A generalized delay-timer for alarm triggering

In process plants, alarms are configured to notify operators of any abnormalities or faults. However, in practice a majority of raised alarms are false or nuisance and create problems for operators as they face an increasing number of alarms to handle. Adding delay-timers is a simple technique that can reduce this problem and is widely exercised in industry. In this work we propose a generalized delay-timer framework where instead of consecutive n samples in the conventional case, n₁ out of n consecutive samples (n₁ ≤ n) are considered to raise an alarm. For the generalized delay-timer, two important performance indices, namely, the false alarm rate (FAR) and the missed alarm rate (MAR) are calculated using Markov processes. Also the performance of generalized delay-timers is compared with conventional delay-timers.