Hierarchical process monitoring system identifies whether significant change of process conditions occurs as a result change in characteristics of certain self-inspecting sensor

摘要

A process monitoring unit (14) and sensors (SEVA 1-36) having self-inspection capability, are provided in the higher and lower levels of the monitoring system. The monitoring unit monitors output signals of the sensors and identifies every significant change of the process conditions, and determines whether the change occurs as a result of the change in characteristics of a certain sensor or due to actual change in process conditions. An Independent claim is also included for process monitoring unit.