Plant areas, alarm priorities, alarm types, and alarm states all affect the way the system manages individual alarms. Understanding these concepts is key to developing a good system alarm strategy.
An SIS alarm type defines a set of characteristics that determines how an alarm appears on displays, in the SIS alarm banner and in the Process History View. Each alarm used in an SIS module must be associated with an SIS alarm type.
You can assign a single alarm type to several alarms to give the alarms the same display characteristics.
The DeltaV system provides several predefined SIS alarm types. The SIS alarm types are uniquely identified to separate them from the non-SIS DeltaV alarm types. This separation provides a mechanism for displaying, recording and managing SIS alarms apart from all other DeltaV alarms. For example, in Process History View, the SIS alarms are identified as the Event Type, SIS_ALARM.
However, all other aspects of alarm configuration (priority, sounds, logging, and so on) are the same as a non-SIS DeltaV system.
SIS alarms share alarm priority definitions with DeltaV alarms. Only a user with the Configure key can create, modify, and delete alarm priority definitions, giving process engineers a way to tailor alarm behavior to plant conditions.
You can use the predefined SIS alarm types as they are, modify them, or create additional types. DeltaV SIS alarms must be created in the DeltaV SIS Alarm Types category of DeltaV Explorer under System Configuration\Setup\Alarm Preferences\SIS Alarm Types. An example of needing a new alarm type is when an alarm requires a message that is different from the available alarm type messages.
Alarm type names are case sensitive. Additionally, alarm types must exist in the DeltaV system before you can assign an alarm using that alarm type to a module.