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VariableTypes

Defining Variable Type​

Variable Types in OPC UA are used to define the data types of variables in the OPC UA server. They are defined within the variableTypes section the YAML file.

Here is an example of defining a Variable Type called MyVariableType:

variableTypes:
  - browseName: MyVariableType
    dataType: ua:Double
    value: 0

inte​

instantiating a Variable Type in a Object Type​

Once a Variable Type has been defined, you can create an instance of it by using the properties or components property.

Here is an example of creating an instance of MyVariableType in an Object Type called MyObjectType:

objectTypes:
  - browseName: MyObjectType
    properties:
      - browseName: MyVariable
        typeDefinition: MyVariableType
        modellingRule: Mandatory # or Optional

By default , the modeler will infer that MyVariable is a Variable by looking at the typeDefinition property.

exposing optional properties of a Variable Type​

Variables can have intrinsic properties.

variableTypes:
  - browseName: MyVariableType
    dataType: ua:Double
    value: 0
    properties:
      - browseName: Units
        dataType: ua:String
        modellingRule: Optional

instances:
   - browseName: MyObject
     components:
       - browseName: MyVariable
         typeDefinition: MyVariableType
         optionals: 
           - Units