GRAFCET specification language for sequential function charts (IEC 60848:2013)

This International Standard defines the GRAFCET1 specification language for the functional description of the behaviour of the sequential part of a control system. This standard specifies the symbols and rules for the graphical representation of this language, as well as for its interpretation. This standard has been prepared for automated production systems of industrial applications. However, no particular area of application is excluded. Methods of development of a specification that makes use of GRAFCET are beyond the scope of this standard. One method is for example the "SFC language" specified in IEC 61131-3, which defines a set of programming languages for programmable controllers.

Entwurfssprache GRAFCET für Ablauf-Funktionspläne (IEC 60848:2013)

Langage de spécification GRAFCET pour diagrammes fonctionnels en séquence (CEI 60848:2013)

La CEI 60848:2013 définit le langage de spécification GRAFCET pour la description fonctionnelle du comportement de la partie séquentielle des systèmes de commande. Elle définit les symboles et les règles nécessaires à la représentation graphique de ce langage, ainsi que l'interprétation qui en est faite. Elle a été établie pour les systèmes automatisés de production des applications industrielles. Cette troisième édition annule et remplace la deuxième édition parue en 2002, dont elle constitue une révision technique générale comprenant la définition étendue du concept de variables qui introduit: la variable interne, la variable d'entrée et la variable de sortie.

Specifikacijski jezik GRAFCET za sekvenčne funkcijske sheme (IEC 60848:2013)

Ta mednarodni standard določa specifikacijski jezik GRAFCET1 za funkcionalni opis obnašanja sekvenčnega dela nadzornega sistema. Ta standard določa simbole in pravila za grafično predstavitev tega jezika ter za njegovo tolmačenje. Ta standard je bil pripravljen za avtomatske proizvodne sisteme v industrijski uporabi. Kljub temu ni nobeno določeno območje uporabe izključeno. Metode razvoja specifikacije, ki uporablja GRAFCET, so zunaj obsega tega standarda. Ena od metod je na primer »jezik SFC«, določen v standardu IEC 61131-3, ki opredeljuje niz programskih jezikov za programirljive krmilnike.

General Information

Status
Published
Publication Date
03-Jul-2013
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
12-Jun-2013
Due Date
17-Aug-2013
Completion Date
04-Jul-2013

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SLOVENSKI STANDARD
SIST EN 60848:2013
01-september-2013
1DGRPHãþD
SIST EN 60848:2003
6SHFLILNDFLMVNLMH]LN*5$)&(7]DVHNYHQþQHIXQNFLMVNHVKHPH ,(&
GRAFCET specification language for sequential function charts (IEC 60848:2013)
Entwurfssprache GRAFCET für Ablauf-Funktionspläne (IEC 60848:2013)
Langage de spécification GRAFCET pour diagrammes fonctionnels en séquence (CEI
60848:2013)
Ta slovenski standard je istoveten z: EN 60848:2013
ICS:
01.100.25 5LVEHVSRGURþMD Electrical and electronics
HOHNWURWHKQLNHLQHOHNWURQLNH engineering drawings
35.060 Jeziki, ki se uporabljajo v Languages used in
informacijski tehniki in information technology
tehnologiji
SIST EN 60848:2013 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 60848:2013
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SIST EN 60848:2013
EUROPEAN STANDARD
EN 60848
NORME EUROPÉENNE
June 2013
EUROPÄISCHE NORM
ICS 29.020 Supersedes EN 60848:2002
English version
GRAFCET specification language for sequential function charts
(IEC 60848:2013)
Langage de spécification GRAFCET pour GRAFCET, Spezifikationssprache für
diagrammes fonctionnels en séquence Funktionspläne der Ablaufsteuerung
(CEI 60848:2013) (IEC 60848:2013)

This European Standard was approved by CENELEC on 2013-04-03. 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.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 60848:2013 E
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SIST EN 60848:2013
EN 60848:2013 - 2 -
Foreword

The text of document 3/1135/FDIS, future edition 3 of IEC 60848, prepared by SC 3B “Documentation”

of IEC/TC 3 “Information structures, documentation and graphical symbols" was submitted to the

IEC-CENELEC parallel vote and approved by CENELEC as EN 60848:2013.
The following dates are fixed:
(dop) 2014-01-03
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2016-04-03
standards conflicting with the
document have to be withdrawn
This document supersedes EN 60848:2002.

EN 60848:2013 includes the following significant technical changes with respect to EN 60848:2002:

This edition constitutes a global technical revision with the extended definition of the concept of

variables introducing: internal variable, input variable and output variable.

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.
Endorsement notice

The text of the International Standard IEC 60848:2013 was approved by CENELEC as a European

Standard without any modification.

In the official version, for Bibliography, the following note has to be added for the standard indicated:

IEC 61131-3:2003 NOTE Harmonised as EN 61131-3:2003 (not modified).
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SIST EN 60848:2013
IEC 60848
Edition 3.0 2013-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
GRAFCET specification language for sequential function charts
Langage de spécification GRAFCET pour diagrammes fonctionnels en séquence
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XA
ICS 29.020 ISBN 978-2-83220-648-5

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
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SIST EN 60848:2013
– 2 – 60848 © IEC:2013
CONTENTS

FOREWORD ........................................................................................................................... 5

INTRODUCTION ..................................................................................................................... 7

1 Scope ............................................................................................................................... 8

2 Normative references ........................................................................................................ 8

3 Terms and definitions ....................................................................................................... 8

3.1 Terms in the GRAFCET ........................................................................................... 8

3.2 Terms, general purpose ......................................................................................... 10

4 General principles ........................................................................................................... 10

4.1 Context .................................................................................................................. 10

4.2 GRAFCET, a behaviour specification language ...................................................... 11

4.3 GRAFCET, short presentation ................................................................................ 12

4.3.1 General ..................................................................................................... 12

4.3.2 Structure .................................................................................................... 12

4.3.3 Elements for interpretation ......................................................................... 12

4.4 Syntax rule ............................................................................................................ 13

4.5 Evolution rules ....................................................................................................... 14

4.5.1 General ..................................................................................................... 14

4.5.2 Initial situation ........................................................................................... 14

4.5.3 Clearing of a transition ............................................................................... 14

4.5.4 Evolution of active steps ............................................................................ 14

4.5.5 Simultaneous evolutions ............................................................................ 14

4.5.6 Simultaneous activation and deactivation of a step ..................................... 14

4.6 Input events ........................................................................................................... 14

4.6.1 General ..................................................................................................... 14

4.6.2 Input events specification ........................................................................... 15

4.7 Internal events ....................................................................................................... 15

4.7.1 General ..................................................................................................... 15

4.7.2 Internal events described by the step activation .......................................... 15

4.7.3 Internal events described by the deactivation of a step ............................... 15

4.7.4 Internal events described by the clearing of a transition .............................. 15

4.8 Output modes ........................................................................................................ 16

4.8.1 General ..................................................................................................... 16

4.8.2 Continuous mode (assignation on state) ..................................................... 16

4.8.3 Stored mode (allocation on event) .............................................................. 16

4.9 Application of the evolution rules ............................................................................ 16

4.9.1 General ..................................................................................................... 16

4.9.2 Non transient evolution .............................................................................. 17

4.9.3 Transient evolution .................................................................................... 17

4.9.4 Consequence of a transient evolution on the assignations .......................... 17

4.9.5 Consequence of a transient evolution on the allocations ............................. 18

4.10 Comparison between the two output modes ........................................................... 18

4.10.1 General ..................................................................................................... 18

4.10.2 Determination of the value of the outputs ................................................... 19

4.10.3 Analysis of the value of the outputs for a grafcet chart at a defined

instant ....................................................................................................... 19

4.10.4 Actions relative to transient evolution ......................................................... 19

4.10.5 Possible conflict on the value of the outputs ............................................... 19

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SIST EN 60848:2013
60848 © IEC:2013 – 3 –

5 Graphical representation of the elements ........................................................................ 19

6 Graphical representation of sequential structures ............................................................ 32

6.1 General ................................................................................................................. 32

6.2 Basic structures ..................................................................................................... 32

6.2.1 Sequence .................................................................................................. 32

6.2.2 Cycle of a single sequence......................................................................... 32

6.2.3 Selection of sequences .............................................................................. 33

6.2.4 Step skip ................................................................................................... 33

6.2.5 Backward sequence skip ............................................................................ 34

6.2.6 Activation of parallel sequences ................................................................. 34

6.2.7 Synchronization of sequences .................................................................... 34

6.2.8 Synchronization and activation of parallel sequences.................................. 35

6.3 Particular structures............................................................................................... 36

6.3.1 Starting of a sequence by a source step ..................................................... 36

6.3.2 End of a sequence by a pit step ................................................................. 36

6.3.3 Starting of a sequence with a source transition ........................................... 37

6.3.4 End of a sequence by a pit transition .......................................................... 38

7 Structuring ...................................................................................................................... 38

7.1 General ................................................................................................................. 38

7.2 Partition of a grafcet chart ...................................................................................... 38

7.2.1 Connected grafcet chart ............................................................................. 38

7.2.2 Partial grafcet ............................................................................................ 39

7.3 Structuring using the forcing of a partial grafcet chart ............................................. 40

7.4 Structuring using the enclosure .............................................................................. 41

7.5 Structuring using the macro-steps .......................................................................... 43

Annex A (informative) Example of the control of a press ....................................................... 45

Annex B (informative) Example: Automatic weighing-mixing .................................................. 46

Annex C (informative) Relations between GRAFCET of IEC 60848 and the SFC of

IEC 61131-3 .......................................................................................................................... 52

Bibliography .......................................................................................................................... 54

Figure 1 – Graphical representation of the sequential part of a system ................................... 11

Figure 2 – Structure and interpretation elements used in a grafcet chart to describe the

behaviour of a sequential part of the system defined by its input and output variables ............ 13

Figure 3 – Example of grafcet with enclosures (including description) .................................... 43

Figure A.1 – Representation of the working press using a grafcet .......................................... 45

Figure B.1 – Overview diagram of weighing-mixing system .................................................... 46

Figure B.2 – Grafcet of a weighing-mixing involving only continuous actions .......................... 47

Figure B.3 – Grafcet of the weighing-mixing, involving continuous and stored actions ........... 48

Figure B.4 – Grafcet of the weighing-mixing, divided into a global description using

macro-steps and a description detailed by the macro-step expansions ................................... 49

Figure B.5 – Structuring with operating modes using forcing orders ....................................... 50

Figure B.6 – Structuring with operating modes using enclosing step ....................................... 51

Table 1 – Steps ..................................................................................................................... 20

Table 2 – Transitions ............................................................................................................. 21

Table 3 – Directed links ......................................................................................................... 22

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SIST EN 60848:2013
– 4 – 60848 © IEC:2013

Table 4 – Associated transition-conditions ............................................................................. 23

Table 5 – Continuous actions ................................................................................................ 27

Table 6 – Stored actions ....................................................................................................... 30

Table 7 – Comments associated with elements of a grafcet chart .......................................... 31

Table 8 – Partial grafcet chart ............................................................................................... 39

Table 9 – Forcing of a partial grafcet chart ............................................................................ 40

Table 10 – Enclosing steps.................................................................................................... 41

Table 11 – Macro-steps ......................................................................................................... 44

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SIST EN 60848:2013
60848 © IEC:2013 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GRAFCET SPECIFICATION LANGUAGE
FOR SEQUENTIAL FUNCTION CHARTS
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.

International Standard IEC 60848 has been prepared by the former subcommittee 3B:

Documentation, of IEC technical committee 3: Information structures, documentation and

graphical symbols.

This third edition cancels and replaces the second edition published in 2002 and constitutes a

global technical revision with the extended definition of the concept of variables introducing:

internal variable, input variable and output variable.
The text of this standard is based on the following documents:
FDIS Report on voting
3/1135/FDIS 3/1138/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.
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SIST EN 60848:2013
– 6 – 60848 © IEC:2013

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

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.
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SIST EN 60848:2013
60848 © IEC:2013 – 7 –
INTRODUCTION

This International Standard is mainly aimed at people such as design engineers, maintenance

engineers, etc., who need to specify the behaviour of a system, e.g. the control and command

of an automation system, safety component, etc. This specification language should also serve

as a communication means between designers and users of automated systems.
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SIST EN 60848:2013
– 8 – 60848 © IEC:2013
GRAFCET SPECIFICATION LANGUAGE
FOR SEQUENTIAL FUNCTION CHARTS
1 Scope

This International Standard defines the GRAFCET specification language for the functional

description of the behaviour of the sequential part of a control system.

This standard specifies the symbols and rules for the graphical representation of this language,

as well as for its interpretation.

This standard has been prepared for automated production systems of industrial applications.

However, no particular area of application is excluded.

Methods of development of a specification that makes use of GRAFCET are beyond the scope

of this standard. One method is for example the "SFC language" specified in IEC 61131-3,

which defines a set of programming languages for programmable controllers.

NOTE See Annex C for further information on the relations between IEC 60848 and implementation languages

such as the SFC of IEC 61131-3.
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.
(void)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

NOTE The definitions of the terms in 3.1 apply only in the context of the GRAFCET specification language.

3.1 Terms in the GRAFCET
3.1.1
action

GRAFCET language element associated with a step, indicating an activity to be performed on

output or internal variables
3.1.2
directed link

GRAFCET language element indicating the evolution paths between steps by connecting steps

to transitions and transitions to steps
3.1.3
grafcet chart
function chart using the GRAFCET specification language
___________
GRAFCET: GRAphe Fonctionnel de Commande Etape Transition.
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SIST EN 60848:2013
60848 © IEC:2013 – 9 –
Note 1 to entry: The “grafcet chart” can, in short form, be called “grafcet”.
3.1.4
input event

event characterized by the change of at least one value of all input variables of the sequential

part of the system
3.1.5
internal event

event characterized by an input event associated with the situation of the sequential part of the

system
3.1.6
interpretation
part of the GRAFCET specification language enabling the linkage of:

– the input variables and the structure, by the means of the transition-condition; and

– the output variables and the structure, by the means of the actions
3.1.7
situation

state of the system described by the GRAFCET specification language and characterized by

the active steps at a given instant
3.1.8
step

GRAFCET language element used for the definition of the state of the sequential part of the

system
Note 1 to entry: A step can be active or inactive.
Note 2 to entry: The set of active steps represents the situation of the system.
3.1.9
transient evolution

evolution characterized by the clearing of several successive transitions on the occurrence of a

single input event
3.1.10
transition

GRAFCET language element indicating a possible evolution of the activity between two or more

steps
Note 1 to entry: The possible evolution is realised by clearing the transition.
3.1.11
transition-condition

GRAFCET language element associated with a transition indicating the result of a boolean

expression
Note 1 to entry: The transition-condition can be either true or false.
3.1.12
variable
scalar quantity defined by its name and Boolean, numeric value
3.1.13
input variable
variable which may influence the behaviour described by the grafcet chart
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SIST EN 60848:2013
– 10 – 60848 © IEC:2013
EXAMPLE Boolean variable indicating the violation of a temperature limit.

Note 1 to entry: The variable may belong to the environment or to some other system component.

3.1.14
output variable
variable which may be influenced by the behaviour described by the grafcet chart
EXAMPLE Setpoint of a PID-controller.

Note 1 to entry: The variable may belong to the environment or to some other system component.

3.1.15
internal variable

variable used inside the grafcet chart and invisible for other system components and the

environment

EXAMPLES Step variable X* (symbol 2.1 of Table 1), step duration T* (symbol 2.2 of Table 1), loop counter within

a grafcet chart.
3.2 Terms, general purpose
3.2.1
chart
graph

graphical presentation describing the behaviour of a system, for example the relations between

two or more variable quantities, operations or states
3.2.2
structure

part of the GRAFCET specification language enabling the description of the possible evolution

between situations
3.2.3
system

set of interrelated elements considered in a defined context as a whole and separated from

their environment

Note 1 to entry: Such elements may be material objects and concepts as well as their results (e.g. forms of

organisation, mathematical methods, programming languages).

Note 2 to entry: The system is considered to be separated from the environment and from the other external

systems by an imaginary surface, which cuts the links between them and the system.

Note 3 to entry: The language GRAFCET can be used to describe the logical behaviour of any kind of system.

[SOURCE: IEC 60050-351:1998, 351-11-01]
4 General principles
4.1 Context

The implementation of an automated system requires, in particular, a description relating cause

and effect. To do this, the logical aspect of the desired behaviour of the system will be

described.

The sequential part of the system is the logical aspect of this physical system (see Figure 1).

The behaviour indicates the way in which the output variables depend on the input variables.

The object of the grafcet chart is to specify the behaviour of the sequential part of the systems.

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SIST EN 60848:2013
60848 © IEC:2013 – 11 –
Environment
System
Sequential part of the system
Init
G10.y := 0 %
Start Λ [L10.x < 2 %]
Dos_R
G10.y := 100 %
Start
G10.y
[L10.x > 50 %]
L10.x
T10.a
Dos_F
G10.y := 10 %
Go_on
[L10.x > 60 %]
Heating
G10.y := 0 % T10.a
Go_on
Non-sequential part of the system
T10.y
T10.w
PID
T10.r
IEC 365/13
L10.x tank level G10.y dosing valve – position
T10.a temperature loop – automatic mode T10.w temperature loop – setpoint

T10.r temperature loop – measured value T10.y temperature loop – manipulated value

Figure 1 – Graphical representation of the sequential part of a system
4.2 GRAFCET, a behaviour specification language

The GRAFCET specification language enables a grafcet chart to be created showing the

expected behaviour of a given sequential system. This language is characterized mainly by its

graphic elements, which, associated with an alphanumerical expression of variables, provides

a synthetic representation of the behaviour, based on an indirect description of the situation of

the system.

The behaviour description on states is the following: the "monomarked" states correspond to

the situations of the grafcet chart, which implies the uniqueness of the situation a

...

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