IEC 61131-3:2003

Programmable controllers - Part 3: Programming languages

IEC 61131-3:2003 specifies syntax and semantics of programming languages for programmable controllers as defined in part 1 of IEC 61131. This second edition of IEC 61131-3 cancels and replaces the first edition, published in 1993, and constitutes a technical revision. This bilingual version (2015-06) corresponds to the English version, published in 2003-01.

Automates programmables - Partie 3: Langages de programmation

L'IEC 61131-3:2003 spécifie la syntaxe et la sémantique des langages de programmation utilisés pour les automates programmables tels que définis dans la Partie 1 de la CEI 61131. Cette seconde édition de la CEI 61131-3 annule et remplace la première édition publiée en 1993, dont elle constitue une révision technique. La présente version bilingue (2015-06) correspond à la version anglaise monolingue publiée en 2003-01.

General Information

• Status: Published
• Publication Date: 20-Jan-2003
• ICS: 25.040.40 - Industrial process measurement and control
• ICS: 35.240.50 - IT applications in industry
• Technical Committee: SC 65B - Measurement and control devices
• Drafting Committee: WG 7 - TC 65/SC 65B/WG 7
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 20-Feb-2013

Relations

• Revised: IEC 61131-3:2013 - Programmable controllers - Part 3: Programming languages
• Effective Date: 05-Sep-2023
• Revises: IEC 61131-3:1993 - Programmable controllers - Part 3: Programming languages
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61131-3
Edition 2.0 2003-01
INTERNATIONAL
STANDARD
Programmable controllers –
Part 3: Programming languages
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.
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please contact the address below or your local IEC member National Committee for further information.

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IEC 61131-3 ®
Edition 2.0 2003-01
INTERNATIONAL
STANDARD
Programmable controllers –
Part 2: Equipment requirements and tests

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XH
CODE PRIX
ICS 25.040; 35.240.50 ISBN 2-8318-6653-7

– 2 – 61131-3  IEC:2003(E)
CONTENTS
FOREWORD .8
1  General.9
1.1 Scope.9
1.2 Normative references .9
1.3 Definitions.9
1.4 Overview and general requirements .14
1.4.1 Software model.14
1.4.2 Communication model.16
1.4.3 Programming model .18
1.5 Compliance.19
1.5.1 System compliance .20
1.5.2 Program compliance.22
2 Common elements .23
2.1 Use of printed characters .23
2.1.1 Character set .23
2.1.2 Identifiers .23
2.1.3 Keywords.24
2.1.4 Use of white space .24
2.1.5 Comments .24
2.1.6 Pragmas .25
2.2 External representation of data .25
2.2.1 Numeric literals.25
2.2.2 Character string literals .26
2.2.3 Time literals .28
2.2.3.1 Duration .28
2.2.3.2 Time of day and date.29
2.3 Data types .29
2.3.1 Elementary data types.30
2.3.2 Generic data types .31
2.3.3 Derived data types.32
2.3.3.1 Declaration .32
2.3.3.2 Initialization.33
2.3.3.3 Usage .35
2.4 Variables.36
2.4.1 Representation .36
2.4.1.1 Single-element variables .36
2.4.1.2 Multi-element variables .38
2.4.2 Initialization.38
2.4.3 Declaration .39
2.4.3.1 Type assignment .41
2.4.3.2 Initial value assignment.42
2.5 Program organization units .45
2.5.1 Functions .45
2.5.1.1 Representation .46
2.5.1.2 Execution control.49
2.5.1.3 Declaration .50
2.5.1.4 Typing, overloading, and type conversion.52
2.5.1.5 Standard functions.55
2.5.1.5.1 Type conversion functions.55
2.5.1.5.2 Numerical functions.56
2.5.1.5.3 Bit string functions .59
2.5.1.5.4 Selection and comparison functions.59
2.5.1.5.5 Character string functions .62
2.5.1.5.6 Functions of time data types .64
2.5.1.5.7 Functions of enumerated data types.66

61131-3  IEC:2003(E) – 3 –
2.5.2 Function blocks.66
2.5.2.1 Representation .67
2.5.2.1a) Use of EN and ENO in function blocks .68
2.5.2.2 Declaration .69
2.5.2.3 Standard function blocks.77
2.5.2.3.1 Bistable elements .77
2.5.2.3.2 Edge detection.78
2.5.2.3.3 Counters .78
2.5.2.3.4 Timers.81
2.5.2.3.5 Communication function blocks.83
2.5.3 Programs.83
2.6 Sequential Function Chart (SFC) elements.84
2.6.1 General.84
2.6.2 Steps.84
2.6.3 Transitions .86
2.6.4 Actions.89
2.6.4.1 Declaration .89
2.6.4.2 Association with steps .91
2.6.4.3 Action blocks .92
2.6.4.4 Action qualifiers .93
2.6.4.5 Action control.94
2.6.5 Rules of evolution.99
2.6.6 Compatibility of SFC elements.107
2.6.7 SFC Compliance requirements .108
2.7 Configuration elements.108
2.7.1 Configurations, resources, and access paths .110
2.7.2 Tasks .114
3 Textual languages .
...

IEC 61131-3 ®
Edition 2.0 2003-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Programmable controllers –
Part 3: Programming languages
Automates programmables –
Partie 3: Langages de programmation

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
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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 corrigenda or an amendment might have been published.

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IEC 61131-3 ®
Edition 2.0 2003-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Programmable controllers –
Part 3: Programming languages
Automates programmables –
Partie 3: Langages de programmation

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040; 35.240.50 ISBN 978-2-8322-2616-2

– 2 – IEC 61131-3:2003  IEC 2003
CONTENTS
FOREWORD . 8
1  General . 9
1.1 Scope . 10
1.2 Normative references . 10
1.3 Definitions . 10
1.4 Overview and general requirements . 15
1.4.1 Software model . 15
1.4.2 Communication model . 17
1.4.3 Programming model . 19
1.5 Compliance . 20
1.5.1 System compliance . 21
1.5.2 Program compliance. 23
2 Common elements . 24
2.1 Use of printed characters . 24
2.1.1 Character set . 24
2.1.2 Identifiers . 24
2.1.3 Keywords . 25
2.1.4 Use of white space . 25
2.1.5 Comments . 25
2.1.6 Pragmas . 26
2.2 External representation of data . 26
2.2.1 Numeric literals . 26
2.2.2 Character string literals . 27
2.2.3 Time literals . 29
2.2.3.1 Duration . 29
2.2.3.2 Time of day and date . 30
2.3 Data types . 30
2.3.1 Elementary data types . 31
2.3.2 Generic data types . 32
2.3.3 Derived data types . 33
2.3.3.1 Declaration . 33
2.3.3.2 Initialization . 34
2.3.3.3 Usage . 36
2.4 Variables . 37
2.4.1 Representation . 37
2.4.1.1 Single-element variables . 37
2.4.1.2 Multi-element variables . 38
2.4.2 Initialization . 39
2.4.3 Declaration . 40
2.4.3.1 Type assignment . 42
2.4.3.2 Initial value assignment . 43
2.5 Program organization units . 46
2.5.1 Functions . 46
2.5.1.1 Representation . 47
2.5.1.2 Execution control . 50
2.5.1.3 Declaration . 51
2.5.1.4 Typing, overloading, and type conversion . 53
2.5.1.5 Standard functions. 56
2.5.1.5.1 Type conversion functions . 56
2.5.1.5.2 Numerical functions . 57
2.5.1.5.3 Bit string functions . 60
2.5.1.5.4 Selection and comparison functions . 60
2.5.1.5.5 Character string functions . 63
2.5.1.5.6 Functions of time data types . 65

2.5.1.5.7 Functions of enumerated data types . 67
2.5.2 Function blocks . 67
2.5.2.1 Representation . 68
2.5.2.1a) Use of EN and ENO in function blocks .
...