Activity: OPC UA Tag Read Write Activity

Use the OPC UA Tag Read Write activity to read or write the tag values from and to the OPC UA server which is connected to the AVEVA Work Tasks Server.

Activity Properties:

Specify appropriate values for the activity properties to configure the OPC UA Tag Read Write activity.

Right-click the activity, and click Properties to open the Activity Properties window. Alternatively, select the activity, and then click Activity Properties in the tool bar of the Process Designer window.

The activity properties of the OPC UA Tag Read Write activity are described below.

Name & Description

Use these properties to specify the name and description for the activity.

• Name: Specify a name for the activity.

  Property Type: Mandatory

• Description: Specifies a brief description to be displayed for the activity.

  Property Type: Optional. Set this property only if required.

Configuration

Use these properties to configure the functionality of the activity.

• OPC UA Server Connection: Use this property to select an OPC UA Server Connection. The drop-down list displays the list of all the OPC UA Server Connections created through the External Connection List.

  Property Type: Mandatory. This property must be set for the workflow to communicate with OPC UA Server.

  For more information, see OPC UA Server Connection.

• Tag Operation: Use this property to set the type of operation, either Read or Write, to be performed on the OPC UA Server.

  Property Type: Mandatory. This property must be set for the workflow to communicate with OPC UA Server.

• Select Attribute: Use this property to read or update the value of variables and XML variables, that can be used in the subsequent activities. The type of operation that can be performed using the Select Attribute property depends on the value selected in the Tag Operation property.

  Property Type: Mandatory. This property must be set for the workflow to communicate with OPC UA Server.

• Retry Count: Use this property to specify the maximum number of attempts the activity should make to connect to the OPC UA Server, if the first attempt to connect to the OPC UA Server fails. The default value is 3.

  Property Type: Optional. Set this property only if required.

  Note: For the Write operation, the tags can be dynamically added to the Variables/XmlVariables. You can select these variables in the "Select Attribute" property.

Exception Behavior

• Raise Error on unhandled linked output: Each activity has the Raise Error on Unhandled Linked Output property. This property shows all the default configured mapped error outputs in red with their check boxes selected.

  Property Type: Optional. Set this property only if required.

  See Mapped Error Output for more details.

Looping Behavior

• Loop through this action if output is: Use this property to specify the looping behavior of the activity.

  Property Type: Optional. Set this property only if required.