INTRODUCTION TO PROCESS CONTROL 1 1
Instructional Objectives 1 1
1 Introduction 1 1
2 Control Systems 2 1
2.1 Process-Control Principles 1
2.2 Servomechanisms 1
2.3 Discrete-State Control Systems 1
3 Process-Control Block Diagram 6 1
3.1 Identification of Elements 1
3.2 Block Diagram 1
4 Control System Evaluation 10 1
4.1 Stability 1
4.2 Steady-State Regulation 1
4.3 Transient Regulation 1
4.4 Evaluation Criteria 1
5 Analog and Digital Processing 14 1
5.1 Data Representation 1
5.2 ON/OFF Control 1
5.3 Analog Control 1
5.4 Digital Control 1
5.5 Programmable Logic Controllers 1
6 Units,Standards,And Definitions 22 1
6.1 Units 1
6.2 Analog Data Representation 1
6.3 Definitions 1
6.4 Process-Control Drawings 1
7 Sensor Time Response 36 1
7.1 First-Order Response 1
7.2 Second-Order Response 1
8 Significance and Statistics 40 1
8.1 Significant Figures 1
8.2 Statistics 1
Summary 2
Problems 2
Supplementary Problems 2
ANALOG SIGNAL CONDITIONING 53 2
Instructional Objectives 53 2
1 Introduction 53 2
2 Principles of Analog Signal Conditioning 54 2
2.1 Signal-Level and Bias Changes 2
2.2 Linearization 2
2.3 Conversions 2
2.4 Filtering and Impedance Matching 2
2.5 Concept of Loading 2
3 Passive Circuits 58 2
3.1 Divider Circuits 2
3.2 Bridge Circuits 2
3.3 RC Filters 2
4 Operational Amplifiers 83 2
4.1 Op Amp Characteristics 2
4.2 Op Amp Specifications 2
5 OP Amp Circuits in Instrumentation 89 2
5.1 Voltage Follower 2
5.2 Inverting Amplifier 2
5.3 Noninverting Amplifier 2
5.4 Differential Instrumentation Amplifier 2
5.5 Voltage-to-Current Converter 2
5.6 Current-to-Voltage Converter 2
5.7 Integrator 2
5.8 Differentiator 2
5.9 Linearization 2
6 Design Guidelines 102 2
Summary 3
Problems 3
Supplementary Problems 3
DIGITAL SIGNAL CONDITIONING 115 3
Instructional Objectives 115 3
1 Introduction 115 3
2 Review of Digital Fundamentals 116 3
2.1 Digital Information 3
2.2 Fractional Binary Numbers 3
2.3 Boolean Algebra 3
2.4 Digital Electronics 3
2.5 Programmable Logic Controllers 3
2.6 Computer Interface 3
3 Converters 125 3
3.1 Comparators 3
3.2 Digital-to-Analog Converters(DACs) 3
3.3 Analog-to-Digital Converters(ADCs) 3
3.4 Frequency-Based Converters 3
4 Data-Acquisition Systems 155 3
4.1 DAS Hardware 3
4.2 DAS Software 3
5 Characteristics of Digital Data 160 3
5.1 Digitized Value 3
5.2 Sampled Data Systems 3
5.3 Linearization 3
Summary 4
Problems 4
Supplementary Problems 4
THERMAL SENSORS 175 4
Instructional Objectives 175 4
1 Introduction 175 4
2 Definition of Temperature 176 4
2.1 Thermal Energy 4
2.2 Temperature 4
3 Metal Resistance versus Temperature Devices 180 4
3.1 Metal Resistance versus Temperature 4
3.2 Resistance versus Temperature Approximations 4
3.3 Resistance-Temperature Detectors 4
4 Thermistors 189 4
4.1 Semiconductor Resistance versus Temperature 4
4.2 Thermistor Characteristics 4
5 Thermocouples 193 4
5.1 Thermoelectric Effects 4
5.2 Thermocouple Characteristics 4
5.3 Thermocouple Sensors 4
6 Other Thermal Sensors 204 4
6.1 Bimetal Strips 4
6.2 Gas Thermometers 4
6.3 Vapor-Pressure Thermometers 4
6.4 Liquid-Expansion Thermometers 4
6.5 Solid-State Temperature Sensors 4
7 Design Considerations 211 4
Summary 5
Problems 5
Supplementary Problems 5
MECHANICAL SENSORS 223 5
Instructional Objectives 223 5
1 Introduction 223 5
2 Displacement,Location,or Position Sensors 224 5
2.1 Potentiometric Sensors 5
2.2 Capacitive and Inductive Sensors 5
2.3 Vairiable-Reluctance Sensors 5
2.4 Level Sensors 5
3 Strain Sensors 232 5
3.1 Strain and Stress 5
3.2 Strain Gauge Principles 5
3.3 Metal Strain Gauges 5
3.4 Semiconductor Strain Gauges(SGs) 5
3.5 Load Cells 5
4 Motion Sensors 246 5
4.1 Types of Motion 5
4.2 Accelerometer Principles 5
4.3 Types of Accelerometers 5
4.4 Applications 5
5 Pressure Sensors 258 5
5.1 Pressure Principles 5
5.2 Pressure Sensors(p＞1 atmosphere) 5
5.3 Pressure Sensors(p＞1 atmosphere) 5
6 Flow Sensors 267 5
6.1 Solid-Flow Measurement 5
6.2 Liquid Flow 5
Summary 6
Problems 6
Supplementary Problems 6
OPTICAL SENSORS 285 6
Instructional Objectives 285 6
1 Introduction 285 6
2 Fundamentals of EM Radiation 286 6
2.1 Nature of EM Radiation 6
2.2 Characteristics of Light 6
2.3 Photometry 6
3 Photodetectors 296 6
3.1 Photodetector Characteristics 6
3.2 Photoconductive Detectors 6
3.3 Photovoltaic Detectors 6
3.4 Photodiode Detectors 6
3.5 Photoemissive Detectors 6
4 Pyrometry 311 6
4.1 Thermal Radiation 6
4.2 Broadband Pyrometers 6
4.3 Narrowband Pyrometers 6
5 Optical Sources 316 6
5.1 Conventional Light Sources 6
5.2 Laser Principles 6
6 Applications 322 6
6.1 Label Inspection 6
6.2 Turbidity 6
6.3 Ranging 6
Summary 7
Problems 7
Supplementary Problems 7
FINAL CONTROL 333 7
Instructional Objectives 333 7
1 Introduction 333 7
2 Final Control Operation 334 7
2.1 Signal Conversions 7
2.2 Actuators 7
2.3 Control Element 7
3 Signal Conversions 336 7
3.1 Analog Electrical Signals 7
3.2 Digital Electrical Signals 7
3.3 Pneumatic Signals 7
4 Power Electronics 342 7
4.1 Switching Devices 7
4.2 Controlling Devices 7
5 Actuators 358 7
5.1 Electrical Actuators 7
5.2 Pneumatic Actuators 7
5.3 Hydraulic Actuators 7
6 Control Elements 371 7
6.1 Mechanical 7
6.2 Electrical 7
6.3 Fluid Valves 7
Summary 8
Problems 8
Supplementary Problems 8
DISCRETE-STATE PROCESS CONTROL 387 8
Instructional Objectives 387 8
1 Introduction 387 8
2 Definition of Discrete-State Process Control 388 8
3 Characteristics of the System 389 8
3.1 Discrete-State Variables 8
3.2 Process Specifications 8
3.3 Event Sequence Description 8
4 Relay Controllers and Ladder Diagrams 403 8
4.1 Background 8
4.2 Ladder Diagram Elements 8
4.3 Ladder Diagram Examples 8
5 Programmable Logic Controllers(PLCs) 413 8
5.1 Relay Sequencers 8
5.2 Programmable Logic Controller Design 8
5.3 PLC Operation 8
5.4 Programming 8
5.5 PLC Software Functions 8
Summary 9
Problems 9
Supplementary Problems 9
CONTROLLER PRINCIPLES 439 9
Instructional Objectives 439 9
1 Introduction 439 9
2 Process Characteristics 440 9
2.1 Process Equation 9
2.2 Process Load 9
2.3 Process Lag 9
2.4 Self-Regulation 9
3 Control System Parameters 442 9
3.1 Error 9
3.2 Variable Range 9
3.3 Control Parameter Range 9
3.4 Control Lag 9
3.5 Dead Time 9
3.6 Cycling 9
3.7 Controller Modes 9
4 Discontinuous Controller Modes 448 9
4.1 Two-Position Mode 9
4.2 Multiposition Mode 9
4.3 Floating-Control Mode 9
5 Continuous Controller Modes 457 9
5.1 Proportional Control Mode 9
5.2 Integral-Control Mode 9
5.3 Derivative-Control Mode 9
6 Composite Control Modes 466 9
6.1 Proportional-Integral Control(PI) 9
6.2 Proportional-Derivative Control Mode(PD) 9
6.3 Three-Mode Controller(PID) 9
6.4 Special Terminology 9
Summary 10
Problems 10
Supplementary Problems 10
ANALOG CONTROLLERS 481 10
Instructional Objectives 481 10
1 Introduction 481 10
2 General Features 482 10
2.1 Typical Physical Layout 10
2.2 Front Panel 10
2.3 Side Panel 10
3 Electronic Controllers 483 10
3.1 Error Detector 10
3.2 Single Mode 10
3.3 Composite Controller Modes 10
4 Pneumatic Controllers 500 10
4.1 General Features 10
4.2 Mode Implementation 10
5 Design Considerations 504 10
Summary 11
Problems 11
Supplementary Problems 11
COMPUTER-BASED CONTROL 513 11
Instructional Objectives 513 11
1 Introduction 513 11
2 Digital Applications 514 11
2.1 Alarms 11
2.2 Two-Position Control 11
3 Computer-Based Controller 519 11
3.1 Hardware Configurations 11
3.2 Software Requirements 11
4 Other Computer Applications 533 11
4.1 Data Logging 11
4.2 Supervisory Control 11
5 Control System Networks 540 11
5.1 Development 11
5.2 General Characteristics 11
5.3 Fieldbus Types 11
6 Computer Controller Examples 550 11
Summary 12
Problems 12
Supplementary Problems 12
CONTROL-LOOP CHARACTERISTICS 559 12
Instructional Objectives 559 12
1 Introduction 559 12
2 Control System Configurations 560 12
2.1 Single Variable 12
2.2 Cascade Control 12
3 Multivariable Control Systems 564 12
3.1 Analog Control 12
3.2 Supervisory and Direct Digital Control 12
4 Control System Quality 568 12
4.1 Definition of Quality 12
4.2 Measure of Quality 12
5 Stability 575 12
5.1 Transfer Function Frequency Dependence 12
5.2 Stability Criteria 12
6 Process-Loop Tuning 580 12
6.1 Open-Loop Transient Response Method 12
6.2 Ziegler-Nichols Method 12
6.3 Frequency Response Methods 12