BOILER AUTOMATION OF TEMPERATURE, WATER LEVEL MONITORING & CONTROL SYSTEM

USING PLC

A PROJECT REPORT

Submitted by

DHIRAJ KUMAR 348074013 Md. ASRARUL HAQUE 348074017 GAURI SHANKAR KUMAR 348074030

In partial fulfillment for the award of the degree

Of

BACHELOR OF ENGINEERING

In

ELECTRONICS AND INSTRUMENTATION ENGINEERING

AARUPADAI VEEDU INSTITUTE OF TECHNOLOGY

VINAYAKA MISSIONS UNIVERSITY, SALEM

OLD MAHABALIPURAM ROAD, PAIYANOOR

DIST-KANCHEEPURAM

APRIL, 2011

VINAYAKA MISSIONS UNIVERSITY

AARUPADAI VEEDU INSTITUTE OF TECHNOLOGYCHENNAI-603104

BONAFIDE CERTIFICATE

This is to certify that this project report on “BOILER AUTOMATION OF

TEMPERATURE, WATER LEVEL MONITORING & CONTROL SYSTEM USING

PLC” is a confide work of “DHIRAJ KUMAR-348074013, Md. ASRARUL HAQUE-

348074017 and GAURI SHANKAR KUMAR-348074030” in partial fulfillment of the

requirements for the award of the Degree of Bachelor of Engineering in Electronics and

Instrumentation Engineering from Aarupadai Veedu Institute of Technology, under our guidance

and supervision.

SIGNATURE SIGNATURE

Dr.N.VEERAPPAN, M.E., Ph.D., Mrs. T.MANJULA, M.E

HEAD OF THE DEPARTMENT, ASSISTANT PROFFESOR (II)

Department of EEE Department of EEE and EIE and EIEAVIT, paiyanoor AVIT, paiyanoorChennai-603104 Chennai-603104 Certified that the candidates was examined in the viva-voce Examination

held on …………………..

INTERNAL EXAMINER EXTERNAL EXAMINER

ACKNOWLEDGEMENT

We thank “THE ALMIGHTY” for his divine guidance and blessings throughout our project work.

We are grateful to Dr.(Mrs.)N.R.ALAMELU M.E.,PhD, principal Aarupadai Veedu Institute Technology -paiyanoor ,for this opportunity to carry out the project work.

We gratefully acknowledge Dr.N.VEERAPPAN, M.E., PhD, Head of Department of Electrical and Electronics & Electronics and Instrumentation Engineering for his encouragement and advice throughout the course of this project.

We express our deep sense of gratitude to our guide Mrs.T.MANJULA Associate professor EIE & EEE for her excellent guidance, constant inspiration and encouragement in the completion of this work.

We would like to thank our entire faculty member and staff of department of Electronics and Instrumentation Engineering who have rendered valuable help in making the project a successful one.

Finally we thank our family members and friends for their help and their perennial encouragement towards realizing this project successfully.

DHIRAJ KUMAR-348074013

Md. ASRARUL HAQUE-348074017

GAURI SHANKAR KUMAR-348074030

I

ABSTRACT

A Boiler or steam generator is employed wherever a source of system is required. A

boiler incorporates a firebox or furnace in order to burn the fuel and generate heat; the heat is

initially transferred to water to make steam; this produces saturated steam at ebullition

temperature. Higher the furnace temperature, faster the steam production. The saturated steam

thus produced can then either be used immediately to produce power via a turbine and alternator,

or else may be further superheated to a higher temperature; this notably reduces suspended water

content making a given volume of steam produce more work.

In this paper, we propose the parameters like the temperature of the steam, the level of water,

control of feed water pump, Pressure of the steam has to be measured and critically monitored

for reliable and safe operation of the generation unit. This kind of operation with critical

importance can be carried out efficiently and implemented employing Programmable Logic

Controller (PLC).Experimental results are presented.

II

LIST OF TABLE

CHAPTER TITLE PAGE NO.

ABSTRACT I

LIST OF TABLES II

LIST OF FIGURES VI

LIST OF ABBREVIATIONS V

1. INTRODUCTION 1.1 SOFTWARE AND COMPONENT USED

1.2 SECTION OF THE PROJECT

2. PROGRAMMABLE LOGIC CONTROLLER

2.1 INTRODUCTION

2.2 PLC HISTORY

2.3 PLC HARDWARE

2.4 WORKING OF PLC

2.5 PROGRAMMING OF THE PLC

3. SOFTWARE DESIGN AND SIMULATION 3.1 FUTURE OF WPL FOR WINDOWS 3.2 CREATING A PROGRAM 3.3 CREATE A PROJECT

4. HARDWARE DESIGN

4.1 LM35 (PRECTION CONTIGRADE TEMPERATURE SENSOR 4.2 LM317 (POSITIVE REGULATOR) 4.3 LM78XX (7805&7812) (SERIES VOLTAGE REGULATOR) 4.4 HCF 4093B: (QUAD 2 I/P NAND SCHMITT TRIGGER)

5. POWER SUPPLY 5.1 RECTFIER 5.2 FILTER 5.3 VOLTAGE REGULATOR

6. CONTROL ACTION 6.1 BUZZER 6.2 SOLONIOD VALVE

7. DESIGN OF LIQUID LEVEL SENSOR.

8. DESIGN OF TEMPERATURE SENSOR

9. DESIGN OF PRESSURE SENSOR

10. APPENDIX

11. REFERENCES

12. CONCLUSION

IV

LIST OF FIGURE

FIG. NO. NAME OF FIGURE PAGE NO.

V

LIST OF ABBREVIATIONS

SYMBOL ABBREVIATION

PLC PROGRAMMABLE LOGIC CONTROLLER

WPL WORLD PROGRAMMING LANGUAGE

CHAPTER 1

INTRODUCTION

1. INTRODUCTION

PLC applications are extensively used in industry to control and facilitate repetitive processes

such as manufacturing cell management, fly-by-wire control, or nuclear plant shutdown systems.

One of these applications is industrial automation which includes numerous automated

processes. This again includes automation of boiler which demands determination of certain

physical parameters (viz. pressure, temperature, etc.) & utilizing these parameters to make the

boiler start-stop or function in any manner we want, but automatically, without involvement of

any personal.

1.1 SOFTWARE AND COMPONENTS USED:

WPL software

PLC module (make DELTA)

Motor

Water reserve

Closed air tight container

Level sensor

Temperature sensor with current output

Pressure sensor

Solenoid valve

The most common parameters that have to be controlled in the boiler are temperature, pressure,

water level. The controlling mechanism can be achieved by using microprocessor and

microcontroller, PID controller or using PLC. Programmable logic control (PLC) provides an

easy and sophisticated method to design automation in industry. It also provides easy trouble

shooting method and flexibility to the industry.

Generally an industry has an emergency stop button to stop the whole process instantly if any

error occurred during operation. The emergency stop buttons are normally closed type. To start

the mechanism a start button (normally open type) switch is used which is connected after stop

button. When start button is made ON the lower level sensor sense the water level below the

lower level hence it start the motor to pump the water in to the boiler. The pump runs till the

water reaches the higher level sensor. After that the pump stops running. The temperature sensor

provides the temperature information to the PLC. If the temp. is less than the present value the

heater starts after 5 sec of motor OFF time. Temperature rises continuously and form water

steam. The temp. Should not raise beyond tolerance level of boiler hence the temp. should rise

up to certain limit and the heater should stop at that moment. The temp. again decreases and if

goes below preset value it start the heater. The above process continues. The steam produce in

the boiler exert a pressure on the boiler which is picked up by the pressure sensor. If pressure

reaches the present value it make the valve open and steam with a definite pressure goes out

through the pipe. The present value of the pressure should be calculated carefully and it should

not exceed maximum limit of boiler tolerance. This process result in decrease in water level and

if falls below the lower level sensor the motor starts during which the heater stops and whole

process repeats.

1.2 DIFFERENT SECTIONS OF THE PROJECT:

The project incorporates the requirement of a physical PLC trainer kit which is responsible for

collection of data from field sensors (within the boiler), evaluate them & generate appropriate

output for the boiler to operate in a specific desired procedure. Initially, we divided our project

into four sections viz., power supply section, water supply section, boiler (including sensors)

section, process controlling section.

Boiler Section: Boiling container, sensors (presssure, temperature & level sensors) & a heater

assemble altogether to give rise to the boiler section.

Controlling Section: This section includes the PLC trainer kit which is responsible for data

collection from field sensors, evaluation of collected data & generation of appropriate output

signals for automatic actuation and termination of different peripherals incorporated in the

overall system.

Water Supply Section: Water supply to the boiler is ensured by a water pump whose actuation

& termination is controlled by the PLC trainer.

Power Supply Section: This takes care of the power requirements for the whole project. This

mostly comprises of the circuits providing DC power for the field sensors and valves (solenoids).

APPLICATIONS: The main advantage of using PLCs is the drastic reduction in the

requirement of electrical components in terms of number of switches, relays, wiring, etc.the

applications of this project are solely the applications of a boiler i.e., production of steam and

using it for numerous processes like rotating the generator fins and hence producing power for

commercial or industrial purposes.

STAGES OF PROJECT DESIGN:

We divided the overall construction of the project in two stages. These are described as follows:

STAGE 1:

This stage basically focuses on:

(i) Software design & simulation

(ii) Hardware design

(A).Power supply &

(b) .Sensing unit

Level Sensing Unit

Temperature sensing unit

CHAPTER 2

PROGRAMMABLE LOGIC

CONTROLLER

2. PROGRAMMABLE LOGIC CONTROLLER

2.1. INTRODUCTION:

Programmable logic controllers (PLCs) are members of the computer family capable of

storing instructions to control functions such as sequencing, timing, and counting, which control

a machine or a process. The PLC is composed of two basic sections, the Central Processing Unit

(CPU) and the Input/Output (I/O) interface system. The PLC measures input signals coming

from a machine and through the internal program provides output or control back to the machine.

Ladder logic is the programming language used to represent electrical sequences of operation. In

hardwired circuits the electrical wiring is connected from one device to another according to

logic of operation. In a PLC the devices are connected to the input interface, the outputs are

connected to the output interface and the actual wiring of the components is done electronically

inside the PLC using ladder logic. This is known as soft wired. PLC is a device that is capable of

being programmed to perform a controlling function. Before the advent of PLC, the problem of

industrial control was usually solved by relays or hardwired solid-state logic blocks. These are

very flexible in design and easy for maintenance personal to understand. However, they involved

a vast amount of interconnection. For the wiring cost to be minimized, relays and logic blocks

had to be kept together. This led to development of control panel concept for larger and more

complex logic control system. The PLC was first conceived by group of engineers from

hydramatic division of GM in 1968.This was designed to provide flexibility in control based on

programming and executing logic instruction. Adopting the ladder diagram programming

language, simplifying maintenance and reducing the cost of spare parts inventories realized

major advantages.

2.2. PLC HISTORY:

In the late 1960's PLCs were first introduced. The primary reason for designing such a device

was eliminating the large cost involved in replacing the complicated relay based machine control

systems. Bedford Associates (Bedford, MA) proposed something called a Modular Digital

Controller (MODICON) to a major US car manufacturer. Other companies at the time proposed

computer based schemes, one of which was based upon the PDP-8. The MODICON 084 brought

the world's first PLC into commercial production. When production requirements changed so did

the control system. This becomes very expensive when the change is frequent. Since relays are

mechanical devices they also have a limited lifetime which required strict adhesion to

maintenance schedules. Troubleshooting was also quite tedious when so many relays are

involved. Now picture a machine control panel that included many, possibly hundreds or

thousands, of individual relays. The size could be mind boggling. How about the complicated

initial wiring of so many individual devices! These relays would be individually wired together

in a manner that would yield the desired outcome. Were there problems You bet! These "new

controllers" also had to be easily programmed by maintenance and plant engineers. The lifetime

had to be long and programming changes easily performed. They also had to survive the harsh

industrial environment. That's a lot to ask! The answers were to use a programming technique

most people were already familiar with and replace mechanical parts with solid-state ones.

In the mid70â„¢s the dominant PLC technologies were sequencer state-machines and the bit-

slice based CPU. The AMD 2901 and 2903 were quite popular in Modicon and A-B PLCs.

Conventional microprocessors lacked the power to quickly solve PLC logic in all but the

smallest PLCs. As conventional microprocessors evolved, larger and larger PLCs were being

based upon them. However, even today some are still based upon the 2903.(ref A-B's PLC-3)

Madison has yet to build a faster PLC than their 984A/B/X which was based upon the 2901.

Communications abilities began to appear in approximately 1973. The first such system was

Madison’s Mudbug. The PLC could now talk to other PLCs and they could be far away from the

actual machine they were controlling. They could also now be used to send and receive varying

voltages to allow them to enter the analog world. Unfortunately, the lack of standardization

coupled with continually changing technology has made PLC communications a nightmare of

incompatible protocols and physical networks. Still, it was a great decade for the PLC!

The 80â„¢s saw an attempt to standardize communications with General Motor's manufacturing

automation protocol(MAP). It was also a time for reducing the size of the PLC and making them

software programmable through symbolic programming on personal computers instead of

dedicated programming terminals or handheld programmers. Today the world's smallest PLC is

about the size of a single control relay!

The 90â„¢s have seen a gradual reduction in the introduction of new protocols, and the

modernization of the physical layers of some of the more popular protocols that survived the

1980's. The latest standard (IEC 1131-3) has tried to merge plc programming languages under

one international standard. We now have PLCs that are programmable in function block

diagrams, instruction lists, C and structured text all at the same time! PC's are also being used to

replace PLCs in some applications. The original company who commissioned the MODICON

084 has actually switched to a PC based control system.

2.3. PLC HARDWARE:

A programmable logic controller consists of the following components:-

Central Processing Unit (CPU). Memory. Input modules. Output modules and Power supply. A

PLC hardware block diagram is shown in Figure. The programming terminal in the diagram is

not a part of the PLC, but it is essential to have a terminal for programming or monitoring a PLC.

In the diagram, the arrows between blocks indicate the information and power-flowing-

directions.

Fig:PLC-Hardware-Block-Diagram

CPU :-

PROCESS

Programming Terminal

CPU MemoryPowerSupply

InputModule

OutputModule

InputDevices

OutputDevices

PLC

Like other computerized devices, there is a Central Processing Unit (CPU) in a PLC. The

CPU, which is the brain of a PLC, does the following operations:

* Updating inputs and outputs. This function allows a PLC to read the status of its input

terminals and energize or deenergize its output terminals.

* Performing logic and arithmetic operations. A CPU conducts all the mathematic and logic

operations involved in a PLC.

* Communicating with memory. The PLCâ„¢s programs and data are stored in memory. When

a PLC is operating, its CPU may read or change the contents of memory locations.

* Scanning application programs. An application program, which is called a ladder logic

program, is a set of instructions written by a PLC programmer. The scanning function allows the

PLC to execute the application program as specified by the programmer.

* Communicating with a programming terminal. The CPU transfers program and data between

itself and the programming terminal. A PLC CPU is controlled by operating system software.

The operating system software is a group of supervisory programs that are loaded and stored

permanently in the PLC memory by the PLC manufacturer.

Memory:-

Memory is the component that stores information, programs, and data in a PLC. The process of

putting new information into a memory location is called writing. The process of retrieving

information from a memory location is called reading. The common types of memory used in

PLCs are Read Only Memory (ROM) and Random Access Memory (RAM). A ROM location

can be read, but not written. ROM is used to store programs and data that should not be altered.

For example, the PLCs operating programs are stored in ROM.

A RAM location can be read or written. This means the information stored in a RAM location

can be retrieved and/or altered. Ladder logic programs are stored in RAM. When a new ladder

logic program is loaded into a PLCs memory, the old program that was stored in the same

locations is over-written and essentially erased. The memory capacities of PLCs vary. Memory

capacities are often expressed in terms of kilo-bytes (K). One byte is a group of 8 bits. One bit is

a memory location that may store one binary number that has the value of either 1 or 0. (Binary

numbers are addressed in Module 2). 1K memory means that there are 1024 bytes of RAM. 16K

memory means there are 16 x 1024 =16384 bytes of RAM.

Input modules and output modules:-

A PLC is a control device. It takes information from inputs and

makes decisions to energize or de-energize outputs. The decisions are made based on the statuses

of inputs and outputs and the ladder logic program that is being executed. The input devices

used with a PLC include pushbuttons, limit switches, relay contacts, photo sensors, proximity

switches, temperature sensors, and the like. These input devices can be AC (alternating current)

or DC (direct current). The input voltages can be high or low. The input signals can be digital or

analog. Differing inputs require different input modules. An input module provides an interface

between input devices and a PLCs CPU, which uses only a low DC voltage. The input

moduleâ„¢s function is to convert the input signals to DC voltages that are acceptable to the

CPU. Standard discrete input modules include 24 V AC, 48 V AC, 120 V AC, 220 V AC, 24 V

DC, 48 V DC, 120 V DC, 220 V DC, and transistor-transistor logic (TTL) level.

The devices controlled by a PLC include relays, alarms, solenoids, fans, lights, and motor

starters. These devices may require different levels of AC or DC voltages. Since the signals

processed in a PLC are low DC voltages, it is the function of the output module to convert PLC

control signals to the voltages required by the controlled circuits or devices. Standard discrete

output modules include 24 V AC, 48 V AC, 120 V AC, 220 V AC, 24 V DC, 48 V DC, 120 V

DC, 220 V DC, and TTL level.

Power Supply:-

PLCs are powered by standard commercial AC power lines. However, many PLC components,

such as the CPU and memory, utilize 5 volts or another level of DC power. The PLC power

supply converts AC power into DC power to support those components of the PLC.

Programming Terminal:-

-A PLC requires a programming terminal and programming software for operation. The

programming terminal can be a dedicated terminal or a generic computer purchased anywhere.

The programming terminal is used for programming the PLC and monitoring the PLCs

operation. It may also download a ladder logic program (the sending of a program from the

programming terminal to the PLC) or upload a ladder logic program (the sending of a program

from the PLC to the programming terminal). The terminal uses programming software for

programming and talking to a PLC.

2.4. WORKING OF PLC:-

Bringing input signal status to the internal memory of CPU

* The field signals are connected to the I/P module. At the output of I/P module the field status

converted into the voltage level required by the CPU is always available.

*At the beginning of each cycle the CPU brings in all the field I/P signals from I/P module &

stores into its internal memory called as PII, meaning process image input.

*The programmable controller operates cyclically meaning when complete program has been

scanned; it starts again at the beginning of the program.

I/O BUS:-

A PLC works by continually scanning a program. We can think of this scan cycle as consisting

of 3 important steps. There are typically more than 3 but we can focus on the important parts and

not worry about the others. Typically the others are checking the system and updating the current

internal counter and timer values.

Step 1-Check Input Status-First the PLC takes a look at each input to determine if it is on or off.

In other words, is the sensor connected to the first input on How about the second input How

about the third... It records this data into its memory to be used during the next step.

Step 2-Execute Program-Next the PLC executes your program one instruction at a time. Maybe

your program said that if the first input was on then it should turn on the first output. Since it

already knows which inputs are on/off from the previous step it will be able to decide whether

the first output should be turned on based on the state of the first input. It will store the execution

results for use later during the next step.

Step 3-Update Output Status-Finally the PLC updates the status of the outputs. It updates the

outputs based on which inputs were on during the first step and the results of executing your

program during the second step. Based on the example in step 2 it would now turn on the first

output because the first input was on and your program said to turn on the first output when this

condition is true.Process Control and Automation Process Control

The process of recognizing the state of the process at all times, analyze the information

according to the set rules and guidelines and accordingly actuate the control elements is referred

to as process control.

RECOGNISING THE STATUS:-

In control of process all these actions can be taken manually with human involvement or in a

semiautomatic or fully automatic manner. Automation -Automation is basically the delegation of

human control functions to technical equipment aimed towards achieving:

- Higher-productivity.

-Superior quality of end product.

-Efficient usage of energy and raw materials.

-Improved safety in working conditions etc.

Methods adopted for Process Control and Automation

- Manual control

- Hard wired logic control

- Electronics control

-PLC control

- Manual Control

Hardwired Control

-This was considered to be the first step towards automation.

- Here the contractor & relays together with timers & counters were used.

Electronics Control

-With the advent of electronics, the logic gates started replacing the relays & auxiliary

contractors in the control circuits & timers.

- With changes, the benefits are:

1) Reduced space requirements

2) Energy saving

3) Less maintenance and hence greater reliability etc.

-With electronics, the implementation of changes in the control logic as well as reducing the

project lead-time was not possible.

Programmable Logic Controller

- With microprocessor and associated peripherals chips, the process of control and automation

went a radical change.

- Instead of achieving the desired control or automation through physical wiring of control

devices, in PLC it is through a program or software. Thus these controllers are referred to as

programmable logic controllers.

- The programmable controllers have experienced an unprecedented growth as universal element.

It can be effectively used in applications ranging from simple control like replacing small

number relays to complex automation problem.

2.5. PROGRAMMING THE PLC:

Ladder Logic:-

Ladder logic is the main programming method used for PLCs. The ladder logic has been

developed to mimic relay logic. The decision to use the relay logic diagrams was a strategic one.

By selecting ladder logic as the main programming method, the amount of retraining needed for

engineers and trades people was greatly reduced.

Modern control systems still include relays, but these are rarely used for logic. A relay is a

simple device that uses a magnetic field to control a switch, as pictured in Fig. When a voltage is

applied to the input coil, the resulting current creates a magnetic field. The magnetic field pulls a

metal switch (or reed) towards it and the contacts touch, closing the switch. The contact that

closes when the coil is energized is called normally open. The normally closed contacts touch

when the input coil is not energized. Relays are normally drawn in schematic form using a circle

to represent the input coil. The output contacts are shown with two parallel lines. Normally open

contacts are shown as two lines, and will be open (non-conducting) when the input is not

energized. Normally closed contacts are shown with two lines with a diagonal line through them.

When the input coil is not energized the normally closed contacts will be closed (conducting).

Fig: Simple Relay Layouts and Schematics

Relays are used to let one power source close a switch for another (often high current) power

source, while keeping them isolated. An example of a relay in a simple control application is

shown in Figure. In this system the first relay on the left is used as normally closed, and will

allow current to flow until a voltage is applied to the input A. The second relay is normally open

and will not allow current to flow until a voltage is applied to the input B. If current is flowing

through the first two relays then current will flow through the coil in the third relay, and close the

switch for output C. This circuit would normally be drawn in the ladder logic form. This can be

read logically as C will be on if A is off and B is on.

Fig: A Simple Relay Controller

The example in Figure does not show the entire control system, but only the logic. When we

consider a PLC there are inputs, outputs, and the logic. Figure 4 shows a more complete

representation of the PLC. Here there are two inputs from push buttons. We can imagine the

inputs as activating 24V DC relay coils in the PLC. This in turn drives an output relay that

switches 115V AC that will turn on a light. Note, in actual PLCs inputs are never relays, but

outputs are often relays. The ladder logic in the PLC is actually a computer program that the user

can enter and change. Notice that both of the input push buttons are normally open, but the

ladder logic inside the PLC has one normally open contact, and one normally closed contact. Do

not think that the ladder logic in the PLC needs to match the inputs or outputs. Many beginners

will get caught trying to make the ladder logic match the input types.

Fig: A Simple Ladder Logic Diagram

There are other methods for programming PLCs. One of the earliest techniques involved

mnemonic instructions. These instructions can be derived directly from the ladder logic diagrams

and entered into the PLC through a simple programming terminal. An example of mnemonics is

shown in Figure. In this example the instructions are read one line at a time from top to bottom.

The first line 00000 has the instruction LDN (input load and not) for input A. This will examine

the input to the PLC and if it is off it will remember a 1 (or true), if it is on it will remember a 0

(or false). The next line uses an LD (input load) statement to look at the input. If the input is off

it remembers a 0, if the input is on it remembers a 1 (note: this is the reverse of the LDN).

The AND statement recalls the last two numbers remembered and if they are both true the result

is a 1; otherwise the result is a 0. This result now replaces the two numbers that were recalled,

and there is only one number remembered. The process is repeated for lines 00003 and 00004,

but when these are done there are now three numbers remembered. The oldest number is from

the AND, the newer numbers are from the two LD instructions. The AND in line 00005

combines the results from the last LD instructions and now there are two numbers remembered.

The OR instruction takes the two numbers now remaining and if either one is a 1 the result is a 1;

otherwise the result is a 0. This result replaces the two numbers, and there is now a single

number there. The last instruction is the ST (store output) that will look at the last value stored

and if it is 1, the output will be turned on; if it is 0 the output will be turned off.

PLC Structure

PLC Divided into 4 parts, I/O Modules, CPU, Memory and Programming Terminal. It operates by examining the input signals from a process and carrying out logic instructions and Producing output signals to drive process equipment. The Standard interfaces built-in to PLC directly connected to process actuators & transducers without the need for intermediate circuitry or relays. It requires short installation & commissioning times and it has Specific features for industrial control:

1. Noise immune equipment2. Modular plug-in construction3. Standard I/O connections & signal levels4. Easily understood programming language5. Ease of programming & reprogramming in-plant6. Capable of communicating with other PLCs, computers & intelligent devices7. Competitive in both cost & space occupied with relay & solid-state logic systems

Features:

The main difference from other computers is that PLCs are armored for severe condition

(dust, moisture, heat, cold, etc) and have the facility for extensive input/output (I/O)

arrangements.

These connect the PLC to sensors and actuators.

PLCs read limit switches, analog process variables (such as temperature and pressure),

and the positions of complex positioning systems. Some even use machine vision.

On the actuator side, PLCs operate electric motors, pneumatic or hydraulic cylinders,

magnetic relays or solenoids, or analog outputs

. The input/output arrangements may be built into a simple PLC, or the PLC may have

external I/O modules attached to a computer network that plugs into the PLC.

Fig. Of PLC

ADVANTAGE OF PLC :-

Cost effective for controlling complex system.

Smaller physical size than hard-wired solutions.

Flexible and can be reapplied to control other systems quickly.

PLCs have integrated diagnostics and override functions.

Computational abilities allow more sophisticated control.

Diagnostics are centrally available.

Troubleshooting aids make programming easier and

reduce downtime.

Applications can be immediately documented.

Applications can be duplicated faster and less

expensively.

Reliable components make these likely operate for

several years successfully.

Communication is possibilities.

DISADVANTAGE OF PLC :-

Programmable controllers are not equipped with enough memory to store big amounts of

data.

In this field the communication system need to be more developed.

CHAPTER 3

SOFTWARE DESIGN AND

SIMULATION

2. SOFTWARE DESIGN & SIMULATION

The software design and simulation part of the whole project is done by using the software

“WPL”. This software is used to design the ladder diagram of the overall project simulation in

order to study it`s behaviour.The ladder design hence obtained is downloaded into the PLC CPU

and thereby generating appropriate output signals required for the simulation.

2.1 Features of WPL for Windows

WPL for Windows is the Programming and Debugging Tool for DELTA Master-K Series.

WPL for Windows has abundant Features as below.

1) Program Compatible between DELTA Master-K Series.

A user can use the Program (*.PGM) created in DELTA Master-K Series for the Program

created in other DELTA Master-K Series As well. The Program, Parameter or

Variable/Comment created in WPL-DOS or GSIWPL can be also used in WPL for Windows.

2) PLC System Configuration by Project Structure

WPL for Windows manages the User-Defined Program as one Project including Parameter and

Variable/Comment. Also a user can save a Program (*.PRG), Parameter (*.PMT), Variable

(*.VAR) or Comment (*.CNT) respectively and the stored each File can be used for other

Project files.

3) User Friendly Interface

Easy and useful interface for Creating, Editing and Monitoring.

4) Online Editing

A Real Time Editing is available in online mode. The Program edited in the online condition can

be downloaded automatically without stopping PLC Hardware.

5) Monitoring the Information from PLC

A user can easily monitor PLC status such as Error Status, Network Information and System

Status.

6) Debugging and Self-diagnosis (in New MASTER-K Series)

Trigger and Forced I/O Enable are available for the accurate Debugging

2.2 CREATIN A PROGRAM

Creating a Ladder Program

This chapter describes creating a program in Ladder Window using the Tool Bar.

#After selecting the Normally Open Contact icon in the Ladder Tool Bar, Move the cursor to

the place to insert the Contact.

#Click the left button of the mouse or press Enter key, then the contact input dialog box appears.

#Type in the contact name (M0000) you want to insert and click OK button or press Enter

key.

#Select the Output Coil icon in the Ladder Tool Bar and move the cursor to the next column

of P000

.

Click the mouse button or press Enter key.

#Type in the Output Coil (P040) and click OK button or press Enter key.

Create a Project

About a Project:-

#A Project is the highest level to communicate with PLC and WPL for Windows.

A Project consists of Program, Parameter and Variable/Comment of Device.

#WPL for Windows deals with User Defined Programs and includes all elements necessary for

describing a Project.

#A Project consists of 3 Items (Program, Parameter and Variable/Comment) and Monitoring

is activated when the Monitoring Window is opened. Each Item can be saved respectively for

another Project.

#Saved Items (Program, Parameter and Variable/Comment) can be used for creating other

Projects or to reuse for other Projects.

#A Project includes not only Program, Parameter and Variable/Comment, but also PLC type,

used status of WPL and various information registered for monitoring. Thus, when you reopen

the Project after saving a Project, the Window keeps the previous working condition.

#Only Program and Parameters can be downloaded to PLC.

#A Project is saved as *.PRJ File.

2.3 CREATE A PROJECT

#To create a New Project file, Select File--New Project… ( ) from the Project pull-down

Menu.

The New Project dialog box will appear as below.

#Open a Blank Project

#It creates a new Project.

#Create from Old Files

#To create a New Project using the already existed Item (Program or Parameters or

Variable/Comment),

Select Item or items to be used by clicking the Find button in the dialog box.

#Click OK button after registering Items.

#Up to 3 items can be selected and non-selected items are set to default (Initial data).

#After selecting PLC Type and Programming Language, press the OK button. Then Project,

Message and Program Windows will be opened.

#Create from DOS WPL file

#To create a New Project using Items (Program, Parameter and Variable/Comment) created in

WPL for DOS,

Select PLC Type and Programming Language after selecting already created Items in KGL for

DOS. Then, a New

Project will be opened.

#Create from WPL file

#To create a New Project from WPL file, Select already created files (*.PGM, *.CMT) from

GSIWPL in the dialog box and select PLC Type and Programming Language.

Hot-Keys for Ladder Program Mode:-

CHAPTER 4 HARDWARE DESIGN

4. HARDWARE DESIGN

CHIP SPECIFICATIONS:

4.1.LM35 (Precision Centigrade Temperature Sensors)

Description:

The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is

linearly proportional to the Celsius (Centigrade) temperature. The LM35 thus has an advantage

over linear temperature sensors calibrated in °Kelvin, as the user is not required to subtract a

large constant voltage from its output to obtain convenient Centigrade scaling.

Features:

Calibrated directly in ° Celsius (Centigrade)

Linear + 10.0 mV/°C scale factor

0.5°C accuracy guarantee able (at +25°C)

Rated for full −55° to +150°C range

Suitable for remote applications

Low cost due to wafer-level trimming

Operates from 4 to 30 volts

Less than 60 μA current drain

Low self-heating, 0.08°C in still air

Nonlinearity only ±1⁄4°C typical

Low impedance output, 0.1 for 1 mA load

Absolute Maximum Ratings:

Supply Voltage +35V to −0.2V

Output Voltage +6V to −1.0V

Output Current 10 mA

Storage Temp. TO-220 Package −65°C to +150°C

Lead Temp. TO-92 and TO-220 Package, 260°C.

(Soldering, 10 seconds)

4.2. LM317 (3-Terminal Positive Adjustable Regulator)

Description:

This monolithic integrated circuit is an adjustable 3-terminal positive voltage regulator designed

to supply more than 1.5A of load current with an output voltage adjustable over a 1.2V to 37V. It

employs internal current limiting, thermal shut-down and safe area compensation.

Features:

Output Current In Excess of 1.5A

Output Adjustable Between 1.2V and 37V

Internal Thermal Overload Protection

Internal Short Circuit Current Limiting

Output Transistor Safe Operating Area Compensation

Absolute Maximum Ratings:

Input-Output Voltage Differential - 40 V.

Operating Junction Temperature Range - 0 ~ +125 °C

Storage Temperature Range -65 ~ +125 °C.

Temperature Coefficient of Output Voltage ±0.02 % /°C

.

4.3 LM78XX (7805 & 7812):-

Series Voltage Regulators

Description:

The LM78XX series of three terminal regulators is available with several fixed output voltages

making them useful in a wide range of applications. Each type employs internal current limiting,

thermal shut down and safe operating area

protection, making it essentially

indestructible. If adequate heat sinking is

provided, they can deliver over 1A output

current. Although designed primarily as

fixed voltage regulators, these devices can

be used with external components to obtain

adjustable voltages and currents.

Features

Output current in excess of 1A

Internal thermal overload protection

No external components required

Output transistor safe area protection

Internal short circuit current limit

Available in the aluminum TO-3 package

Voltage Range:

LM7805C 5V

LM7812C 12V

LM7815C 15V

Absolute Maximum Ratings:

Input Voltage (For VO = 5V to 18V) 35V.

(For VO = 24V) 40V.

Thermal Resistance Junction-Cases (TO-220) 5 ｰ C/W.

Thermal Resistance Junction-Air (TO-220) 65 ｰ C/W.

Operating Temperature Range (KA78XX/A/R) 0 ~ +125 ｰ C.

Storage Temperature Range - -65 ~ +150 ｰ C.

4.4 HCF4093B:

QUAD 2 INPUT NAND SCHMITT TRIGGER

Description:

The HCF4093B is a monolithic integrated circuit fabricated in Metal Oxide

Semiconductor technology available in DIP and SOP packages. The HCF4093B type consists of

four Schmitt trigger circuits. Each circuit functions as a two input NAND gate with Schmitt

trigger action on both inputs. The gate switches at different points for positive and negative

going signals. The difference between the positive voltage (VP) and the negative voltage (VN) is

defined as hysteresis voltage (VH).

Features:

SCHMITT TRIGGER

ACTION ON EACH

INPUT WITH NO

EXTERNAL

COMPONENTS

HYSTERESIS

VOLTAGE TYPICALLY

0.9V at VDD = 5V AND

2.3V at VDD = 10V

NOISE IMMUNITY

GREATER THAN

50%OF VDD (Typ.)

NO LIMIT ON INPUT RISE AND FALL TIMES

QUIESCENT CURRENT SPECIFIED UP TO 20V

STANDARDIZED SYMMETRICAL OUTPUT CHARACTERISTICS

5V, 10V AND 15V PARAMETRIC RATINGS

INPUT LEAKAGE CURRENT II = 100nA (MAX) AT VDD = 18V TA = 25°C

100% TESTED FOR QUIESCENT CURRENT.

ABSOLUTE MAXIMUM RATINGS:

Supply Voltage -0.5 to +22 V

DC Input Voltage -0.5 to VDD + 0.5 V

DC Input Current ± 10 mA

Power Dissipation per Package 200 mW

Power Dissipation per Output Transistor 100 mW

Operating Temperature -55 to +125 °C

Storage Temperature -65 to +150 °C

CHAPTER 5

Power supply

5.1.RECTIFIER:

1.. Rectifier is a device which offers a low resistance to the current in one direction and a

high resistance in the opposite direction.

2. Such a device is capable of converting A.C. voltage into a pulsating D.C. voltage.

3. The rectifier employs one or more diodes. It may be either a vacuum diode or a

semiconductor diode.

4. There are three types:

1. Half wave rectifier

2. Full wave rectifier

3. Bridge rectifier

Bridge rectifier:

1. Bridge rectifier is a full wave rectifier. It consists of four diodes , arranged in the form

of a bridge .

2. It utilizes the advantages of the full wave rectifier and at the same time it eliminates

the need for a centre tapped transformer.

3. The supply input and the rectified output are the two diagonally opposite

Terminals of the bridge.

4. During the positive half cycle, the secondary terminal A is positive with respect to

Terminal B.

5. Now the diodes D1 and D3 are forward biased and hence do not conduct.

6. The current flows from terminal A to terminal B through D1, load resistance RL and

the diode D3 and then through the secondary of the transformer.

7. During the negative half cycle, terminal B is positive with respect to point A.

8. Now diodes D2 and D4 are forward biased and hence conduct.

9. Diode D1 and D3 are reversed biased and hence do not conduct.

10. The current flows from terminal B to terminal A through diode D2, the load

resistance RL and diode D4 and then through the secondary of the transformer.

11. On both positive and negative half cycles of the A.C. input, the current flows through

the load resistance RL in the same direction.

12. The polarity of the voltage developed across RL is such that the end connected to the

Junction of the diodes D1 and D2 will be positive.

Fig. Of Bridge rectifier

5.2.FILTER:

1. Output from the rectifier unit having harmonic contents , so we can provided the filter

circuit, filter circuit is used to reduce the harmonics.

2. Here we can use the electrolytic capacitor.

3. This eliminates the harmonics from both voltage and current signals.

Fig of filter

5.3.VOLTAGE REGULATOR:

1 .Voltage regulator is used to maintain the constant voltage with the variation of the

supply voltage and the load current,

2 .When specifying individual ICs within this family, the xx is replaced with a two-digit

number, which indicates the output voltage the particular device is designed to provide

(for example, the 7805 has a 5 volt output, while the 7812 produces 12 volts).

3. The 78xx line are positive voltage regulators, meaning that they are designed to

produce a voltage that is positive relative to a common ground.

Fig. Of voltage regulator

5.3.1 VOLTAGE REGULATOR CIRCUIT:

A voltage regulator circuit provides a fixed value of voltage for particular values of circuit

components. A 12 volt DC voltage circuit can be designed by connecting a 230:12 volt

transformer, a bridge rectifier circuit and a capacitor, an IC7812.The transform gives 12 volt AC

output which is rectified by bridge circuit, a capacitor is used to bypass the AC component and

the IC7812 is used to provide constant 12 volt output which is use to drive other instruments.

Circuit diagram for voltage regulator circuit

CHAPTER 6 CONTROL ACTION

6.1. BUZZER:

A buzzer or beeper is an audio signaling device. Typical uses of buzzers and beepers include

alarms, timers and confirmation of user input such as a mouse click or keystroke.

TYPES OF BUZZER:

1. Mechanical

2. Electromechanical

3. Piezoelectric

1. Mechanical:

A joy buzzer is an example of a purely mechanical buzzer.\

2. Electromechanical:

Early devices were based on an electromechanical system identical to an electric bell

without the metal gong. Similarly, a relay may be connected to interrupt its own actuating

current, causing the contacts to buzz. Often these units were anchored to a wall or ceiling to use

it as a sounding board. The word "buzzer" comes from the rasping noise that electromechanical

buzzers made.

3. Piezoelectric:

A piezoelectric element may be driven by an oscillating electronic circuit or other audio

signal source, driven with a piezoelectric audio amplifier. Sounds commonly used to indicate

that a button has been pressed are a click, a ring or a beep.

Fig. Of buzzers

Circuit diagram of buzzer:

Circuit diagram of electronic buzzer:

Fig. Of electronic buzzer( PS1420P02CT)

FEATURES:

• Low frequency tone(2kHz).• Suitable for automatic radial taping machine(15mm-pitch).

SPECIFICATIONS AND CHARACTERISTICS:

1. Sound pressure:70dBA,10cm min.[at 2kHz, 5V0-P rectangular wave,measuring temperature: 25±5°C,humidity: 60±10%]

2.Temperature range: Operating –20 to +70°C Storage –30 to +80°C

3.Maximum input voltage 30V0-P max. [without DC bias]

4.Minimum delivery unit 1750 pieces [350 pieces/1 reel×5 reels]

6.2. SOLONIOD VALVE:

A solenoid valve is an electromechanical valve for use with liquid or gas. The valve is controlled by an electric current through a solenoid: in the case of a two-port valve the flow is switched on or off; in the case of a three-port valve, the outflow is switched between the two outlet ports. Multiple solenoid valves can be placed together on a manifold.

Solenoid valves are the most frequently used control elements in fluidics. Their tasks are to shut off, release, dose, distribute or mix fluids. They are found in many application areas. Solenoids offer fast and safe switching, high reliability, long service life, good medium compatibility of the materials used, low control power and compact design.

Besides the plunger-type actuator which is used most frequently, pivoted-armature actuators and rocker actuators are also used.

Construction:

A solenoid valve has two main parts: the solenoid and the valve. The solenoid converts electrical energy into mechanical energy which, in turn, opens or closes the valve mechanically. A direct acting valve has only a small flow circuit, shown within section E of this diagram (this section is mentioned below as a pilot valve). This diaphragm piloted valve multiplies this small flow by using it to control the flow through a much larger orifice.

Solenoid valves may use metal seals or rubber seals, and may also have electrical interfaces to allow for easy control. A spring may be used to hold the valve opened or closed while the valve is not activated

Fig. Of SOLONIOD VALVE

CHAPTER 7

DESIGN OF LIQUID LEVEL

SENSOR

7. DESIGN OF LIQUID LEVEL SENSOR:

Most of the sensor placed inside the water cause electrolytic reaction between liquid and sensor

causing loss of effectiveness. One solution to this problem is to ensure an AC potential rather

than DC potential between the electrodes. The constant reversal of electrode polarity drastically

inhibits the electrolytic process so that corrosion is considerable reduced and effectiveness

doesn’t hampered.

In this liquid level sensor AC is generated by an oscillator by connecting a capacitor (C1) to the

input of IC4093 (a NAND) gate and proving a feedback through the resistor (R1). This AC

current is given to the capacitor (C4) to charge up through the AC coupled capacitors C2 and C3.

Between C2 and C3 two sensor electrodes are placed so that when the liquid touches the

electrode, a conducting path is being created by the liquid so that C4 can be charged. Two diodes

D1 and D2 provide blockage to discharge capacitor C4. This high input of the charged capacitor

C4 is given to the IC4093 whose output is used to drive the base of transistor BC557. A relay is

connected to ground through BC557. As the transistor is driven by IC4093 which drive relay in

and the 230 volt ac output of relay is used to drive the motor.

Circuit diagram of liquid level sensor

CHAPTER 8

DESIGN OF TEMPERATURE

SENSOR

8. Design of temperature sensor

Future work:

The 2nd stage of the project is to be done in the successive semester.

2nd stage of the project involves:

1. Designing the pressure sensor circuit

2. Interfacing of sensors with the plc trainer kit.

3. Implementing the software program.

4. Construction of boiler setup & incorporation of the sensor within the boiler.

REFERENCE

1. LM 35 Precision Centigrade Temperature Sensors, National semiconductors, November

– 2000.

2. LM78XX Series Voltage Regulators, National semiconductors, May – 2000.

3. User Manual for PLC Trainer Kit, LG Programmable logic controller WPL for windows

[MASTER-K Series].

4. www.fairchildsemi.com

PROJECT GUIDE: PROJECT GROUP MEMBERS:

MS. T.MANJULA DHIRAJ KUMAR (348074013

Md. ASRARUL HAQUE (348074017)

GAURI SHANKAR KUMAR (348074030)