Alarms

Alarms are used to notify the Controller of a significant event or state. Alarming generates database and system alarms and its alarm conditions are highly configurable.

The system generates three kinds of alarms: database alarms, system alarms, and application alarms. A database alarm is always associated with a specific record in the RealTime database (RTDB).

A condition that generates a system or application alarm may or may not have a specific RealTime record associated with it. System and application alarms are similar in that they do not need to be tied to a specific point in the database; however, you should elect to configure an application alarm in situations where you want to use one or multiple fields in the alarm database that are not available for system alarms. Another benefit of application alarms is the ability to have them replicated based on the dataset field. Most alarms are database alarms.

Alarms refer to either a state or a significant event. If the alarm refers to a state, it persists until the alarm is acknowledged and the condition that caused the alarm is cleared. For example, a value that moved an analog record into a high alarm state would generate a state alarm, which persists for the entire time that the record remains in that state. Even if the Controller acknowledges the alarm, the record remains in the Alarm Summary until the record’s value moves out of that high alarm state.

If the alarm is caused by a transient condition or an event, the alarm is not persistent: it vanishes from the Alarm Summary after the Controller acknowledges it. For example, a Rate-of-Change (ROC) alarm for an analog record is a non-persistent alarm. Such an alarm serves to notify the Controller of a condition that has occurred, even though the record may still be well within its normal operational range.

The alarm/event inhibit features available through easy eXtended Operator Station (ezXOS) provide you with the flexibility to specify whether or not a given point generates event messages or alarms.

The following windows notify the Controller of alarms:

• The Alarm Summary window.

• The Newest Priority Alarms window.

• The Station Alarm Summary window.

• Alarm summaries for individual tables, such as analog, rate, and status.

For more information on these windows, refer to the AVEVA Enterprise SCADA HMI Controller documentation.

Note: Within easy eXtended Operator Station (ezXOS), the system identifies an alarm condition by replacing the color of the affected device or monitored value with a different solid or flashing color.