The presentation provided an overview of programmable logic controllers (PLCs). It discussed what a PLC is, the history of PLCs beginning in the 1960s, the major components of a PLC including the power supply, I/O modules, processor, and programming device. The presentation also covered common PLC programming languages like ladder logic and functional block diagrams, how to communicate with a PLC, examples of ladder logic exercises, advantages and disadvantages of PLCs, common applications of PLCs in industries, and some leading PLC brands.

1. Presentation on PLC
Mentoring Tutor :
Mr. Rajiv Vyas Sir
Professor (EE)
Presented By :
Harshvardhan Solanki
EE 3th year

2. CONTENTS
• What is PLC?
• History of PLC.
• Major components of PLC.
• Programming languages of PLC.
• How to communicate with PLC.
• How to create connection and interface.
• Exercises on ladder logic.
• Advantages and disadvantages.
• Applications.
• Few leading brands of PLC.

3. What is a PLC
Full form of PLC is Programmable logic controller.
PLC’s are also known as industrial computers and PLC’s can be used as an
stand alone unit..
We use PLC in industry because of its low cost and its easy to program
function.
It is a simplest form of control system which are basically replacing hard
wired logic relays. PLC is a industrial computer which get the input signal
from sensors and make output according to the programming done in it. PLC
can be used in extreme conditions also.
A PLC is an example of a real time system.

4. History of PLC
PLC was first made by Bedford in late 1960’s after seeing this invention of
Bedford other companies also made this device and then the name PLC was
given.
First commercial & successful Programmable Logic Controllers was
designed and developed by Modicon as a relay replacer for General
Motors.

5. Major components of PLC
• POWER SUPPLY: Provides the voltage needed
to run the primary PLC components
• I/O MODULES: Provides signal conversion and
isolation between the internal logic-level
signals inside the PLC and the field’s high level
signal.
• PROCESSOR: Provides intelligence to
command and govern the activities of the
entire PLC systems.
• PROGRAMMING DEVICE: Used to enter the
desired program that will determine the
sequence of operation and control of process
equipment or driven machine.

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

7. How to communicate with PLC
We can communicate with PLC using a twisted pair of wire or by
remotely through a telephone or radio modem.
Many types of PLC also communicates with RS232, RS422, RS485, or
using Ethernet cable.

8. Exercises on ladder logic
• 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:

9. Exercises 1

10. Exercises 2
NOR Gate

11. Exercises 3
NAND Gate

12. Exercises 4

13. Advantages and disadvantages
• Easily programmable
• Versatile and flexible
• Reliable , compact and required
less maintenance
• Simple programming language
• User friendly
• Energy saving
• High speed of operation
• PLC devices are proprietary it
means that part or software of
one manufacturer can’t be
used in combination with parts
of another manufacturer
• Limited design and cost option
• Fixed Circuit Operations
• PLCs manufacturers offer only
closed architectures

14. Applications
• Wherever automation is desired the PLCs are best suited to meet
the task.
• Few examples of industries where PLCs are used :
1) Robots manufacturing and control
2) Car park control
3) Train control station system
4) Food processing
5) Materials handling
6) Machine tools
7) Conveyer system etc.

15. Few leading brands of PLC
• Allen Bradley
• General Electric
• Siemens
• Texas Instruments
• Mitsubishi Electric
• Schneider Electric