The HLS-II alarm system optimization for removing nuisance alarms

Abstract

Hefei Light Source II (HLS-II) is a vacuum ultraviolet synchrotron light source. The HLS-II alarm system is responsible for monitoring the alarms of the process variables and distributing the alarm events in time. Nuisance alarms reduce the functionality, credibility and trustworthiness of the alarm system. This paper proposes a method for design alarm deadband and delay timers to remove the nuisance alarm events to the expected ratio. An optimal deadband width is calculated to reduce the alarm events while balancing the effects of reducing the occurrence number of alarm events and increasing the duration of alarm events. If the expected ratio is not met after using the optimal deadband width, the delay timers are set additionally. The Bayesian estimation approach is used to estimate the probability that the delay timers eliminate the alarm events. This method is based on statistical properties of the process variables and can effectively remove nuisance alarm events. Two examples of the HLS-II alarm system are provided to illustrate the proposed method. In the two examples, the optimal deadband removed 99.27% and 88.92% of nuisance alarms respectively.