plc course1

8/11/2019 Plc Course1

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PROGRAMMABLE

LOGIC

CONTROLLER

(PLC)


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The PLC Concept Requested by GeneralMotors and Landis .The Major

Automotive

Industry of America.


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THE INVENTER

The First PLC Invented in 1968

Made By Bedford Associates of Bedford,

Massachusetts.

One of the People worked for this Project

Mr.Dick Morley, The Father of the PLC


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WHY PLC

Earlier Industry

Larger Length of Panels( about 50 Feet).

100s and 1000s of Relays.

Noise.

Excessive Heating.

Confusion of wiring.

Delay Timing.

Updating was time consuming and Expensive.

Rewired by Skilled persons.


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THE FIRST PLC

The First PLC named is 084

The 84thProject of Bedford Associates.

125 words of memory

1/60 of Response Time


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The Bedford Associates Started a New

Company MODICON ( Modular Digital

Controller )

In 1977 Sold to Gould Electronics

Later acquired by German Company AEG

Now, Schneider Electric, France


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Electrical Panel


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PLC Adopted Panel


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Advantages of PLC

Rugged in Construction

Armored for severe conditions (dust,moisture, Heat, Cool)

Replace Electromechanical Relays Easy Programmable

Easy understandable

Compact in Size Low Cost

Easy Installation


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High Speed Response

Data Handling, Storage, Processing Power

and Communication Capabilities equivalent

to desktop Computers

Accommodate Multiple Inputs and Outputs

Extended Temperature Ranges Immunity to Electrical Noises

Resistance to Vibration


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PLC MANUFACTURER

MODICON HITACHI

SIEMENS HONEYWELL

ALLAN BRADLY IDEC

ABB KEYENCE

OMRON LG

CROZET MESSUNG

FATEK MITSUBISHI GE-FANUC SCHNEIDER

TELEMECHANIC TOSHIBA


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PLC

CONTROL

PROGRAM

OUTPUTS TODEVICES

INPUTS FROMDEVICES


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Architecture of a PLC

BATTERY USERRAM

CPU CKSYSTEM

ROM

DATA

RAM

I/O

UNIT

DATA BUS

CONTROL

ADDRESS BUS


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OUTPUT

INPUT

INPUTOUTPUT

UNIT

LATCH DRIVER

BUFFEROPTO

COUPLER


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PLC MODE

RUN Mode

PLC Execute the Application Program

STOP Mode

USER can Download the Program and Edit


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PLC SCAN

Input Processing

Program Processing

Output Processing


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INPUT PROCESSING

INPUTMODULE

INPUTS READ IN

I/P MEM


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PROGRAM PROCESSING

PROGRAMPROCESSING

I/P MEM O/P MEM


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OUTPUT PROCESSING

OUTPUTMODULE

OUTPUTWRITE OUT

O/P MEM


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INPUTS DEVICES

PUSH BUTTONS

RELAY CONTACTS

LIMIT SWITCHES

SELECTOR SWITCHES PROXIMITY SWITCHES

PRESSURE SWITCHES

ANALOG SENSORS

ENCODER

POTENTIOMETER


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OUTPUT DEVICES

RELAYS

MOTOR STARTERS

SOLENOID VALVES

INDICATING LAMPS LED DISPLAYS

SOLIDSTATE RELAYS

TRANSISTOR OUTPUT PWM OUTPUT

MMI OR HMI (Man Machine Interface)


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POWER SUPPLY FOR PLC

AC VERSION110 V AC, 230 V AC FOR SIGNAL ANDPOWER

DC VERSION24 V , 12 V DC FOR SIGNAL AND POWER

AC/DC VERSION230 V AC FOR POWER

24 V DC FOR SIGNAL


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COMMUNICATION

RS 232 (9 PIN)

RS 485

ETHERNET

MODBUS

PROFIBUS

DEVICENET


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INPUTS

NO. OF INPUTS

MINIMUM 6 TO MAX 100

EXPANSION AVAILABLE


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0 STATE AND 1 STATE

ON STATE AND OFF STATE

12 V DC MODEL- BELOW 5 V 0 STATE

ABOVE 5 V 1 STATE

24 V DC MODEL- BELOW 17 V 0 STATE

ABOVE 17 V 1 STATE

230 V AC MODEL-BELOW 70 V - 0 STATE

ABOVE 70 V - 1 STATE


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INPUT ISOLATION


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OUTPUT

NO. OF OUTPUT

MIN 4 TO MAX 80

EXPANSION

PID MODULE

PWM MODULE


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OUTPUT ISOLATION


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PROGRAMMING LANGUAGES

IEC (International Electrotechnical

Commission) 61131-3 Defines 5 Languages

LADDER (LD)

FUNCTIONAL BLOCK (FBD)

INSTRUCTION LISTING (IL)

SEQUENTIAL FUNCTION CHART ( SFC)

STRUCTURED TEXT (ST)


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LADDER DIAGRAM

VERTICAL LINES - LADDER

HORIZONTAL LINES RUNGS -

INSTRUCTIONS

LEFT to RIGHT

TOP to BOTTOM


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LADDER DIAGRAM

I1

I2


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STANDARD SYMBOLS

NORMALLY OPEN

CONTACT

NORMALLY CLOSED

CONTACT


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OUTPUT

SPECIAL

INSTRUCTION


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Logical Control

with Relays 115VACwall plug

relay logic

input A(normally closed)

input B(normally open)

output C(normally open)

ladder logic

A B C


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Simple Example


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Ladder construction


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PLC Registers

15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

1 0

Register 00


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PLC Registers

15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

0

Register 05


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LOGIC FUNCTION

AND

OR

NAND

NOR

EX-OR


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AND FUNCTION

I1 I2


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AND FUNCTION

A B C

0 0 01 0 0

0 1 0

1 1 1

I1 I2


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OR FUNCTION

I1

I2


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OR FUNCTION

A B C

0 0 01 0 1

0 1 1

1 1 1

I1

I2


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NOR FUNCTION

I1 I2


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NOR FUNCTION

A B C

0 0 11 0 0

0 1 0

1 1 0

I1 I2


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NAND FUNCTION

I1

I2


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NAND FUNCTION

A B C

0 0 11 0 1

0 1 1

1 1 0

I1

I2


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XOR FUNCTION

I1I2

I1 I2


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XOR FUNCTION

A B C

0 0 0

1 0 1

0 1 1

1 1 0

I1I2

I1 I2

000000000100002

LDNLDAND

AB

the mnemonic code is equivalent to


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Mnemonics0000200003000040000500006

ANDLDLDANDOR

CD

A B

C D

X

END

the mnemonic code is equivalent tothe ladder logic below

ST00007 XEND00008

Note: The notation shown above isnot standard Allen-Bradley

notation. The program to the

right would be the A-B equivalent.

SORBST

XIC A

XIO BNXB

XIO C

XIO DBND

OTE X

EOREND


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SFCs

Start

End

power up

power down

flash

Execution followsmultiple paths


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