PLC(Programmable Logic Controller) Programmable Logic Controller (PLC) is an industrial computer that monitors inputs, makes decisions based on its program and controls outputs to automate a process or machine. The automation of many different processes , such as controlling machines or factory assembly lines, is done through the use of small computers called a programmable logic controllers(PLCs).

1. Programmable Logic Controller
Prepared by
Tahmid Rongon and Ahad hossain

2.  History
 What is PLC ?
 Why PLC ?
 Architecture of a PLC
 Components
 Programing Language Of
PLC
 Ladder Logic
 Programming Example
 Block Diagram
 Our Project
 Circuit
 Project video
 Advantage
 Disadvantage
 Area of Applications
 Conclusion
 Summery
 References

3.  PLC was introduced in late 1960’s.
 First commercial and successful programmable logic
controllers was designed and developed by modicon as a
relay replacer for General Motors.
 Earlier , it was a machine with thousand of electronic
parts.
 Later in late 1970’s the microprocessor became and
greatly enhanced the role of PLC permitting it to evolve
from simply relay to the sophisticated system as it is
today.

4.  The automation of many different processes , such as controlling machines or
factory assembly lines, is done through the use of small computers called a
programmable logic controllers(PLCs).
 Programmable Logic Controller (PLC) is an industrial
computer that monitors inputs, makes decisions based
on its program and controls outputs to automate a
process or machine.

5.  To reduce human efforts .
 To get maximum
efficiency from machine
and control them with
human logic .
 To reduce complex
circuitry of entire system
.
 To eliminate the high
costs associated with
inflexible, relay-
controlled systems.

6. INPUT
Power
Supply
PLC OUTPUT
MEMORY INTERFACE

8.  INPUT MODULES accepts and converts signals from sensors into
a logic signal
Ex. : Switches, Pushbuttons.
 OUTPUT MODULES that convert control instructions a signal that
can be used by actuators.
Ex. : lamps, alarm.
INPUT
(PUSH
BUTTON)
PLC OUTPUT
(INDICATOR LIGHT)

9.  Most common languages encountered
in PLC programming are:
1) Ladder Logic.
2) Functional Block Diagram.
3) Sequential Function Chart.
4) Boolean mnemonics.

10.  The ladder logic is the oldest programming
language for PLC.
 It is well suited to express Combinational logic.
 The main ladder logic symbols represent the
elements :

11. Ladder Logic Program for Start/Stop of Motor :

12. Liquid-1 Liquid-2
Mixture
Tank
Dump
Tank

13. Automatic liquid mixing machine for industrial use.

14. Neutral Mood

15. Liquid Coming Mood

16. Motor Starting Mood

17. Dump Mood

18.  Machine controls

19.  Machine controls
 Food/Beverage processing

20.  Machine controls
 Food/Beverage processing
 Car park & Train station
control system.

21.  Machine controls
 Food/Beverage processing
 Car park & Train station
control system.
 Manufacturing, Packaging,
Palletizing

22.  Machine controls
 Food/Beverage processing
 Car park & Train station
control system.
 Manufacturing, Packaging,
Palletizing
 Material handling

23.  Machine controls
 Food/Beverage processing
 Car park & Train station control
system.
 Manufacturing
 Packaging, Palletizing
 Material handling
 Textile,Travel,printing Industry
 similar Sequential task as well as
Process control etc.

24.  very Fast , High speed of operation.
 Small physical size, shorter project time Reduced space.
 inputs and outputs already inside the controller.
 Low power consumption
 designed to withstand vibrations,temperature,humidity,noise
etc.
 Easy maintenance due to modular assembly and flexibility
 Improves Productivity
 Improves Quality

25. Initial Costs Are High
PLC hold only one copy of programmes
PLC Devices Are Proprietary
Unemployment Rate Increases
There's difficulty with changes or
replacements.
When a problem occurs, hold-up time is
indefinite, usually long, It's always difficult to
find errors.

26. The PLC have in recent years experienced an
unprecedented growth as universal element in
industrial automation .
It can be effectively used in applications ranging
from simple control like replacing a small number
of relays to complex automation problems.
Today the PLCs are used for control & automation
job in a single machine & it increases up to full
automation of manufacturing / testing process in
a factory.

27. In this presentation we have discussed about:
What is PLC.
Why we use PLC.
Description of PLC.
A project over PLC.
Area of application.
Advantages & disadvantages

28. Wikipedia
Industrial Control Handbook, Industrial Press Inc.
W. Bolton, Programmable Logic Controllers, Fifth
Edition.
 Maher, Michael J. Real-Time Control and
Communications.