PLC in Automation Technology,IECEP

8/3/2019 PLC in Automation Technology,IECEP

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PLC Programming

By:

Cabingas, Ben T., ECE

1


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Basic PLC

Objectives: Describe the major components of common

PLC

Use Automation Studio Simulation

Convert conventional relay logic to PLClanguage

Operate and program a PLC (Siemens S7200PLC) for a given application using LadderProgramming

2PLC in Automation Technology


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Basic PLC

Programmable Logic Controllers(Definition according to NEMA Standard ICS3-1978)

A digitally operating electronic apparatus whichuses a programming memory for the internalstorage of instructions for implementing specificfunctions such as logic, sequencing, timing,

counting and arithmetic to control through digital oranalog modules, various types of machines orprocess.

3PLC in Automation Technology


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Basic PLC

PLC other definition:

Considered as the Brain of modern

industrial control and as the hub for wide

varieties of automation and control

PLC Utilization in the Industries in Region X

A microprocessor based controller specificallydesigned for industrial control applications

PLC in Automation Technology 4
http://../The%20Level%20of%20Programmable%20Logic%20Controller%20Utilization%20in%20the%20Industries%20of%20Region%20X.docxhttp://../The%20Level%20of%20Programmable%20Logic%20Controller%20Utilization%20in%20the%20Industries%20of%20Region%20X.docx


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Basic PLC

Historical BackgroundThe Hydramatic Division of the General

Motors Corporation specified the design

criteria for the first programmablecontroller in 1968

Goal:

To eliminate the high costs associatedwith inflexible, relay-controlled systems



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Basic PLC

Historical BackgroundNew control system had to meet the following

requirements:

Survive in an industrial environment Easily programmed and maintained

Reusable



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Basic PLC

Other initial specifications: Price competitive with the use of relay systems

The controller had to be designed in modular form

The input and output had to be easily replaceable

The control system needed the capability to pass

data collection to a central system



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Basic PLC

Programmable Logic Controller Development1968 Programmable concept developed

1969 Hardware CPU controller, with logic

instructions, 1 K of memory and 128I/O points

1974 Use of several (multi) processors

within a PLC - timers and counters;arithmetic operations; 12 K of memory

and 1024 I/O points



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Basic PLC

Programmable Logic Controller Development

1976 Remote input/output systems introduced

1977 Microprocessors - based PLC introduced1980 Intelligent I/O modules developed

Enhanced communications facilities

Enhanced software features

Use of personal microcomputers asprogramming aids



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Basic PLC

1983 Low - cost small PLCs introduced

1985on Networking of all levels of PLC,computer and machine usingSCADA software



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Basic PLCLeading Brands of PLC

AMERICAN

1. Allen Bradley

2. Gould Modicon

3. Texas Instruments

4. General Electric

5. Westinghouse

6. Cutter Hammer

7. Square D

EUROPEAN

1. Siemens

2. Klockner & Mouller

3. Festo

4. TelemechaniquePLC in Automation Technology 11


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Basic PLC

Leading Brands of PLC

Japanese

1. Toshiba2. Omron

3. Fanuc

4. Mitsubishi



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Basic PLC

Areas of ApplicationsManufacturing / Machining

Food / Beverage

Metals Power

Mining

Petrochemical / Chemical



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Major Components of PLC


PROCESSOR

POWERSUPPLY

I M

N OP DU UT L

E

O M

U OT DP UU LT E

PROGRAMMINGDEVICE

FromSENSORS

Pushbuttons,

contacts,limit switches,etc.

ToOUTPUT

Solenoids,

contactors,alarms

etc.


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1. Power Supply Provides voltage needed to run the

primary PLC components

2. I/O Modules Provides signal conversion and isolation

between the internal logic- level signals

inside the PLC and the fields high levelsignal (analog or discrete)



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3. Processor

Provides intelligence to command andgovern the activities of the entire PLC

systems4. Programming device

used to enter the desired program that will

determine the sequence of operation andcontrol of process equipment or drivenmachine



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Programming Device

Types:

Hand held unit with LED / LCD display

Desktop type with a CRT display



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Programming Device

Handheld programmers:

Industrial terminal (Allen Bradley)



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Programming Device


Program Development Terminal (General Electric)



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Programming Device


Programming Panel ( Gould Modicon )



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Programming Device


Programming Console ( Keyence / Omron )



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Programming Device


Siemens



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Discrete Input


Discrete input also referred as digital input (ON or OFF) connected to

the PLC digital input.ON condition = logic 1 or a logic highOFF condition= logic o or logic low.

Normally Open Pushbutton

Normally Closed Pushbutton

Normally Open switch

Normally Closed switch

Normally Open contact

Normally closed contact


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Basic PLC


OFFLogic 0

IN

PLC

InputModule

OFFLogic 1

IN

PLC

InputModule

24 V dc


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Basic PLC


An analog input is an input signal that has a continuoussignal.Typical input signals are 0 to 20mA, 4 to 20mA or 0 to10V.

IN

PLCAnalogInputModule

Tank

Level Transmitter


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Basic PLC


Digital OutputA discrete output is either in an ON or OFF condition.Examples: Solenoids, contactors coils, and lamps.

OUT

PLC

DigitalOutputModule

Lamp


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Basic PLC


Analog Output

An analog output is an output signal that has a continuoussignal. Typical outputs may vary from 0 to 20mA, 4 to 20mAor 0 to10V.

OUT

PLC

AnalogOutputModule

EP

Pneumatic control valve

Supply air

Electric to pneumatic transducer

0 to 10V


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PLC Communications

Common Uses of PLC CommunicationsPorts

Changing resident PLC programs - uploading/downloading

from a supervisory controller (Laptop or desktop computer). Forcing I/O points and memory elements from a remote

terminal.

Linking a PLC into a control hierarchy containing several sizesof PLC and computer



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PLC Communications

Serial CommunicationsPLC communications facilities normally providesserial transmission of information

Common Standards

RS 232

Used in short-distance computer communications, withthe majority of computer hardware and peripherals Has a maximum effective distance of approx. 30 m at

9600 baud



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PLC Communications

Local Area Network (LAN)

provides a physical link between all devices

Provides overall data exchange management or protocol

provide the common, high-speed data communicationsbus which interconnects any or all devices within thelocal area.

RS 422 / RS 485

longer-distance links, often between several PCs in adistributed system

maximum distance of about 1000 meters



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PLC Programming

Types of Programming (IEC 1131-3)

Ladder Language

Instruction List language

Sequential Function Chart Language

Function Block diagram Language

Statement List Language



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Ladder Programming



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Instruction List Programming



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Sequential Function Chart



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Function Block Programming



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Drilling Robot Application

Diagram:


y+y-

DC motor (M)

z+z-

x+

x-

LIOC2.OUT0

LIOC2.OUT1

LIOC2.OUT2


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Drilling Robot Application

Problem Statement:

Materials from the feeder line is to be pushed by means asolenoid controlled double acting cylinder in horizontalposition (x coordinate) refer to set up diagram. After the

material is pushed, the solenoid controlled double actingcylinder in vertical position(y coordinate) will be activatedallowing the dc motor controlled drilling machine in position.The drilling of the material is for about 5s to ensure that thematerial is properly bore. After the material is properly borethen the solenoid double acting cylinder in vertical position will

return to its original position at the same time deactivating thedc motor. The material that is bore properly will be placed inthe storage area by means of solenoid controlled doubleacting cylinder (z coordinate) placed in adjacent between thetwo double acting cylinders.



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Motion Sequence Diagram

x+ t=5s z+ x-

X+ Y+ M+ Y-/M- Z+ Z- X- RST

Start/stop y+ y- z-


Note:

+ = Activation

- = Deactivation


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SUGGESTED PATTERN IN PROGRAMMABLE LOGIC

CONTROLLER (PLC)

SEQUENCE CONTROL by: Ruvel J. Cuasito, PECE1. A step (rung) is executed and represented by arelay.

2. The first step of the sequence shall be connected

in series with the triggering switches and isconnected in series with normally closedinterlocking contact. Each relay representing a stepis self-latched

Interlocking

contact

; X+

Latching contact


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3.The proceeding steps shall also represented by arelay unique from the other and is connected inseries with normally open step marker (relay markerprevious rung). The step is also self-latched.

Step Marker


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4. Reset rung shall also be connected in series withthe triggering switch and the step marker. No self-latching is required. (This rung is the termination of

the control circuit.)

5. The relay representing the reset step shall beused and assigned to the interlocking contact ofthe first step (1st rung).

6. The power circuits shall be represented by theappropriate tag name designated to its outputcomponent. (Solenoid Coil, Lamp, Buzzer, and

etc.)

Step marker


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7. The power circuit rung shall be connected in serieswith the normally open relay representing step activationof the output component, and then it is connected in

series with the normally closed relay representing stepdeactivation of the concerned output component.

Activation Deactivation

; X+/-


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8. If the activation and deactivation are repetitive, its

relay representation shall be connected in parallel tothe previous step activation and deactivation bearingthe same output component

; X+/-

First Activation and

deactivation

Second Activation and

deactivation


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Documents

PLC in Automation Technology,IECEP