The DeltaV system supports the following process alarms:
predefined (standard) alarms
custom alarms
Standard alarms consist of HIGH-HIGH, HIGH, LOW-LOW, LOW, DEVIATION HIGH, and DEVIATION LOW. Standard alarms are only available in function blocks with built-in alarm state computation.
Custom alarms are supported at the module level (except unit modules and phase logic modules). Custom alarms reference existing parameters or user-defined expressions. A custom alarm can be used as an alarm for the operator or an event to be logged. You customize the alarm by selecting from a set of options.
DeltaV process alarms require alarm calculation and alarm detection.
Calculation - Many DeltaV function blocks include alarm state calculations. Any Boolean parameter can provide the alarm calculation component for a module. This component is the input to alarm detection. You can also create your own alarm state calculations by using function blocks that support expressions (for example, the Calc/Logic and Condition function blocks).
Detection - In order for a module to detect the result of an alarm state calculation, you must associate the result of that calculation with a specific alarm parameter. When the alarm state calculates to the TRUE value, the associated alarm parameter triggers.
For the standard alarms, simply right-click the function block on the diagram, and then click Assign Alarm. The software determines the detection parameters for you. For custom alarms, right-click the alarm view pane (lower-right window in Control Studio), and then click Add. You select the detection parameters for the alarm.