Designing alarm system using modified generalized delay-timer

Abstract

Alarm systems are of crucial importance in ensuring safety and efficiency of industrial installations. In practice, alarm systems are not properly designed or given the attention they deserve; their performance is unsatisfactory. The main role of alarms is to inform the operator of any incident in the plant. Regrettably, most occurred alarms are false and nuisance. To avoid this, industrial community developed techniques like deadbands, filters and delay-timers. Delay-timer is largely exercised in industry. This article presents a new concept for designing a Generalized delay-timer. out of n consecutive samples is not the only condition to activate an alarm, we will use additional setpoints to rise or clear an alarm. Three performance indicators namely, False Alarm Rate (), Missed Alarm Rate () and Average Alarm Delay () are computed for the proposed method. At the end, the modified Generalized delay-timer method is examined and compared with the Generalized delay-timer using a simulation and industrial case studies The obtained results show that alarm system performance is improved and even optimized using the modified Generalized delay-timer