Shaw J.A. The PID Control Algorithm. How it works, how to tune it, and how to use it

2nd Edition. — Process Control Solutions, 2003. — 68 p.The heart of the process control loop is the PID algorithm. Proper understanding of controller tuning requires understanding of the PID algorithm. The PID algorithm comprises three types of responses: Proportional, Integral, and Derivative
The first part of this book will examine the PID control algorithm, as typically implemented in industry. Each of the three elements will be discussed in detail.
The book will then discuss common process responses, including dead time, process lags, and their combinations.
The amount that each of these elements contribute to the control must be adjusted to correspond to the process being controlled. This adjustment is known as "tuning" the control loop. An incorrectly tuned loop will not function correctly, providing less than the desired performance. The book will first look at how to determine if a loop is properly tuned and then cover some of the typical methods of tuning loops.
The remainder of the book will discuss multiple loop control in which two or more PID control algorithms are connected together to improved the control or perform specialized control functions.The PID algorithm.
Implementation Details of the PID Equation.
Advanced Features of the PID algorithm.
Process responses.
Loop tuning.
Multiple Variable Strategies.
Cascade.
Ratio.
Override.
Feedforward.