Classic event subsystem features and benefits

You can obtain a number of distinct operational benefits from properly using the features of the Classic Event subsystem. A list of key benefits is as follows:

• Unlike real-time alarming, the Classic Event subsystem determines events from stored historical data and is not dependent on real-time detection. No events are missed unless the machine is severely overloaded for a long period of time.

• The Classic Event subsystem is SQL-based, thus providing a means of managing database-related tasks within the system. You can use custom SQL queries as detectors, as well as create custom SQL-based actions.

• A number of preconfigured detectors and actions are available.

• Detections may be made by external sources. (A COM mechanism is available for invoking the detector in the Classic Event subsystem.)

• Time-based detection (based on the system clock time) allows you to schedule certain tasks, such as data aggregations (summaries).

• The Classic Event subsystem is designed to manage overload situations. If the system is currently busy due to some other processing for a period of time, the Classic Event subsystem will "catch up" at a later time during off-peak periods. If the overall AVEVA Historian is continuously overloaded, the Classic Event subsystem degrades in functionality gracefully.

• You can select which actions have priority and can assign certain actions (preferably only a few) never to be compromised, even under overload conditions.

• System tags are available to monitor Classic Event subsystem conditions.