Microcomputer Control of Thermal and Mechanical Systems

1 Microcomputer Control.- 1-1 The Penetration of Microprocessors into Engineering Fields.- 1-2 The Path by which Microcomputer Control Has Grown.- 1-3 Chemical and Process Industries.- 1-4 Environmental Control of Buildings.- 1-5 Automobiles.- 1-6 Home Appliances.- 1-7 Computer Control in Manufacturing.- 1-8 Electric Power Generation and Regulation.- 1-9 Agricultural Applications of Computer Control.- 1-10 What the Engineer Who Applies Computers Needs to Know.- References.- 2 DC Circuits and Power Supplies.- 2-1 Understanding Circuits.- 2-2 Kirchhoff’s Laws.- 2-3 Thévenin Equivalent.- 2-4 Norton Equivalent.- 2-5 RC Circuits.- 2-6 Resistors.- 2-7 Diodes.- 2-8 Rectifying Circuit.- 2-9 Voltage Ripple.- 2-10 Commercial Power Supplies.- 2-11 Voltage Regulators.- Problems.- 3 Operational Amplifiers.- 3-1 Application of Operational Amplifiers.- 3-2 Basic Characteristic of the Op Amp.- 3-3 Comparator.- 3-4 Inverting Amplifier.- 3-5 Choice of Resistances.- 3-6 Non-inverting Op Amp.- 3-7 Buffer or Follower Amp.- 3-8 Signal Conditioning.- 3-9 Summing and Multiplying Amplifier.- 3-10 Generalized Circuit for an Op Amp.- 3-11 Integrator.- 3-12 Pin Diagram of 741 Op Amp.- 3-13 Limitations and Ratings of the Op Amp.- General References.- Problems.- 4 Transistors.- 4-1 Impact of the Transistor.- 4-2 Symbols and Terminology.- 4-3 Current Characteristics.- 4-4 Bipolar-Junction and Field-Effect Transistors.- 4-5 Voltages at the Transistor Terminals.- 4-6 Voltage Amplifier.- 4-7 Transistor as a Switch, and Saturating the Transistor.- 4-8 Common Emitter and Common Collector Circuits.- 4-9 Zener Diode.- 4-10 Constant-Current Source.- 4-11 Designing a Constant-Current Source.- 4-12 Operating Limits of a Transistor.- 4-13 Transistor Packages.- References.- Problems.- 5 Transducers.- 5-1 Importance of Good Instrumentation.- 5-2 Thermocouples.- 5-3 Thermocouple Reference Junction.- 5-4 Metal and Thermistor Resist ance-Temperature Devices.- 5-5 Series Circuit.- 5-6 Bridge Circuits.- 5-7 Amplification of a Bridge Output.- 5-8 RTD Circuits Supplied with Constant Current.- 5-9 Temperature-Dependent Integrated Circuits.- 5-10 Application of Sensors—Liquid Temperature.- 5-11 Application of Sensors—Temperature of Air and Other Gases.- 5-12 An Overview of Temperature Sensors and Transducers.- 5-13 Flow Rate and Velocity Measurement.- 5-14 Venturi Tubes—Liquid Flow Measurement.- 5-15 Orifice—Liquid Flow Measurement.- 5-16 Flow Measurement of a Compressible Fluid in a Venturi or Orifice.- 5-17 Pitot Tubes.- 5-18 Hot-Wire Anemometer.- 5-19 Turbine Flow Meter.- 5-20 Ultrasonic Flow Meters.- 5-21 Vortex-Shedding Flow Meters.- 5-22 Evaluation of Flow-Measuring Devices.- 5-23 Pressure Transducers.- 5-24 Evaluation of Types of Pressure Transducers.- 5-25 Force.- 5-26 Torque.- 5-27 Electric Current.- 5-28 Humidity Sensors.- 5-29 Chemical Composition.- 5-30 Liquid Level.- 5-31 Position and Motion Sensors.- 5-32 Rotative Speed.- 5-33 How to Choose Transducers.- References.- General References.- Problems.- 6 Actuators.- 6-1 Actuators for Computer Control Systems.- 6-2 Two-Position DC Electric Switch.- 6-3 Silicon-Controlled Rectifier (SCR) for DC Switching.- 6-4 Triac—Alternating Current Switching.- 6-5 Optically Isolated Switch.- 6-6 Solid-State Relays.- 6-7 Electric-Motor Actuators.- 6-8 Magnetic Operator.- 6-9 Hydraulic Actuator.- 6-10 Pneumatic Valve and Damper Operators.- 6-11 Electric-to-Pneumatic Transducer.- 6-12 Stepping Motors.- 6-13 Performance of Stepping Motors.- References.- Problems.- 7 Binary Numbers and Digital Electronics.- 7-1 Transition to Digital Electronics.- 7-2 Binary Numbers.- 7-3 Conversion between Binary and Decimal Numbers.- 7-4 Addition of Binary Numbers.- 7-5 Basic Logic Operations.- 7-6 OR Gate.- 7-7 AND Gate.- 7-8 Inverter.- 7-9 NOT-OR (NOR) Gate.- 7-10 NOT-AND (NAND) Gate.- 7-11 Exclusive-OR (XOR) Gate.- 7-12 Combining and Cascading Gates.- 7-13 De Morgan’s Laws.- 7-14 Gate Chips.- 7-15 Ladder Diagrams for Conditional and Sequential Control.- 7-16 Ladder Diagram Using Gates.- 7-17 Sequential Logic Circuits.- 7-18 Binary Addition with Gates.- 7-19 Pull-Up Resistor.- 7-20 Three Classes of Outputs Found on Inverters and Buffer Gates.- 7-21 Debounced Switch.- 7-22 Clocks and Oscillators.- 7-23 Flip-Flops.- 7-24 Divide-By Counters.- 7-25 Schmitt Trigger.- 7-26 Monostable Multivibrator.- 7-27 Low-Frequency Pulses.- 7-28 Latches.- 7-29 Comparators.- 7-30 Analog Switches—Field-Effect Transistors.- 7-31 Binary-Coded Decimal (BCD).- 7-32 Seven-Segment LEDs.- 7-33 Summary.- General References.- Problems.- 8 Conversion Between Digital and Analog.- 8-1 Elements of a Microcomputer Controller.- 8-2 A Simple DAC.- 8-3 DAC Using R-2R Ladder Circuit.- 8-4 The 1408 DAC.- 8-5 Applying the 1408 DAC.- 8-6 Multiplexers.- 8-7 Fidelity of Voltage Transmission Through a MUX.- 8-8 Sample-and-Hold Circuits.- 8-9 Operating Sequence with Multichannel Control.- 8-10 Where Analog-to-Digital Conversion Is Needed.- 8-11 Internal Functions of One Class of ADCs.- 8-12 More Complete Description of the Internal Functions of an ADC.- 8-13 Staircase and Successive Approximation Search Routines and Dual-Slope Integration.- 8-14 Pin Diagram of an 8-Bit ADC.- 8-15 Characteristics of the ADC 0800.- 8-16 Analog-to-Digital Conversion Using a DAC in Combination with Software.- 8-17 Choosing the ADC.- Problems.- 9 Memories.- 9-1 Function and Types of Memories.- 9-2 ROMs.- 9-3 EPROMs.- 9-4 RAMs.- 9-5 The MCM6810 RAM.- 9-6 Four-Bit RAMs—the MCM2114.- 9-7 Dynamic RAMs.- 9-8 EEPROMs.- 9-9 Memories on the Microcomputer.- General References.- Problems.- 10 Binary Arithmetic.- 10-1 The Eight-Bit Microcomputer.- 10-2 Two’s Complement Arithmetic—Subtraction.- 10-3 Multiplication.- 10-4 Hexadecimal System.- 10-5 Labeling Conventions.- 10-6 Signed and Unsigned Numbers.- 10-7 Unsigned Numbers—The Carry Flag.- 10-8 Signed Numbers—Two’s Complement Overflow.- 10-9 Status Registers on Microprocessors.- References.- Problems.- 11 Programming a Microprocessor.- 11-1 A Generic Microprocessor.- 11-2 Data and Address Buses in a Generic Microcomputer.- 11-3 The Accumulator with its Arithmetic, Logic, and Transfer Operations.- 11-4 The Fetch-Decode-Execute Sequence.- 11-5 Preliminary Instruction Set.- 11-6 Program Counter.- 11-7 Status Register and Jumps.- 11-8 Another Accumulator—Incrementing and Decrementing.- 11-9 Additional Addressing Modes.- 11-10 The Index Register and the Use of Register Addressing.- 11-11 Subroutines and the Stack.- 11-12 The Intel 8080/8085 Microprocessor.- 11-13 Loading Into and Storing From the Accumulator.- 11-14 Forms of Addressing on the 8080/8085.- 11-15 Flag Register.- 11-16 Subroutines.- 11-17 The 8080/8085 Programming Guide.- 11-18 The Motorola 6800 Family.- 11-19 Registers in the 6800 Microprocessor.- 11-20 The Instruction Set of the 6800.- 11-21 Condition Codes.- 11-22 Forms of Addressing.- 11-23 Branches—Relative Addressing.- 11-24 Index Register—Indexed Addressing.- 11-25 Loops.- 11-26 Stack Pointer.- 11-27 Subroutines.- 11-28 The 6800 Microprocessor Programming Guide.- 11-29 Summary.- References.- Problems.- 12 Assembly Language Programming.- 12-1 Machine Language and Assembly Language.- 12-2 An Overview of the Assembly Process.- 12-3 Major Components of the Program.- 12-4 Assembly Language Statements.- 12-5 Assembler Directives.- 12-6 The Location Counter.- 12-7 Using Assembler Labels and Symbols.- 12-8 Relocating Assemblers and Loaders.- 12-9 The Operation of an Assembler.- References.- Problems.- 13 The Structure of an Elementary Microcomputer.- 13-1 Definition of an Elementary Microcomputer.- 13-2 The Bus Structure.- 13-3 Flow of Information on the Buses During Execution of a Program.- 13-4 The Intel 8080 Microprocessor.- 13-5 Structure of the SDK-85 System Design Kit.- 13-6 Memory Map of the SDK-85.- 13-7 The Motorola 6802 Microprocessor.- 13-8 Structure of the MEK6802D5 Evaluation Kit.- 13-9 Memory Map of the D5 Evaluation Kit.- 13-10 Common Features of an Elementary Microcomputer.- References.- Problems.- 14 Parallel Input/Output and Interrupts.- 14-1 Parallel Input/Output.- 14-2 A Generic Parallel I/O Chip.- 14-3 Processing Interrupts.- 14-4 The Motorola Peripheral Interface Adapter (PIA).- 14-5 Registers in the PIA.- 14-6 Preparing the PIA to Send and Receive Data.- 14-7 Interrupt from a Peripheral—An Overview.- 14-8 The Control Register and the Control Lines.- 14-9 Setting the Microprocessor to Receive an Interrupt.- 14-10 Structure of an Interruptible Program.- 14-11 User I/O Socket.- 14-12 Intel 8155/8156 RAM with I/O.- 14-13 Intel 8212 I/O Chip.- 14-14 Rudimentary Control Capability Now Available.- Problems.- 15 Serial Input/Output and Modems.- 15-1 Serial Data Transmission.- 15-2 Mark, Space, and Baud Rate.- 15-3 Synchronous and Asynchronous Communication.- 15-4 Parity.- 15-5 Shift Register.- 15-6 A Generic Universal Asynchronous Receiver/ Transmitter (UART).- 15-7 The MC6850 Asynchronous Receiver/Transmitter (ACIA).- 15-8 Registers in the ACIA.- 15-9 The Control Register.- 15-10 The Status Register.- 15-11 Transmitting and Receiving with the ACIA.- 15-12 The Intel 8251A Programmable Communication Interface.- 15-13 The Control and Status Register on the 8251A.- 15-14 Communicating Using RS-232-C and Modems.- 15-15 RS-232-C Interface.- 15-16 Level Conversion Between RS-232-C and TTL.- 15-17 Communicating Between Two Elementary Microcomputers Using RS-232-C.- 15-18 Transmission over Telephone Lines Using Modems.- 15-19 Dial-Up Modems.- 15-20 ASCII Characters.- 15-21 One-on-One Communication.- References.- Problems.- 16 Dynamic Behavior of Systems.- 16-1 Returning to the Thermal and Mechanical System.- 16-2 On/Off Controls.- 16-3 Make/Break Sensor with On/Off Actuator.- 16-4 Analog Sensor with On/Off Actuator.- 16-5 Modulating Control Strategies.- 16-6 Proportional Control.- 16-7 Proportional-Integral Control.- 16-8 Proportional-Integral-Derivative (PID) Control.- 16-9 Dynamic Analysis.- 16-10 Laplace Transforms.- 16-11 Inverting a Transform.- 16-12 Transforms of Derivatives.- 16-13 Solving Differential Equations by Means of Laplace Transforms.- 16-14 Transfer Functions.- 16-15 Feedback Loops.- 16-16 Stability Criteria for a Feedback Control Loop.- 16-17 A Proportional Controller Regulating the Pressure in an Air-Supply System.- 16-18 Response of a Proportional Air-Pressure Controller to a Disturbance in Air-Flow Rate.- 16-19 The Integral Mode of Control.- 16-20 The Proportional-Integral (PI) Mode of Control.- References.- Problems.- 17 The Computer and Its Sampling Processes.- 17-1 Unique Features of Computer Control.- 17-2 Numerical Simulation.- 17-3 Sampled Data.- 17-4 Responses to Sampled Values.- 17-5 The z-Transform.- 17-6 Response to a Series of Impulses.- 17-7 The Zero-Order Hold (ZOH).- 17-8 Inverting a z-Transform.- 17-9 Cascading z-Transforms and Transforms of a Feedback Loop.- 17-10 How a z-Transform Can Indicate Stability of a Control Loop.- 17-11 Proportional Control.- 17-12 Proportional-Integral Control.- 17-13 Forms of Actuator Signals.- 17-14 Non-linearities—Dead Time.- 17-15 Non-linearities—Hysteresis.- 17-16 Summary.- References.- Problems.- 18 Field Application of Microcomputer Controllers.- 18-1 Applying Microcomputer Controllers to Field Processes.- 18-2 Practical Control Algorithms.- 18-3 Incremental PI Control Algorithm.- 18-4 Position PI Control Algorithm.- 18-5 Criteria for Tuning.- 18-6 Manual Control Test.- 18-7 Trial-and-Error Tuning.- 18-8 Closed-Loop Tuning.- 18-9 Open-Loop Tuning.- 18-10 Hysteresis Compensation.- 18-11 Summary.- References.- Problems.