Control using self-validating sensors

Abstract

The correct funetioraing of sensors is of paramount importance to the operation of industrial processes. The concept of a self-validating (SEVA) sensor, capable of detecting and correcting for its own faults and accompanying each measurement with an estimate of its uncertainty and standard quality indicators, has been proposed. This paper aims to investigate how the extra information provided by SEVA sensors can be used to enhance the performance of simple three-term (PID) controllers in the single-loop configuration. An implementation of the SEVA interface on a dissolved oxygen sensor and the device response to a common fault is described. SEVA sensor measurement quality indicators can be used to decide whether to continue closed-loop operation and, if so, how the controller should be retuned to counteract the of sensor faults: control strategies in the presence of a range of sensor malfunctions are illustrated by simulation examples.