oSIST prEN IEC 62541-17:2024
(Main)OPC unified architecture - Part 17: Alias names
OPC unified architecture - Part 17: Alias names
IEC 62541-17:2025 provides a definition of AliasNames functionality. AliasNames provide a manner of configuring and exposing an alternate well-defined name for any Node in the system. This is analogous to the way domain names are used as an alias to IP addresses in IP networks. Like a DNS Server, an OPC UA Server that supports AliasNames provides a lookup Method that will translate an AliasName to a NodeId of the related Node on a Server. An aggregating Server can collect these AliasNames from multiple Servers and provide a lookup Method to allow Client applications to discover NodeIds on a system wide basis. An aggregating Server could also define AliasNames for Nodes in other Servers that do not support AliasNames. A GDS can be constructed that would automatically aggregate all AliasNames that are defined on any Server that has registered with the GDS. In this case, the GDS also provides the lookup mechanism for Clients at a well-known endpoint and address.
OPC Unified Architecture – Teil 17: Alias Namen
Architecture unifiée OPC - Partie 17: Alias
IEC 62541-17:2025 donne une définition de la fonctionnalité des AliasNames. Les AliasNames permettent de configurer et d'exposer un nom alternatif bien défini pour n'importe quel Nœud du système. Il s'agit d'un principe analogue à la manière dont les noms de domaine sont utilisés comme alias pour les adresses IP dans les réseaux IP. Comme un Serveur DNS, un Serveur OPC UA qui prend en charge les AliasNames fournit une Méthode de recherche qui permet de traduire un AliasName en un NodeId du Nœud correspondant sur un Serveur. Un Serveur de regroupement peut collecter ces AliasNames auprès de plusieurs Serveurs et fournir une Méthode de recherche pour permettre aux applications du Client de découvrir les NodeIds à l'échelle du système. Un Serveur de regroupement peut également définir des AliasNames pour des Nœuds d'autres Serveurs qui ne prennent pas en charge les AliasNames. Il est possible de créer un Serveur de découverte global (GDS, Global Discovery Server) qui regroupe automatiquement tous les AliasNames définis sur tout Serveur qui s'est enregistré auprès du GDS. Dans ce cas, le GDS fournit également le mécanisme de recherche pour les Clients à un point d'extrémité et une adresse connus.
Enotna arhitektura OPC - 17. del: Nadomestna imena
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-marec-2024
Enotna arhitektura OPC - 17. del: Nadomestna imena
OPC unified architecture - Part 17: Alias names
Ta slovenski standard je istoveten z: prEN IEC 62541-17:2024
ICS:
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
35.240.50 Uporabniške rešitve IT v IT applications in industry
industriji
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
65E/1042/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 62541-17 ED1
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2024-01-26 2024-04-19
SUPERSEDES DOCUMENTS:
65E/952/NP, 65E/1012/RVN
IEC SC 65E : DEVICES AND INTEGRATION IN ENTERPRISE SYSTEMS
SECRETARIAT: SECRETARY:
United States of America Mr Donald (Bob) Lattimer
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:
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in this CDV to the secretary.
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clauses to be included should this proposal proceed. Recipients are reminded that the CDV stage is the final stage for
submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).
TITLE:
OPC Unified Architecture – Part 17: Alias Names
PROPOSED STABILITY DATE: 2026
NOTE FROM TC/SC OFFICERS:
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
permission in writing from IEC.
IEC CDV 62541-17 © IEC 2023
1 CONTENTS
2 Page
4 1 Scope . 1
5 2 Normative references . 1
6 3 Terms and abbreviated terms . 1
7 3.1 Terms . 1
8 3.2 Abbreviated terms . 2
9 4 Use cases . 2
10 4.1 Complex configuration . 2
11 4.2 Automatic reconfiguration . 2
12 4.3 Cloud based system . 2
13 4.4 Aggregated systems . 2
14 5 AliasNames Information Model overview . 3
15 6 OPC UA ObjectTypes . 4
16 6.1 Overview. 4
17 6.2 AliasNameType ObjectType Definition . 4
18 6.3 AliasNameCategoryType ObjectType Definition . 5
19 6.3.1 Definition . 5
20 6.3.2 FindAlias Method . 5
21 7 OPC UA DataTypes . 7
22 7.1 Overview. 7
23 7.2 AliasNameDataType . 7
24 8 Reference Types . 8
25 8.1 Overview. 8
26 8.2 AliasFor ReferenceType. 8
27 9 Instances . 8
28 9.1 Overview. 8
29 9.2 Aliases . 8
30 9.3 TagVariables . 9
31 9.4 Topics . 9
32 Annex A (informative): Examples . 10
33 A.1 Overview. 10
34 A.2 AliasNames used within a single Server . 10
35 A.3 AliasNames in an aggregating Server . 11
36 A.4 Standalone AliasNames Server . 11
37 A.5 Aggregating Server with a collection of Aggregates . 12
38 A.6 GDS . 13
39 A.7 Client use of an AliasName Server . 14
40 Annex B GDS functionality (normative) . 15
41 B.1 Overview. 15
42 B.2 Register a Server . 16
43 B.3 Unregister a Server . 16
44 B.4 Disconnect between a Client and an AliasName Server . 17
45 Bibliography . 19
IEC CDV 62541-17 © IEC 2023 ii
47 Figures
49 Figure 1 - AliasNames Overview . 3
50 Figure 2 - AliasNames Example . 4
51 Figure A-3 - AliasNames in a Server example . 10
52 Figure A-4 - Aggregating AliasNames Server example . 11
53 Figure A-5 - AliasNames Server example . 12
54 Figure A-6 - Aggregating Server example 2 . 13
55 Figure A-7 - GDS with merged AliasNames example . 14
56 Figure B-8 - Example GDS aggregating AliasNames . 15
57 Figure B-9 - Server Registration Process. 16
58 Figure B-10 - Unregister Server Process . 17
59 Figure B-11 - Example Client Process for Server subscription with errors . 18
61 Tables
62 Table 1 – AliasNameType Definition . 4
63 Table 2 – AliasNameCategoryType Definition . 5
64 Table 3 - FindAlias Method Arguments . 6
65 Table 4 - FindAlias Method Error Codes . 6
66 Table 5 - FindAlias Method AddressSpace definition . 6
67 Table 6 - AliasNameDataType DataType structure . 7
68 Table 7 – AliasNameDataType Definition . 7
69 Table 8 – AliasFor Definition . 8
70 Table 9 - Aliases definition . 8
71 Table 10 – TagVariables definition . 9
72 Table 11 - Topics definition . 9
iii IEC CDV 62541-17 © IEC 2023
75 INTERNATIONAL ELECTROTECHNICAL COMMISSION
76 ____________
78 OPC UNIFIED ARCHITECTURE –
80 Part 17: Alias Names
82 FOREWORD
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114 committee may propose the publication of a technical report when it has collected data of a different
115 kind from that which is normally published as an International Standard, for example "state of the art".
116 International Standard IEC 62541-17 has been prepared by subcommittee 65E: Devices and integration
117 in enterprise systems, of IEC technical committee 65: Industrial-process measurement, control and
118 automation.
119 The text of this international standard is based on the following documents:
CDV Report on voting
65E/XX/CDV 65E/XX/RVC
121 Full information on the voting for the approval of this international standard can be found in the report
122 on voting indicated in the above table.
123 This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
124 Throughout this document and the other Parts of the series, certain document conventions are used:
IEC CDV 62541-17 © IEC 2023 iv
125 Italics are used to denote a defined term or definition that appears in the “Terms and definition” clause
126 in one of the parts of the series.
127 Italics are also used to denote the name of a service input or output parameter or the name of a structure
128 or element of a structure that are usually defined in tables.
129 The italicized terms and names are also often written in camel-case (the practice of writing compound
130 words or phrases in which the elements are joined without spaces, with each element's initial letter
131 capitalized within the compound). For example, the defined term is AddressSpace instead of Address
132 Space. This makes it easier to understand that there is a single definition for AddressSpace, not
133 separate definitions for Address and Space.
134 A list of all parts of the IEC 62541 series is included in IEC 62541-1 clause 4 Structure of the OPC UA
135 series and published under the general title OPC Unified Architecture, can be found on the IEC website.
136 The committee has decided that the contents of this publication will remain unchanged until the stability
137 date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to the specific
138 publication. At this date, the publication will be
139 • reconfirmed,
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141 • replaced by a revised edition, or
142 • amended.
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IMPORTANT – The 'colour inside' logo on the cover page of this publication 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.
IEC CDV 62541-17 © IEC 2023 1
151 OPC Unified Architecture Specification
153 Part 17: Alias Names
156 1 Scope
157 This specification provides a definition of AliasNames functionality. AliasNames provide a manner of
158 configuring and exposing an alternate well-defined name for any Node in the system. This is analogous
159 to the way domain names are used as an alias to IP addresses in IP networks. Like a DNS Server, an
160 OPC UA Server that supports AliasNames provides a lookup Method that will translate an AliasName
161 to a NodeId of the related Node on a Server. An aggregating Server can collect these AliasNames
162 from multiple Servers and provide a lookup Method to allow Client applications to discover NodeIds
163 on a system wide basis. An aggregating Server might also define AliasNames for Nodes in other
164 Servers that do not support AliasNames. A GDS may be constructed that would automatically
165 aggregate all AliasNames that are defined on any Server that has registered with the GDS. In this
166 case the GDS also provides the lookup mechanism for Clients at a well-known endpoint and address.
167 The GDS functionality for AliasNames is formally defined in Annex B.
168 2 Normative references
169 The following referenced documents are indispensable for the application of this specification. For
170 dated references, only the edition cited applies. For undated references, the latest edition of the
171 referenced document (including any amendments and errata) applies.
172 IEC 62541-1, OPC Unified Architecture – Part 1: Overview and Concepts
173 IEC 62541-3, OPC Unified Architecture – Part 3: Address Space Model
174 IEC 62541-4, OPC Unified Architecture – Part 4: Services
175 IEC 62541-5, OPC Unified Architecture – Part 5: Information Model
176 IEC 62541-12, OPC Unified Architecture – Part 12: Discovery and Global Services
177 IEC 62541-14, OPC Unified Architecture – Part 14: PubSub
179 http://www.opcfoundation.org/UA/Part14/
180 3 Terms and abbreviated terms
181 3.1 Terms
182 For the purposes of this document, the terms and definitions given in IEC 62541-1, IEC 62541-3,
183 IEC 62541-4, IEC 62541-5, IEC 62541-12, and IEC 62541-14 apply.
184 All used terms are italicized in the specification.
185 3.1.1
186 AliasName
187 alternate well-defined name for any Node in the system
2 IEC CDV 62541-17 © IEC 2023
188 3.2 Abbreviated terms
190 GDS Global Discovery Server
192 4 Use cases
193 4.1 Complex configuration
194 For systems that are large and complex, engineering is often done in multiple tools and by multiple
195 individuals. The separate configurations are required to work together, but resolving the references
196 between these different configurations can be a significant task. A common solution to simplify this
197 task is a naming convention for the items that are being referenced. Providing an automatic lookup
198 capability for these names would greatly simplify configuration. Each system can specify its own names
199 and configurations can be built to just use the names, without having to know the exact address of the
200 items. The exact address would include the address of the Server, the address of the tag in the Server,
201 the required protocol for connecting to the Server, security settings etc. OPC UA defines a GDS that
202 can provide information about what Servers are available in a system and how to connect to them, but
203 it does not currently provide information about the tags that are available in a given Server.
205 4.2 Automatic reconfiguration
206 In a system where many smaller Servers exist and these Servers might be dynamic, in that new
207 Servers can appear and disappear. Configuration might move between Servers. The automatic
208 resolution of where a specific piece of information is located would greatly simplify these systems.
210 4.3 Cloud based system
211 Much like the previous use case, a cloud-based system, where Servers can be spun up in a new cloud
212 system or adjusted and split based on loading to multiple Servers. The automatic resolution of where
213 a specific piece of information is located would greatly simplify these systems.
215 4.4 Aggregated systems
216 In systems where many simple devices exist, any given simple device might not have the ability to
217 provide name resolution, yet these systems can be much like systems in one of the previous use
218 cases. In a system such as this an aggregating Server might exist, where the aggregating Server
219 would provide the names as well as the lookup for the underlying Server. This aggregating Server
220 might also provide other functionality such as aggregation of values, but it might only provide the name
221 definitions and resolutions. The underlying Server might have no knowledge of the name.
IEC CDV 62541-17 © IEC 2023 3
222 5 AliasNames Information Model overview
223 The AliasNames functionality (illustrated in Figure 1) defines a number of ObjectTypes, Methods,
224 DataTypes and References. Figure 2 illustrates an example of the Object model defined for
225 AliasNames.
NonHierarchical
FolderType AliasNameType
AliasFor
AliasNameCategory
Type
AliasFor MyObject
AliasFor MyVariable
AliasFor MyMethod
FindAlias
227 Figure 1 - AliasNames Overview
229 The model also includes some well-known fixed instances. The key functionality of AliasNames is to
230 reference the information that an AliasName is assigned to. These can be any Node. The AliasNames
231 can be grouped according to types of functionality. The OPC Foundation defines some initial groups,
232 but the groups can be extended by companion specifications, vendors or end users to meet their
233 needs.
4 IEC CDV 62541-17 © IEC 2023
Specification
Objects
Example Information Model
Defined
MyWell
Alias Model
AliasNameCategoryType:
Alias Model
Aliases
MyValve
Examples
AliasNameCategoryType:
TagVariables
Instrument01
AliasNameType:
LI201
ProcessValue
AliasFor
AliasNameType:
TI101
Instrument02
AliasFor
AliasNameType:
ProcessValue
LI101
Instrument03
AliasNameCategoryType:
Wells
ProcessValue
AliasFor
Pub/Sub
AliasFor MyDataset1
AliasNameCategoryType:
Topics
AliasFor
DataSetWriter
AliasNameType:
WellData
MyDataset2
AliasNameType:
FastFixed
DataSetWriter
AliasNameType:
AliasFor
OneSecondFixed
235 Figure 2 - AliasNames Example
237 6 OPC UA ObjectTypes
238 6.1 Overview
239 An overview of this object model is provided in section 5. Figure 1 illustrates the overall AliasName
240 Object Model
241 6.2 AliasNameType ObjectType Definition
242 Instances of the AliasNameType ObjectType provide alternate names for Nodes. The AliasNameType
243 is formally defined in Table 1.
244 Table 1 – AliasNameType Definition
Attribute Value
BrowseName AliasNameType
IsAbstract False
References Node BrowseName DataType TypeDefinition Modelling
Class Rule
Subtype of the BaseObjectType defined in IEC 62541-5
ConformanceUnits
AliasName Base
246 This ObjectType has no Properties or Variables. The BrowseName of the Object is used as the alias
247 name. The string part of the BrowseName shall be the DisplayName with an empty locale id and no
248 other locale shall be provided. This Object shall have at least one AliasFor Reference (or sub-type).
249 A Client shall always ignore the namespace associated with an AliasName for comparison with other
250 AliasNames.
Organizes
Organizes
IEC CDV 62541-17 © IEC 2023 5
251 The AliasName Object’s BrowseName shall not be modified once it is defined. If an AliasName needs
252 to be changed, it is considered as a deletion of the old AliasName and the addition of new AliasName.
253 This requirement allows AggregatingServers to detect new AliasNames.
254 6.3 AliasNameCategoryType ObjectType Definition
255 6.3.1 Definition
256 AliasNameCategoryType instances are used to organize the AliasNameType instances that a Server
257 defines. They can also include instances of AliasNameCategoryType to allow hierarchical groupings
258 of AliasNames. It includes a mandatory Method for finding instances of AliasNameType in the
259 AliasName hierarchy, starting at this instance of AliasNameCategoryType. For example, if the Method
260 call is made on the Aliases AliasNameCategoryType instance (see 9.2), it would apply the
261 AliasNameSearchPattern to all AliasNames that are defined under TagVariables, Topics and any other
262 AliasNameCategoryType instance in the hierarchy.
263 The AliasNameCategoryType is a subtype of FolderType and is formally defined in Table 2.
264 Table 2 – AliasNameCategoryType Definition
Attribute Value
BrowseName AliasNameCategoryType
IsAbstract False
References Node BrowseName DataType TypeDefinition Modelling
Class Rule
Subtype of the FolderType from IEC 62541-5
Organizes Object AliasNameType OptionalPlaceholder
Organizes Object AliasNameCategoryType OptionalPlaceholder
HasComponent Method FindAlias Defined in 6.3.2 Mandatory
HasProperty Variable LastChange VersionTime PropertyType Optional
Conformance Units
AliasName Base
266 The list of AliasNames that an Object contains may be dynamic. For example, AliasNames may be
267 added in an aggregating Server as underlying Servers become available or may be removed if a Server
268 is no longer available.
269 represents any number of instances of AliasNameType. Each instance shall have at least one
270 AliasFor Reference to a Node. Multiple instances can point to the same Node.
271 a
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