Manda Institute of Technology Raisar, Bikaner

Manda Institute of Technology Raisar, Bikaner

-Submitted by Mahendra Bhakar EC IV Year

TOPIC

1. PLC2. SCADA TOPIC

1. PLC2. SCADA

What is Programmable Logic Controller (PLC) ??

Definition:

A PLC is a digital operating electronic apparatus which uses a programmable memory for internal storage of instruction for implementing specific function such as logic, sequencing, timing, counting and arithmetic to control through analog or digital input/output modules various types of machines or process.

In 1968, a group of engineers from General Motors developed the concept of PLC with an initial specification. The PLC must be:

i . Easy to program.

ii. Not need rewiring the control system if change the program.

iii. Smaller in size, cheaper and high reliability.

iv. simple construction and low maintenance

v. Cost- competitive

Historical Background:

Simple PLC

network

digital inputs

digital outputs

analog inputs / outputs

Major Components of a Common PLC

PROCESSOR

POWERSUPPLY

I MN O P D U UT L E

O M U OT DP UU LT E

PROGRAMMING DEVICE

From SENSORS

Pushbuttons,contacts,

limit switches,etc.

ToOUTPUT

Solenoids, contactors,

alarmsetc.

AMERICAN: 1. Allen Bradley 2. Gould Modicum

3. Texas Instruments 4. General Electric5. Westinghouse6. Cutter Hammer7. Square D

EUROPEAN: 1. Siemens 2. Klockner & Mouller 3. Festo 4. Telemechanique

Leading Brands Of PLC

JAPANESE: 1. Toshiba 2. Omron 3. Fanuc 4. Mitsubishi

Leading Brands Of PLC

Manufacturing / Machining

Food / Beverage

Metals

Power

Mining

Petrochemical / Chemical

Areas of Application

1. SMALL - it covers units with up to 128 I/O’s and memories up to 2 Kbytes.

- these PLC’s are capable of providing simple to advance levels or machine controls.

2. MEDIUM - have up to 2048 I/O’s and memories up to 32 Kbytes.

3. LARGE - the most sophisticated units of the PLC family. They have up to 8192 I/O’s and memories up to 750

Kbytes. - can control individual production processes or entire plant.

PLC Size

Tank Used To Mix Two Liquids

A

B

C

FS

MOTOR

TIMER

SOLENOIDS

SOLENOID

1 -MINUTE

FLOAT SWITCH

SCADA

Supervisory Control And Data Acquisition is an Industrial

Control System.

To run a Process Control Network (PCN).

Monitors and controls industrial plant/ equipment.

E.g. water, energy, fuel, telecommunications.

Coordinate data transfer between Remote Terminal Units (RTUs) & central host.

Display information to operators.

Introduction (What Is SCADA?)

SCADA Components

Field Instrumentation. Sensors, devices to control.

Remote Terminal Units.RTU Vs. PLC

Communications Network. Equipment needed to transfer data to and

from different sites

Central Monitoring StationCollecting information gathered by the remote stations to

generate the necessary action

A Typical SCADA System

13

Relays used only for on/off control.

Complicated control systems

Expensive System.

System takes up much floor and space.

Control relays are power- hungry, heat generation.

Any change in control program requires the rewiring of relays.

For complicated control systems, it is difficult to troubleshoot and locate the faults.

Disadvantages Of Relay Systems

Advantages Of SCADA systems

Easily programmed or reprogrammed Easy maintained (self diagnostic). Capability to do arithmetic function. The ability to communicate with other controller or a master host

computer. PLCs. were able to move past simple on/off control to more complex

schemes as PID control.

Applications Of SCADA

Almost every business in the manufacturing sector and many in the service sector

Aerospace Bottling and Canning Chemicals Plants Petroleum, Petrochemical

ANY QUIRY….??

Thank you