Introduction to Process Measurement and Control

Table of Contents

Chapter 1: The Nature of Process Control

Topics: Process variables; On-off control; Measuring data; Controlling variables, Error and feedback; Open- and closed-loop control

Learning Objectives:

• Define setpoint and error.
• Explain how measurement and control are related in industrial processes.
• Describe the four essential functions of an automatic control system.
• Discuss the functions of the CRT and PLC in control systems.
• Identify variables in industrial processes.
• Explain the importance of feedback in a closed-loop control system.

Chapter 2: Elements of Process Control

Topics: Analog and digital control signals; ASCII; Measuring pressure, level, and flow rate; Digital pulse control; System terminology; Controller action

Learning Objectives:

• Discuss the differences between modern automatic control systems and older ones.
• Identify the standard signals used in process control.
• Define the terms commonly used in control terminology.
• Explain the differences between open-loop control and closed-loop control.
• Describe on-off, proportional, integral, derivative, and PID controller action.

Chapter 3: Process Control Signals

Topics: Linear and nonlinear transducers; Signal operating values; Error; Controller output; Pneumatic and electrical signal transmission; Control loops

Learning Objectives:

• Discuss standard signals and linearity and explain how to calculate the value of a variable from an instrument's span and range.
• Describe five common sources of error in signal measurement.
• Discuss the basic principles governing pneumatic signal transmission and explain how a flapper-nozzle device works.
• Describe the function of the controller in a control loop.
• Discuss the basic principles governing electrical signal transmission, including Ohm's law, and list standard current and voltage signals.
• Explain the function of I/P devices in a typical control system and discuss the use of digital signals and optical signals.

Chapter 4: Process Measurement Fundamentals

Topics: Measurement and display requirements; Remote and local display; Calibration; Noise; Response time; Measurement system and observation error

Learning Objectives:

• Explain why measurement is necessary and discuss conditions that affect the degree of accuracy required.
• Compare the advantages of linear and nonlinear displays.
• Compare analog and digital devices and explain how each is applied to measurement.
• Name five sources of measurement error.

Chapter 5: Principles of Transducer Operation

Topics: Outputs; Mechanical, electrical, and pneumatic elements and response; Resistance, voltage, and frequency devices; Combining elements

Learning Objectives:

• Discuss the need for linearity in a process.
• List examples of mechanical and electrical transducer elements.
• Compare pneumatic response and electrical/electronic response in transducers.
• Describe the operation of the bourdon tube, bellows, and diaphragm.
• Name examples of resistance, voltage response, frequency response, and electromechanical devices and explain how they work.

Chapter 6: Basic Process Measurement Systems

Topics: Interaction of system elements; Transmitters; Electrical vs. pneumatic output; Converters; Signal conditioning; Indicators and recorders

Learning Objectives:

• Discuss the basic elements of measuring systems and explain how they interact.
• Describe how a physical quantity is translated into another quantity.
• Discuss the use of transmitters to relay information from one location to another and explain the transfer function.
• Describe the operation of at least five kinds of converters.

Request Exam Copies