Alarm Acknowledgement

To acknowledge an activated alarm a Set or Pub with a JSON payload of type string must be performed on the alarm object node Id. The alarm node reference must be prefixed with /acknowledge? followed by the standard OPC-UA identifier ns=<idx>;[s|i]=<OPC ID>. The string value in the payload represents the comment to be added to the acknowledgement.

 { "type": "string", "val": "my comment" }

SET /acknowledge?ns=2;MyLevel.Alarm

This will change ns=2;s=MyLevel.Alarm/0:AckedState to "Acknowledged" and ns=2;s=MyLevel.Alarm/0:Comment to "my comment".

To be notified of an alarm becoming active or inactive simply perform a Get or Sub on the Active State variable of the alarm object.

Example: The prosys opcua simulation server (https://www.prosysopc.com/products/opc-ua-simulation-server/) has an alarm object ns=2;s=MyLevel.Alarm.

Using the OPC-UA Protocol Adapter you can subscribe to the tag ns=2;s=MyLevel.Alarm/0:ActiveState to be notified when the alarm has been activated.

"data_map": [
    {
      "alias": "example_alarm",
      "id": "ns=2;s=MyLevel.Alarm/0:ActiveState"
    }
]

If simulation is running, an alarm will activate/deactivate approximately every 30 seconds.