overview . 70 SIST EN 61158-6-20:2015

IEC 61158-6-20:2014 © IEC 2014 – 3 – C.1.1 General . 70 C.1.2 Enumeration . 70 C.1.3 Bit Field . 70 C.2 Table definitions . 70 C.2.1 Publish mode control codes . 70 C.2.2 Write device variable codes . 70 C.2.3 Device variable family codes . 70 C.2.4 Device variable classification codes . 70 C.2.5 Analog channel saturated codes . 70 C.2.6 Analog channel fixed codes . 70 C.2.7 Standardized status 0 codes . 71 C.2.8 Standardized status 1 codes . 71 C.2.9 Standardized status 2 codes . 71 C.2.10 Standardized status 3 codes . 71 C.2.11 Publish trigger mode codes . 71 C.2.12 Transfer function codes . 71 C.2.13 Alarm Selection Codes . 71 C.2.14 Write Protect Codes. 72 C.2.15 Physical layer signalling codes . 72 C.2.16 Flag Assignment codes . 72 C.2.17 Loop current mode codes . 73 C.2.18 Trim point codes . 73 C.2.19 Analog channel flag codes . 73 C.2.20 Device variable codes . 73 C.2.21 Device profile codes . 74 Annex D (normative)
Command requirements . 75 D.1 General . 75 D.2 Stateless request and response. 75 D.3 Read command . 75 D.4 Write command . 75 D.5 Action command . 75 D.6 Indexed command . 76 D.7 Multi-transaction command . 76 Bibliography . 77
Figure 1 – Request APDU . 22 Figure 2 – Normal response APDU . 22 Figure 3 – Command error response from slave to master . 23 Figure 4 – Aggregated command APDU . 24 Figure 5 – Coding without identification. 51 Figure 6 – Coding of Integer type data . 51 Figure 7 – Coding of Integer16 type data . 52 Figure 8 – Coding of Unsigned type data . 52 Figure 9 – Coding of Unsigned16 type data . 52 Figure 10 – Coding of single precision Floating Point type data . 52 Figure 11 – Coding of double precision Floating Point type data . 53 Figure 12 – Coding of Date type data . 53 SIST EN 61158-6-20:2015

– 4 – IEC 61158-6-20:2014 © IEC 2014 Figure 13 – Client state machine . 58 Figure 14 – Server state machine . 60 Figure A.1 – Loop current saturation and alarm levels . 65 Figure B.1 – Device and Dynamic variables . 66 Figure B.2 – Primary variable domains . 67 Figure B.3 – Device variable status . 69
Table 1 – Conventions used for state machines . 19 Table 2 – Response code values . 20 Table 3 – Application process status values . 21 Table 4 – Extended status values . 21 Table 5 – Identify request APDU . 24 Table 6 – Identify response value field . 25 Table 7 – Identify command specific response codes . 25 Table 8 – Read primary variable response value field . 26 Table 9 – Read primary variable command specific response codes . 26 Table 10 – Read loop current and percent of range value field . 26 Table 11 – Read loop current and percent of range command specific response codes . 27 Table 12 – Read dynamic variables and loop current value field . 27 Table 13 – Read dynamic variables and loop current command specific response codes . 27 Table 14 – Write loop configuration value field . 28 Table 15 – Write loop configuration command specific response codes . 28 Table 16 – Read loop configuration value field . 29 Table 17 – Read loop configuration command specific response codes . 29 Table 18 – Read dynamic variable families classifications value field . 29 Table 19 – Read dynamic variable families classifications command specific response codes . 29 Table 20 – Read device variables with status request value field . 30 Table 21 – Read device variables with status value field . 30 Table 22 – Read device variables with status command specific response codes. 31 Table 23 – Read message response value field . 32 Table 24 – Read message command specific response codes . 32 Table 25 – Read tag, descriptor, date response value field . 33 Table 26 – Read tag, descriptor, date command specific response codes . 33 Table 27 – Read primary variable transducer information response value field . 33 Table 28 – Read primary variable transducer information command specific response codes . 34 Table 29 – Read device information response value field . 34 Table 30 – Read device information command specific response codes . 35 Table 31 – Read final assembly number response value field . 35 Table 32 – Read final assembly number command specific response codes . 35 Table 33 – Write message value field . 35 Table 34 – Write message command specific response codes . 36 SIST EN 61158-6-20:2015

IEC 61158-6-20:2014 © IEC 2014 – 5 – Table 35 – Write tag, descriptor, date value field . 36 Table 36 – Write tag, descriptor, date command specific response codes . 36 Table 37 – Write final assembly number value field . 37 Table 38 – Write final assembly number command specific response codes . 37 Table 39 – Read long tag response value field . 37 Table 40 – Read long tag command-specific response codes . 37 Table 41 – Write long tag value field . 38 Table 42 – Write long tag command specific Response codes . 38 Table 43 – Write primary variable range value field . 39 Table 44 – Write primary variable range command specific response codes . 39 Table 45 – Enter-exit fixed current mode request value field . 40 Table 46 – Enter-exit fixed current mode response value field. 40 Table 47 – Enter-exit fixed current mode command specific response codes . 40 Table 48 – Write primary variable unit value field . 41 Table 49 – Write primary variable unit command specific response codes . 41 Table 50 – Trim loop current zero request value field . 41 Table 51 – Trim loop current zero command specific response codes . 41 Table 52 – Trim loop current gain request value field . 42 Table 53 – Trim loop current gain command specific response codes . 42 Table 54 – Read dynamic variable assignment response value field . 43 Table 55 – Read dynamic variable assignment command specific response codes . 43 Table 56 – Write dynamic variable assignment value field . 44 Table 57 – Write dynamic variable assignment command specific response codes . 44 Table 58 – Write number of response preambles value field. 45 Table 59 – Write number of response preambles command specific response codes . 45 Table 60 – Read device variable trim points request value field . 45 Table 61 – Read device variable trim points response value field . 46 Table 62 – Read device variable trim points command specific response codes . 46 Table 63 – Read device variable trim guidelines request value field . 46 Table 64 – Read device variable trim guidelines response value field . 46 Table 65 – Read device variable trim points command specific response codes . 47 Table 66 – Write device variable trim point value field . 47 Table 67 – Write device variable trim point command specific response codes . 48 Table 68 – Reset device variable trim value field . 48 Table 69 – Reset device variable trim command specific response codes . 49 Table 70 – Aggregated command specific response codes . 50 Table 71 – Coding for Date type . 53 Table 72 – Coding for one octet Enumerated Type . 54 Table 73 – One octet bit field . 54 Table 74 – Packed ASCII character set . 55 Table 75 – Acceptable subset of ISO Latin-1 characters . 56 Table 76 – Client machine state transitions . 59 Table 77 – Server machine state transitions . 61 SIST EN 61158-6-20:2015

– 6 – IEC 61158-6-20:2014 © IEC 2014 Table 78 – Function FormReqApdu . 61 Table 79 – Function Command . 61 Table 80 – Function CommErr. 61 Table 81 – Function RespCode . 62 Table 82 – Function Commcode . 62 Table 83 – Function ApStatus . 62 Table 84 – Function Value . 62 Table A.1 – Commands that cause configuration change . 63 Table C.1 – Transfer function codes . 71 Table C.2 – Alarm Selection codes . 72 Table C.3 – Write Protect codes . 72 Table C.4 – Physical layer signalling codes . 72 Table C.5 – Flag Assignment codes . 73 Table C.6 – Loop current mode codes . 73 Table C.7 – Trim point codes . 73 Table C.8 – Analog channel flag codes . 73 Table C.9 – Device variable codes . 74
IEC 61158-6-20:2014 © IEC 2014 – 7 – INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 6-20: Application layer protocol specification –
Type 20 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 61158-6-20 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.
– 8 – IEC 61158-6-20:2014 © IEC 2014 The main changes with respect to the previous edition are listed below: a) added protocol for new services that are added to IEC 61158-5-20; b) added normative annexes; c) updated then references, terms, definitions, symbols, abbreviations; d) corrected the editorial errors and the text. The text of this standard is based on the following documents: FDIS Report on voting 65C/764/FDIS 65C/774/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 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 "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 61158-6-20:2014 © IEC 2014 – 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 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 standard 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 implementors 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 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.
– 10 – IEC 61158-6-20:2014 © IEC 2014 INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 6-20: Application layer protocol specification –
Type 20 elements
1 Scope The Fieldbus Application Layer (FAL) provides user programs with a means to access the fieldbus communication environment. In this respect, the FAL can be viewed as a “window between corresponding application programs.” This standard 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 20 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 standard defines in an abstract way the externally visible behavior provided by the Type 20 of the fieldbus Application Layer in terms of a) the abstract syntax defining the application layer protocol data units conveyed between communicating application entities, b) the transfer syntax defining the application layer protocol data units conveyed between communicating application entities, c) the application context state machine defining the application service behavior visible between communicating application entities; and d) the application relationship state machines defining the communication behavior visible between communicating application entities; and. The purpose of this standard is to define the protocol provided to define a) the wire-representation of the service primitives defined in IEC 61158-5-20, and b) the externally visible behavior associated with their transfer. This standard specifies the protocol of the Type 20 IEC fieldbus application layer, in conformance with the OSI Basic Reference Model (ISO/IEC 7498-1) and the OSI Application Layer Structure (ISO/IEC 9545). 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 61158-1:2014, Industrial communication networks – Fieldbus specifications – Part 1: Overview and guidance for the IEC 61158 and IEC 61784 series SIST EN 61158-6-20:2015

IEC 61158-6-20:2014 © IEC 2014 – 11 – IEC 61158-5-20:2014, Industrial communication networks – Fieldbus specifications – Part 5-20: Application layer service definition – Type 20 elements IEC 62591:2010, Industrial communication networks – Wireless communication network and communication profiles – WirelessHART™ ISO/IEC 7498-1, Information technology – Open Systems Interconnection – Basic Reference Model: The Basic Model ISO/IEC 8824-1, Information technology – Abstract Syntax Notation One (ASN.1): Specification of basic notation ISO/IEC 8859-1, Information technology – 8-bit single-byte coded graphic character sets – Part 1: Latin alphabet No. 1 ISO/IEC 9545, Information technology – Open Systems Interconnection – Application Layer structure ISO/IEC/IEEE 60559, Information technology – Microprocessor Systems – Floating-Point arithmetic IEEE 802.15.4: IEEE Standard for Local and metropolitan area networks – Part 15.4: Low-Rate Wireless Personal Area Networks (LR-WPANs) 3 Terms, definitions, symbols, abbreviations and conventions For the purposes of this document, the following terms, definitions, symbols, abbreviations and conventions apply.
Terms and definitions from other ISO/IEC standards 3.1 Terms and definitions from ISO/IEC 7498-1 3.1.1a) abstract syntax b) application entity c) application process d) application protocol data unit e) application service element f) application entity invocation g) application process invocation h) transfer syntax
Terms and definitions from ISO/IEC 9545 3.1.2a) application-entity-invocation b) application-process-invocation c) application-service-element
Terms and definitions from ISO/IEC 8824-1 3.1.3a) object identifier b) type c) value d) simple type SIST EN 61158-6-20:2015

– 12 – IEC 61158-6-20:2014 © IEC 2014 e) structured type f) component type g) tag h) true i) false j) integer type k) octet string type m) null type
Terms and definitions from ISO/IEC 8825-1 3.1.4a) encoding (of a data value) b) data value c) identifier octets (the singular form is used in this standard) d) length octet(s) (both singular and plural forms are used in this standard) e) contents octets
IEC 61158-1 terms 3.2
3.2.1application function or data structure for which data is consumed or produced
3.2.2application object object class that manages and provides the run time exchange of messages across the network and within the network device Note 1 to entry:
Multiple types of application object classes may be defined.
3.2.3application process part of a distributed application on a network, which is located on one device and unambiguously addressed
3.2.4application process object component of an application process that is identifiable and accessible through an FAL application relationship Note 1 to entry:
Application process object definitions are composed of a set of values for the attributes of their class (see the definition for Application Process Object Class Definition). Application process object definitions may be accessed remotely using the services of the FAL Object Management ASE. FAL Object Management services can be used to load or update object definitions, to read object definitions, and to dynamically create and delete application objects and their corresponding definitions.
3.2.5application process object class class of application process objects defined in terms of the set of their network-accessible attributes and services
3.2.6application relationship cooperative association between two or more application-entity-invocations for the purpose of exchange of information and coordination of their joint operation Note 1 to entry:
This relationship is activated either by the exchange of application-protocol-data-units or as a result of pre-configuration activities. SIST EN 61158-6-20:2015

IEC 61158-6-20:2014 © IEC 2014 – 13 –
3.2.7application relationship endpoint context and behavior of an application relationship as seen and maintained by one of the application processes involved in the application relationship Note 1 to entry:
Each application process involved in the application relationship maintains its own application relationship endpoint.
3.2.8attribute description of an externally visible characteristic or feature of an object Note 1 to entry:
The attributes of an object contain information about variable portions of an object. Typically, they provide status information or govern the operation of an object. Attributes may also affect the behaviour of an object. Attributes are divided into class attributes and
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