SIST EN 60848:2003

SLOVENSKI STANDARD
SIST EN 60848:2003
01-maj-2003
GRAFCET specification language for sequential function charts (IEC 60848:2002)
GRAFCET specification language for sequential function charts
Entwurfssprache GRAFCET für Ablauf-Funktionspläne
Langage de spécification GRAFCET pour diagrammes fonctionnels en séquence
Ta slovenski standard je istoveten z: EN 60848:2002
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 60848:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60848:2003

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SIST EN 60848:2003
EUROPEAN STANDARD EN 60848
NORME EUROPÉENNE
EUROPÄISCHE NORM April 2002
ICS 29.020
English version
GRAFCET specification language for sequential function charts
(IEC 60848:2002)
Langage de spécification GRAFCET Entwurfssprache GRAFCET
pour diagrammes fonctionnels en séquence für Ablauf-Funktionspläne
(CEI 60848:2002) (IEC 60848:2002)
This European Standard was approved by CENELEC on 2002-04-01. 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 Central Secretariat 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 Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands,
Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2002 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60848:2002 E

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SIST EN 60848:2003
EN 60848:2002 - 2 -
Foreword
The text of document 3B/344/FDIS, future edition 2 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 was approved by CENELEC as EN 60848 on 2002-04-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2003-01-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2005-04-01
Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, annex ZA is normative and annexes A, B and C are informative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60848:2002 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 NOTE Harmonized as EN 61131-3:1993 (not modified).
__________

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SIST EN 60848:2003
- 3 - EN 60848:2002
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
IEC 60050-351 1998 International Electrotechnical --
Vocabulary
Part 351: Automatic control
IEC 60617-12 1997 Graphical symbols for diagrams EN 60617-12 1998
Part 12: Binary logic elements

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SIST EN 60848:2003

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SIST EN 60848:2003
NORME
CEI
INTERNATIONALE IEC
60848
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
2002-02
Langage de spécification GRAFCET
pour diagrammes fonctionnels en séquence
GRAFCET specification language
for sequential function charts
© IEC 2002 Droits de reproduction réservés ⎯ Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch  Web: www.iec.ch
CODE PRIX
XA
Commission Electrotechnique Internationale PRICE CODE
International Electrotechnical Commission
ɆɟɠɞɭɧɚɪɨɞɧɚɹɗɥɟɤɬɪɨɬɟɯɧɢɱɟɫɤɚɹɄɨɦɢɫɫɢɹ
Pour prix, voir catalogue en vigueur
For price, see current catalogue

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SIST EN 60848:2003
60848 © IEC:2002 – 3 –
CONTENTS
FOREWORD.5
INTRODUCTION.7
1 Scope and object .9
2 Normative references.9
3 Terms and definitions .9
4 General principles.13
4.1 Context.13
4.2 GRAFCET, a behaviour specification language .15
4.3 GRAFCET, short presentation.15
4.4 Syntax rule .19
4.5 Evolution rules.19
4.6 Input events.21
4.7 Internal events.21
4.8 Output modes.23
4.9 Application of the evolution rules.23
4.10 Comparison between the two output modes .29
5 Graphical representation of the elements .31
6 Graphical representation of sequential structures .57
6.1 Basic structures.57
6.2 Particular structures .63
7 Structuring.69
7.1 Partition of a grafcet .69
7.2 Structuring using the forcing of a partial grafcet .73
7.3 Structuring using the enclosure.75
7.4 Structuring using the macro-steps.81
Annex A (informative) Example of control of a press.83
Annex B (informative) Example: Automatic weighing-mixing.85
Annex C (informative) Relations between the GRAFCET of IEC 60848
and the SFC of IEC 61131-3.97
Bibliography . 101

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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GRAFCET SPECIFICATION LANGUAGE
FOR SEQUENTIAL FUNCTION CHARTS
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and can not be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60848 has been prepared by subcommittee 3B: Documentation, of
IEC technical committee 3: Information structures, documentation and graphical symbols.
This second edition cancels and replaces the first edition published in 1988 and constitutes a
global technical revision with the addition of the following main concepts: input event, internal
event, assignation, allocation, forcing, macro-step and enclosure.
The text of this standard is based on the following documents:
FDIS Report on voting
3B/344/FDIS 3B/346/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 the ISO/IEC Directives, Part 3.
Annexes A, B and C are for information only.
The committee has decided that the contents of this publication will remain unchanged until
2006. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.

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INTRODUCTION
The main reason for the revision of this standard is the desire of the users to increase the
standardised specification language with new concepts, allowing a structured and hierarchical
description.
Otherwise, in addition to the descriptive and functional aspects of the first edition, it now seems
necessary to add the formal and behavioural aspects, which are essential for the definition of a
real specification language.
For all these reasons, an overall review of the document is required.
This standard is mainly for people (design engineers, realisation engineers, maintenance
engineers, etc.) who need to specify the behaviour of a system (control-command of an
automatic machine, safety component, etc.). This specification language should also serve as
a communication means between designers and users of automated systems.

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GRAFCET SPECIFICATION LANGUAGE
FOR SEQUENTIAL FUNCTION CHARTS
1 Scope and object
1)
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 the 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 normative documents contain provisions, which, through reference in this text,
constitute provisions of this International Standard. For dated references, subsequent
amendments to, or revisions of, any of these publications do not apply. However, parties to
agreements based on this International Standard are encouraged to investigate the possibility
of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of IEC
and ISO maintain registers of currently valid International Standards.
IEC 60050-351:1998, International Electrotechnical Vocabulary (VEI – Part 351: Automatic
control
IEC 60617-12:1997, Graphical symbols for diagrams – Part 12: Binary logical elements
3 Terms and definitions
For the purposes of this International Standard, the following definitions apply. The definitions
of the terms preceded by an asterisk apply only in the context of the GRAFCET specification
language. The chosen order is the alphabetic one.
3.1
* action
GRAFCET language element associated with a step, indicating an activity to be performed on
output variables
———————
1)
 GRAFCET , GRAphe Fonctionnel de Commande Etape Transition.

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3.2
chart, graph
graphical presentation describing the behaviour of a system, for example the relations between
two or more variable quantities, operations or states
3.3
* directed link
GRAFCET language element indicating the evolution paths between steps by connecting steps
to transitions and transitions to steps
3.4
* grafcet chart
function chart using GRAFCET
NOTE The “grafcet chart” can, in short form, be called “grafcet”.
3.5
* input event
event characterized by the change of at least one value of all input variables of the sequential
part of the system
3.6
* internal event
event characterized by an input event associated with the situation of the sequential part of the
system
3.7
* interpretation
part of the GRAFCET enabling the linkage of:
– the input variables and the structure, by the means of the transition-condition;
– the output variables and the structure, by the means of the actions
3.8
* situation
name of the state of the system described by grafcet and characterised by the active steps at a
given instant
3.9
* step
GRAFCET language element used for the definition of the state of the sequential part of the
system
NOTE 1 A step can be active or inactive.
NOTE 2 The set of active steps represents the situation of the system.
3.10
* structure
part of the GRAFCET enabling the description of the possible evolution between situations
3.11
system
a set of interrelated elements considered in a defined context as a whole and separated from
their environment
[IEV 351-11-01]
NOTE 1 Such elements may be material objects and concepts as well as their results (e.g. forms of organisation,
mathematical methods, programming languages).

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NOTE 2 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 The language GRAFCET can be use to describe the logical behaviour of any kind of system.
3.12
* transient evolution
evolution characterized by the clearing of several successive transitions on the occurrence of a
single input event
3.13
* transition
GRAFCET language element indicating a possible evolution of the activity between two or more
steps
NOTE The possible evolution is realised by clearing the transition.
3.14
* transition-condition
GRAFCET language element associated with a transition indicating the result of a boolean
expression
NOTE The transition-condition can be either true or false.
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, which is accessed via Boolean input and output variables, is
the logical aspect of this physical system. The behaviour indicates the way in which the output
variables depend on the input variables (see note to figure 1). The object of the GRAFCET is to
specify the behaviour of the sequential part of the systems.
SYSTEM
SEQUENTIAL PART OF THE SYSTEM
fi
fr
auto
Boolean Boolean
P/P
hg
inputs outputs
fi
Dcy
0 fr
hg
Pv
(auto Pv ) + (P/P Dcy)
⋅ ⋅
1
mr fr
Non boolean
[C > 6]
[C > 6]
C
outputs
Test
Non boolean mr
inputs
PID
NOTE  The sequential part of the system is characterised by its input variables, its output variables, and its
behaviour. This sequential part comprises only input and output boolean variables. However the GRAFCET
specification language by extension allows the description of the behaviour of the non Boolean variables (for
example: evaluation of an assertion or allocation of a numeric value for a variable).
Figure 1 – Graphical representation of the sequential part of a system

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4.2 GRAFCET, a behaviour specification language
The GRAFCET specification language enables a grafcet 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 GRAFCET situations, which implies the uniqueness of the situation at a given instant. The
states are connected to each other by means of an evolution condition, which allows the
passage from one situation to another one to be described.
For reasons of convenience, the behaviour description based on states is better replaced by a
description based on steps called GRAFCET. In the GRAFCET, several steps may be active
simultaneously, the situation being then characterized by the set of active steps at the
considered moment. The evolution of one set of steps to another are translated by one or
several transitions, each characterized by:
• its preceding steps,
• its succeeding steps,
• its associated transition-condition.
NOTE These reasons lead to the syntax rule enforcing the alternation step-transition.
4.3 GRAFCET, short presentation
The GRAFCET is used for the design of grafcet charts to provide a graphical and synthetic
representation of the sequential systems behaviour. The representation (figure 2) distinguishes:
• the structure, which allows possible evolutions between the situations to be described,
• the interpretation, which enables the relationship between input, output variables and the
structure (evolution, assignation and allocation rules are necessary to achieve this
interpretation).
4.3.1 The structure comprises the following basic items
• Step (definition: 3.9, symbol 1). A step is either active or inactive, the set of the active
steps of a grafcet chart at any given instant represents the situation of this grafcet at this
instant.
• Transition (definition: 3.13, symbol 7). A transition indicates that an evolution of the activity
between two or more steps may evolve. This evolution is realized by the clearing of the
transition.
• Directed link (definition: 3.3, symbol 10). A directed link connects one or several steps to a
transition, or a transition to one or several steps.
4.3.2 The following elements are used for the interpretation
• Transition-condition (definition: 3.14, symbol 13). Associated with each transition, the
transition-condition is a logical expression which is true or false and which is composed of
input variables and/or internal variables.
• Action (definition: 3.1). The action indicates, in a rectangle, what shall be done to the
output variable, either by assignation (continuous action, symbol 20), or allocation (stored
action, symbol 26).

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QuickDescent
On
SEQUENTIAL Boolean
HighPosition DriftRotation
Boolean
ouput
PART OF A
input
SlowDescent variables
LowPosition
variables
SYSTEM
EndApproch Ascent
Input variables forming the
transition condition with the
logic operator : « AND »
1
Steps 1 and 2
(1)
On AND HighPosition
2 QuickDescent DriftRotation
Ouput variables assigned in
Directed links
(2)
EndApproch
the associated actions to
the step 2
3 SlowDescent DriftRotation
(3)
Continuous actions
LowPosition
associated to the steps
3 and 4
4
Ascent
Transitions 3 and 4
Transition condition
(4)
HighPosition
associated to transition 4
STRUCTURE
INTERPRETATION
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

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4.4 Syntax rule
Step transition and transition step alternation shall always be respected whatever the sequence.
Consequences:
• Two steps shall never be connected directly by a directed link.
• The directed link shall only connect a step to a transition or a transition to a step.
4.5 Evolution rules
As each situation is characterized by the set of active steps at a given instant, the GRAFCET
evolution rules only affect the application, on the steps, of the evolution principle between the
situations of the sequential part of the system.
4.5.1 Initial situation
The initial situation is the situation at the initial time. Therefore it is described by the set of
steps active at this time. The choice of the situation at the initial time depends on the
methodology relating to the type of sequential part of the system considered.
Rule 1: The initial situation, chosen by the designer, is the situation at the initial time.
4.5.2 Clearing of a transition
Rule 2: A transition is said to be enabled when all immediately preceding steps linked to this
transition are active. The clearing of a transition occurs:
• when the transition is ENABLED,
• AND WHEN its associated transition-condition is TRUE.
4.5.3 Evolution of active steps
Rule 3: The clearing of a transition simultaneously provokes the activation of all the immediate
succeeding steps and the deactivation of all the immediate preceding steps.
4.5.4 Simultaneous evolutions
The evolution between two active situations implies that no other intermediate situation is
possible, the change from one representation of the situation by a set of steps to another
representation is instantaneous.
Rule 4: Several transitions, which can be cleared simultaneously, are simultaneously cleared.
4.5.5 Simultaneous activation and deactivation of a step
If a step is included in the description of the preceding situation and in that of the following one,
it can therefore only remain active.
Rule 5: If during the operation, an active step is simultaneously activated and deactivated, it
remains active.

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4.6 Input events
The evolution rules show that only a change in the values of the input variables may cause the
evolution of the grafcet. This change called "input event" shall be defined by the preceding
value and the succeeding value of all the input variables to characterise this single event. In
practice, a set of input events is specified only by the characterised state change (rising edge
or falling edge) of one or several boolean input variables.
NOTE The rising edge of a logical variable, indicated by the sign "↑" in front of a boolean variable, indicates that
this rising edge is only true for the change from value 0 to value 1 of the variable concerned. The falling edge of a
logical variable noted by the sign "↓" in front of a boolean variable, indicates that this falling edge is only true for
the change from value 1 to value 0 of the variable concerned.
It is said that "the event occurs" at the date of the change of state of the input variables which
characterize it.
4.6.1 Input events specification
The input events specification is implemented by a logical expression of one or several
characteristic variables, often in a transition-condition. More rarely, it may also directly specify
an internal event (see 4.7).
EXAMPLE 1:
The expression "↑a" describes the set of all input events for which the preceding
↑↑a
↑↑
value of the input variable a is 0 and its succeeding value is 1, regardless of the
value of the other input variables of the system.
EXAMPLE 2:
The expression "a ⋅↑b" describes the set of all input events for which the succeeding
a ⋅⋅⋅↑⋅ ↑↑↑b
value of the input variable a is 1, and the preceding value of the input variable b is 0
and its succeeding value is 1, regardless of the value of the other input variables of
the system.
EXAMPLE 3:
The expression "a" describes the sets of all input events for which the succeeding
a
value of the input variable a is 1, regardless of the value of the other input variables
of the system.
NOTE Used in a transition-condition, this expression could lead to a transient evolution (see 3.12)
4.7 Internal events
Only certain input events could occur from a given situation. The connection between a
situation and input event, which may occur from this situation, is called internal event (see 3.6).
This notion is mainly used by the designer to condition an output allocation to a set of internal
events (see 4.8.2). The description of a set of internal events is realized by one of the following
ways.
4.7.1 Internal events described by the step activation
The step activation, noted graphically (symbol 27), describes the set of internal events each of
which has this step activation as a consequence.
4.7.2 Internal events described by the deactivation of a step
The graphically noted deactivation of a step, (symbol 28), describes the set of the internal
events each of which have this step deactivation as consequence.

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4.7.3 Internal events described by the clearing of a transition
The graphically noted clearing of a transition (symbol 29), describes the set of internal events
each of which have the clearing of this transition as consequence.
4.8 Output modes
The actions enable lin
...