Implementation Issues for Discrete PID Algorithms Using Shift and Delta Operators Parameterizations

Abstract

PID controllers have been the most popular controllers in process and industrial control applications for over 50 years and continue to maintain popularity despite opportunities to apply more exotic methodologies. This is because of their simple structure, robustness and successful commercial performance. Although the tuning concepts of PID controllers dominate the studies in this are, few studies address the parameterization issues and the Implementational concepts of such controllers. In this paper a comparative study of the coefficient finite word length effects for the canonical realizations of different discrete PID algorithms using delta (δ) and shift (z) operators is described. The problem of coefficient quantization for different PID algorithms for fixed-word length for the two realizations is discussed. A generic PID hardware architecture is proposed to perform the controller structures for both operators.