Alarm Bracketing

Under normal, steady-state operating conditions, a RealTime point should display only small deviations from the current value. The Alarm Bracketing application calculates tight deviation limits around a bracketed value to aid in detecting abnormal pipeline conditions. If the value exceeds, or falls below, the positive or negative deviation limits, respectively, AVEVA Enterprise SCADA generates an alarm.

Certain set points and control commands, such as opening a valve, can cause a surge in pressure. To avoid nuisance alarms from such events, Administrators can configure the system to do one of the following:

• Automatically suspend bracketing on a collection of points (or "bracket set") near the area of disturbance until such time that the values settle back to normal readings.

• Suspend bracketing on a collection of points (or "bracket set") near the area of disturbance for a configured period of time.

Controllers can also manually suspend bracketing, as described in the corresponding Controller documentation.