Analysis and design of multimode delay-timers

For acceptable performance of an alarm system for a mulitmode process, it is inevitable to have appropriate alarm configurations for every mode of the process. Delay-timers, being very effective in reducing false and nuisance alarms, are analyzed and designed for multimode processes. A Hidden Markov model with Markov chain observations is used to capture the configuration of delay-timers in various modes of the process. Based on the proposed model, analytical expressions for the false alarm rate, missed alarm rate, and expected detection delay are derived. For the design, a particle swarm optimization based algorithm is proposed. Application examples demonstrate the utility of the proposed method.