IEC 61360-2:2002

INTERNATIONAL IEC
STANDARD
61360-2
Second edition
2002-01
Standard data element types with associated
classification scheme for electric components –
Part 2:
EXPRESS dictionary schema
Types normalisés d'éléments de données avec plan
de classification pour composants électriques –
Partie 2:
Schéma d'un dictionnaire EXPRESS
Reference number
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INTERNATIONAL IEC
STANDARD
61360-2
Second edition
2002-02
Standard data element types with associated
classification scheme for electric components –
Part 2:
EXPRESS dictionary schema
Types normalisés d'éléments de données avec plan
de classification pour composants électriques –
Partie 2:
Schéma d'un dictionnaire EXPRESS
 IEC 2002  Copyright - all rights reserved
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 the publisher.
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Commission Electrotechnique Internationale
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International Electrotechnical Commission
For price, see current catalogue

– 2 – 61360-2  IEC:2002(E)
CONTENTS
FOREWORD.3
INTRODUCTION.5
1 General .6
1.1 Scope.6
1.2 Normative references .7
2 Definitions .8
3 Abbreviations.9
4 Overview of the common dictionary schema and compatibility with ISO 13584.9
4.1 Use of the common dictionary schema to exchange IEC 61360-1 compliant
data.9
4.2 Compatibility with ISO 13584-42 .9
4.3 Naming correspondence between IEC 61360-1 and IEC 61360-2 .10
4.4 Main structure of the common dictionary schema .10
5 ISO13584_IEC61360_dictionary_schema.11
5.1 References to other schemata .11
5.2 Constant definitions .12
5.3 Basic semantic units: defining and using the dictionary .12
5.4 Supplier data .18
5.5 Class data .20
5.6 Data element type/properties data.26
5.7 Domain data: the type system .31
5.8 Basic type and entity definitions .45
5.9 Function definitions.55
6 IEC 61360 extensions to the common dictionary schema.65
7 ISO13584_IEC61360_language_resource_schema .65
7.1 ISO13584_IEC61360_language_resource_schema type and entity definitions .66
7.2 ISO13584_IEC61360_language_resource_schema function definitions .69
7.3 ISO13584_IEC61360_language_resource_schema rule definition .70
8 Templates .70
8.1 Templates derived from the EXPRESS code .70
8.2 Some example data.73
Annex A (informative) Example Physical File .74
Annex B (informative) EXPRESS-G diagram.78
Bibliography .86

61360-2  IEC:2002(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
STANDARD DATA ELEMENT TYPES WITH ASSOCIATED
CLASSIFICATION SCHEME FOR ELECTRIC COMPONENTS –
Part 2: EXPRESS dictionary schema
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 cannot 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 61360-2 has been prepared by subcommittee 3D: Data sets for
libraries, of IEC technical committee 3: Information structures, documentation and graphical
symbols.
This second edition cancels and replaces the first edition published in 1998 and constitutes a
technical revision
The text of this standard is based on the following documents:
FDIS Report on voting
3D/92/FDIS 3D/95/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 and B are for information only.

– 4 – 61360-2  IEC:2002(E)
IEC 61360 consists of the following parts, under the general title Standard data element types
with associated classification scheme for electric components:
– Part 1 : Definitions – Principles and methods
– Part 2 : EXPRESS dictionary schema
– Part 3 : Maintenance and validation procedures
– Part 4 : IEC reference collection of standard data element types, component classes and
terms.
– Part 5 : Extensions to the EXPRESS dictionary schema .
The committee has decided that the contents of this publication will remain unchanged until
2004. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
___________
To be published
61360-2  IEC:2002(E) – 5 –
INTRODUCTION
The common ISO/IEC dictionary schema presented here is based on the intersection of the
scopes of the following standards:
– IEC 61360-1
– ISO 13584-42
Relevant parts of the scope clauses of these standards include the following:
IEC 61360-1:
"This part of IEC 61360 specifies the principles to be used for defining technical data element
types with associated classification schemes needed to describe fully electric components,
including electronic and electromechanical components and materials used in electro-technical
equipment and systems."
ISO 13584-42:
" This part of ISO 13584 specifies:
• the attributes that shall be provided by library suppliers to describe the families and
properties of parts. These attributes are part of the content of their parts library and shall
be stored in the dictionary of the user library;
• the specifications of these attributes in the EXPRESS information model that provides for
the exchange of such dictionary data".
IEC SC 3D and ISO TC 184/SC4 agreed NOT to change and/or modify the presented EXPRESS
model independent of each other in order to guarantee the harmonization and the reusability of
the work of both committees.
Requests for amendments should therefore be sent to both committees. These requests
should be adopted by both committees before modifying the EXPRESS information model.

– 6 – 61360-2  IEC:2002(E)
STANDARD DATA ELEMENT TYPES WITH ASSOCIATED
CLASSIFICATION SCHEME FOR ELECTRIC COMPONENTS –
Part 2: EXPRESS dictionary schema
1 General
1.1 Scope
This part of IEC 61360 presents a common ISO/IEC dictionary schema based on the
intersection of the scopes of two base standards IEC 61360-1 and ISO 13584-42.
The presented EXPRESS model represents a common formal model for the two standards and
facilitates a harmonization of both.
The IEC 61360-2 standard forms the master document. ISO 13584-42 contains a copy of
the IEC 61360-2 EXPRESS model in an informative annex
This standard provides a formal model for data according to the scope as given in the
publications cited above, and thus provides a means for the computer-sensible representation
and exchange of such data.
The intention is to provide a common information model for the work of IEC TC 3D and
ISO TC 184/SC4, thus allowing for the implementation of dictionary systems dealing with data
delivered according to either of the standards elaborated by both committees.
Two schemas are provided in this part of IEC 61360 defining the two options that may be
selected for an implementation. Each of these options is referred to as a conformance class.
• The ISO13584_IEC61360_dictionary_schema provides for modelling and exchanging
technical data element types with associated classification scheme but without modelling
the definitions of the terms used in the data element type definitions. It constitutes
conformance class 1 of this part of IEC 61360.
• The ISO13584_IEC61360_language_resource_schema provides resources for permitting
strings in various languages. It has been extracted from the dictionary schema, since it
could be used in other schemata. It is largely based on the support_resource_schema
from ISO 10303-41: STEP part 41: "Fundamentals of Product Description and Support",
and can be seen as an extension to that. It allows for the usage of one specific language
throughout an exchange context (Physical File) without the overhead introduced when
multiple languages are used.
When used together with ISO 10303-21, each schema defines one single exchange format.
The exchange format defined by conformance class 1 is fully compatible with the ISO 13584
series.
The exchange format defined by conformance class 2 also provides for exchanging the
definitions of the terms used in the defining of data element types and their associated
classification scheme when such an exchange is required, despite the lack of compatibility with
implementations compliant with the ISO 13584 series.
___________
All the names that stand for items, formally defined within the EXPRESS model, are presented in bold face.

61360-2  IEC:2002(E) – 7 –
1.2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 61360. For dated references, subsequent amendments
to, or revisions of, any of these publications do not apply. However, parties to agreements
based on this part of IEC 61360 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 61360-1:1995, Standard data element types with associated classification scheme for
electric components – Part 1: Definitions – Principles and methods
IEC 61360-4:1997, Standard data element types with associated classification scheme for
electric components – Part 4: IEC reference collection of standard data element types,
component classes and terms
ISO 31 (all parts), Quantities and units
ISO 639:1988, Code for the representation of names of languages
ISO 843:1997, Information and documentation – Conversion of Greek characters into Latin
characters
ISO 4217:1995, Codes for the representation of currencies and funds
ISO 6093:1985, Information processing – Representation of numerical values in character
strings for information interchange
ISO 8601:2000, Data elements and interchange formats – Information interchange –
Representation of dates and times
ISO 8859-1:1998, Information technology – 8-bit single-byte coded graphic character sets –
Part 1: Latin alphabet No. 1
ISO 8879:1986, Information processing – Text and office systems – Standard Generalized
Markup Language (SGML)
ISO 9735:1988, Electronic data interchange for administration, commerce and transport
(EDIFACT) – Application level syntax rules
ISO 10303-11:1994, Industrial automation systems and integration – Product data
representation and exchange – Part 11: Description methods: The EXPRESS language
reference manual
ISO 10303-21:1994, Industrial automation systems and integration – Product data
representation and exchange – Part 21: Implementation methods: Clear text encoding of the
exchange structure
ISO 10303-41:2000, Industrial automation systems and integration – Product data
representation and exchange – Part 41: Integrated generic resources: Fundamentals of product
description and support
ISO 10303-42:2000, Industrial automation systems and integration – Product data
representation and exchange – Part 42: Integrated generic resources: Geometric and topo-
logical representation
– 8 – 61360-2  IEC:2002(E)
ISO 12083:1994, Information and documentation – Electronic manuscript preparation and
markup
ISO 13584-26, Industrial automation systems and integration – Parts library – Part 26: Logical
resource: Information supplier identification
ISO 13584-42, Industrial automation systems and integration – Parts library – Part 42:
Description methodology: Methodology for structuring part families
2 Definitions
For the purpose of this part of IEC 61360 the following definitions apply:
2.1
basic semantic unit (BSU)
entity that provides an absolute and universal identification of certain objects of the application
domain (for example classes, data element types)
2.2
dictionary element
set of attributes that constitutes the dictionary description of certain objects of the application
domain (for example classes, data element types)
2.3
common dictionary schema
information model for a dictionary, using the information modelling language EXPRESS
2.4
data type
set of allowed values of a data element type
NOTE Within IEC the data_type that is either a unit of measure or a value domain is defined separately for each
data element type.
2.5
IEC root class
class that is the superclass of all the classes defined in IEC 61360-4; its class code is
‘AAA000' and its version is ‘001'
2.6
applicable data element type
data element type that is defined for some component class and that applies to any component
that belongs to this component class
2.7
visible data element type
data element type that is defined for some component class and that may or may not apply to
the different components of this component class
NOTE 1 The code of the class where a data element type is defined as visible is part of the identification of this
data element type.
NOTE 2 Within IEC all data element types are defined as visible at the level of the root class, that is the
superclass of both the component class and the material class.
2.8
item
a thing whose description can be captured by a class structure and a set of properties

61360-2  IEC:2002(E) – 9 –
3 Abbreviations
In this part of IEC 61360 the following abbreviations are used:
• BSU: Basic Semantic Unit;
• DET: Data Element Type;
• ICS: International Classification of Standards;
• SI: International System of Units.
4 Overview of the common dictionary schema and compatibility with ISO 13584
In the following subclauses, the architecture of the common dictionary schema will be
presented and it will be explained how the same information model has to be used in the
International Standards to ensure their compatibility.
The common dictionary schema combines the requirements of IEC 61360 and ISO 13584.
Therefore, it contains resources to accommodate the specific requirements of both Inter-
national Standards. These resources are provided either as optional capabilities or as subtypes
of the types defined to fulfil the common requirements.
4.1 Use of the common dictionary schema to exchange IEC 61360-1 compliant data
a) The ISO 13584 specific extensions to support multilingual capability are not reguired for the
exchange of dictionary elements defined according to IEC 61360-1. However, these
extensions, that is present_translations, translated_label and translated_text, shall be
used in the exchange structure for compatibility reasons.
b) If a component class has a superclass, the coded_name shall be defined as a value_code
in the domain of the classifying data element type of the superclass.
c) If a classifying data element type exists within a specific component class, for each value
in its domain a subclass and a term shall be defined.
d) A classifying data element type, optional in conformance class 2 in the common dictionary
schema, shall always be provided for the component classes defined according to
IEC 61360-1.
e) Only SI units shall be used although the common dictionary schema enables the use of
many kind of system units. When using this schema however for the exchange of
IEC 61360 compliant data, only SI shall be used for quantitative data element types.
4.2 Compatibility with ISO 13584-42
An implementation compliant with this part of IEC 61360 shall support all the entities, types and
associated constraints that belong to the conformance class it claims to support.
Therefore, conformance to conformance class 1 of this part of IEC 61360 requires that all the
entities, types and associated constraints defined in the common dictionary schema be
supported. ISO 13584 data conforming to the common dictionary schema may thus be
processed by an IEC 61360 implementation, whether it conforms to conformance class 1, or to
conformance class 2 that includes all the features of conformance class 1.
In ISO 13584, a specific conformance class is intended to contain all the entities, types and
associated constraints defined in the common dictionary schema. An ISO 13584 compliant
implementation conforming to this conformance class shall therefore be able to support IEC
data that belongs to conformance class 1 of this part of IEC 61360.
___________
This conformance class is defined as conformance class 0 in ISO 13584-24.

– 10 – 61360-2  IEC:2002(E)
4.3 Naming correspondence between IEC 61360-1 and IEC 61360-2
Due to specific application restrictions, for example the EXPRESS language allows no spaces
in entity names, a number of similar 'EXPRESS names' are created by replacing the blank in a
name by an underscore (e.g. preferred name is presented as preferred_name).
At other places, names are used in the EXPRESS model that deviate from those used in
IEC 61360-1. This is a consequence of the effort to reach one common EXPRESS information
model together with parts libraries.
The table below presents a help for matching the names used in the two parts of IEC 61360.
Table 1 – X-REFERENCE table
Naming in IEC 61360-2 Naming in IEC 61360-1
component_class Component class
condition_DET Condition data element type
dependent_P_DET Data element type
det_classification Data element type class
(DER)dic_identifier Identifier
dic_value Value
material_class Material class
meaning Value meaning
Data element type
non_dependent_P_DET
Preferred letter symbol
preferred_symbol
Revision number
revision
source_doc_of_definition Source document of data element type definition
source_doc_of_definition Source document of component class definition
synonymous_symbols Synonymous letter symbol
unit Unit of measure
value_code Value code
version Version number
4.4 Main structure of the common dictionary schema
This subclause explains the main resource constructs provided by the common dictionary
schema:
• dictionary_element is any element defined in the dictionary;
• supplier_element captures the data of suppliers of dictionary elements (classes,
properties, data types);
• class models the dictionary element of classes (families) which are described by
properties;
• property_DET is the dictionary element of a property;
• data_type specifies the type of a property.
These parts of the dictionary schema are presented in more detail in clause 5:
ISO13584_IEC61360_dictionary_schema.

61360-2  IEC:2002(E) – 11 –
In the presentation of the common dictionary schema, some overview diagrams are provided
as planning models (see figure 1 to figure 12). These planning models use the EXPRESS-G
graphical notation for the EXPRESS language.
For clarification of the diagrams, some of the relationships that are defined in the EXPRESS
model are omitted. Figure 1 below outlines as a planning model the main structure of the
common dictionary schema.
Most of these figures contain overview models (or planning models) but show only that level of
detail which is appropriate at a certain place.
(ABS) dictionary_element
(ABS)
(ABS)
supplier_element (ABS) data_type
property_DET
defined_by class domain
described_by L[0:?]
IEC  216/02
Figure 1 – Overview of the dictionary schema
5 ISO13584_IEC61360_dictionary_schema
This clause, which constitutes the main part of the common information model of ISO 13584-42
and IEC 61360, contains the full EXPRESS listing of the dictionary schema, annotated with
comments and explanatory text. The order of text in this clause is determined primarily by the
order imposed by the EXPRESS language, secondarily by importance.
*)
SCHEMA ISO13584_IEC61360_dictionary_schema;
(*
5.1 References to other schemata
This subclause contains references to other EXPRESS schemata which are used in the
Dictionary Schema. Their source is indicated in the respective comment.
*)
REFERENCE FROM support_resource_schema (identifier, label, text);
(* from ISO 10303-41: STEP Part 41: "Fundamentals of Product
Description and Support" *)
REFERENCE FROM person_organization_schema (organization, address);
(* from ISO 10303-41: STEP Part 41: "Fundamentals of Product
Description and Support" *)
REFERENCE FROM measure_schema;
(* from ISO 10303-41: STEP Part 41: "Fundamentals of Product
Description and Support" *)
REFERENCE FROM ISO13584_IEC61360_language_resource_schema;
(* see clause 6 "ISO13584_IEC61360_language_resource_schema"

– 12 – 61360-2  IEC:2002(E)
5.2 Constant definitions
This subclause contains constant definitions used later in clause 5.8 (Basic type and entity
definitions).
EXPRESS specification:
*)
CONSTANT
property_code_len: INTEGER := 14;
class_code_len: INTEGER := 14;
data_type_code_len: INTEGER := 14;
supplier_code_len: INTEGER := 70;
version_len: INTEGER := 9;
revision_len: INTEGER := 3;
value_code_len: INTEGER := 18;
pref_name_len: INTEGER := 70;
short_name_len: INTEGER := 15;
syn_name_len: INTEGER := pref_name_len;
DET_classification_len: INTEGER := 3;
source_doc_len: INTEGER := 80;
value_format_len: INTEGER := 80;
sep_cv: STRING := '-';
sep_id: STRING := '.';
END_CONSTANT;
(*
5.3 Basic semantic units: defining and using the dictionary
5.3.1 Requirements for exchange
In the exchange of dictionary and part library data it is customary to partition the data. For
example, a dictionary could be updated with some classes that specify their superclass by a
reference to a pre-existing class, or when the content of a library is exchanged, dictionary
elements are only referenced and not included every time. It must be possible to refer
unambiguously and consistently to the dictionary data.
Thus it is a clear requirement first, to be able to exchange pieces of data, and second, to have
relationships between these pieces. This is depicted in figure 2.
Every one of these pieces corresponds to a Physical File (according to ISO 10303-21).
EXPRESS (see ISO 10303-11) attributes can only contain references to data within the same
Physical File. Thus it is impossible to use EXPRESS attributes directly to implement inter-piece
references.
61360-2  IEC:2002(E) – 13 –
Pieces of
Dictionary data
Pieces of
Content data
IEC  217/02
Figure 2 – Pieces of data with relationships
5.3.2 Three-level architecture of the dictionary data
In this clause the concept of basic_semantic_unit (BSU) is introduced as a means to
implement these inter-piece references. A BSU provides a universally unique identification for
dictionary descriptions. This is depicted in figure 3.
Assume some piece of content (content_item) wants to refer a certain dictionary description,
for example to convey the value of a property of a component. It does this by referring to a
basic semantic unit through the attribute dictionary_definition.
A dictionary description (dictionary_element) refers to a basic semantic unit through the
attribute identified_by. From the correspondence of the absolute identifiers of the basic
semantic units this indirect relation is established.
Note that:
• both dictionary element and content item can be present in the same Physical File, but
need not be;
• the dictionary element does not need to be present for the exchange of some content item
referring to it. In this case it is assumed to be present in the dictionary of the target system
already. Conversely, dictionary data can be exchanged without any content data;
• the basic semantic unit can be one single instance in the case where both dictionary
element and content item instances are in the same Physical file;
• the same mechanism applies also to references between various dictionary elements (for
example between a component class and the associated property_DETs).
A BSU provides a reference to a dictionary description in any place where this is needed, e.g.
dictionary delivery, update delivery, library delivery, component data exchange. The data
associated with a property for example could be exchanged as a couple (property_BSU,
).
Figure 3 outlines the implementation of this general mechanism.

– 14 – 61360-2  IEC:2002(E)
Dictionary Element
identified by
absolute id:
Basic Semantic Unit IEC.root.XYZ
absolute id:
Basic Semantic Unit
IEC.root.XYZ
dictionary definition
Content Item
IEC  218/02
Figure 3 – Implementation of "inter-piece" relationships using basic semantic units
5.3.2.1 basic_semantic_unit
A basic_semantic_unit is a unique identification of a dictionary_element.
EXPRESS specification:
*)
ENTITY basic_semantic_unit
ABSTRACT SUPERTYPE OF ( ONEOF (
supplier_BSU,
class_BSU,
property_BSU,
data_type_BSU,
supplier_related_BSU,
class_related_BSU));
code: code_type;
version: version_type;
DERIVE
dic_identifier: identifier := code + sep_cv + version;
INVERSE
definition: SET [ 0 : 1 ] OF dictionary_element FOR
identified_by;
referenced_by: SET[ 0 : 1 ] OF content_item FOR
dictionary_definition;
END_ENTITY; -- basic_semantic_unit
(*
Attribute definitions:
code : the code assigned to identify a certain dictionary element.
version : the version number of a certain dictionary element.
dic_identifier : the full identification, consisting of concatenation of code and version.
___________
See relevant clause in IEC 61360-1.

61360-2  IEC:2002(E) – 15 –
definition: a reference to the dictionary element identified by this BSU. If not present in some
exchange context, it is assumed to be present in the dictionary of the target system already.
referenced_by: items making use of the dictionary element associated with this BSU.
5.3.2.2 dictionary_element
A dictionary_element is a full definition of the data required to be captured in the semantic
dictionary for some concept. For every concept a separate subtype shall be used. The
dictionary_element is associated with a basic_semantic_unit, which serves to uniquely iden-
tify this definition in the dictionary.
Figure 4 presents a planning model of the relationship between basic semantic unit and the
dictionary element.
(ABS) dictionary_element
(INV)
identified_by
definition S[0:1]
code
STRING
(ABS)
version
STRING
basic_semantic_unit
(DER) dic_identifier
STRING
(INV)
dictionary_definition
referenced_by S[0:1]
(ABS) content_item
IEC  219/02
Figure 4 – Relationship between basic semantic unit and dictionary element
By including the version attribute in the basic_semantic_unit entity, it forms part of the identi-
fication of a dictionary element (in contrast to the revision and time_stamps attributes).
EXPRESS specification:
*)
ENTITY dictionary_element
ABSTRACT SUPERTYPE OF ( ONEOF (
supplier_element,
class_and_property_elements,
data_type_element));
identified_by: basic_semantic_unit;
time_stamps: OPTIONAL dates;
revision: revision_type;
END_ENTITY;
(*
Attribute definitions:
identified_by: the BSU identifying this dictionary element.
time_stamps: the optional dates of creation and update of this dictionary element.

– 16 – 61360-2  IEC:2002(E)
revision : the revision number of this dictionary element.
5.3.2.3 content_item
A content_item is a piece of data referring to its description in the dictionary. It shall be
subtyped.
EXPRESS specification:
*)
ENTITY content_item
ABSTRACT SUPERTYPE;
dictionary_definition: basic_semantic_unit;
END_ENTITY;
(*
Attribute definitions:
dictionary_definition: the basic semantic unit to be used for referring to the definition in the
dictionary.
5.3.3 Overview of basic semantic units and dictionary elements
For every kind of dictionary data a pair of basic_semantic_unit and dictionary_element
subtypes shall be defined. Figure 5 outlines, as a planning model, the basic semantic units and
dictionary elements defined later. Note that the relationship between BSU and dictionary
elements is redefined for each type of data, so that only corresponding pairs can be related.
This is not graphically depicted here, however.
identified_by
(ABS) basic_semantic_unit (ABS) dictionary_element
(INV) definition S[0:1]
1 1
(ABS)
supplier_BSU property_BSU supplier_element
property_DET
(ABS)
class_BSU data_type_element
data_type_BSU
class
IEC  220/02
Figure 5 – Current BSUs and dictionary elements
Every kind of dictionary data is treated in one of the following subclauses:
• for suppliers see 5.4 "Supplier data";
• for classes see 5.5 "Class data";
• for properties/data element types see 5.6 "data element type/properties data";
• for data types see 5.7 "Domain data: the type system".
___________
See relevant clause in IEC 61360-1

61360-2  IEC:2002(E) – 17 –
5.3.4 Identification of dictionary elements: three-levels structure
The absolute identification of basic semantic units is based on the following three-levels
structure:
• supplier (of dictionary data);
• class;
• class-related dictionary elements (any dictionary element defined in the context of a class;
in this standard class-related dictionary elements are property_DET and data_type_
element, but there are provisions to extend this mechanism to other items).
An absolute identification can be achieved by concatenation of the applicable code for each
level.
This identification scheme is appropriate within a multi-supplier context. If, in a certain appli-
cation area, only data of one single (data-) supplier are relevant, the corresponding parts of the
identification, which are then constant, can be eliminated. For the purpose of exchange,
however, all the levels must be present, to avoid clashes of identifiers.
This identification scheme is described formally in the._BSU entities in 5.3 through 5.7,
attribute absolute_id.
5.3.5 Extension possibilities for other types of data
The BSU – dictionary element mechanism is very general and not limited to the four kinds of
data used here (see figure 5). This subclause specifies some facilities which allow for
extensions for other kinds. Depending on whether the scope of the identifier is given by a class
or a supplier, the corresponding._related_BSU entity has to be subtyped. It is necessary to
redefine the identified_by attribute of the entity dictionary_element (as is done in 5.4 through
5.7 for the current kinds of data).
5.3.5.1 supplier_related_BSU
The supplier_related_BSU provides for the dictionary elements to be associated with
suppliers, for example for the ISO 13584 series: program libraries.
EXPRESS specification:
*)
ENTITY supplier_related_BSU
ABSTRACT SUPERTYPE
SUBTYPE OF (basic_semantic_unit);
END_ENTITY;
(*
5.3.5.2 class_related_BSU
The class_related_BSU provides for the dictionary elements to be associated with classes, for
example for ISO 13584 tables, documents, etc.
EXPRESS specification:
*)
ENTITY class_related_BSU
ABSTRACT SUPERTYPE
SUBTYPE OF (basic_semantic_unit);
END_ENTITY;
(*
– 18 – 61360-2  IEC:2002(E)
5.3.5.3 supplier_BSU_relationship
The supplier_BSU_relationship is a provision for association of BSUs with suppliers.
EXPRESS specification:
*)
ENTITY supplier_BSU_relationship
ABSTRACT SUPERTYPE;
relating_supplier: supplier_element;
related_tokens: SET [ 1 : ? ] OF supplier_related_BSU;
END_ENTITY;
(*
Attribute definitions:
relating_supplier: the supplier_element which identifies the data supplier.
related_tokens: the set of dictionary elements associated to the supplier identified by the
relating_supplier attribute.
5.3.5.4 class_BSU_relationship
The class_BSU_relationship entity is a provision for association of BSUs with classes.
EXPRESS specification:
*)
ENTITY class_BSU_relationship
ABSTRACT SUPERTYPE;
relating_class: class;
related_tokens: SET [ 1 : ? ] OF class_related_BSU;
END_ENTITY;
(*
Attribute definitions:
relating_class: the class which identifies the dictionary element.
related_tokens: the set of dictionary elements associated to the class identified by the
relating_class attribute.
5.4 Supplier data
This subclause contains definitions for the representation of data about a supplier itself. In a
multi-supplier environment it is necessary to be able to identify the source of a certain
dictionary element. Figure 6 presents a planning model of the data associated with suppliers,
followed by the EXPRESS definition.
identified_by
defined_by
supplier_BSU
class_BSU
org
supplier_element
person_organization_schema.organization
addr
person_organization_schema.address
IEC  221/02
Figure 6 – Overview of supplier data and relationships

61360-2  IEC:2002(E) – 19 –
5.4.1 supplier_BSU
The supplier_BSU entity provides for unique identification of suppliers of dictionary data.
EXPRESS specification:
*)
ENTITY supplier_BSU
SUBTYPE OF (basic_semantic_unit);
SELF\basic_semantic_unit.code: supplier_code_type;
DERIVE
SELF\basic_semantic_unit.version: version_type:='001';
absolute_id: identifier := SELF\basic_semantic_unit.code ;
UNIQUE
UR1: absolute_id;
END_ENTITY;
(*
Attribute definitions:
code: the supplier's code assigned according to ISO 13584-26.
version: the version number of a supplier code shall be equal to 001.
absolute_id: the absolute identification of the supplier.
Formal propositions:
UR1: the supplier identifier defined by the absolute_id attribute is unique.
5.4.2 supplier_element
The supplier_element entity gives the dictionary description of suppliers.
EXPRESS specification:
*)
ENTITY supplier_element
SUBTYPE OF (dictionary_element);
SELF\dictionary_element.identified_by: supplier_BSU;
org: organization;
addr: address;
INVERSE
associated_items: SET [ 0 : ? ] OF supplier_BSU_relationship
FOR relating_supplier;
END_ENTITY;
(*
Attribute definitions:
identified_by: the supplier_BSU used to identify this supplier_element.
org: the organizational data of this supplier.
addr: the address of this supplier.
associated_items: allows access to other kinds of data via the BSU mechanism (for example
program library in ISO 13584).

– 20 – 61360-2  IEC:2002(E)
5.5 Class data
This subclause contains definitions for the representation of dictionary data of classes.
5.5.1 General
Figure 7 outlines, as a planning model, the data associated with classes and their relationship
to other dictionary elements.
As indicated in figure 7 with the its_superclass attribute, classes form an inheritance tree. It is
important to note that throughout this standard the terms "inheritance" and "to inherit" stand for
this relationship between classes (defined in the dictionary), although EXPRESS has an
inheritance concept, too. These shall be clearly distinguished to avoid misunderstandings.
defined_by described_by L[0:?]
identified_by
property_BSU
supplier_BSU class_BSU
(DER) subclasses SET[0:?]
(DER) known_applicable_properties SET[0:?]
defined_types S[0:?]
definition
data_type_BSU
STRING
(ABS)
note
STRING
class
(DER) known_applicable_data_types SET[0:?]
remark
STRING
its_superclass
source_doc_of_definition
revision
(ABS) document
STRING
time_stamps
dates
names
preferred_name synonymous_names S[0:?]
STRING STRING
item_names
icon
short_name
STRING (ABS) graphics
IEC  222/02
Figure 7 – Overview of class data and relationships
The dictionary data for component classes (as shown in figure 7) is spread over four
inheritance levels:
• class_and_property_elements defines data common to both classes and property_DETs;
• class allows for other kinds of classes to be specified later (for example in ISO 13584-24);
• item_class is the entity to hold data of different classes of application domain objects (e.g.
components, materials,.);
• component_class is the entity that models component classes and material_class is the
entity that models class of materials.
5.5.1.1 class_BSU
The class_BSU entity provides for the identification of classes.

61360-2  IEC:2002(E) – 21 –
EXPRESS specification:
*)
ENTITY class_BSU
SUBTYPE OF (basic_semantic_unit);
SELF\basic_semantic_unit.code: class_code_type;
defined_by: supplier_BSU;
DERIVE
absolute_id: identifier:= defined_by.absolute_id + sep_id +
dic_identifier;
known_visible_properties : SET [0 : ?]OF property_BSU
:=compute_known_visible_properties(SELF);
known_visible_data_types: SET [0 : ?]OF data_type_BSU
:=compute_known_visible_data_types(SELF);
INVERSE
subclasses: SET [0 : ?] OF class FOR its_superclass;
added_visible_properties:SET [0 : ?] OF property_BSU
FOR name_scope;
added_visible_data_types:SET [0 : ?] OF data_type_BSU
FOR name_scope;
UNIQUE
UR1: absolute_id;
END_ENTITY; -- class_BSU
(*
Attribute definitions:
code: the code assigned to this class by its supplier.
defined_by: the supplier defining this class and its dictionary element.
absolute_id: the unique identification of this class.
: the set of property_BSUs that refer to the class as their
known_visible_properties
name_scope attribute or to any known superclass of this class and that are therefore visible
for the class (and any of its subclass).
known_visible_data_types : the set of data_type_BSUs that refer to the class as their
name_scope attribute or to any known superclass of this class and that are therefore visible
for the class (and any of its subclass).
subclasses: the set of classes specifying this class as their superclass.
added_visible_properties : the set of property_BSUs that refer to the class as their
name_scope and that are therefore visible for the class (and any of its subclass).
added_visible_data_types : the set of data_type_BSUs that refer to the class as their
name_scope and that are therefore visible for the class (and any of its subclass).
___________
Within IEC, all the data element types refer to the IEC root at their name_scope attribute. Therefore all the data
element types defined within IEC are visible for every IEC class.
The capability to define visible data types that may be re-used for different data element types is not used in the
current version of IEC 61360
...