- •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 fuzzy - 26.7
final motor control voltage of 15.8V.
n
∑ ( Vmotori) ( membershipi)
Vmotor = i---------------------------------------------------------------------= 1 |
n |
∑( membershipi)
i= 1
Vmotor = |
0.6---------------------------------------------------( 17V) |
+ 0.4( 14V) |
= 15.8V |
|
0.6 |
+ 0.4 |
|
Figure 26.6 Rule Results Calculation
26.2 COMMERCIAL CONTROLLERS
At the time of writing Allen Bradley did not offer any Fuzzy Logic systems for their PLCs. But, other vendors such as Omron offer commercial controllers. Their controller has 8 inputs and 2 outputs. It will accept up to 128 rules that operate on sets defined with polygons with up to 7 points.
It is also possible to implement a fuzzy logic controller manually, possible in structured text.
26.3 REFERENCES
Li, Y.F., and Lau, C.C., “Application of Fuzzy Control for Servo Systems”, IEEE International Conference on Robotics and Automation, Philadelphia, 1988, pp. 1511-1519.
26.4SUMMARY
•Fuzzy rules can be developed verbally to describe a controller.
•Fuzzy sets can be developed statistically or by opinion.
•Solving fuzzy logic involves finding fuzzy set values and then calculating a value for each rule. These values for each rule are combined with a weighted average.
plc fuzzy - 26.8
26.5PRACTICE PROBLEMS
26.6PRACTICE PROBLEM SOLUTIONS
26.7ASSIGNMENT PROBLEMS
1.Find products that include fuzzy logic controllers in their designs.
2.Suggest 5 control problems that might be suitable for fuzzy logic control.
3.Two fuzzy rules, and the sets they use are given below. If verror = 30rps, and d/dtverror = 3rps/s, find Vmotor.
1.If (verror is ZE) and (d/dtverror is ZE) then (Vmotor is ZE).
2.If (verror is SP) or (d/dtverror is SP) then (Vmotor is SP).
|
v |
error |
|
|
|
|
d/ |
dt |
v |
error |
|
|
|
V |
motor |
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||
|
1 |
|
|
|
|
|
1 |
|
|
|
|
|
|
|
1 |
|
|
|
|
SN |
0 |
|
|
50 |
100 |
rps |
0 |
-3 |
|
0 |
3 |
6 |
rps/s |
0 |
6 |
12 |
18 |
V |
|
|
-100 -50 0 |
|
-6 |
|
|
0 |
24 |
||||||||||||
|
1 |
|
|
|
|
|
1 |
|
|
|
|
|
|
|
1 |
|
|
|
|
ZE |
0 |
|
|
|
|
rps |
0 |
|
|
|
|
|
|
rps/s |
0 |
|
|
|
V |
|
-100 -50 0 |
50 |
100 |
-6 |
-3 |
|
0 |
3 |
6 |
0 |
6 |
12 |
18 |
||||||
|
|
|
|
24 |
|||||||||||||||
|
1 |
|
|
|
|
|
1 |
|
|
|
|
|
|
|
1 |
|
|
|
|
SP |
0 |
|
|
|
|
rps |
0 |
|
|
|
|
|
|
rps/s |
0 |
|
|
|
V |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
|
-100 -50 |
0 |
50 |
100 |
|
-6 |
-3 |
|
0 |
3 |
6 |
|
0 |
6 |
12 |
18 |
24 |
4.Develop a set of fuzzy control rules adjusting the water temperature in a sink.
5.Develop a fuzzy logic control algorithm and implement it in structured text. The fuzzy rule set below is to be used to control the speed of a motor. When the error (difference between desired and actual speeds) is large the system will respond faster. When the difference is smaller the
plc fuzzy - 26.9
response will be smaller. Calculate the outputs for the system given errors of 5, 20 and 40.
100%
Big Error
error
0%
10 |
30 |
100%
Small Error
0% |
error |
|
|
10 |
30 |
20 |
|
Big Output |
|
|
error |
|
50 |
Small Output
5
error
50
if (big error) then (big output)
if (small error) then (small output)