Dead time is often present in control systems as computational or informational delay but in most cases it is very small and is neglected. Dead time is widely found in the process industries when transporting materials or energy. Generally stable processes are represented by first-order-plus-dead-time or second order- plus-dead-time models for analysis. The problem of control design for processes with dead time is quite crucial and long-standing. The advent of the Smith Predictor provided the industrial control community with another tool to tackle the control of processes where the presence of dead time was impairing closed-loop performance. In this paper analysis of stable processes with dead time is done. Here PI controller and Smith Predictor are used as dead time compensators. Also how to improve robustness and disturbance rejection points with respect to Smith Predictor has been also discussed.
Keywords: Process Dead Time, Smith Predictor (SP), Tuning
