Creating rules for state changes of OPC entity properties - OPC Client 3.1

OPC Client Plugin Guide 3.1

OPC Client 3.1

To receive events and alarms in Security Center when the states of OPC tags change on the OPC server, you can set up rules for the associated OPC entity properties using the rule engine of the OPC Client plugin.

What you should know

When a rule is created for OPC entity properties, the plugin subscribes to data changes for the properties selected in the rule configuration. When data changes are received by the plugin, the rule is evaluated. If the value received matches the conditions in the rule, then either an event or an alarm is triggered, according to the configured action.


  1. From the Config Tool home page, open the Plugins task.
  2. Select the OPC Client plugin from the entity browser, and click the Rules tab.
  3. At the bottom of the Rules page, click .
  4. In the Create a rule dialog box, enter the following parameters for the rule:
    Enter a name for the rule.
    Enter a description for the rule.
    Select the type of OPC entity to monitor.
    Select a specific OPC entity to monitor, or select All to monitor all OPC entities of the same type.
    Select which OPC entity property to monitor. When you select a property, its data type is displayed (boolean, string, and so on).
    Select what the property value must be in relation to the Value option (equal to, not equal to, lesser than, greater than, and so on) in order to trigger the event.
    Enter a value that the Operator is tested against.
    Select either Raise a custom event or Trigger an alarm.
    This option is displayed when you select Raise a custom event as the action type. Select which custom event to trigger.
    This option is displayed when you select Trigger an alarm as the action type. Select which alarm to trigger.
    NOTE: You can select the option Automatically acknowledge when value is back to normal, so that you do not have to manually acknowledge the alarm after if it is triggered.
  5. Click Save.


Events and alarms are triggered in Security Desk based on the rules you created. For more information about monitoring events in Security Desk, see the Security Desk User Guide.