programmable logic controller(plc)

PLCProgrammable Logic Controller

Content

▪ History▪ Definition of PLC?▪ Why we use PLC ?▪ Architecture of a PLC ▪ Components▪ Relay▪ Circuit diagram of relay▪ Sample of relay▪ Programing Language Of PLC ▪ Block Diagram

▪ Our Project▪ Circuit▪ Project video▪ Advantage▪ Disadvantage▪ Area of Applications▪ Conclusion▪ Summery▪ References

HISTORY

▪ 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.

Definition Of PLC?

▪ 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).

Why We Use PLC?

▪ 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.

Architecture of a PLC 

INPUT

Power Supply

Processor OUTPUT

MEMORY INTERFACE

COMPONENTS

COMPONENTS

▪ 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)

Three Phase Motor

Terminal BoxDriver Shaft Cooling FanStatorRotorStator Winding

Connection Of Motor with PLC

▪ This is the basic connection of Induction motor with PLC .

▪ Here we use a circuit breaker & a three phase relay.

▪ We also use two push button for start and stop.

▪ In plc we start an induction motor at Delta connection so that motor can get enough current to start and then running motor in Star connection.

Use Of Motor in Our Project

We use a three phase induction motor with 500 RPM for our project .

Relay

Frist ever Relay

Circuit Diagram Of Relay

Sample Of Relay

Programing Language Of PLC

PLC Language

LadderLogic

Functional Block Diagram

Sequential Function Chart

Boolean mnemonics

Block Diagram Of Our Project

Liquid-1 Liquid-2

MixtureTank

DumpTank

Our Project

Automatic liquid mixing machine for industrial use.

CIRCUIT

Neutral Mood

CIRCUIT

Liquid Coming Mood

CIRCUIT

Motor Starting Mood

CIRCUIT

Dump Mood

Area Of Application

Machine controls

Area Of Application

Machine controls

Food/Beverage processing

Area Of Application

Machine controls

Food/Beverage processing

Car park & Train station control system.

Area Of Application

Machine controls

Food/Beverage processing

Car park & Train station control system.

Manufacturing, Packaging, Palletizing

Area Of Application

Machine controls

Food/Beverage processing

Car park & Train station control system.

Manufacturing, Packaging, Palletizing

Material handling

Area Of Application

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.

ADVANTAGESvery 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

DISADVANTAGES

Initial Costs Are HighPLC hold only one copy of programmesPLC Devices Are ProprietaryUnemployment Rate IncreasesThere's difficulty with changes or replacements.When a problem occurs, hold-up time is

indefinite, usually long, It's always difficult to find errors.

Conclusion

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.

Summary

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

References

WikipediaIndustrial Control Handbook, Industrial Press

Inc.W. Bolton, Programmable Logic Controllers,

Fifth Edition. Maher, Michael J. Real-Time Control and

Communications.

Any Question

TheEnd