components & programming of plc

8/7/2019 Components & Programming of PLC

http://slidepdf.com/reader/full/components-programming-of-plc 1/41

CCOMPONENTS &OMPONENTS &

PROGRAMMING OFPROGRAMMING OF

PLCPLC By Nurdiana binti Nordin



LEARNING OUTCOMESLEARNING OUTCOMESfor lecture today



Learning outcomesLearning outcomes



LECTURE CONTENTSLECTURE CONTENTS



Today’s Lecture Today’s Lecture

Continuation from last weekv Hardware Components of PLC

v PLC Hardware Configurations

v Power Supply

v CPU/Processor

vMemoryvI/O Modules

vProgramming DevicevAdditional/Optional componentsvProgramming of PLC



PLC HARDWAREPLC HARDWARE

COMPONENTS:COMPONENTS: MEMORY MEMORY



MemoryMemory



Factors affecting memory sizeFactors affecting memory size




COMPONENTS:COMPONENTS:

INPUT & OUTPUT MODULESINPUT & OUTPUT MODULES



Input & Output ModulesInput & Output Modules




Input devices (push

button, limit switches,

various of sensors, etc)

are wired /connected

to the terminal on the

input modules




Output devices

(motor, light, valve,

motor starter, etc)

are wired/connected

to terminal on the

output modules




- I/O modules can be located near the I/O devices

by using Remote I/O hence minimizing wiring

connection.




Common voltage rating for DISCREET /I Omodules

Input InterfacesInput Interfaces Output InterfaceOutput Interface

12V/24V AC/DC12V/24V AC/DC 12-48V AC12-48V AC

48V AC/DC48V AC/DC 120V AC120V AC

120V AC120V AC 230V AC230V AC

230V AC/DC230V AC/DC 120V AC120V AC

5V DC5V DC 230V DC/5V DC/230V DC/5V DC/24V DC24V DC




COMPONENTS:COMPONENTS:

PROGRAMMING DEVICEPROGRAMMING DEVICE



Programming DevicesProgramming Devices

Also called asProgram Terminal

(PT)



Programming DevicesProgramming Devices



Programming DeviceProgramming Device



PROGRAMMING OF PLCPROGRAMMING OF PLC



IntroductionIntroduction

qProgramming means: user entersthe control instruction/controlprogram to PLC throughprogramming devices

qqPLC programming is based on basic

logic function stored in processor

(programmable & easily changed)q

qPLC programming languages



PLC Program ScanPLC Program Scan

- The process that processor readsinput data, execute the control

program, and send output data

for complete cycle operation is

called program scan

- PLC program scan consist of

three stages:

i. input scan




∆ PLC required certain amount of time to execute onecomplete cycle

operation of program scan

∆

∆ Typical scan time : 1 – 25mSec

/perating cycle scan time:epends on



Logic Control and SequenceLogic Control and Sequence



I/O devices for Logic Control &I/O devices for Logic Control &

SequenceSequence

Sensor One/ZeroInterpretation

Actuator One/ZeroInterpretation

Limit switch Contact/no contact Motor On/off

Photo detector On/off Control relay Contact/no contact

PB switch On/off Light On/off

Timer On/off Valve Closed/open

Control relay Contact/no contact Clutch Engaged/notengaged

Circuit breaker Contact/no contact Solenoid Energized/not

energized



Programming of PLCProgramming of PLC



Basic Gates and BooleanBasic Gates and Boolean

equationsequations Truth table and Boolean equations

vAND gate

vOR gatevNOT gate

vNAND gate

vNOR gate



Basic Gates and BooleanBasic Gates and Boolean

equationsequations

AND

XOR



Programming of PLCProgramming of PLC



PLC Programming LanguagePLC Programming Language

5 types of programming languagesaccording to

IEC 61131-3 (International Standard for

PLC)

i. Ladder diagram (LD) – graphical, discretecontrol

ii. Function block diagram (FBD) – graphical,continuous control iii. Sequential function chart (SFC) – graphical,

sequencing

iv. Instruction list (IL) – textual, discrete control –



Ladder DiagramLadder Diagram

- Ladder diagram is the most common PLClanguage programming

- Logic input elements and output

components are displayed alonghorizontal line (called rungs) andconnected on two vertical rail

- Logic input elements located to the left

and output element to the far right of each rung

- Power is provided by the two vertical rails



Ladder DiagramLadder Diagram

- In ladder diagram,logic instructions areexecutes from top tobottom, left to the right

- Logic inputs areconnected in series,parallel or some

combinations to obtaindesired logic

- Use ladder symbols



Ladder Diagram : SymbolsLadder Diagram : Symbols

( ) ( / / .)Normally open NO contacts switch relay etc

( / / / / .)Output loads motor solenoid valve light etc

( ) ( / / .)Normally open NO contacts switch relay etc

TMR 3s Timer

CTR Counter



MM Y 2 CENTS Y 2 CENTS



eing happy doesn eing happy doesn ’ mean mean hat everything is perfec hat everything is perfec ut rather it means ut rather it means

’ou ve decided to ou ve decided to ook beyondook beyond

he imperfectionshe imperfections

components & programming of plc

Documents