Alias Names

Available from 2022.6

The eUA Server supports Alias Names according to the OPC UA specification OPC 10000-17 - Part 17: Alias Names.

The functionality of Alias Names is to reference one or multiple nodes in a server address space using a custom name.
The eUA Server supports references to nodes in its own address space according to AliasNames used within a single Server.

Note: References to other servers are not supported.

Alias Names are nodes that have AliasNameType and are organized by the the AliasNameCategoryType folder Aliases, below Objects

By default no Alias Names are created and the Aliases folder does not exist. Alias nodes are created through external information models. Refer to Integration of external information models for further information.  

For example, node Float64_1 will be created in the server address space by adding e.g. the following UAObject to a NodeSet.xml

<UAObject NodeId="ns=1;i=1000" BrowseName="1:Float64_1">
      <Reference ReferenceType="i=23469">ns=2;s=OpcUA.Test/Base.Primitive.Scalar.Float64</Reference>
      <Reference ReferenceType="HasTypeDefinition">i=23455</Reference>
      <Reference ReferenceType="Organizes" IsForward="false">i=23479</Reference>

Aliases, as well as TagVariables (i=23479) and Topics (i=23488) are created automatically. Also, the FindAlias method, being a mandatory component of AliasNameCategoryType objects, is created and implemented.

Calling FindAlias requires two input arguments:

  1. The AliasNameSearchPattern input argument should not be empty. It supports wildcard characters according to the OPC UA Online Reference
    For example use % to match any string.
  2. The ReferenceTypeFilter input argument should be the AliasFor (i=23469) ReferenceType or a subtype of AliasFor to further filter the results.

The output is an array of AliasNameDataType that match AliasNameSearchPattern and ReferenceTypeFilter. Each  array element contains an array of ReferenceNodes to AliasName, since one AliasName can reference multiple nodes. 

Note: FindAlias recursively searches all AliasNames in the corresponding AliasNameCategory.



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• Published/reviewed: 2022-09-14 • Revision 046 •