Adding a server point with alarm and history extensions
Server points provide live and historical data as well as alarm events. Server points are visible to connected OPC UA clients.
Prerequisites:
- You are connected to a running station that is configured with the OpcUaServer.
- The opcUaServer palette is open.
- The station does not already have control points available.
NOTE: Adding a history extension to a control point in the OPC UA server's namespace makes the associated history visible to a connected
OPC UA client. Similarly, adding an alarm extension to a control point in the OPC UA server's namespace and setting the alarm
extension's
Alarm Class to OpcUaAlarmClass sends OPC UA events to a connected OPC UA client that subscribes to these events.
Perform the following steps:
- In the Nav tree, expand .
- From the palette, add an OpcUAServerPointFolder to the Points container.
- Under the station’s folder, add a new NumericWritable point. Configure it with a NumericCov history extension and an OutOfRangeAlarmExt.
- To open the Opc Ua Server Point Manager, double-click the OpcUaServerPointFolder, click Discover, then, in the
ORDproperty, select the folder to search and click OK.The Discovered pane presents a list of control points that exist in the station. You can map these to the OpcUaServerPointFolder.
- Select the NumericWritable in the Discovered pane and click Add.The driver adds the point to the Database pane where it becomes visible under the OpcUaServerPointFolder.
By default, the driver exports a discovered writable point from the server as read-only. However, you can add a writable point that you can import. The driver imports the point (which the client writes) to the server. The server reads the data from the client.
After adding the point in the server, you can add history or alarm extensions to enable histories or alarms for the point.
- To do this, expand the writable point in the Discovered pane, select the point with a
Directionvalue ofImportand click Add.
The driver serves up the server points in this OpcUaServerPointFolder as consumable data including live and historical data and alarm events. These data are visible to a connected OPC UA client.