Contents: PART ONE HARDWARE 1 About PLCs 1.1 History 1.2 Structure 1.3 PLC operation 2 Digital signals and digital inputs and outputs 2.1 Introduction 2.2 Terminology 2.3 Switches 2.4 Logical sensors 2.5 Connection of logical sensors 2.6 Properties of discrete inputs 2.7 Discrete actuators 2.8 Test problems 3 Analog signals and analog I/O 3.1 Introduction 3.2…