Process Control: Modeling, Design, and Simulation

Chapter 13. Control-Loop Interaction

Most process unit operations have a number of manipulated inputs, each of which affects some measured output, and it is not always clear which input should be “paired” with which output for control-system design. This general pairing problem is known as control structure selection and is often more important than the actual controller design and tuning method used. After studying this chapter, the reader should be able to do the following:

• Use the relative gain array (RGA) to determine the proper input-output pairings for multiple single input–single output controllers

• Understand that the RGA gives insight about process sensitivity

• Discuss the implications of the RGA for failure sensitivity

The major sections ...