- •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
continuous sensors - 23.12
on off on off
Figure 23.11 Measuring Motion with Moire Fringes
These are used in high precision applications over long distances, often meters. They can be purchased from a number of suppliers, but the cost will be high. Typical applications include Coordinate Measuring Machines (CMMs).
23.2.3.4 - Accelerometers
Accelerometers measure acceleration using a mass suspended on a force sensor, as shown in Figure 23.12. When the sensor accelerates, the inertial resistance of the mass will cause the force sensor to deflect. By measuring the deflection the acceleration can be determined. In this case the mass is cantilevered on the force sensor. A base and housing enclose the sensor. A small mounting stud (a threaded shaft) is used to mount the accelerometer.
|
Base |
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Mounting |
Force |
Mass |
Housing |
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Stud |
Sensor |
|||
|
|
Figure 23.12 A Cross Section of an Accelerometer
Accelerometers are dynamic sensors, typically used for measuring vibrations
continuous sensors - 23.13
between 10Hz to 10KHz. Temperature variations will affect the accuracy of the sensors. Standard accelerometers can be linear up to 100,000 m/s**2: high shock designs can be used up to 1,000,000 m/s**2. There is often a trade-off between a wide frequency range and device sensitivity (note: higher sensitivity requires a larger mass). Figure 23.13 shows the sensitivity of two accelerometers with different resonant frequencies. A smaller resonant frequency limits the maximum frequency for the reading. The smaller frequency results in a smaller sensitivity. The units for sensitivity is charge per m/s**2.
resonant freq. (Hz) |
sensitivity |
|
|
22 KHz |
4.5 pC/(m/s**2) |
180KHz |
.004 |
Figure 23.13 Piezoelectric Accelerometer Sensitivities
The force sensor is often a small piece of piezoelectric material (discussed later in this chapter). The piezoelectic material can be used to measure the force in shear or compression. Piezoelectric based accelerometers typically have parameters such as,
-100 to 250°C operating range 1mV/g to 30V/g sensitivity
operate well below one forth of the natural frequency
The accelerometer is mounted on the vibration source as shown in Figure 23.14. The accelerometer is electrically isolated from the vibration source so that the sensor may be grounded at the amplifier (to reduce electrical noise). Cables are fixed to the surface of the vibration source, close to the accelerometer, and are fixed to the surface as often as possible to prevent noise from the cable striking the surface. Background vibrations can be detected by attaching control electrodes to non-vibrating surfaces. Each accelerometer is different, but some general application guidelines are;
•The control vibrations should be less than 1/3 of the signal for the error to be less than 12%).
•Mass of the accelerometers should be less than a tenth of the measurement mass.
•These devices can be calibrated with shakers, for example a 1g shaker will hit a peak velocity of 9.81 m/s**2.
continuous sensors - 23.14
Sealant to prevent moisture
hookup wire
isolated |
accelerometer |
|
|
stud |
isolated |
|
wafer |
|
surface |
Figure 23.14 Mounting an Accelerometer
Equipment normally used when doing vibration testing is shown in Figure 23.15. The sensor needs to be mounted on the equipment to be tested. A pre-amplifier normally converts the charge generated by the accelerometer to a voltage. The voltage can then be analyzed to determine the vibration frequencies.
Sensor
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Source of vibrations, |
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or site for vibration |
pre- |
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measurement |
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amp |
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signal processor/ |
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control system |
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recorder |
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Figure 23.15 Typical Connection for Accelerometers
Accelerometers are commonly used for control systems that adjust speeds to reduce vibration and noise. Computer Controlled Milling machines now use these sensors to actively eliminate chatter, and detect tool failure. The signal from accelerometers can be