Estimation of alarm chattering

Chattering alarms (alarms that repeat excessively in a short time interval) create a level of nuisance to the operator. According to industrial alarm standards, no chattering is acceptable. Therefore, reducing the amount of alarm chatter is a primary goal in redesigning alarm parameters. A quantitative measure to assess the degree of chattering for an alarm has recently been proposed. This measure is based on run length distribution which is the distribution of time differences between consecutive alarms. This chattering index is currently calculated empirically based on alarm data. In this paper, we develop a method to estimate the chattering index based on statistical properties of the process variable as well as alarm parameters. The estimation can be used for developing analytical methods to optimally design alarm parameters for minimal chattering.

► We study alarm chattering in industrial alarm systems.
► We estimate alarm run length distributions from data and alarm parameters.
► We compute the alarm chattering index based on statistic properties of data.
► We illustrate the results in optimal alarm design.