An alternative method to compute the expected detection delay for deadbands and delay-timers

False and nuisance alarms are major problems in the process industry. Techniques like deadbands, delay-timers and filtering can significantly reduce these false and nuisance alarms. However, using these techniques will bring some delay in raising the alarm (detection delay) which is one of the most important performance indexes for alarm systems. A method via Markov chain was proposed to compute the expected detection delay for deadbands and delay-timers. In this paper, an alternative method will be explored. The method computes the probability of alarm or no alarm at a sample in iteration, and posed a new insight on the techniques of deadbands and delay-timers.