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AddIns

Introduction​

AddIns in OPC UA are a way to extend the functionality of an OPC UA server by adding custom components using aggregation.

This page will guide you through creating AddIn object types and their instances using the OPC UA Modeler. It also explains how to define AddIn ObjectTypes in the YAML configuration.

Creating AddIn ObjectTypes​

An AddIn ObjectType must have a 0:DefaultInstanceBrowseName property that specifies the BrowseName of the default instance of the AddIn. For simplicity, we have added a defaultInstanceBrowseName property in the YAML configuration.

Example​

objectTypes:
    - browseName: MyComponentType
      defaultInstanceBrowseName: MyComponent

This is equvalent to

objectTypes:
    - browseName: MyComponentType
      properties:
        - name: ua:DefaultInstanceBrowseName
          type: QualifiedName
          value: MyComponent

Creating Instances of AddIn object types​

Once an AddIn object type has been created, you can create an instance of it by using the addIns: property

Example​

instances:
    - browseName: MyDevice
      type: di:DeviceType
      addIns:
        -typeDefinition: MyComponentType

By default, the AddIns instance name will be the same as the value stored in the defaultInstanceBrowseName property of the AddIn ObjectType.

Specifying Different Names for AddIn Instances​

If you want to specify a different name for the AddIn instance or add multiple instances of the same component inside your object or object type, you can do so by using the browseName property

instances:
    - browseName: MyDevice
      type: di:DeviceType
      addIns:
        -typeDefinition: MyComponentType
        -typeDefinition: MyComponentType
         browseName: MyComponent1
        -typeDefinition: MyComponentType
         browseName: MyComponent2

Instantiating AddIn inside an object type Declaration​

You can also instantiate AddIn inside an object type declaration in the same way. When doing this, you can add the modellingRule property to specify whether the AddIn is optional or mandatory.

example:​

objectTypes:
    - browseName: MyDeviceType
      addIns:
        - typeDefinition: MyComponentType
          browseName: MyComponent1
          # modellingRule: Mandatory  # by default, the AddIn is mandatory, so you only need to specify modellingRule if the AddIn is optional
        - typeDefinition: MyComponentType
          browseName: MyComponent2
          modellingRule: Optional # only specify modellingRule if the AddIn is optional, by default it is mandatory

In this example, MyComponentType is instantiated inside MyDeviceType. The modellingRule property is used to specify whether each AddIn is optional or mandatory.

references:​