Calculation of Process Immunity Time with Gantt Chart

Abstract

To evaluate the process immunity time (PIT) for the industrial process, an approach to calculate PIT based on Gantt chart is proposed. The relationships between PIT and Gantt chart are investigated at first. Immunity time constant (ITC) of sensitive component in industrial process is defined to correspond to the duration of the subtask in Gantt chart. Gantt chart is used to describe the connections of the components. PIT is calculated with the critical path in Gantt chart. An experimental test platform is setup to verify the proposed method. An escalator is taken as the experimental object. Different type voltage sags are imposed into the escalator. The calculation PITs with Gantt chart are very close to the measurement PITs under different type voltage sags. Therefore, the proposed method can provide an effective tool to evaluate PITs for industrial process.