Considerations in the Application of Self-Tuning PID Controllers Using EXACT-Tuning Algorithm

The paper reviews the operation of an on-line continuously adaptive PID controller which uses an expert system approach to self-tune. The benefits of using continuously adaptive control have been demonstrated by trial installations and have produced financial returns running into six figure values per annum per loop. Indirect benefits such as better insight into plant controllability (used to indicate a need for plant maintenance) and faster plant startups have been identified by users. The paper stresses the need for experience feedback in developing the understanding of the industry in the correct and best use of this new technology, a technology which promises to become the industry standard. An application guideline is provided and some limitations are pointed out. Some features that help make it a robust and secure product in a process control environment are also indicated.