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Mapping Tags to OPC UA Variables

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    Last Modified: September 27, 2018

    Read variables from an OPC server as SystemLink tags to track and visualize external data within your system.

    Variables are the OPC equivalent of SystemLink tags. Before you can read an OPC UA variable as a SystemLink tag, you must install NI SystemLink Server OPC Module, connect to an OPC server, and ensure SystemLink supports the data type of the variable.
    1. In the Address Space on your OPC session, navigate to the location of the variable on the OPC server.
    2. Click Create monitor to start mapping the variable to a tag. Refer to the following table to determine which SystemLink data type corresponds to the data type of your OPC UA variable.
      OPC UA variable data type SystemLink tag data type
      • bool
      • boolean
      Boolean
      • float
      • double
      Double
      • int
      • int32
      • byte
      • short
      • int16
      • uint16
      • uint
      • number
      Int
      • uint32
      • uint64
      UInt64
      • bytestring
      • string
      String
      • datetime
      • utctime
      DateTime
      A monitor watches the OPC UA variable and writes its values to a corresponding SystemLink tag. Data from the OPC UA variable will now show as tag data in Tag Viewer, and you can visualize this tag data with Dashboard Builder.
    3. Optional: To temporarily stop the monitor from writing to a tag, click Pause. To remove the connection between SystemLink and the OPC UA variable, click Delete.

    After you map a variable to a tag, you can read values of the tag as it updates.


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