- •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
plc function ref - 34.5
OSR, OSF - One Shot Rising, One Shot Falling
A
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OSR |
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ONE SHOT RISING |
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Storage Bit B3:4/5 |
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Output Bit 2 |
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Output Word O:001 |
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Description: |
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This instruction will convert a single positive edge and convert it to a bit |
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that is on for only one scan. When ’A’ goes from false to true a positive |
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(or rising) edge occurs, and bit ’O:001/2’ will be on for one scan. Bit |
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’B3:4/5’ is used to track the state of the input to the function, and it can |
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be considered equivalent to an enable bit. |
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The OSF function is similar to the OSR function, except it is triggered on a |
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negative edge where the input falls from true to false. |
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Status Bits: |
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none |
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Registers: |
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none |
Available on: Micrologix, PLC-5
TND - Temporary eND
A
TND
Description: |
When ’A’ is true this statement will cause the PLC to stop examining the |
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ladder logic program, as if it has encountered the normal end-of-pro- |
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gram statement. |
Status Bits: |
none |
Registers: |
none |
Available on: Micrologix, PLC-5
34.1.3 Timers and Counters
Counter memory instructions can share the same memory location, so some redundant bits are mentioned here.
plc function ref - 34.6
CTD - CounT Down |
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A |
CTD |
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COUNT DOWN |
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Counter |
C5:0 |
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Preset |
50 |
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Accum. |
0 |
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Description: |
The counter accumulator will decrease once each time the input goes from |
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false to true. If the accumulator value reaches the preset the done bit, |
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DN, will be set. The accumulator value will still decrease even when the |
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done bit is set |
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Status Bits: |
CU |
Not used for this instruction |
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CD |
Will be true when the input is true |
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DN |
Will be set when ACC < PRE |
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OV |
Not used for this instruction |
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UN |
Will be set if the counter value has gone below -32,768 |
Registers: |
ACC |
The time that has passed since the input went true |
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PRE |
The maximum time delay before the timer goes on |
Available on: Micrologix, PLC-5
plc function ref - 34.7
CTU - CounT Up |
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A |
CTU |
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COUNT UP |
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Counter |
C5:0 |
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Preset |
50 |
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Accum. |
0 |
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Description: |
The counter accumulator will increase once each time the input goes from |
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false to true. If the accumulator value reaches the preset the done bit, |
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DN, will be set. The accumulator value will still increase even when the |
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done bit is set |
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Status Bits: |
CU |
Will be true when the input is true |
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CD |
Not used for this instruction |
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DN |
Will be set when ACC >= PRE |
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OV |
Will be set if the counter value has gone above 32,767 |
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UN |
Not used for this instruction |
Registers: |
ACC |
The total count |
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PRE |
The maximum count before the counter goes on |
Available on: Micrologix, PLC-5
plc function ref - 34.8
TOF - Timer OFf |
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A |
TOF |
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TIMER OFF DELAY |
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Timer |
T4:0 |
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Time Base |
1.0 |
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Preset |
10 |
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Accum. |
0 |
Description: |
This timer will delay turning off (the done bit, DN, will turn on immedi- |
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ately). Once the input turns off the accumulated value (ACC) will start |
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to increase from zero. When the preset (PRE) value is reached the DN |
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bit is turned off and the accumulator will reset to zero. If the input turns |
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on before the off delay is complete the accumulator will reset to zero. |
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Status Bits: |
EN |
This bit is true while the input to the timer is true |
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TT |
This bit is true while the accumulator value is increasing |
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DN |
This bit is true when the accumulator value is less than the preset |
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value and the input is true, or the accumulator is changing |
Registers: |
ACC |
The time that has passed since the input went false |
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PRE |
The maximum time delay before the timer goes off |
Available on: Micrologix, PLC-5
plc function ref - 34.9
TON - Timer ON |
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A |
TON |
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TIMER ON DELAY |
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Timer |
T4:0 |
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Time Base |
1.0 |
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Preset |
10 |
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Accum. |
0 |
Description: |
This timer will delay turning on, but will turn off immediately. Once the |
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input turns on the accumulated value (ACC) will start to increase from |
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zero. When the preset (PRE) value is reached the DN bit is set. The done |
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bit will turn off and the accumulator will reset to zero if the input goes |
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false. |
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Status Bits: |
EN |
This bit is true while the input to the timer is true |
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TT |
This bit is true while the accumulator value is increasing |
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DN |
This bit is true when the accumulator value is equal to the preset |
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value |
Registers: |
ACC |
The time that has passed since the input went true |
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PRE |
The maximum time delay before the timer goes on |
Available on: Micrologix, PLC-5