Chapter 7 - Discrete logic control

Abstract

This chapter examines discrete logic controllers where the inputs and outputs are discrete variables that change values as a result of the occurrence of events. The controller is called a discrete logic controller since the control action is given by logic equations with discrete values. The control problem of interest is the design and implementation of a discrete logic controller that carries out some desired control actions or some sequences of desired control actions. The control action is achieved by controlling the on/off status of output devices using measurements of the on/off status of the input devices. The design of a discrete logic controller can be carried out by generating Boolean logic equations that describe the desired control action. Boolean logic equations can be determined in a systematic manner from the statements comprising the desired control action by first defining state variables and then the state transitions for each of the state variables.