1- P L C - General

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PROGRAMMABLELOGIC

CONTROLLER

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Control Systems TypesControl S

ystems Types

Programmable Logic Controllers

Distributed Control System PC- Based Controls

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IntroductionIntroduction

The PLC is an assembly of solid state digital

logic elements design to make logicaldecisions and provide outputs.

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Programmale LogicPro

grammale Logic

ControllersControllers

Seuential logic solver

P!D Calculations. "dvanced Subroutines

B!T #perations.

Data Transfer.

Te$t %andling.

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"pplications & 'achine controls( Packaging( Palleti)ing( 'aterial handling(

similar Seuential task as *ell as Process control

"dvantages of PLC & They are fast and designed for the rugged industrial

environment.

They are attractive on Cost-Per-Point Basis.

These Devices are less Proprietary + ,.g.. sing #pen Bus

!nterface. These Systems are upgraded to add more !ntelligence and

Capabilities *ith dedicated P!D and ,thernet 'odules.

Disadvantages of PLC & PLC *ere Designed for /elay Logic Ladder and have Di0culty

*ith some Smart Devices.


grammale Logic


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PLC Types

2ano +Small

'icro +'edium

Large

Basic criteria for PLC Types

'emory Capacity !3# /ange

Packaging and Cost per Point


grammale Logic


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Central Processing nit +CP

!nput #utput 'odules

Po*er Supply

Bus system

Programming Device

P L C ComponentsP L C Components

CPU

PROGRAM

DEVICE

IN OUT

m

MODULEMODULE

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!t is a micro-controller based circuitary. The CP consists offollo*ing blocks &

"rithmatic Logic nit +"L( Program memory

Process image memory +!nternal memory of CP

!nternal timers and counters

1lags CP performs the task necessary to ful4ll the PLC funtions. These

tasks include Scanning( !3# bus tra0c control( Program e$ecution(Peripheral and ,$ternal device communication( special functionsor data handling e$ecution and self diagnistics.

P L C ! Central ProcessingP L C ! Central Processing

"nit"nit

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These modules act as interface bet*een real-time status ofprocess variable and the CP.

"nalog input module & Typical input to these modules is

5-67 m"( 7-87 9

,$ & Pressure( 1lo*( Level T$( /TD +#hm( Thermocouple +m9 Digital input module & Typical input to these modules is 65 9

DC( 88: 9 "C( 6;7 9 "C

,$. & S*itches( Pushbuttons( /elays( pump valve on o< status

PLC ! Input modulePLC ! Input module

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867 9 acL8 L6

L6

L8

8

6

;

5

PB

input4elddevice

!nput moduleterminal board

!nput status

indicator

PLC ! Input modulePLC ! Input module

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These modules act as link bet*een the CP and the outputdevices in the 4eld.

"nalog output module & Typical output from these modulesis 5-67 m"( 7-87 9

,$ & Control 9alve( Speed( 9ibration Digital output module & Typical output from these modules is

65 9 DC( 88: 9 "C( 6;7 9 "C

,$. & Solenoid 9alves( lamps( "ctuators( dampers( Pumpvalve on o< control

PLC ! Output modulePLC ! Output module

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120 V acL1 L2

L2

L1

1

2

3

4

Output statusindicator

Output field

device

Module blown

Fuse indicator

Output module

PLC ! Output modulePLC ! Output module

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I#O SPECI$ICATIONI#O SPECI$ICATION

!2PT 9#LT"=, > 'agnitude and type of voltage #2-ST"T, !2PT 9#LT"=, /"2=, > voltage at *hich signal is

recogni)ed 2ominal current per input > 'in. current to operate input circuit "'B!,2T T,'P /"T!2= > 'a$ temp of surrounding the !3#

module !2PT D,L"? > Time duration for input signal to be on before

kno*n as valid input. + @-ms to 6:ms 2#'!2"L #TPT 9#LT"=, > !t is min and ma$ o3p operating

voltage.e.g. /ated 867 v ac o3p ckt. Aorks in @6 to 8; v range.

'" #3P C//,2T /"T!2= > 'a$ current a single o3p or modulecan safely carry under load #11 >ST"T,L," C//,2T P,/ #3P > 'a$ value of leak current

Eo*s through the o3p in #11 position ,L,CT/!C"L !S#L"T!#2 > 'a$ volts bet*een !3o and logic ckt.

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The po*er supply gives the voltage reuired forelectronics module +!3# Logic signals( CP( memory unitand peripheral devices of the PLC from the line supply.

The po*er supply provides isolation necessary toprotect the solid state devices from most high voltageline spikes.

"s !3# is e$panded( some PLC may reuire additionalpo*er supplies in order to maintain proper po*erlevels.

P L C ! Po%er SupplyP L C ! Po%er Supply

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!t is path for the transmission of the signal . Bu

system is responsible for the signal e$changebet*een processor and !3# modules

The bus system comprise of several single line ie*ires 3 tracks

P L C ! Bus SystemP L C ! Bus System

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Relay ConnectionRelay Connection

L2

L1

1

2

3

4

L2

L1

1

2

3

4

C

M

M

C CL

M

M MM

T1 T2 T3

L1 L2 L3

MOTO

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Ad&antage o' PLC O&er RelayAd&antage o' PLC O&er Relay

StyleStyle

/,L"? PLC

8-%ard *iring 8-Less *iring

6-Changes di0cult 6-,asy modi4cation

;-'ore po*er ;-Lo* po*er

5-'ore maintenance 5-Solid state reliability

:-Di0cult to e$pand -,ase of e$pansion

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PLC CyclePLC Cycle

Outputs

Machine

or

Process

Programmable

controller

Inputs

Sense the !nput

Process the Logic

=ive #utput

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PLC Signal $lo%PLC Signal $lo%

Programming Terminal

O!"#$

O!"#$

O!%#&

Output De'ices

Output Mo(ulesProcessor Memor)Input Mo(ule

Input De'ices

La((er Program

O!"#$

O!%#&

I!"#*

I!%#+

O!%#&

I!"#*

I!%#+

I!"#*

I!%#+

Data Input

Image Table

Output

Image Table

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PLC Arc(itecture E&olutionPLC Arc(itecture E&olution

'id - 8@F7s & Discrete 'achine Control

Programming

Terminal

PLC

I#O

Connection is Point to Point

ProgrammingLanguage &

- /elay ladder logic - 1le$ibility in altering

Control systemoperation

Connection is Point to Point

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,arly - to - 'id 8@7 & Discrete and ProcessControl


Reasonable Computer

Running PLC

Programming ,o-t.are

PLC

I#O

Programming Language !

/ La((er Program

/ PID

/ Data ,torage

M, / DO,

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Late 8@7Gs to early 8@@7Gs & Discrete andProcess Control

PC runningPLC Programming ,o-t.are

PLC

I#O

Connection in net.or0e( allo.ing

Multiple PLC

PLC became a part o- the

(e'eloping enterprise resource

s)stem

1in(o.s

PLC

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TodayToday&&Distributed !3# 'odulesDistributed !3# 'odules

Distributed !3# modules

!L

C

Distributed !3# scanner

Data Communication Bus

PLC Arc(itecturePLC Arc(itecture

E&olutionE&olution

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Remote

I/O Network

SPLITTERS

FIBER OPTIC LINK

TAPS

Remote I/O

Today &Today & %ot /edundant System%ot /edundant System


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Controller Controller

Controller

Controller

1or0station 1or0station 1or0station 1or0station

,.itche( 2ub


Today &Today & ,thernet Technology in PLCs,thernet Technology in PLCs

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Remote

Plat-orm

1ireless Mo(em

1ireless Mo(em

PLC

2 M IDispla) PC


Today &Today & Aireless communicationAireless communication

PLC

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PLC Systems o' &arious &endorsPLC Systems o' &arious &endors

Siemens S: -887( 88:( 8;:

SF - 677( ;77( 577

"llen Bradley 'icrologi$ 8777( 8677(

8:77

SLC :378( :376( :37;

PLC :387( :36: and :357

'odicon

2ano 'icro

Premium

Huantum

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8 Analog Inputs Analog Output

!p/"own FastCounter

!p Counter

Programm#ng Term#nal PC Conne$t#on

!n#telwa% Port &or $onne$t#ono& up to ' Sla(es

PC)CIA memor% e*pans#on port

PC)CIA $ommun#$at#ons port

TS+,-.

Bu#lt #n 0#spla% &or I/O1#n.ra$k2 AS.#3 an0 "#ag

I/O )o0ules

Con)guration o' PLC !Con)guration o' PLC !

ModiconModicon

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Con)guration o' PLC !Con)guration o' PLC !

SiemensSiemens

CP!

E*ternal Power

Suppl%

I/O )o0ules

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Con)guration o' PLC ! AllenCon)guration o' PLC ! Allen

BradleyBradley

CP!

Power Suppl%I/O )o0ules

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Con)guration o' PLC ! GE $AN"CCon)guration o' PLC ! GE $AN"C

CP!

I/O )o0ules Ba$k plane

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PLC Programming StandardsPLC Programming Standards

The open( manufacturer-independent programmingstandard for automation is !,C I88;8-;. ?ou can thus choose*hat con4guration interface you *ish to use *hen *riting yourapplication &

Ladder Diagram Statement List !nstruction List 1unction Block Diagram Seuential 1unction Chart Structured Te$t

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Scan RateScan Rate

The completion of one cycle of theseuence is called- SC"2

Time reuired for one cycle is calledSC"2 T!',

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Cost of hard*are( soft*are( !ntegration ,ngineering(Design( !nstallation( Start-up and Commissioning(9alidation documentation and ,$ecution( Training(Spare parts( 'aintenance( System service contract

and system life cycle. /eliability( 1le$ibility( Scalability and 9alidatability.

,ase of Database con4guration( =raphicsdevelopment( !nterlocks and Batch processing.

!ntegration of %igh-level "pplication. Control Philosophy for Centrali)ed versus /emote

#perator Console or both.

Compliance *ith an !ndustry batch standard such as

!S" SP and ne* Communication Protocol.

PLC *CS Selection CriteriaPLC *CS Selection Criteria

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Memory TypesMemory Types

/#' +/ead #nly 'emory

/"' +/andom "ccess 'emory

P/#' +Programmable /#'

,P/#' +,rasable P/#'

,"/#'- ,lectrically alterable /#'

,,P/#'-,lectrically erasable P/#'

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Binary SystemBinary System

B!T > ,ach digit of a binary number

B?T, > =roup of bit

A#/D > =roup of one or more byte

LSB > Least signi4cant bit orsmallest value

'SB > 'ost signi4cant bit or largestvalue

1 0234"#$

% &'T (O)

L*&M*&

&+T, &+T,

1% &'T (O)

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PLC ! TerminologyPLC ! Terminology

!2PT is referred by > !$$yy

#TPT is referred by > H$$yy

T!',/ is referred by > T $yy)))) 1L"=S are referred by > ' $$$$

C#2T,/S are referred by > C $$$$

Documents

1- P L C - General