Alarm threshold

This parameter is applicable to sensor measurements used to instigate alarms. It may be used to balance missing with improper alarms

Definition

alarm thresholds are low and high limits of sensory data, used to instigate warning and alarms, respectively.

Method

The designers may define low and high limits per sensor, based on statistics, and store them in the rule database. At run time, the

Predicting the grace time

alarm thresholds define a state set, which is a compressed form of the measurements. Crossing an alarm threshold involves changing the state.

grace time and indicate about it to the supervisor at the supervision station. In addition, it can compare the grace time to the recovery time, to allocate the control over the system to the machine.

This method, commonly used in Statistical process control (SPC) is exemplified in the following chart ...

These thresholds can be set automatically, by statistics of prior measurements.

Example

A medical monitor may generate a warning signal when a medical parameter is out of the range of normal values, and an alarm when the measurement is out of the range of exceptional values.

The functional unit can send the measurements to the activity analyzer, which informs that alarm unit about the exceptions.

Guidelines

The functional unit should send the measurements to the