Some alarm events aren't important when they occur in isolation, but are dangerous threats when they happen in conjunction. In the example shown, neither the generator failure nor the low backup battery are critical alarms in themselves, but it is a critical situation if both events happen simultaneously, especially during times of peak network activity.
A high quality master can combine and correlate these events, providing truly intelligent alarm monitoring. Both the generator failure and the low backup battery generate alarms, but the combination of the two generates an alarm of the highest severity level.
Alarms that combine and correlate multiple alarm inputs - called derived alarms - are created through user-defined formulas using simple Boolean logic. You can create derived alarms for many different combinations of events, such as a failed air conditioner AND high temperature, or excessive heat OR excessive cold. You can also create derived alarms for highly complex events, even notifications for when scheduled events, like equipment self-tests, don't happen on time.
Derived alarms are an important component of intelligent alarm monitoring - an alarm management system that clearly distinguishes between nuisance alarms and major threats, letting you focus on keeping your network up and running.