Embed Size (px)
Citation preview
7/9/2017
1
Programmable Logic Controller
(PLC)
Dr. Ibrahim Al-Naimi
Chapter one
Traditional Controller
(Hard-wired Controller)
7/9/2017
2
Closed-loop Control System
7/9/2017
3
7/9/2017
4
7/9/2017
5
Traditional Controller
(Hard-wired Control)
7/9/2017
6
7/9/2017
7
7/9/2017
8
7/9/2017
9
7/9/2017
10
7/9/2017
11
7/9/2017
12
7/9/2017
13
7/9/2017
14
7/9/2017
15
7/9/2017
16
7/9/2017
17
7/9/2017
18
7/9/2017
19
7/9/2017
20
7/9/2017
21
7/9/2017
22
7/9/2017
23
7/9/2017
24
7/9/2017
25
7/9/2017
26
7/9/2017
27
7/9/2017
28
7/9/2017
29
7/9/2017
30
7/9/2017
31
7/9/2017
32
7/9/2017
33
7/9/2017
34
7/9/2017
35
7/9/2017
36
7/9/2017
37
7/9/2017
38
7/9/2017
39
7/9/2017
40
7/9/2017
41
7/9/2017
42
Hard-wired Controller
Disadvantages• Very low reliability.
• Inflexibility (very hard to expand and
modify).
• No communication, data collection, and
data handling capabilities.
• Very hard to troubleshoot.
• Very large size.
7/9/2017
43
Chapter Two
Programmable Logic
Controller (PLC)
Programmable Logic Controller
(PLC)Definition:
Programmable logic controller (PLC) is a
specialized computer used to control
machines and processes. It uses a
programmable memory to store instructions
and execute specific functions that include:
On/off control, timing, counting, sequencing,
arithmetic, signal processing, and data
handling.
7/9/2017
44
PLC and Personal Computer
(PC)
Unlike the PC, the PLC has been
designed to operate in the industrial
environment and is equipped with
special input/output interfaces and
also a special control program
language.
PLC and Traditional
Controller• Initially, the PLC was used to replace relay
logic (hard-wired controller).
• Many technological advances in the
programmable logic controller industry
continue today. Changes include both
hardware (physical components) and
software (control program) upgrades.
Therefore, PLC can be used in many
and more complex applications.
7/9/2017
45
PLC and Traditional
Controller• Because the structure of PLC is based on
the same principles as those employed in
computer architecture, PLC is capable not
only to performing relay switching tasks
but also capable to perform other functions
such as counting, arithmetic, data
handling, comparing, analogue signal
processing, and so forth.
When to use PLC
• Is there a need for flexibility in control logic changes?
• Is there a need for high reliability?
• Are space requirements important?
• Are increased capability and output required?
• Are there data collection requirements?
• Will there be frequent control logic changes?
• Will there be a need for rapid modification?
• Must similar control logic be used on different machines?
• Is there a need for future growth?
• What are the overall costs?
7/9/2017
46
PLC Advantages
• Relatively low cost
• High reliability: The program takes the
place of much of external wiring that would
normally be required for controlling the
process
• Flexibility/programmability: It is easier to
create and change a program in the PLC
than to wire and rewire a control circuit.
PLC Advantages
• Communication capabilities: PLC can
communicate with other controllers,
computers, and/or equipments to perform
several functions.
• Fast scan and response time.
• Easier to troubleshoot: PLCs have
diagnostics and override functions that
allow users to easily track and correct
software and hardware problems.
7/9/2017
47
PLC Advantages
• Special interfaces have allowed certain
devices to be connected directly to the
controller, such as thermocouples and
strain gauges
• Powerful instructions have been provided
and advanced functional block instructions
have been implemented
PLC Advantages
• Expandability/modular
• Ease of use in an industrial environment
• Ease of installation
• Used less space (small size)
7/9/2017
48
PLC Applications
• Automotive.
• Chemical and Petrochemical.
• Glass Processing.
• Manufacturing and Machining.
• Materials Handling.
• Metals.
• Power.
• Pulp and Paper.
• Rubber and Plastic.
PLC Applications:
Automotive
• Internal Combustion Engine Monitoring.
• Carburetor Production Testing.
• Monitoring Automotive Production Machines.
• Power Steering Valve Assembly and Testing.
7/9/2017
49
PLC Applications:
Chemical and Petrochemical
• Dyes.
• Chemical Batching.
• Fan Control.
• Gas Transmission and Distribution.
• Pipeline Pump Station Control.
• Oil Fields.
PLC Applications:
Manufacturing / Machining
• Production Machines.
• Transfer Line Machines.
• Wire Machine.
• Tool Changing.
• Paint Spraying.
7/9/2017
50
PLC Applications:
Power• Plant Power System.
• Energy Management.
• Coal Fluidization Processing.
• Compressor Efficiency Control.
7/9/2017
51
7/9/2017
52
7/9/2017
53
7/9/2017
54
7/9/2017
55
