
- •1.1 TODO LIST
- •2. PROGRAMMABLE LOGIC CONTROLLERS
- •2.1 INTRODUCTION
- •2.1.1 Ladder Logic
- •2.1.2 Programming
- •2.1.3 PLC Connections
- •2.1.4 Ladder Logic Inputs
- •2.1.5 Ladder Logic Outputs
- •2.2 A CASE STUDY
- •2.3 SUMMARY
- •2.4 PRACTICE PROBLEMS
- •2.5 PRACTICE PROBLEM SOLUTIONS
- •2.6 ASSIGNMENT PROBLEMS
- •3. PLC HARDWARE
- •3.1 INTRODUCTION
- •3.2 INPUTS AND OUTPUTS
- •3.2.1 Inputs
- •3.2.2 Output Modules
- •3.3 RELAYS
- •3.4 A CASE STUDY
- •3.5 ELECTRICAL WIRING DIAGRAMS
- •3.5.1 JIC Wiring Symbols
- •3.6 SUMMARY
- •3.7 PRACTICE PROBLEMS
- •3.8 PRACTICE PROBLEM SOLUTIONS
- •3.9 ASSIGNMENT PROBLEMS
- •4. LOGICAL SENSORS
- •4.1 INTRODUCTION
- •4.2 SENSOR WIRING
- •4.2.1 Switches
- •4.2.2 Transistor Transistor Logic (TTL)
- •4.2.3 Sinking/Sourcing
- •4.2.4 Solid State Relays
- •4.3 PRESENCE DETECTION
- •4.3.1 Contact Switches
- •4.3.2 Reed Switches
- •4.3.3 Optical (Photoelectric) Sensors
- •4.3.4 Capacitive Sensors
- •4.3.5 Inductive Sensors
- •4.3.6 Ultrasonic
- •4.3.7 Hall Effect
- •4.3.8 Fluid Flow
- •4.4 SUMMARY
- •4.5 PRACTICE PROBLEMS
- •4.6 PRACTICE PROBLEM SOLUTIONS
- •4.7 ASSIGNMENT PROBLEMS
- •5. LOGICAL ACTUATORS
- •5.1 INTRODUCTION
- •5.2 SOLENOIDS
- •5.3 VALVES
- •5.4 CYLINDERS
- •5.5 HYDRAULICS
- •5.6 PNEUMATICS
- •5.7 MOTORS
- •5.8 COMPUTERS
- •5.9 OTHERS
- •5.10 SUMMARY
- •5.11 PRACTICE PROBLEMS
- •5.12 PRACTICE PROBLEM SOLUTIONS
- •5.13 ASSIGNMENT PROBLEMS
- •6. BOOLEAN LOGIC DESIGN
- •6.1 INTRODUCTION
- •6.2 BOOLEAN ALGEBRA
- •6.3 LOGIC DESIGN
- •6.3.1 Boolean Algebra Techniques
- •6.4 COMMON LOGIC FORMS
- •6.4.1 Complex Gate Forms
- •6.4.2 Multiplexers
- •6.5 SIMPLE DESIGN CASES
- •6.5.1 Basic Logic Functions
- •6.5.2 Car Safety System
- •6.5.3 Motor Forward/Reverse
- •6.5.4 A Burglar Alarm
- •6.6 SUMMARY
- •6.7 PRACTICE PROBLEMS
- •6.8 PRACTICE PROBLEM SOLUTIONS
- •6.9 ASSIGNMENT PROBLEMS
- •7. KARNAUGH MAPS
- •7.1 INTRODUCTION
- •7.2 SUMMARY
- •7.3 PRACTICE PROBLEMS
- •7.4 PRACTICE PROBLEM SOLUTIONS
- •7.5 ASSIGNMENT PROBLEMS
- •8. PLC OPERATION
- •8.1 INTRODUCTION
- •8.2 OPERATION SEQUENCE
- •8.2.1 The Input and Output Scans
- •8.2.2 The Logic Scan
- •8.3 PLC STATUS
- •8.4 MEMORY TYPES
- •8.5 SOFTWARE BASED PLCS
- •8.6 SUMMARY
- •8.7 PRACTICE PROBLEMS
- •8.8 PRACTICE PROBLEM SOLUTIONS
- •8.9 ASSIGNMENT PROBLEMS
- •9. LATCHES, TIMERS, COUNTERS AND MORE
- •9.1 INTRODUCTION
- •9.2 LATCHES
- •9.3 TIMERS
- •9.4 COUNTERS
- •9.5 MASTER CONTROL RELAYS (MCRs)
- •9.6 INTERNAL RELAYS
- •9.7 DESIGN CASES
- •9.7.1 Basic Counters And Timers
- •9.7.2 More Timers And Counters
- •9.7.3 Deadman Switch
- •9.7.4 Conveyor
- •9.7.5 Accept/Reject Sorting
- •9.7.6 Shear Press
- •9.8 SUMMARY
- •9.9 PRACTICE PROBLEMS
- •9.10 PRACTICE PROBLEM SOLUTIONS
- •9.11 ASSIGNMENT PROBLEMS
- •10. STRUCTURED LOGIC DESIGN
- •10.1 INTRODUCTION
- •10.2 PROCESS SEQUENCE BITS
- •10.3 TIMING DIAGRAMS
- •10.4 DESIGN CASES
- •10.5 SUMMARY
- •10.6 PRACTICE PROBLEMS
- •10.7 PRACTICE PROBLEM SOLUTIONS
- •10.8 ASSIGNMENT PROBLEMS
- •11. FLOWCHART BASED DESIGN
- •11.1 INTRODUCTION
- •11.2 BLOCK LOGIC
- •11.3 SEQUENCE BITS
- •11.4 SUMMARY
- •11.5 PRACTICE PROBLEMS
- •11.6 PRACTICE PROBLEM SOLUTIONS
- •11.7 ASSIGNMENT PROBLEMS
- •12. STATE BASED DESIGN
- •12.1 INTRODUCTION
- •12.1.1 State Diagram Example
- •12.1.2 Conversion to Ladder Logic
- •12.1.2.1 - Block Logic Conversion
- •12.1.2.2 - State Equations
- •12.1.2.3 - State-Transition Equations
- •12.2 SUMMARY
- •12.3 PRACTICE PROBLEMS
- •12.4 PRACTICE PROBLEM SOLUTIONS
- •12.5 ASSIGNMENT PROBLEMS
- •13. NUMBERS AND DATA
- •13.1 INTRODUCTION
- •13.2 NUMERICAL VALUES
- •13.2.1 Binary
- •13.2.1.1 - Boolean Operations
- •13.2.1.2 - Binary Mathematics
- •13.2.2 Other Base Number Systems
- •13.2.3 BCD (Binary Coded Decimal)
- •13.3 DATA CHARACTERIZATION
- •13.3.1 ASCII (American Standard Code for Information Interchange)
- •13.3.2 Parity
- •13.3.3 Checksums
- •13.3.4 Gray Code
- •13.4 SUMMARY
- •13.5 PRACTICE PROBLEMS
- •13.6 PRACTICE PROBLEM SOLUTIONS
- •13.7 ASSIGNMENT PROBLEMS
- •14. PLC MEMORY
- •14.1 INTRODUCTION
- •14.2 MEMORY ADDRESSES
- •14.3 PROGRAM FILES
- •14.4 DATA FILES
- •14.4.1 User Bit Memory
- •14.4.2 Timer Counter Memory
- •14.4.3 PLC Status Bits (for PLC-5s and Micrologix)
- •14.4.4 User Function Control Memory
- •14.4.5 Integer Memory
- •14.4.6 Floating Point Memory
- •14.5 SUMMARY
- •14.6 PRACTICE PROBLEMS
- •14.7 PRACTICE PROBLEM SOLUTIONS
- •14.8 ASSIGNMENT PROBLEMS
- •15. LADDER LOGIC FUNCTIONS
- •15.1 INTRODUCTION
- •15.2 DATA HANDLING
- •15.2.1 Move Functions
- •15.2.2 Mathematical Functions
- •15.2.3 Conversions
- •15.2.4 Array Data Functions
- •15.2.4.1 - Statistics
- •15.2.4.2 - Block Operations
- •15.3 LOGICAL FUNCTIONS
- •15.3.1 Comparison of Values
- •15.3.2 Boolean Functions
- •15.4 DESIGN CASES
- •15.4.1 Simple Calculation
- •15.4.2 For-Next
- •15.4.3 Series Calculation
- •15.4.4 Flashing Lights
- •15.5 SUMMARY
- •15.6 PRACTICE PROBLEMS
- •15.7 PRACTICE PROBLEM SOLUTIONS
- •15.8 ASSIGNMENT PROBLEMS
- •16. ADVANCED LADDER LOGIC FUNCTIONS
- •16.1 INTRODUCTION
- •16.2 LIST FUNCTIONS
- •16.2.1 Shift Registers
- •16.2.2 Stacks
- •16.2.3 Sequencers
- •16.3 PROGRAM CONTROL
- •16.3.1 Branching and Looping
- •16.3.2 Fault Detection and Interrupts
- •16.4 INPUT AND OUTPUT FUNCTIONS
- •16.4.1 Immediate I/O Instructions
- •16.4.2 Block Transfer Functions
- •16.5 DESIGN TECHNIQUES
- •16.5.1 State Diagrams
- •16.6 DESIGN CASES
- •16.6.1 If-Then
- •16.6.2 Traffic Light
- •16.7 SUMMARY
- •16.8 PRACTICE PROBLEMS
- •16.9 PRACTICE PROBLEM SOLUTIONS
- •16.10 ASSIGNMENT PROBLEMS
- •17. OPEN CONTROLLERS
- •17.1 INTRODUCTION
- •17.3 OPEN ARCHITECTURE CONTROLLERS
- •17.4 SUMMARY
- •17.5 PRACTICE PROBLEMS
- •17.6 PRACTICE PROBLEM SOLUTIONS
- •17.7 ASSIGNMENT PROBLEMS
- •18. INSTRUCTION LIST PROGRAMMING
- •18.1 INTRODUCTION
- •18.2 THE IEC 61131 VERSION
- •18.3 THE ALLEN-BRADLEY VERSION
- •18.4 SUMMARY
- •18.5 PRACTICE PROBLEMS
- •18.6 PRACTICE PROBLEM SOLUTIONS
- •18.7 ASSIGNMENT PROBLEMS
- •19. STRUCTURED TEXT PROGRAMMING
- •19.1 INTRODUCTION
- •19.2 THE LANGUAGE
- •19.3 SUMMARY
- •19.4 PRACTICE PROBLEMS
- •19.5 PRACTICE PROBLEM SOLUTIONS
- •19.6 ASSIGNMENT PROBLEMS
- •20. SEQUENTIAL FUNCTION CHARTS
- •20.1 INTRODUCTION
- •20.2 A COMPARISON OF METHODS
- •20.3 SUMMARY
- •20.4 PRACTICE PROBLEMS
- •20.5 PRACTICE PROBLEM SOLUTIONS
- •20.6 ASSIGNMENT PROBLEMS
- •21. FUNCTION BLOCK PROGRAMMING
- •21.1 INTRODUCTION
- •21.2 CREATING FUNCTION BLOCKS
- •21.3 DESIGN CASE
- •21.4 SUMMARY
- •21.5 PRACTICE PROBLEMS
- •21.6 PRACTICE PROBLEM SOLUTIONS
- •21.7 ASSIGNMENT PROBLEMS
- •22. ANALOG INPUTS AND OUTPUTS
- •22.1 INTRODUCTION
- •22.2 ANALOG INPUTS
- •22.2.1 Analog Inputs With a PLC
- •22.3 ANALOG OUTPUTS
- •22.3.1 Analog Outputs With A PLC
- •22.3.2 Pulse Width Modulation (PWM) Outputs
- •22.3.3 Shielding
- •22.4 DESIGN CASES
- •22.4.1 Process Monitor
- •22.5 SUMMARY
- •22.6 PRACTICE PROBLEMS
- •22.7 PRACTICE PROBLEM SOLUTIONS
- •22.8 ASSIGNMENT PROBLEMS
- •23. CONTINUOUS SENSORS
- •23.1 INTRODUCTION
- •23.2 INDUSTRIAL SENSORS
- •23.2.1 Angular Displacement
- •23.2.1.1 - Potentiometers
- •23.2.2 Encoders
- •23.2.2.1 - Tachometers
- •23.2.3 Linear Position
- •23.2.3.1 - Potentiometers
- •23.2.3.2 - Linear Variable Differential Transformers (LVDT)
- •23.2.3.3 - Moire Fringes
- •23.2.3.4 - Accelerometers
- •23.2.4 Forces and Moments
- •23.2.4.1 - Strain Gages
- •23.2.4.2 - Piezoelectric
- •23.2.5 Liquids and Gases
- •23.2.5.1 - Pressure
- •23.2.5.2 - Venturi Valves
- •23.2.5.3 - Coriolis Flow Meter
- •23.2.5.4 - Magnetic Flow Meter
- •23.2.5.5 - Ultrasonic Flow Meter
- •23.2.5.6 - Vortex Flow Meter
- •23.2.5.7 - Positive Displacement Meters
- •23.2.5.8 - Pitot Tubes
- •23.2.6 Temperature
- •23.2.6.1 - Resistive Temperature Detectors (RTDs)
- •23.2.6.2 - Thermocouples
- •23.2.6.3 - Thermistors
- •23.2.6.4 - Other Sensors
- •23.2.7 Light
- •23.2.7.1 - Light Dependant Resistors (LDR)
- •23.2.8 Chemical
- •23.2.8.2 - Conductivity
- •23.2.9 Others
- •23.3 INPUT ISSUES
- •23.4 SENSOR GLOSSARY
- •23.5 SUMMARY
- •23.6 REFERENCES
- •23.7 PRACTICE PROBLEMS
- •23.8 PRACTICE PROBLEM SOLUTIONS
- •23.9 ASSIGNMENT PROBLEMS
- •24. CONTINUOUS ACTUATORS
- •24.1 INTRODUCTION
- •24.2 ELECTRIC MOTORS
- •24.2.1 Basic Brushed DC Motors
- •24.2.2 AC Motors
- •24.2.3 Brushless DC Motors
- •24.2.4 Stepper Motors
- •24.2.5 Wound Field Motors
- •24.3 HYDRAULICS
- •24.4 OTHER SYSTEMS
- •24.5 SUMMARY
- •24.6 PRACTICE PROBLEMS
- •24.7 PRACTICE PROBLEM SOLUTIONS
- •24.8 ASSIGNMENT PROBLEMS
- •25. CONTINUOUS CONTROL
- •25.1 INTRODUCTION
- •25.2 CONTROL OF LOGICAL ACTUATOR SYSTEMS
- •25.3 CONTROL OF CONTINUOUS ACTUATOR SYSTEMS
- •25.3.1 Block Diagrams
- •25.3.2 Feedback Control Systems
- •25.3.3 Proportional Controllers
- •25.3.4 PID Control Systems
- •25.4 DESIGN CASES
- •25.4.1 Oven Temperature Control
- •25.4.2 Water Tank Level Control
- •25.5 SUMMARY
- •25.6 PRACTICE PROBLEMS
- •25.7 PRACTICE PROBLEM SOLUTIONS
- •25.8 ASSIGNMENT PROBLEMS
- •26. FUZZY LOGIC
- •26.1 INTRODUCTION
- •26.2 COMMERCIAL CONTROLLERS
- •26.3 REFERENCES
- •26.4 SUMMARY
- •26.5 PRACTICE PROBLEMS
- •26.6 PRACTICE PROBLEM SOLUTIONS
- •26.7 ASSIGNMENT PROBLEMS
- •27. SERIAL COMMUNICATION
- •27.1 INTRODUCTION
- •27.2 SERIAL COMMUNICATIONS
- •27.2.1.1 - ASCII Functions
- •27.3 PARALLEL COMMUNICATIONS
- •27.4 DESIGN CASES
- •27.4.1 PLC Interface To a Robot
- •27.5 SUMMARY
- •27.6 PRACTICE PROBLEMS
- •27.7 PRACTICE PROBLEM SOLUTIONS
- •27.8 ASSIGNMENT PROBLEMS
- •28. NETWORKING
- •28.1 INTRODUCTION
- •28.1.1 Topology
- •28.1.2 OSI Network Model
- •28.1.3 Networking Hardware
- •28.1.4 Control Network Issues
- •28.2 NETWORK STANDARDS
- •28.2.1 Devicenet
- •28.2.2 CANbus
- •28.2.3 Controlnet
- •28.2.4 Ethernet
- •28.2.5 Profibus
- •28.2.6 Sercos
- •28.3 PROPRIETARY NETWORKS
- •28.3.1 Data Highway
- •28.4 NETWORK COMPARISONS
- •28.5 DESIGN CASES
- •28.5.1 Devicenet
- •28.6 SUMMARY
- •28.7 PRACTICE PROBLEMS
- •28.8 PRACTICE PROBLEM SOLUTIONS
- •28.9 ASSIGNMENT PROBLEMS
- •29. INTERNET
- •29.1 INTRODUCTION
- •29.1.1 Computer Addresses
- •29.1.2 Phone Lines
- •29.1.3 Mail Transfer Protocols
- •29.1.4 FTP - File Transfer Protocol
- •29.1.5 HTTP - Hypertext Transfer Protocol
- •29.1.6 Novell
- •29.1.7 Security
- •29.1.7.1 - Firewall
- •29.1.7.2 - IP Masquerading
- •29.1.8 HTML - Hyper Text Markup Language
- •29.1.9 URLs
- •29.1.10 Encryption
- •29.1.11 Compression
- •29.1.12 Clients and Servers
- •29.1.13 Java
- •29.1.14 Javascript
- •29.1.16 ActiveX
- •29.1.17 Graphics
- •29.2 DESIGN CASES
- •29.2.1 Remote Monitoring System
- •29.3 SUMMARY
- •29.4 PRACTICE PROBLEMS
- •29.5 PRACTICE PROBLEM SOLUTIONS
- •29.6 ASSIGNMENT PROBLEMS
- •30. HUMAN MACHINE INTERFACES (HMI)
- •30.1 INTRODUCTION
- •30.2 HMI/MMI DESIGN
- •30.3 DESIGN CASES
- •30.4 SUMMARY
- •30.5 PRACTICE PROBLEMS
- •30.6 PRACTICE PROBLEM SOLUTIONS
- •30.7 ASSIGNMENT PROBLEMS
- •31. ELECTRICAL DESIGN AND CONSTRUCTION
- •31.1 INTRODUCTION
- •31.2 ELECTRICAL WIRING DIAGRAMS
- •31.2.1 Selecting Voltages
- •31.2.2 Grounding
- •31.2.3 Wiring
- •31.2.4 Suppressors
- •31.2.5 PLC Enclosures
- •31.2.6 Wire and Cable Grouping
- •31.3 FAIL-SAFE DESIGN
- •31.4 SAFETY RULES SUMMARY
- •31.5 REFERENCES
- •31.6 SUMMARY
- •31.7 PRACTICE PROBLEMS
- •31.8 PRACTICE PROBLEM SOLUTIONS
- •31.9 ASSIGNMENT PROBLEMS
- •32. SOFTWARE ENGINEERING
- •32.1 INTRODUCTION
- •32.1.1 Fail Safe Design
- •32.2 DEBUGGING
- •32.2.1 Troubleshooting
- •32.2.2 Forcing
- •32.3 PROCESS MODELLING
- •32.4 PROGRAMMING FOR LARGE SYSTEMS
- •32.4.1 Developing a Program Structure
- •32.4.2 Program Verification and Simulation
- •32.5 DOCUMENTATION
- •32.6 COMMISIONING
- •32.7 REFERENCES
- •32.8 SUMMARY
- •32.9 PRACTICE PROBLEMS
- •32.10 PRACTICE PROBLEM SOLUTIONS
- •32.11 ASSIGNMENT PROBLEMS
- •33. SELECTING A PLC
- •33.1 INTRODUCTION
- •33.2 SPECIAL I/O MODULES
- •33.3 SUMMARY
- •33.4 PRACTICE PROBLEMS
- •33.5 PRACTICE PROBLEM SOLUTIONS
- •33.6 ASSIGNMENT PROBLEMS
- •34. FUNCTION REFERENCE
- •34.1 FUNCTION DESCRIPTIONS
- •34.1.1 General Functions
- •34.1.2 Program Control
- •34.1.3 Timers and Counters
- •34.1.4 Compare
- •34.1.5 Calculation and Conversion
- •34.1.6 Logical
- •34.1.7 Move
- •34.1.8 File
- •34.1.10 Program Control
- •34.1.11 Advanced Input/Output
- •34.1.12 String
- •34.2 DATA TYPES
- •35. COMBINED GLOSSARY OF TERMS
- •36. PLC REFERENCES
- •36.1 SUPPLIERS
- •36.2 PROFESSIONAL INTEREST GROUPS
- •36.3 PLC/DISCRETE CONTROL REFERENCES
- •37. GNU Free Documentation License
- •37.1 PREAMBLE
- •37.2 APPLICABILITY AND DEFINITIONS
- •37.3 VERBATIM COPYING
- •37.4 COPYING IN QUANTITY
- •37.5 MODIFICATIONS
- •37.6 COMBINING DOCUMENTS
- •37.7 COLLECTIONS OF DOCUMENTS
- •37.8 AGGREGATION WITH INDEPENDENT WORKS
- •37.9 TRANSLATION
- •37.10 TERMINATION
- •37.11 FUTURE REVISIONS OF THIS LICENSE
- •37.12 How to use this License for your documents

plc software - 32.2
Sabotage - For various reasons, some individuals may try to damage a system. These problems can be minimized preventing access.
Random failure - Each component is prone to random failure. It is worth considering what would happen if any of these components were to fail.
Some design rules that will help improve the safety of a system are listed below.
Programs
•A fail-safe design - Programs should be designed so that they check for problems, and shut down in safe ways. Most PLC’s also have imminent power failure sensors, use these whenever danger is present to shut down the system safely.
•Proper programming techniques and modular programming will help detect possible problems on paper instead of in operation.
•Modular well designed programs.
•Use predictable, non-configured programs.
•Make the program inaccessible to unauthorized persons.
•Check for system OK at start-up.
•Use PLC built in functions for error and failure detection.
People
•Provide clear and current documentation for maintenance and operators.
•Provide training for new users and engineers to reduce careless and uninformed mistakes.
32.2DEBUGGING
Most engineers have taken a programming course where they learned to write a program and then debug it. Debugging involves running the program, testing it for errors, and then fixing them. Even for an experienced programmer it is common to spend more time debugging than writing software. For PLCs this is not acceptable! If you are running the program and it is operating irrationally it will often damage hardware. Also, if the error is not obvious, you should go back and reexamine the program design. When a program is debugged by trial and error, there are probably errors remaining in the logic, and the program is very hard to trust. Remember, a bug in a PLC program might kill somebody.
Note: when running a program for the first time it can be a good idea to keep one hand on the E-stop button.