Chapter 5. Introduction to Feedback Control

The objective of this chapter is to introduce the Laplace domain analysis of feedback control systems. After studying this chapter, the reader should be able to do the following:

• Convert a process and instrumentation diagram (P&ID) to a control block diagram

• Find the controller transfer function for standard feedback controllers

• Find the closed-loop transfer function for a given process and controller transfer function

• Determine the stability of a closed-loop system

• Find the transfer function relationship between any two signals on a block diagram

The major sections of this chapter are as follows:

5.1 Motivation

5.2 Development of Control Block Diagrams

5.3 Response to Setpoint Changes

5.4 PID Controller Algorithms

5.5 Routh Stability Criterion

5.6 Effect of Tuning Parameters

5.7 Response to Disturbances

5.8 Open-Loop Unstable Systems

5.9 SIMULINK Block Diagrams

5.10 Summary