Control loop performance assessment using minimum variance benchmarking

Abstract

This paper discusses the practical application of continuous performance assessment as a requisite for monitoring and maintaining the advanced process control (APC) assets in the process industry. In this paper complemented with the presentation, the theory of performance assessment is introduced as a technique for continuously assessing the performance of the basic control loops in a plant, as a means towards maintaining APC assets. The continuous performance assessment allows detection of performance degradation in the basic control loops in a plant by monitoring the variance in the process variable and comparing it to that of a minimum variance controller. The resulting index gives an indication of the level of performance of the controller and an indication of the action required to improve its performance, e.g., re-tune the controller or consider process re-engineering. (6 pages)