Configure an OPC UA group object

Add a group object to your OPC UA data source hierarchy

1. Select the new data source object, right-click it, and then select Add OPCUAGroup Connection on the shortcut menu.

   A new object is created in the hierarchy tree and is named New_OPCUAGroup_000 by default. Rename it, if desired. You are allowed to add up-to maximum of 10 new group objects.

   The New_OPCUAGroup_000 Parameters configuration view (right pane) is displayed.

2. Configure the new group object parameters.

   

   1. Device Group Name: This parameter is configured on the hierarchy tree, and is displayed in a non-editable text box in the parameters configuration pane.

   2. Update Interval: Expressed in milliseconds, this parameter controls the frequency at which the Gateway Communication Driver requests for data updates from the OPC UA Server.

   3. Data Sampling Interval: Expressed in milliseconds, this parameter indicates the fastest rate at which the OPC UA server should sample its underlying source for data changes. If exception-based reporting is supported by the OPC UA server, this parameter may be set to 0 to request exception-based data changes.

      Since the Update Interval indicates how often the Gateway Communication Driver retrieves the data from the OPC UA server, you should set the Data Sampling Interval at a rate faster than the Update Interval.

      For example, if you set the Update Interval as 5000ms and the Data Sampling Interval as 1000ms, then the Gateway Communication Driver records 5 data samples every 5 seconds.

      Note: Do not use this parameter if the Demand Read option is checked.

   4. Read Only: When selected, all items connected through the OPC UA group are read only. This parameter is hot configurable.

   5. Demand Read: If this option is checked, the value of the Update Interval is used to poll the OPC UA server for data.This option uses less resources on the OPC UA server but imposes limit on data throughput and hence, should only be used when low throughput condition is acceptable.

      For high performance data throughput in runtime, leave this option unchecked (default). Gateway Communication Driver will request the OPC UA server to monitor data changes in the data items. Whenever there are value changes in the data items, the OPC UA server will publish the changes to Gateway Communication Driver.

   6. Demand Read After Poke: When enabled, a read transaction is performed on an item whenever it has a write transaction irrespective of the subscription group interval. When unchecked, the value of the item is updated at the specified subscription interval after a write operation on the item. Default value is unchecked.

      Note: Enabling the Demand Read After Poke check box may cause undue strain on the server, which may result in performance issues.

3. Configure the Device Items by one of the following methods:

   1. Configure Device Items. Select the Device Items tab and add item names and references. For more information, see Configure device item definitions.

   2. To browse OPC UA server items and populate in Device Items tab, select Browse OPCUA Server to browse OPC UA server items and populate in Device Items tab. For more information, see Browse the OPC UA server namespace.