ENGINEERING MANUAL OF AUTOMATIC CONTROL
vii
CONTENTS
Foreward ............................................................................................................ iii
Preface ............................................................................................................ v
Control System Fundamentals .......................................................................................... 1
Control Fundamentals ............................................................................................................ 3
Introduction.......................................................................................... 5
Definitions............................................................................................ 5
HVAC System Characteristics ............................................................. 8
Control System Characteristics ........................................................... 15
Control System Components .............................................................. 30
Characteristics and Attributes of Control Methods .............................. 35
Psychrometric Chart Fundamentals ............................................................................................................ 37
Introduction.......................................................................................... 38
Definitions............................................................................................ 38
Description of the Psychrometric Chart............................................... 39
The Abridged Psychrometric Chart ..................................................... 40
Examples of Air Mixing Process .......................................................... 42
Air Conditioning Processes ................................................................. 43
Humidifying Process............................................................................ 44
Process Summary ............................................................................... 53
ASHRAE Psychrometric Charts .......................................................... 53
Pneumatic Control Fundamentals ............................................................................................................ 57
Introduction.......................................................................................... 59
Definitions............................................................................................ 59
Abbreviations ....................................................................................... 60
Symbols............................................................................................... 61
Basic Pneumatic Control System ........................................................ 61
Air Supply Equipment .......................................................................... 65
Thermostats ........................................................................................ 69
Controllers ........................................................................................... 70
Sensor-Controller Systems ................................................................. 72
Actuators and Final Control Elements ................................................. 74
Relays and Switches ........................................................................... 77
Pneumatic Control Combinations ........................................................ 84
Pneumatic Centralization .................................................................... 89
Pneumatic Control System Example ................................................... 90
Electric Control Fundamentals ............................................................................................................ 95
Introduction.......................................................................................... 97
Definitions............................................................................................ 97
How Electric Control Circuits are Classified ........................................ 99
Series 40 Control Circuits.................................................................... 100
Series 80 Control Circuits.................................................................... 102
Series 60 Two-Position Control Circuits............................................... 103
Series 60 Floating Control Circuits ...................................................... 106
Series 90 Control Circuits.................................................................... 107
Motor Control Circuits.......................................................................... 114
ENGINEERING MANUAL of
AUTOMATIC
CONTROL