Engineering Manual o.. - HVAC.Amickracing

CONTROL FUNDAMENTALSControl System FundamentalsENGINEERING MANUAL OF AUTOMATIC CONTROLCONTENTSControl Fundamentals ............................................................................................................ 8Introduction.......................................................................................... 8Definitions............................................................................................ 8HVAC System Characteristics ............................................................. 11Control System Characteristics ........................................................... 18Control System Components .............................................................. 33Characteristics And Attributes Of Control Methods ............................. 38Psychrometric Chart Fundamentals ............................................................................................................ 39Introduction.......................................................................................... 39Definitions............................................................................................ 39Description of the Psychrometric Chart............................................... 40The Abridged Psychrometric Chart ..................................................... 41Examples of Air Mixing Process .......................................................... 43Air Conditioning Processes ................................................................. 44Humidifying Process............................................................................ 45ASHRAE Psychrometric Charts .......................................................... 54Pneumatic Control Fundamentals ............................................................................................................ 57Introduction.......................................................................................... 57Definitions............................................................................................ 57Abbreviations ....................................................................................... 58Symbols............................................................................................... 59Basic Pneumatic Control System ........................................................ 59Air Supply Equipment .......................................................................... 63Thermostats ........................................................................................ 67Controllers ........................................................................................... 68Actuators and Final Control Elements ................................................. 72Relays and Switches ........................................................................... 75Pneumatic Control Combinations ........................................................ 82Pneumatic Centralization .................................................................... 87Pneumatic Control System Example ................................................... 88Electric Control Fundamentals ............................................................................................................ 93Introduction.......................................................................................... 93Definitions............................................................................................ 93How Electric Control Circuits are Classified ........................................ 95Series 40 Control Circuits.................................................................... 96Series 80 Control Circuits.................................................................... 98Series 60 Two-Position Control Circuits............................................... 99Series 60 Floating Control Circuits ...................................................... 102Series 90 Control Circuits.................................................................... 103Motor Control Circuits.......................................................................... 110ENGINEERING MANUAL OF AUTOMATIC CONTROL6