Instrumentation and Process Control Book

Preface     xi
Industrial Control Overview
Introduction to Industrial Control Systems     3
Introduction     3
Industrial Control Classifications     4
Motion and Process Controls     4
Open- and Closed-Loop Systems     5
Elements of Open- and Closed-Loop Systems     8
Feedback Control     10
Practical Feedback Application     12
Dynamic Response of a Closed-Loop System     13
Feed-Forward Control     13
Problems     15
Interfacing Devices     17
Introduction     17
Fundamental Operational Amplifiers     17
Operational Amplifier Comparator     18
Inverting Op Amp     19
Summing Amplifier     20
Noninverting Amplifier     21
Difference Operational Amplifier     21
Signal Processors     22
Integrator Operational Amplifier     22
Differentiator Operational Amplifier     23
Wave-Shaping Schmitt Trigger     24
Comparator Devices     26
Digital Magnitude Comparator     26
Optoelectronic Interface Devices     27
Photodiodes     29
Phototransistors     29
Photo SCR     29
Photo Triac     30
Optoelectronic Packaging     30
Digital-to-Analog Converters     31
Integrated-Circuit Digital-to-Analog Converter     34
Analog-to-Digital Converters     34
Integrated-Circuit Analog-to-Digital Converter     36
Timing Devices     38
555 Astable Multivibrator     40
555 Monostable Multivibrator     42
Problems     44
The Controller
The Controller Operation     49
Introduction     49
Control Modes     50
On-Off Control     50
Proportional Control     53
Controller Amplification     55
Steady-State Error     56
Proportional-Integral Control     59
Proportional-Integral-Derivative Control     61
Time-Proportioning Control     65
Time-Proportioning Circuit     66
Problems     68
Process Control and Instrumentation
Pressure Systems     73
Introduction     73
Pressure Laws     74
Properties of a Liquid     74
Height      74
Weight     75
Temperature     75
Atmospheric Pressure     75
Mechanical Machines     76
Properties of a Gas     76
Temperature of the Gas     76
Volume of the Gas Container     76
Gas Removal from a Container     77
Pressure Measurement Scales     77
Gauge Pressure Scale     77
Absolute Pressure Scale     78
Differential Pressure Scale     79
Vacuum Pressure Scale     80
Pressure Measurement Instruments     80
Nonelectrical Pressure Sensors     80
Liquid Column Gauges     80
Mechanical Gauges     83
Electronic Pressure Sensors     85
Semiconductor Strain Gauges     85
Transverse Voltage Strain Gauge     85
Variable Capacitor Pressure Detector     87
Pressure Control Systems     87
Hydraulic Systems     87
Pneumatic Systems     89
Vacuum Systems     89
Static Pressure Systems     90
Steam Pressure Systems     91
Problems     92
Temperature Control     93
Introduction      93
Fundamentals of Temperature     94
Thermal Control Systems     94
Thermodynamic Transfer     94
Thermal Energy Source     95
Industrial Furnaces     95
Cooling Systems     96
Temperature Measurements     97
Temperature Scales     98
Differential Temperature     99
Temperature Indicating Devices     100
Crayons     101
Paints     101
Pellets     101
Labels     101
Liquid Crystal Indicator     101
Liquid Filled Thermometers     102
Electronic Sensors     103
Thermistor     103
Resistance Temperature Detectors     105
Thermocouple     106
Probe Assemblies     111
Radiation Thermometry     112
Problems     115
Flow Control     117
Introduction     117
Systems Concepts     118
Reasons for Control     119
Flow Units of Measurement     119
Volumetric Flow Rate     119
Flow Velocity     120
Mass Flow Rate     120
Solid Flow Measurement      120
Fluid Flow Measurement     121
Pipe Flow Principles     122
Fluid Flowmeter Classification     123
Electronic Sensors     129
Coriolis Meters     129
Rotor Flow Detectors     129
Electromagnetic Flow Detectors     129
Thermal Flowmeters     130
Vortex Flowmeters     130
Ultrasonic Flowmeters     131
Time-of-Flight Flowmeter     132
Flowmeter Placement     133
Selecting a Flowmeter     133
Problems     134
Level Control Systems     135
Introduction     135
A Level Control System     136
Power Sources     137
Transfer Systems     137
Methods of Measurement     137
Point Level Measurements     138
Continuous Level Measurements     138
Level Measurement Methods     138
Float and Displacement Methods     139
Electronic Sensors     144
Conductive Probes     144
Capacitive Probes     144
Ultrasonic Sensors     145
Selecting a Level Sensor     147
Problems      148
Analytical Instrumentation     149
Introduction     149
pH Measurement and Control     150
pH Measurements     152
Controlling pH     154
Conductivity     156
Conductivity Electrode Probe     157
Conductivity Inductive Probe     158
Conductivity Applications and Control     158
Combustion Analyzers and Control     160
Combustible Gases     160
Hydrocarbon Gases     161
Controlling Combustion     162
Humidity     163
Quantitative Measures of Humidity     163
Absolute Humidity Sensor     164
Relative Humidity Detectors     165
Dew Point Measurements     167
Controlling Humidity     168
Sampling Measurement System     169
Problems     169
Industrial Process Techniques and Instrumentation     171
Introduction     172
Batch Processes     172
Control Requirements     173
Types of Batch Processes     174
Chemical Reaction     174
Continuous Processes     175
Control Requirements      175
Instrumentation     178
Measurement Devices (Sensors)     179
Dynamic     179
Static     179
Feedback Loop Interface Instruments     182
Transmitters     182
Transducers     183
Controllers     186
Pneumatic Controllers     186
Panel-Mounted Controllers     187
Personal Computers     187
Programmable Logic Controllers     188
Distributed Control Systems (DCS)     188
Monitoring Instruments     189
Indicators     189
Alarms     190
Recorders     190
Manipulation Devices (The Final Control Element)     191
The Control Valve     191
DC and AC Motors     199
Problems     199
Instrumentation Symbology     201
Introduction     201
General Instrument Symbols     201
Individual Instruments     201
Tag Numbers     202
Line Symbols     205
Valve and Actuator Symbols     206
Control Valves     206
Actuators     207
Reading a Single Loop      207
Information Block     208
Problems     210
Process Control Methods     213
Introduction     214
Open-Loop Control     214
Closed-Loop Control     214
Process Behavior     215
Single-Variable Control Loop     216
Response Time of the Instruments     216
Pure Lag of the Controlled Variable     217
Dead Time     218
Selecting a Controller     219
On-Off Control     219
Case Studies-Using Different Control Modes     221
Continuous Control     223
Proportional Mode     223
Integral Mode     229
Derivative Mode     231
Advanced Control Techniques     234
Cascade Control     235
Feed-Forward Control     237
Ratio Control     238
Adaptive Control     239
Problems     241
Instrument Calibration and Controller Tuning     245
Introduction     245
Instrument Calibration     246
Reasons for Performing Calibrations     246
Calibration Preparation     247
Standard Calibration Procedure      248
Five-Point Calibration Procedure     249
Calibration Check     250
Calculating the Input Values     250
Calculating the Output Values     250
Analysis of Calibration Data     250
Transmitter Zero and Span Adjustments     250
Verification of Adjustments     251
Tuning the Controller     252
Trial-and-Error Tuning Method     253
Ziegler-Nichols Tuning Methods     254
Ziegler-Nichols Continuous Cycling Method     254
Ziegler-Nichols Reaction Curve Tuning Method     260
Controller Autotuning     265
Problems     265
Answers to Odd-Numbered Problems     267
Glossary     271
Index     277