Lesson 1 - Introduction to Control Systems
Topics:
Automatic control; Control system basics; Two-position, floating, and proportional control; Open- and closed-loop control; Operating power
Learning Objectives:
– Explain why control systems are needed and name devices used to control environmental conditions.– Define the terms used to describe control systems-controlled variable, controller, controlled device, setpoint, control point, and controlled medium-and
name the basic elements of a control system.
– Describe the action of two-position, floating, and proportional control.
– Explain how anticipators work.
– Compare open-loop and closed-loop control.
– Compare the basic requirements of pneumatic/hydraulic control systems to those of electric/electronic control systems.
– Describe the action of two-position, floating, and proportional control.
– Explain how anticipators work.
– Compare open-loop and closed-loop control.
– Compare the basic requirements of pneumatic/hydraulic control systems to those of electric/electronic control systems.
Lesson 2 - Sensors and Controlled Devices
Topics:
Temperature, humidity, and pressure sensors; Dampers; Valves; Variable-speed drives
Learning Objectives:
– Explain the need for a sensor in a control system.– Name and explain the operation of three kinds of temperature sensors.
– Define relative humidity, state the range required for human comfort, and describe common humidity sensors.
– Name three common pressure sensors and explain their operation.
– Explain the operation of two-position dampers and valves in shutoff and throttling applications.
– List the advantages of variable-speed drives over older methods of speed control.
Lesson 3 - Automatic Control Systems
Topics:
Two-position, floating, and proportional electric control; Pneumatic systems, controllers, actuators, relays, and switches; Electronic systems; Proportional band, gain, and PID control
Learning Objectives:
– Describe the operation of two-position, floating, and proportional electric controllers.– List the equipment needed for a pneumatic control system.
– Name several pneumatic relays and switches, and explain why each is used.
– Discuss the advantages and basic operation of electronic controls.
– Define resolution, sensitivity, proportional band, and gain, and explain how they are related.
– Distinguish between integral and derivative action, and explain how each can improve system performance.
Lesson 4 - Control of Refrigeration and Air-Conditioning Processes
Topics:
Primary control; Low-pressure, high-pressure, and high-temperature controls; Anti-recycle timers; Pressure regulators; Oil-level controls; Overload protection; Capacity control
Learning Objectives:
– Explain how pumpdown control operates and why pumpdown is often preferred over other methods of primary control.– Describe the location, function, and operation of a high-pressure control.
– Name three ways to control condenser pressure and at least three ways to control system capacity.
– Explain how a differential oil pressure safety control works.
– Compare the two methods of modulating the flow of water to hydronic terminals.
Lesson 5 - Maintaining and Troubleshooting Controls
Topics:
Maintaining pressure controls, thermostats, switches, valves, timers, controllers, relays, and power supplies; Troubleshooting the system
Learning Objectives:
– List the four basic steps involved in setting up a PM program.– Explain the importance of high-pressure controls as safety devices and explain their testing procedures.
– Explain how oil pressure is maintained in various kinds of compressors.
– Describe the testing and maintenance required for condenser water regulating valves and compressor capacity controls.
– Explain how to check for oil and water contamination in control air and what measures to take to minimize them.
– Explain the major maintenance requirements of a pneumatic control system.
– Describe the maintenance required by electric and electronic controllers.
– Explain how to use a troubleshooting chart.
