You can monitor state changes of OPC entity properties by receiving custom events and alarms generated by the OPC Client rule engine, or by viewing the changes from Security Desk and Config Tool.
State change monitoring in Config Tool
From the Properties page of an OPC entity, you can view real-time state changes of the associated properties by enabling Live monitoring () at the bottom of the list of properties.
State change monitoring in Security Desk
In addition to native Security Center functionality in the Monitoring, Alarm monitoring, and Maps tasks, when monitoring an OPC entity in a canvas tile or from a map, you can also view data changes of all the properties of that entity in real time.
This view is available by clicking , and then selecting the option named after the OPC entity.