The goal of a well-designed alarm system is to ensure that an Operatoris made aware of issues, both critical and non-critical, but is not overwhelmed by alarms/alerts or other messages. When designing an alarm system, criteria are defined for alarm rates and general performance of the system at various levels (Operatorstation, plant area, overall system etc.). Evaluating the performance of an alarm system with regard to these design criteria requires the collection of alarm metrics. These metrics provide summaries of alarm rates and other alarm related information.

This section defines a standard structure for metrics. This structure can be implemented at multiple levels allowing a Serverto collect metrics as needed. For example, an Objectof this type might be added to the Server Objectproviding a summary of the Alarmperformance for the entire Server. An instance might also be provided on an Objectthat includes a HasNotifierhierarchy, such as a tank Object. In this case, it would provide the summary of all of the Alarmsthat are part of the tank HasNotifierhierarchy.