IEC 62769-8:2023

IEC 62769-8 ®
Edition 1.0 2023-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside ®
Field device integration (FDI ) –
Part 8: EDD to OPC-UA Mapping ®
Intégration des appareils de terrain (FDI ) –
Partie 8: Mapping de l'EDD avec l'OPC-UA

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IEC 62769-8 ®
Edition 1.0 2023-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside ®
Field device integration (FDI ) –

Part 8: EDD to OPC-UA Mapping ®
Intégration des appareils de terrain (FDI ) –

Partie 8: Mapping de l'EDD avec l'OPC-UA

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.040.40 ISBN 978-2-8322-6792-9

– 2 – IEC 62769-8:2023 © IEC 2023
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions, abbreviated terms, acronyms and conventions . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms and acronyms . 8
3.3 Conventions . 8
3.3.1 Capitalization . 8
3.3.2 Graphical notation . 8
4 Overview . 10
5 Basic principles of explicit mapping . 11
5.1 Semantic maps to tag EDD constructs . 11
5.2 Alias collections . 12
5.2.1 General . 12
5.2.2 Syntax of semantic id for alias mappings . 12
5.3 Namespace Alias Collection . 12
5.4 Reference Type Alias Collection . 14
5.5 Semantic maps for OPC-UA type mapping . 16
5.5.1 General . 16
5.5.2 Syntax of semantic Id for OPC-UA . 16
5.6 Semantic maps for unit mapping . 17
5.6.1 General . 17
5.6.2 Syntax of semantic Id for Units . 17
5.7 Explicit mapping of OPC-UA variable types . 17
5.8 Explicit mapping of complex OPC-UA types . 19
5.9 Explicit mapping of nested object and variable types . 21
5.9.1 General . 21
5.9.2 When to use collections . 21
5.9.3 When to use menus . 21
5.9.4 OPC-UA diagram of nested mapping example . 21
5.9.5 EDD snippet of nested mapping example . 22
5.10 Explicit mapping of methods . 26
5.10.1 Mapping EDD methods to OPC-UA objects, variables or properties . 26
5.10.2 Mapping EDD methods to OPC-UA methods . 26
5.11 Explicit mapping of alarms . 28
5.12 Explicit mapping of units . 35
5.13 Explicit mapping of aggregated data by methods . 36
5.14 Explicit mapping with reference types . 38
5.14.1 General . 38
5.14.2 Example: Adding an additional property to an instance of variable . 39
5.14.3 Example: Adding an additional variable to an instance of a variable or
an object . 40
5.14.4 Example: Adding an OPC-UA alias to a variable . 42
6 Implicit rules . 44
6.1 BrowseName of OPC-UA object . 44
6.1.1 General . 44
6.1.2 Overruling of BrowseName implicit rule . 44

6.2 DisplayName of OPC-UA object . 44
6.2.1 General . 44
6.2.2 Overruling of DisplayName implicit rule . 44
6.3 HANDLING and AccessLevel . 44
6.4 VALIDITY and availability. 44
6.5 Return values of EDD methods . 45
6.5.1 EDD methods mapped to OPC-UA objects, variables, properties or
attributes . 45
6.5.2 EDD methods mapped to OPC-UA methods . 45
6.6 Units . 45
6.7 Range . 45
6.8 Forward cast . 45
6.9 Backward cast . 45
6.10 Abstract OPC-UA types . 45
6.11 Unmapped mandatory OPC-UA properties, components and folders . 46
6.12 Semantic Identifiers and Dictionary References . 46
6.13 Implicit Type Casts for OPC-UA DataTypes . 47
7 Mapping the EDD device model into PA-DIM (OPC 30081) . 48
7.1 General . 48
7.2 Explicit mapping of sub-devices . 48
7.3 Adding sub-devices . 48
Bibliography . 52

Figure 1 – OPC UA Graphical notation for NodeClasses . 8
Figure 2 – OPC UA Graphical notation for References . 9
Figure 3 – OPC UA Graphical notation example . 9
Figure 4 – Optimized Type Reference . 10
Figure 5 – Similarity of OPC-UA objects and EDD collections . 10
Figure 6 – Syntax of sematic ids for EDD entry points . 12
Figure 7 – Syntax of sematic id for alias mapping . 12
Figure 8 – Namespace Collection . 14
Figure 9 – Reference Type Collection . 15
Figure 10 – Use of SEMANTIC_MAP for OPC-UA types . 16
Figure 11 – Syntax of OPC-UA type identifier . 16
Figure 12 – Semantic map example . 16
Figure 13 – Syntax of Unit Identifier . 17
Figure 14 – Most simple mapping example . 17
Figure 15 – EDD variable mapped to an OPC-UA BaseDataVariableType . 18
Figure 16 – Simple mapping example with range and unit . 19
Figure 17 – Mapping of a collection to an OPC-UA variable . 20
Figure 18 – Nested objects and variables . 22
Figure 19 – Example of nested objects and variables . 25
Figure 20 – Simple method . 26
Figure 21 – Example of simple method mapping . 28
Figure 22 – Supported Alarms . 32
Figure 23 – Example of alarm mapping . 35

– 4 – IEC 62769-8:2023 © IEC 2023
Figure 24 – EDD example of explicit unit mapping . 36
Figure 25 – Instance of PADIMType . 37
Figure 26 – Method of type DD_STRING mapped to a string variable . 38
Figure 27 – Adding a property which is not defined in mapped type . 39
Figure 28 – EDD example of adding a property . 40
Figure 29 – Adding a component . 41
Figure 30 – EDD example adding a component . 42
Figure 31 – Adding an alias . 43
Figure 32 – EDD example adding an alias . 43
Figure 33 – Explicit mapping of dictionary entries . 46
Figure 34 – Combination with an implicitly mapped dictionary entry . 47
Figure 35 – Subdevices . 49
Figure 36 – Subdevices example . 51

Table 1 – Alarm properties mapping. 29
Table 2 – Implicit Type Casts . 47

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________ ®
FIELD DEVICE INTEGRATION (FDI ) –

Part 8: EDD to OPC-UA Mapping
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,
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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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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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
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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.
IEC 62769-8 has been prepared by subcommittee 65E: Devices and integration in enterprise
systems, of IEC technical committee 65: Industrial-process measurement, control and
automation. It is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
65E/851/CDV 65E/909/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.

– 6 – IEC 62769-8:2023 © IEC 2023
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 62769 series, published under the general title Field device ®
), can be found on the IEC website.
integration (FDI
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.
®
FIELD DEVICE INTEGRATION (FDI ) –

Part 8: EDD to OPC-UA Mapping
1 Scope
This part of IEC 62769 specifies how the internal view of a device model represented by the
EDD can be transferred into an external view as an OPC-UA information model by mapping
EDD constructs to OPC-UA objects.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
NOTE For undated references, the edition of the referenced document (including any amendments), which applies
®1 ®
for a specific FDI Technology Version is defined within the FDI Technology Management Document and on the
support portals of FieldComm Group and PI International.
IEC 61804-3, Devices and integration in enterprise systems − Function blocks (FB) for process
control and electronic device description language (EDDL) − Part 3: EDDL syntax and
semantics
IEC 62541-3, OPC Unified Architecture – Part 3: Address Space Model
IEC 62541-4, OPC Unified Architecture – Part 4: Services
IEC 62541-5, OPC Unified Architecture – Part 5: Information Model
IEC 62541-8, OPC Unified Architecture – Part 8: Data Access
IEC 62541-9:2020, OPC Unified Architecture – Part 9: Alarms and Conditions
OPC 10000-17, OPC Unified Architecture – Part 17: Alias Names
OPC 10000-19, OPC Unified Architecture – Part 19: Dictionary Reference
IEC 62541-100, OPC unified architecture – Part 100: Device Interface ®
IEC 62769-1, Field Device Integration (FDI ) – Part 1: Overview
® ®
IEC 62769-5, Field Device Integration (FDI ) – Part 5: FDI Information Model
® ®
IEC 62769-6, Field Device Integration (FDI ) – Part 6: FDI Technology Mappings
___________
1 ®
FDI is a registered trademark of the non-profit organization Fieldbus Foundation, Inc. This information is given
for the convenience of users of this document and does not constitute an endorsement by IEC of the trademark
holder or any of its products. Compliance does not require use of the trade name. Use of the trade name requires
permission of the trade name holder.

– 8 – IEC 62769-8:2023 © IEC 2023
ISO/IEC 11179-6, Information technology – Metadata registries (MDR) – Part 6: Registration
OPC 30081, Process Automation Devices – PADIM
UN/CEFACT, UNECE Recommendation 20, Codes for Units of Measure Used in International
Trade
available at https://www.unece.org/cefact/codesfortrade/codes_index.html [viewed 2023-02-07]
3 Terms, definitions, abbreviated terms, acronyms and conventions
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62769-1,
IEC 62769-5, IEC 62769-6, IEC 62541-3, IEC 62541-4, IEC 62541-5, IEC 62541-8,
IEC 62541-9, OPC 10000-17, IEC 62541-100, and OPC 30081 apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.2 Abbreviated terms and acronyms
For the purposes of this document, the abbreviated terms and acronyms given in IEC 62769-1
as well as the following apply.
PA-DIM Process Automation Device Information Model
3.3 Conventions
3.3.1 Capitalization ®
Capitalization of the first letter of words is used in the IEC 62769 series to emphasize an FDI
defined term.
3.3.2 Graphical notation
OPC UA defines a graphical notation for an OPC UA AddressSpace. It defines graphical
symbols for all NodeClasses and how different types of References between Nodes can be
visualized. Figure 1 shows the symbols for the NodeClasses used in this document.
NodeClasses representing types always have a shadow.

Figure 1 – OPC UA Graphical notation for NodeClasses

Figure 2 shows the symbols for the ReferenceTypes used in this document. The Reference
symbol is normally pointing from the source Node to the target Node. The only exception is the
HasSubType Reference. The most important References such as HasComponent, HasProperty,
HasTypeDefinition and HasSubType have special symbols avoiding the name of the Reference.
For other ReferenceTypes or derived ReferenceTypes, the name of the ReferenceType is used
together with the symbol.
Figure 2 – OPC UA Graphical notation for References
Figure 3 shows a typical example for the use of the graphical notation. Object_A and Object_B
are instances of the ObjectType_Y indicated by the HasTypeDefinition References. The
ObjectType_Y is derived from ObjectType_X indicated by the HasSubType Reference. The
Object_A has the components Variable_1, Variable_2 and Method_1.
To describe the components of an Object on the ObjectType, the same NodeClasses and
References are used on the Object and on the ObjectType such as for ObjectType_Y in the
example. The Nodes used to describe an ObjectType are instance declaration Nodes.
To provide more detailed information for a Node, a subset or all Attributes and their values can
be added to a graphical symbol (see for example Variable_1, the component of Object_A in
Figure 3).
Figure 3 – OPC UA Graphical notation example

– 10 – IEC 62769-8:2023 © IEC 2023
To improve readability, this document frequently includes the type name inside the instance
box rather than displaying both boxes and a reference between them. This optimization is shown
in Figure 4.
Figure 4 – Optimized Type Reference
4 Overview
There are two types of mapping mechanisms – explicit and implicit mapping. Explicit mapping
is provided by the EDD constructs SEMANTIC_MAP in combination with COLLECTIONS,
METHODS and VARIABLES including the mapping of enumerations and is done by the EDD-
developer. Implicit mapping is provided by the implementation of the OPC-UA server in ®
conjunction with a FDI Server and covers definitions like default casts (e.g. any number value
to float64) or even the mapping of complete lists of unit codes from a fieldbus domain (HART
®2 ®3
HART , PROFIBUS , …) into an OPC-UA domain (e.g. UNECE, CDD, …).
Looking at OPC-UA objects containing named data items like attributes, properties, variables
and other objects, the most similar EDD objects are collections containing named data items
like variables, menus and other collections (see Figure 5).

Figure 5 – Similarity of OPC-UA objects and EDD collections
In fact, the EDD construct collection is the key element for the basic principle of how EDD
device model data shall be mapped into an OPC-UA information model. The following clauses
___________
2 ®
HART is a registered trademark of the non-profit organization FieldComm Group, Inc. This information is given
for convenience of users of this document and does not constitute an endorsement by IEC of the trademark holder
or any of its products. Compliance does not require use of the trademark. Use of the trademark requires
permission of the trademark holder.
3 ®
PROFIBUS is the registered trademark of the non-profit organization PROFIBUS Nutzerorganisation e.V. (PNO).
This information is given for the convenience of users of this document and does not constitute an endorsement
by IEC of the trademark holder or any of its products. Compliance does not require use of the trademark. Use of
the trademark requires permission of the trademark holder.

describe and define how this shall be done. Therefore, this document has normative character ®
for EDD developers and developers of OPC-servers accessing an FDI Server to publish an
OPC-UA information model according to a specific OPC-UA namespace and the mapping
information provided by the EDD.
Clause 5 covers in detail how the mapping works in principle and for any OPC-UA information
model based on any namespace.
Based on Clause 5, Clause 7 describes some details how to map the EDD into PA-DIM.
Additional normative definitions how to map fieldbus specific data (e.g. identification) into PA-
®4
DIM is provided by the FDI-Profile specifications for HART, FF, PROFINET , PROFIBUS,
®5 ®6
Modbus and ISA100 Wireless .
Before starting with doing some EDD mapping, it is strongly recommended to get a basic
understanding of OPC-UA concerning how object types, variable types and reference types are
defined.
5 Basic principles of explicit mapping
5.1 Semantic maps to tag EDD constructs
For not having to use naming conventions for EDD constructs to link a specific purpose to an
EDD construct, semantic maps shall be used to kind of tag an EDD construct by a specifically
defined semantic id. For the time being, three syntax definitions exist for three specific
purposes. The details of how to use them will be explained in the corresponding context.
The syntax of semantic ids for EDD entry points is illustrated in Figure 6.
___________
4 ®
PROFINET is the registered trademark of the non-profit organization PROFIBUS Nutzerorganisation e.V. (PNO).
This information is given for the convenience of users of this document and does not constitute an endorsement
by IEC of the trademark holder or any of its products. Compliance does not require use of the trademark. Use of
the trademark requires permission of the trademark holder.
5 ®
Modbus is a registered trademark of Schneider Electric USA, Inc. This information is given for the convenience
of users of this document and does not constitute an endorsement by IEC of the trademark holder or any of its
products. Compliance does not require use of the trademark. Use of the trademark requires permission of the
trademark holder.
6 ®
ISA100 Wireless is the registered trademark of the non-profit organization Automation Standards Compliance
Institute. This information is given for convenience of users of this document and does not constitute an
endorsement by IEC of the trademark holder or any of its products. Compliance does not require use of the
trademark. Use of the trademark requires permission of the trademark holder.

– 12 – IEC 62769-8:2023 © IEC 2023

Figure 6 – Syntax of sematic ids for EDD entry points
5.2 Alias collections
5.2.1 General
Alias collections are used to define aliases for lengthy strings having a specific meaning. The
alias should be short and shall be unique across the complete EDD. Aliases will be used as
member identifiers or as a part of member identifiers or in SEMANTIC_MAPs for OPC-UA type
mapping. Alias collections are the main entry points to resolve EDD to OPC-UA mapping and
shall not depend on each other (see 5.3 and 5.4).
5.2.2 Syntax of semantic id for alias mappings
The syntax of semantic id for alias mapping is illustrated in Figure 7.

Figure 7 – Syntax of sematic id for alias mapping
5.3 Namespace Alias Collection
To prevent name conflicts, any OPC-UA type is defined in scope of a specific namespace. A
namespace collection and appropriate variables shall be defined to provide suitable names for
the namespace URIs. The member identifier of the collection item shall be used as an alias
wherever a namespace identifier is needed. In the following example "__UA_" represents the
namespace http://opcfoundation.org/UA/ which is defined by the default value of the referenced
variable "UA_Namespace".
It is mandatory to define at least one namespace collection for an EDD defining EDD to OPC-
UA mapping.
Definition:
The name of the namespace collection shall be tagged by a SEMANTIC_MAP with the following
semantic ID:
"EDD//AliasCollection/Namespaces"
The name of the namespace COLLECTION, the name of the SEMANTIC_MAP and the names
of the referenced string variables can be freely chosen. The default value of the referenced
string variable shall contain a valid namespace.
Figure 8 shows an EDD namespace Collection example.

– 14 – IEC 62769-8:2023 © IEC 2023
SEMANTIC_MAP Namespace_Map
{
"EDD//AliasCollection/Namespaces": Namespace_Collection
}
COLLECTION OF VARIABLE Namespace_Collection
{
LABEL "OPC-UA Namespaces";
MEMBERS
{
__UA_, UA_Namespace;
__DI_, DI_Namespace;
__PADIM_, PADIM_Namespace;
UNECE, UNECE_Namespace;
}
}
VARIABLE UA_Namespace
{
LABEL  "UA namespace";
HELP  [blank];
CLASS  LOCAL;
HANDLING READ;
TYPE  ASCII(100);
DEFAULT_VALUE  "http://opcfoundation.org/UA/";
}
VARIABLE DI_Namespace
{
LABEL  "DI namespace";
HELP  [blank];
CLASS  LOCAL;
HANDLING READ;
TYPE  ASCII(100);
DEFAULT_VALUE  "http://opcfoundation.org/UA/DI/";
}
VARIABLE PADIM_Namespace
{
LABEL  "PADIM namespace";
HELP  [blank];
CLASS  LOCAL;
HANDLING READ;
TYPE  ASCII(100);
DEFAULT_VALUE  "http://opcfoundation.org/UA/PADIM/";
}
VARIABLE UNECE_Namespace
{
LABEL  "UNECE namespace";
HELP  [blank];
CLASS  LOCAL;
HANDLING READ;
TYPE  ASCII(100);
DEFAULT_VALUE  "http://www.opcfoundation.org/UA/units/un/cefact/";
}
Figure 8 – Namespace Collection
5.4 Reference Type Alias Collection
For the use of OPC-UA references where the specific reference type cannot be unambiguously
derived from the two objects the reference is connecting, the reference type shall be explicitly
defined.
This collection is only mandatory if mappings as described in 5.14 are used.

The name of the reference type collection shall be tagged by a SEMANTIC_MAP with the
following semantic id:
"EDD//AliasCollection/ReferenceTypes"
The name of the reference type COLLECTION, the name of the SEMANTIC_MAP and the
names of the referenced string variables can be freely chosen. The default value of the
referenced string variable shall contain a valid nodeid of a reference type.
SEMANTIC_MAP ReferenceType_Map
{
"EDD//AliasCollection//ReferenceTypes": ReferenceType_Collection
}
COLLECTION OF VARIABLE ReferenceType_Collection
{
LABEL "OPC-UA reference types"
MEMBERS
{
__HasAlias, HasAlias_Definition;
__HasComponent, HasComponent_Def;
__HasProperty, HasProperty_dfn;
}
}
VARIABLE HasAlias_Definition
{
LABEL "HasAlias reference type";
HELP [blank];
CLASS LOCAL;
HANDLING READ;
TYPE ASCII(100);
DEFAULT_VALUE "http://opcfoundation.org/UA/HasAlias";
}
VARIABLE HasProperty_dfn
{
LABEL "HasProperty reference type";
HELP [blank];
CLASS LOCAL;
HANDLING READ;
TYPE ASCII(100);
DEFAULT_VALUE "http://opcfoundation.org/UA/HasProperty";
}
VARIABLE HasComponent_Def
{
LABEL "HasComponent reference type";
HELP [blank];
CLASS LOCAL;
HANDLING READ;
TYPE ASCII(100);
DEFAULT_VALUE "http://opcfoundation.org/UA/HasComponent";
}
Figure 9 – Reference Type Collection

– 16 – IEC 62769-8:2023 © IEC 2023
5.5 Semantic maps for OPC-UA type mapping
5.5.1 General
The EDD construct SEMANTIC_MAP shall be used to assign an OPC-UA object type or variable
type to an EDD construct (collections in most cases) (see Figure 10). Based on this assignment,
the OPC-UA server instantiates an object of the specified object/variable type and fills it with
the data of the EDD construct.

Figure 10 – Use of SEMANTIC_MAP for OPC-UA types
5.5.2 Syntax of semantic Id for OPC-UA
The semantic id referencing the OPC-UA object type shall comply to the syntax illustrated in
Figure 11.
Figure 11 – Syntax of OPC-UA type identifier
In respect of the example from 5.2, a semantic map could look like the example shown in
Figure 12.
Figure 12 – Semantic map example
In Figure 12, the object type ‘PressureMeasurementVariableType’ from the namespace
‘http://opcfoundation.org/UA/PADIM/’ is mapped to an EDD construct with the name
‘PressureVariableColl’.
5.6 Semantic maps for unit mapping
5.6.1 General
According to the IEC 61804-3, SEMANTIC_MAP can be used to map semantic ids to unit
enumerations of EDD unit variables. The unit ids shall be used in the enumeration of the OPC-
UA type that is mapped to EDD unit variable and as unit codes in the EUInformation structure
of OPC-UA variables. This definition applies only to unit identifiers not compliant with
ISO/IEC 11179-6 naming convention.
5.6.2 Syntax of semantic Id for Units
The semantic id referencing a unit not compliant with ISO/IEC 11179-6 shall comply to the
following syntax illustrated in Figure 13.

Figure 13 – Syntax of Unit Identifier
5.7 Explicit mapping of OPC-UA variable types
The most basic case maps an EDD variable to an instance of an OPC-UA variable type is
illustrated in Figure 14.
Figure 14 – Most simple mapping example
In this case, the value of the EDD variable SMR_HighBlockDistance_2 has been mapped to the
value of an OPC-UA variable with the name SMR_HighBlockDistance_2 as an instance of
BaseDataVariableType (see Figure 15).

– 18 – IEC 62769-8:2023 © IEC 2023
SEMANTIC_MAP BlockingDistance_mp
{
"OPC-UA//__UA_/BaseDataVariableType": SMR_HighBlockDistance_2
}
UNIT SU_Length_UR
{
SU_Length_1: SMR_HighBlockDistance_2
}
VARIABLE SMR_HighBlockDistance_2
{
LABEL T_19_BlockingDistance;
HELP T_BlockDistance_TT;
CLASS DEVICE;
HANDLING IF (HWLock||SILLock||SWLock||WHGLock) {READ;} ELSE {READ & WRITE;}

TYPE FLOAT
{
MAX_VALUE
SELECT (SU_Length_1)
{
CASE e_Length_milliMeter_LONG:/*Max*/200000.0;
CASE e_Length_Meter_LONG:/*Max*/200.0;
CASE e_Length_Foot_LONG:/*Max*/656.167979002625;
CASE e_Length_Inch_LONG:/*Max*/7874.0157480315;
}
MIN_VALUE
SELECT (SU_Length_1)
{
CASE e_Length_milliMeter_LONG:/*Min*/0.0;
CASE e_Length_Meter_LONG:/*Min*/0.0;
CASE e_Length_Foot_LONG:/*Min*/0.0;
CASE e_Length_Inch_LONG:/*Min*/0.0;
}
EDIT_FORMAT
SELECT (SU_DecimalPlacesLength_1)
{
CASE e_DecimalPlacesSelector_X_LONG: ".0f";
CASE e_DecimalPlacesSelector_X_X_LONG: ".1f";
CASE e_DecimalPlacesSelector_X_XX_LONG: ".2f";
CASE e_DecimalPlacesSelector_X_XXX_LONG: ".3f";
CASE e_DecimalPlacesSelector_X_XXXX_LONG: ".4f";
}
DISPLAY_FORMAT
SELECT (SU_DecimalPlacesLength_1)
{
CASE e_DecimalPlacesSelector_X_LONG: ".0f";
CASE e_DecimalPlacesSelector_X_X_LONG: ".1f";
CASE e_DecimalPlacesSelector_X_XX_LONG: ".2f";
CASE e_DecimalPlacesSelector_X_XXX_LONG: ".3f";
CASE e_DecimalPlacesSelector_X_XXXX_LONG: ".4f";
}
}
DEFAULT_VALUE 0;
}
Figure 15 – EDD variable mapped to an OPC-UA BaseDataVariableType

Because of an implicit rule (see 6.1), the name of the EDD variable became the BrowseName
of the OPC-UA variable. Another implicit rule has been applied for the HANDLING attribute (see
6.3) and an implicit typecast has been applied to map the type of the value attribute of the EDD
variable to an appropriate datatype in the OPC-UA object (see 6.13). Besides name, label,
value and value datatype, none of the other attributes of the EDD variable could be implicitly
mapped to this OPC-UA object – not even the unit. This is because a BaseVariableType does
not support units and it also does not support a range with something like a MIN_VALUE or a
MAX_VALUE. For this purpose, a more convenient datatype like AnalogUnitRangeType could
be used which has additional properties for an engineering range and an engineering unit.

Figure 16 – Simple mapping example with range and unit
In this case, two additional implicit rules were applied, one for the unit (see 6.5) and one for the
range (see 6.7). If the default mapping of the implicit rules does not suit the needs, these rules
could be overwritten by some more explicit mapping (see 5.8 and 5.9).
5.8 Explicit mapping of complex OPC-UA types
For OPC-UA types which contain more than one attribute, object, variable or property which
cannot be implicitly mapped by some implicit mapping rule or if the implicit mapping needs to
be overruled, a
...