AUTOMATION OF BOX FILLING MACHINE USING

PROGRAMMABLE LOGIC CONTROLLER

Supervisor

Dr. Inamul Hasan Shaikh

Assistant Professor

Submitted By

Hanan Bin Ahmed 10-EE-47

Muhammad Jawad Kareem 10-EE-27

H. M. Atif Imtiaz 10R/09-EE-62

DEPARTMENT OF ELECTRICAL ENGINEERING

FACULTY OF ELECTRONICS & ELECTRICAL ENGINEERING

UNIVERSITY OF ENGINEERING AND TECHNOLOGY

TAXILA.

JUNE 2014

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AUTOMATION OF BOX FILLING MACHINE USING

PROGRAMMABLE LOGIC CONTROLLER

Supervisor

Dr. Inamul Hasan Shaikh

Assistant Professor

Submitted By

Hanan Bin Ahmed 10-EE-47

Muhammad Jawad Kareem 10-EE-27

H. M. Atif Imtiaz 10R/09-EE-62

A Project Report Submitted in Partial Fulfillment of the Requirements

for the Award of Bachelor’s Degree in

Electrical Engineering

DEPARTMENT OF ELECTRICAL ENGINEERING FACULTY OF ELECTRONICS & ELECTRICAL ENGINEERING

UNIVERSITY OF ENGINEERING AND TECHNOLOGY

TAXILA.

JUNE 2014

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Undertaking

We certify that project work titled “Automation of Box Filling Machine Using PLC” is our own

work. No portion of the work presented in this project has been submitted in support of another

award or qualification either at this institution or elsewhere. Where material has been used from

other sources it has been properly acknowledged / referred.

a) Hanan Bin Ahmed

Regd. # 10-EE-47

b) M. Jawad Kareem

Regd. # 10-EE-27

c) H.M. Atif Imtiaz

Regd. #10R/09-EE-62

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DEDICATION

A bird learns flying from his parents, a child learns walking from his parents and teacher is guide

to success. So,

“All from us is dedicated to our parents.”

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ACKNOWLEDGEMENT

Success and achievement is possible only through hard work, determination and strong will.

We are grateful to ALLMIGHTY ALLAH who gave me the strength to think, plan and act

accordingly which make us possible to complete our visit. Through it is a literary tradition to

acknowledge the contribution and help by different people and organization in the completion of

our Project. But as a matter of fact some words cannot express our gratitude to the various

helping hands. It is very difficult to appreciate each person for his contribution, but there is a

standing contribution of our advisor Dr. Inamul Hasan Shaikh, who was there with us at the

time we needed him and without his guidelines, it would be difficult for us to complete this

project successfully.

We would like to thank all our teachers especially “Sayd Aftab Ali Shah” and “Eng. Adil

Usman” guiding us in solving our problems.

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Abstract

In the last era, before 1892 it was a very difficult task to carry heavy load from one place to

another especially in industries. A man can carry a very small load and tired very soon. So, a

very big labor was required for this. In 1892 a concept of a Mechanical Structure named

conveyor Belt System was introduced. It was operated through big motors.it can carry the big

loads.

So, we as a group members of final year project, arise this point of view and make a small but

latest carrying equipment. This equipment resembles to a small industrial part. It has two

conveyor belts, one is for manufactured products and second is for boxes to be filled. The

carrying and transferring of products and boxes is controlled by Programmable logic controller

without any man interference. PLC is a small, simple, latest and accurate electronic device used

to control small as well as big machinery systems. By performing this automated controlled

industrial conveyor belt system, we have given to industries a new point of view to control their

heavy machinery systems and other industrial parts through PLCs. These PLCs will make their

works easy, simple and more accurate.

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Contents List of Figures .............................................................................................................................................. 10

List of Tables ............................................................................................................................................... 11

Chapter 1 .................................................................................................................................................. 12

1.1 Introduction to Automation ........................................................................................................... 12

1.2 Automation ...................................................................................................................................... 12

1.3 Industrial Automation .................................................................................................................... 13

1.4 Advantages of Automation ........................................................................................................... 13

1.5 Disadvantages of Automation ...................................................................................................... 14

1.6 Applications .................................................................................................................................... 14

1.7 Industrial Automation Tools ......................................................................................................... 14

1.8 Devices used for Automation ....................................................................................................... 14

1.8.1 Sensors ................................................................................................................................... 14

1.8.2 Controllers ............................................................................................................................. 15

1.8.3 Motion Devices ..................................................................................................................... 15

1.8.4 Indicator Lights ..................................................................................................................... 15

1.9 Programmable Logic Controller ................................................................................................... 15

1.9.1 History ..................................................................................................................................... 15

1.9.2 Introduction to Programmable Logic Controller ......................................................... 16

1.9.3 Development ......................................................................................................................... 16

1.9.4 Programming ......................................................................................................................... 16

1.9.5 PLC Configurations and Types ........................................................................................ 16

1.9.6 Single Frame PLCs .............................................................................................................. 17

1.9.7 Shoe Box PLCs ..................................................................................................................... 17

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1.9.8 Modularized PLCs ................................................................................................................ 18

1.10 Typical Components of a PLC Based System ........................................................................ 18

1.10.1 Processor or Main Case ................................................................................................... 18

1.10.2 Input and Output Modules ............................................................................................... 19

1.10.3 Digital Input/output Modules .......................................................................................... 19

1.10.4 Analog Input/output Modules ......................................................................................... 19

1.10.5 High Speed Counters ........................................................................................................ 19

1.10.6 Register Input and Output Modules .............................................................................. 19

1.10.7 Mounting Rack .................................................................................................................... 19

1.11 Programming Unit ....................................................................................................................... 20

1.12 Power Supply ............................................................................................................................... 20

1.13 Block Diagram of PLC ................................................................................................................ 20

1.14 PLC Ladder Logic Programming ............................................................................................... 21

1.15 An Example Program .................................................................................................................. 23

Chapter 2 ................................................................................................................................................... 24

2.1 Problem Statement ........................................................................................................................ 24

2.2 List of Main Components .............................................................................................................. 24

2.2.1 Conveyor Belt System ........................................................................................................ 24

2.2.2 DC Series Motor ................................................................................................................... 27

This can lead to damage of some internal components. ...................................................................... 30

Chapter #3 ................................................................................................................................................ 33

3.1 Implementation of Project............................................................................................................. 33

3.1.1 Implementation of Electric circuitry ................................................................................ 34

FEATURES ........................................................................................................................................... 35

Connection Diagrams .......................................................................................................................... 36

SCHEMATIC DIAGRAM ..................................................................................................................... 36

We are using two types of DC relays .......................................................................................................... 37

24 V DC Relay for Actuator Circuit ................................................................................................... 37

12 V DC Relay for Sensor Circuit ...................................................................................................... 37

Definition .................................................................................................................................................. 37

Connection Diagram ............................................................................................................................ 37

What is a relay? .................................................................................................................................... 37

Why is a relay used? ..................................................................................................................... 38

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NPN Relay Switch Circuit ................................................................................................................... 38

NPN Relay Switch Circuit ............................................................................................................. 39

Features ................................................................................................................................................. 39

Specifications ........................................................................................................................................ 39

COIL SPECIFICATION AT 20 ........................................................................................................ 40

Advantages ........................................................................................................................................... 45

Disadvantages ...................................................................................................................................... 45

Individual devices in the series .......................................................................................................... 46

Features ............................................................................................................................................ 47

Project hardware ........................................................................................................................................ 48

Chapter 4 .................................................................................................................................................. 50

Simulation Results ................................................................................................................................... 50

Ladder Logic programming ..................................................................................................................... 50

Explanation ................................................................................................................................................ 51

Inputs: ........................................................................................................................................................ 51

Outputs: ..................................................................................................................................................... 51

Other instructions: .................................................................................................................................... 51

Simulation Results: .................................................................................................................................. 52

Basic commands used in PLC ladder logic .......................................................................................... 52

Counter: ..................................................................................................................................................... 55

Function .................................................................................................................................................. 57

Conclusion ............................................................................................................................................... 58

Recommendations ................................................................................................................................. 59

APPENDIX ................................................................................................................................................ 60

References ............................................................................................................................................... 61

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List of Figures

Figure 1.1 industrial automation ................................................................................................................ 13

Figure 2 PLC module ................................................................................................................................... 17

Figure 3 Omron PLC Kit ............................................................................................................................... 18

Figure 4 modular PLC .................................................................................................................................. 18

Figure 5 ladder parts ................................................................................................................................... 22

Figure 6 IEC 1131-3 symbles ....................................................................................................................... 23

Figure 7 old conveyor belt .......................................................................................................................... 25

Figure 8 dc series motor ............................................................................................................................. 29

Figure 9 Motor Gear System ....................................................................................................................... 30

Figure 10 rotation of motor ........................................................................................................................ 30

Figure 11 Efficiency graph ........................................................................................................................... 32

Figure 12 DC Series Motor .......................................................................................................................... 33

Figure 13 Block Diagram ............................................................................................................................. 34

Figure 14 LM 741 IC .................................................................................................................................... 35

Figure 15 Connection Diagram of LM 741 .................................................................................................. 36

Figure 16 Schematic Diagram LM 741 ........................................................................................................ 36

Figure 17 12V DC Relay ............................................................................................................................... 37

Figure 18 Connection Diagram of Relay ..................................................................................................... 37

Figure 19 C945 ............................................................................................................................................ 41

Figure 20 Collector Current vs Vce.............................................................................................................. 42

Figure 21 Dimension of LDR ........................................................................................................................ 44

Figure 22 Voltage Regulator 7812.............................................................................................................. 45

Figure 23 Assembly of conveyors ............................................................................................................... 48

Figure 24 Assembly 2 .................................................................................................................................. 48

Figure 25 Omron PLC .................................................................................................................................. 49

Figure 26 Interfacing Circuit ........................................................................................................................ 49

Figure 27 Ladder logic code ........................................................................................................................ 50

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List of Tables Table 1 Coil Specification of Relay .............................................................................................................. 40

Table 2 Electrical Characteristics of Transistor ........................................................................................... 42

Table 3 Electrical Characteristics of LDR ..................................................................................................... 43

Table 4 Instructions used in code ............................................................................................................... 51

Table 5 Timer .............................................................................................................................................. 54

Table 6 Counter ........................................................................................................................................... 55

Table 7 Interlock instruction ....................................................................................................................... 57

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Chapter 1

1.1 Introduction to Automation

This chapter will gives you a brief introduction about the automation, history of automation and

recent advancements made in this field. This chapter will also through the light on the

advantages and disadvantages of the automation. Further, detailed information about the

applications of automation, devices employed for automation is also given in this chapter.

Automation is the back bone of industry and it is involved in each kind of process that is being

running in industry. With the invention of programmable logic controller the field of automation

has totally changed. Prior to programmable logic controllers, a large number of relays were used

for automation and this method is very costly. In addition to cost, if you want to change the

control scheme you have to rewire all the circuitry that is very time consuming and a tough job.

But programmable logic controller has changed the whole world of automation. In our final year

project we are focusing on the automation of a box filling machine using programmable logic

controller. We have tried our best to make an efficient and fully automated machine that can

place the objects of different type accurately in the box according to the user’s desire.

1.2 Automation

1.2.1 Definition

Automation may be defined as” the technique, method, or system of operating or

controlling a process by highly automatic means, as by electronic devices, reducing human

intervention to a minimum.” The term automation refers to devices such as automated machinery

or other intelligent devices that are used to control and execute some required task. The devices

used for automation ranges from small sensors like IR sensors, Proximity sensors, thermocouples

to large robots and highly efficient computers.

1.2.2 Introduction to Automation

Automation employs modern control systems and algorithms to make a process fully

automated and reduce the human interference. Automation has greatly reduced the need of

human operator and mental exercise. Everything to be performed is downloaded in the intelligent

systems in the form of program and no more human monitoring and controlling is required.

Automated machines have made the life of human easy. Automation plays an increasingly

important role in the world economy and in daily experience.

1.2.3 Why is Automation Vital?

The question is that why to employ automation, its answer is as given below. There are several

factors that force to employ automation. This first one is productivity. This is the major reason of

using automated machines in industry. By using such automated machines productivity increases

and industry get more profit for same labor hours. Second factor is the high cost of out dated

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relay automation system that employs hundreds of switches, fuses and contactors. To make a

small change you need to rewire the whole system and operators are also required. The need of

operators further increases the labor cost. Hence to make the system flexible, durable, and

productive and to eliminate human error automation is preferred. Decisions associated with

automation are usually concerned with some or all of these economic and social considerations.

1.3 Industrial Automation “The control of industrial machines and process with the help of computer by replacing human

operators is known as Industrial Automation. “

Automation is used in almost every field on earth. It is used in industry; homes; offices; schools;

military applications and in transportation system. The devices employed for automation include

different king of sensors, programmable logic controllers, actuating systems, intelligent control

systems, modern control algorithms, robotics, electronic systems and many other devices.

Figure 1.1 industrial automation

1.4 Advantages of Automation Automation has several advantages over older relay system. Automation increases productivity,

reliability, durability and safety. Automation brings many advantages when incorporated

properly. The main advantages are listed below:

1. Low production cost

2. Decrease in service cycle time

3. Better quality and reliability

4. Better utilization of floor space

5. Less by products

6. Stay competitive

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1.5 Disadvantages of Automation There are several disadvantages associated with automation. Some of them are listed below:

1. High starting cost

2. Skilled operator is required

3. Not always produce the required result

4. Difficult to maintain

1.6 Applications Automation finds its applications in every discipline. It is found in offices, homes, schools and

industry. Some of its applications are listed below:

1. Automated video surveillance

2. Automated highway airway systems

3. Automated military applications

4. Automated manufacturing and production

5. Home and office automation

1.7 Industrial Automation Tools There is a list of tools used for the industrial automation. These tools ranges from HMI by mean

on which operator controls the process, to SACDA, used for data acquisition. Different types of

industrial automation tools are listed below:

1. Simulator

2. Distributed Control System (DCS)

3. Programmable Logic Controller (PLC)

4. Human Machine Interface (HMI)

5. Supervisory Control and Data Acquisition (SCADA)

6. Batch Management System (BMS)

7. Manufacturing Execution System (MES)

8. Laboratory Information Management System (LIMS)

1.8 Devices used for Automation Some of the devices employed for the automation are given below:

1. Sensors

2. Controllers

3. Motion Devices

4. Indicator Lights

1.8.1 Sensors Sensors used for automation falls into different categories. Some of them are listed below:

1. Proximity sensors

2. Photoelectric sensors

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3. Area sensors

4. Door sensors

5. Fiber optic sensors

6. Rotary encoders

7. Pressure sensors

1.8.2 Controllers Different controllers used for automation are:

1. Temperature controllers

2. Counters

3. Timers

4. Panel meters

5. Pulse rate meters

6. Display units

1.8.3 Motion Devices Motion devices used for automation are:

1. Stepping motors

2. Stepping motor drivers

3. Motion controllers

1.8.4 Indicator Lights Different types of indicators used for automation are:

1. Indicator lights

2. Push buttons

3. Control switches

1.9 Programmable Logic Controller Programmable Logic controller is just a digital computer that is designed for

specific applications mostly for the control of industrial processes. Its applications include

conveyor belt control, control of different valves in industrial processes like bottle filling,

temperature control of boilers etc. Programmable logic controller is designed in such a way

that it can bear the harsh environment of industry. It should be able to with stand high

temperatures, vibrations and electromagnetic interferences.

1.9.1 History

The programmable logic controller was invented in response to the need of

automation industry to control various manufacturing, production and packaging processes.

In the early days to control the industrial processes a large number of relays, timers, hand

driven switches, fuses and different bulky and large components ware used. It is very

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difficult to control and manage these bulky circuits and it is too difficult to make changes in

the control scheme as whole the system is needed to be rewired and in addition to time

consuming it is also expensive. Electricians or technicians were required to do this.

1.9.2 Introduction to Programmable Logic Controller Stand harsh environment and they also lacks in the availability of a number

of discrete input/output ports. Further a computer’s response time should be fast enough to

perfectly control a process. Response time requirements vary from process to process. The

first PLC, designated the 084 because it was Bedford Associates' eighty-fourth project, was

the result. Bedford Associates started a new company dedicated to developing,

manufacturing, selling, and servicing this new product: Modicon, which stood for Modular

Digital Controller. One of the people who worked on that project was Dick Morley, who is

considered to be the "father" of the PLC.

1.9.3 Development The Programmable Logic controller was invented to replace the relay logic and

hard wired circuitry. In early days the commonly used programming languages for

programmable logic controller are ladder logic and instruction list programming. Ladder

logic programming resembles the relay logic and is easy. Other modern languages used for

programmable logic controller are BASIC and C.With the invention of remote programming

terminals that graphically displays the states of different relays, contacts, timers and counters

the use of ladder logic programming gain popularity.

1.9.4 Programming In early days programmable logic controller was programmed using special

programming terminals provided by the manufacturer of the controller, which often had

dedicated function keys representing the various logical elements of programmable logic

controller programs. The facility for printing and storing program on non-volatile memory

was minimal. Now a day, programmable logic controller is programmed using application

software on personal computers. The computer is connected to the programmable logic

controller through Ethernet, RS-232, RS-485 or RS-422 communication ports using a variety

of communication protocols. User can edit the program; perform debugging using graphical

display and troubleshooting very easily using the software. The software has the functionality

of upload and downloads the program for backup and restoration purposes. In some models

of programmable logic controller, the program is transferred from a personal computer to the

PLC though a programming board which writes the program into a removable chip such as

an EEPROM or EPROM.

1.9.5 PLC Configurations and Types Programmable logic controller is much like a typical personal computer with a vast variety of

functions and options available. It is available in a number of different configurations and

specifications. The best model or configuration to be used depends on a particular situation

that how many input/output ports you need, how much memory is required etc. One can learn

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Fig. 1.1 Figure 2 PLC module

all such things only through experience and that’s why during installing a new system a

professional experienced person is required. The most basic configuration is available to a

single printed circuit board as shown in

1.9.6 Single Frame PLCs

This type of programmable logic controllers are often called single frame or open frame

programmable logic controller. This controller is totally a self-contained unit and to put it to

use it has to be installed on a control cabinet. Screws are used to make input/output

connections with the printed board. Most of the time, power supply is also external to the unit

and is provided externally through a pair of wires. This type of configuration or card can’t be

upgraded and has a limited number of input/output ports. Hence while designing the system

the user should consider the number of ports and memory required, then choose a proper

card. Single board PLC is not expensive, small easy to program and consume little power.

But on the other hand it has less number of input/output ports.

1.9.7 Shoe Box PLCs PLC is also available in another configuration named as shoe box. This type of

PLC consist of a single case in which all the input/output ports and power supply is housed.

This type of configuration is chosen depending upon the number of ports, memory and voltage

level required. Such type of PLC often has an extension port to extend the number of

input/output ports, memory or to attach external modules like analog input/output module, high

speed counter module, touch pad and addition digital ports. To connect these modules a cable is

used or sometimes these modules are directly plugged with the PLC. Figure 2.2 shows a shoe

box PLC.

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Figure 3 Omron PLC Kit

1.9.8 Modularized PLCs Finally the most recent and widely used form of PLC is modularized PLC. It has a

large number of options and you can make addition of different modules easily and its

maintenance is also easy. A modularized PLC is shown in figure 1.4

Figure 4 modular PLC

1.10 Typical Components of a PLC Based System A Programmable logic controller based system consists of a number of modules

connected to a main case or processor. Below is given the description of some of the normally

used module.

1.10.1 Processor or Main Case Processor is generally specified according to the memory required for the program to be

implemented. In modular system capability can also be a factor. This includes the features

such as PID control loops, math functions and addition commands. A self-contained processor

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usually consists of a microprocessor, program memory, communication ports, and input/output

modules and in some cases power supply.

1.10.2 Input and Output Modules Input and output modules are of different types depending on the type on the input signal and

particular application. There are digital input/output modules, analog input/output modules, high

speed counters and registers etc.

1.10.3 Digital Input/output Modules This type of input/output modules deals with digital input/output signals. These modules usually

have 8 or 16 points but some special modules may also have 32 points. These modules also have

two categories depending on the type of signal it deals with AC or DC along with the voltage

levels it is designed for.

1.10.4 Analog Input/output Modules These modules deal with the analog signals and are categorized depending on their

resolution and current or voltage range. These modules can deal with analog current as well as

analog voltage signal. Analog modules are also available that can be directly interfaced with

temperature measuring devices such as thermocouples.

1.10.5 High Speed Counters

These modules are used for the pulse type input to the PLC. These modules are

capable of measuring the frequency of input signal or can be used to count the high frequency

input signal pulses.

1.10.6 Register Input and Output Modules These types of modules are used to transfer 8 or 16 bit of data to and from the PLC.

This type of module is generally used with encoders to receive the information and with display

unit to give it the data to display. In addition to these modules there are also other modules for

specific purposes like communication modules to make serial communication between PLC and

other remote devices.

1.10.7 Mounting Rack Mounting rack is made up of metal and everything including processor, input/output

modules and power supply is mounted on it. It is normally used with modularized systems. It consist

of a printed board attached at the back and is used to attach all the devices to module. It consists of

the communication busses that connect different modules to gather and power rails that provide the

power to each module. Sometime cables are also used in addition to printed board. These mounting

racks can be mounted directly in a cabinet. Mounting racks are cascaded to interconnect several to

increase the number of input/output modules that can be accommodated.

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1.11 Programming Unit The programming unit is a hand held device that is used to download and edit the program with

the help of keypad and has a display unit to monitor the status of different coil and timers etc.

Recent advance systems employ the proprietary software that can be installed on a personal computer

and can be used to edit, debug and download the program into the PLC. Devices such as inter relays,

coil, registers that are not visible internally can be monitored through these software and help a

person in debugging a program or making a program more efficient by analyzing the values of

different registers, counters and timers. A typical programming unit is shown in figure. There is

special port on PLC that is used to connect these units to PLC.

1.12 Power Supply These units are used to supply power to PLC. As stated earlier some PLC contains their own

supply in the same case while other requires external power supplies. There are certain cases

when the internal supply of the PLC is not enough to provide the required current or voltage in

that case a separate external supply is necessary. A power supply should be chosen such that it is

capable of providing enough current required to fulfill the need of all the modules connected to

PLC.

1.13 Block Diagram of PLC Typically a PLC system has the basic functional components of processor unit, memory, power

supply unit, input/output interface section, communications interface, and the programming

device. Figure 2.5 shows the basic arrangement. The processor unit or central processing unit

(CPU) is the unit containing the microprocessor. This unit interprets the input signals and

carries out the control actions according to the program stored in its memory, communicating

the decisions as action signals to the output.

The power supply unit is needed to convert the mains AC voltage to the low DC voltage (5 V) necessary for the processor and the circuits in the input and output interface modules. The programming device is used to enter the required program into the memory of the processor. The program is developed in the device and then transferred to the memory unit of the PLC. The memory unit is where the program containing the control actions to be exercised by the microprocessor is stored and where the data is stored from the input for processing and for the output. The input and output sections are where the processor receives information from external

devices and communicates information to external devices. The inputs might thus be from

switches with the automatic drill, or other sensors such as photoelectric cells, temperature

sensors, flow sensors, or the like. The outputs might be to motor starter coils, solenoid valves, or

similar things. Input and output devices can be classified as giving signals that are discrete,

digital or analog (Figure 2.7). Devices giving discrete or digital signals are ones where the

signals are either off or on.Thus a switch is a device giving a discrete signal, either no voltage or

a voltage. Digital devices can be considered essentially as discrete devices that give a sequence

of on/off signals. Analog devices give signals of

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Which the size is proportional to the size of the variable being monitored. For example, a

temperature sensor may give a voltage proportional to the temperature.

Figure 1.5: Signals: (a) Discrete, (b) Digital, and (c) Analog

1.14 PLC Ladder Logic Programming

A very commonly used method of programming PLCs is based on the use of

ladder diagrams. Writing a program is then equivalent to drawing a switching circuit. The ladder

diagram consists of two vertical lines representing the power rails. Circuits are connected as

horizontal lines, that is, the rungs of the ladder, between these two verticals.

In drawing a ladder diagram, certain conventions are adopted:

1. The vertical lines of the diagram represent the power rails between which circuits are

connected. The power flow is taken to be from the left-hand vertical across a rung.

2. Each rung on the ladder defines one operation in the control process.

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3. A ladder diagram is read from left to right and from top to bottom. Figure 2.7 shows the

scanning motion employed by the PLC. The top rung is read from left to right. Then the

second rung down is read from left to right and so on. When the PLC is in its run mode, it

goes through the entire ladder program to the end, the end rung of the program being

clearly denoted, and then promptly resumes at the start. This procedure of going through

all the rungs of the program is termed a cycle. The end rung might be indicated by a

block with the word END or RET, for return, since the program promptly returns to its

beginning. The scan time depends on the number of runs in the program, taking about

1ms per 1000 bytes of program and so typically ranging from about 10ms up to 50ms.

4. Each rung must start with an input or inputs and must end with at least one output. The term

input is used for a control action, such as closing the contacts of a switch. The term output

is used for a device connected to the output of a PLC, such as a motor. As the program is

scanned, the outputs are not updated instantly, but the results stored in memory and all

the outputs are updated simultaneously at the end of the program scan.

5. Electrical devices are shown in their normal condition. Thus a switch that is normally

open until some object closes it is shown as open on the ladder diagram. A switch that is

normally closed is shown closed.

6. A particular device can appear in more than one rung of a ladder. For example, we might

have a relay that switches on one or more devices. The same letters and/or numbers are

used to label the device in each situation.

7. The inputs and outputs are all identified by their addresses; the notation used depends

8. On the PLC manufacturer. This is the address of the input or output in the memory of

the PLC.

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Figure 6 IEC 1131-3 symbles

1.15 An Example Program To illustrate the drawing of the rung of a ladder diagram, consider a situation where

energizing an output device, such as a motor, depends on a normally open start switch

being activated by being closed. The input is thus the switch and the output the motor.

Figure 2.9a shows the ladder diagram. Starting with the input, we have the normally open

symbol | | for the input contacts. There are no other input devices and the line terminates

with the output, denoted by the symbol ( ). When the switch is closed, that is, there is an

input; the output of the motor is activated. Only while there is an input to the contacts is

there an output. If there had been a normally closed switch |/| with the output (Figure

2.9b), there would have been an output until that switch was opened. Only while there

was no input to the contacts would there has been an o

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Chapter 2

2.1 Problem Statement Before 1892 the heavy and low load was carried from one place to another through men

labor. So, it was a difficult task to transfer heavy loads especially in industries. By

considering this point we choose such small industry project which carries some

manufactured products to their final destination using conveyor belts. In it transferring is

performed without any men labor. The whole system is automated controlled.

In our Project “Automation of Box Filling Machine Using PLC” There are different

Objects which join to each other and make a complete apparatus these are two conveyor

belt systems, two DC Series gear Motors to move conveyors, two Sensor circuits to

control the motion of motors, Actuator Circuit and The Brain of our project

Programmable Logic Controllers.

2.2 List of Main Components Conveyor Belt System

DC Series Motor

Sensor Circuit(Light Dependent Resistor and 12V DC Relays)

Actuator Circuit(24V DC Relays)

Programmable Logic Controller(PLCs)

2.2.1 Conveyor Belt System

What is Conveyor Belts?

A conveyor belt consists of two or more pulleys, with a continuous loop of material - the

conveyor belt - that rotates about them. One or both of the pulleys are powered, moving

the belt and the material on the belt forward. The powered pulley is called the drive

pulley while the unpowered pulley is called the idler. There are two main industrial

classes of belt conveyors:

a) Those in general material handling such as those moving boxes along inside a

factory and bulk material handling such as those used to transport industrial and

agricultural materials, such as grain, coal, ores, etc. generally in outdoor

locations. Generally companies providing general material handling type belt

conveyors do not provide the conveyors for bulk material handling.

b) In addition there are a number of commercial applications of belt conveyors such

as those in grocery stores.

Construction Material

The belt consists of one or more layers of material. They can be made out of rubber.

Many belts in general material handling have two layers. An under layer of material to

provide linear strength and shape called a carcass and an over layer called the cover. The

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carcass is often a cotton or plastic web or mesh. The cover is often various rubber or

plastic compounds specified by use of the belt. Covers can be made from more exotic

materials for unusual applications such as silicone for heat or gum rubber when traction is

essential.

A wide variety of related conveying machines are available, different as regards principle

of operation, means and direction of conveyance, including screw conveyors, vibrating

conveyors, pneumatic conveyors, the moving floor system, which uses reciprocating slats

to move cargo, and roller conveyor system, which uses a series of powered rollers to

convey boxes or pallets

History of Conveyor Belt System

In 1892, Thomas Robins developed a conveyor belt for carrying coal, ore and

other raw materials. Some years later, in 1901, the Swedish firm Sandvik started

with the production of conveyor belts made out of steel. In 1905, the British

mining engineer Richard Suttcliffe, designed the world’s first conveyor belt for

underground mining (to be used in coal mines). His invention revolutionized the

whole mining industry.

Figure 7 old conveyor belt

From 1907 on, conveyor belts were also used in Germany, more precisely in a

coffee company in Bremen. In 1913 famous Henry Ford became the first car

manufacturer using assembly lines with conveyor belts. In 1957, the B.F.

Goodrich Company filed a patent for the so-called Turnover Conveyor Belt

System. This system had an integrated half-twist that extended a belts lifetime

significantly, because it allowed the belt to wear and tear off on both sides.

A French society created in 1972 a straight conveyor belt with a length of 13.8

km, at the time it was the longest conveyor belt in the world. Today, the longest

conveyor belt has a length of 100 km and transports phosphate from the mines in

the Western Sahara to the coast. Nowadays such heavy belts for outdoor

transporting of bulk materials like stone, coal or boulder, are rugged rubber belt

with a steel cord traction member.

The light, fully synthetic fabric conveyor belt goes back to the 1960s, when the

industrial production of consumer goods started. These belts are mainly used for

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indoor transportation of unit loads – such as food, boxes, cans, and luggage and so

on. Constant effort on research and innovation – steady amelioration of materials

and production techniques – turned light conveyor belts gradually to versatile and

indispensable machine elements for uncountable applications in almost every

industry range.

Types of conveyor Belt System

1. Long belt conveyors

i. The longest belt conveyor system in the world is in Western Sahara. It is 98 km

(61 mi) long, from the phosphate mines of Bu Craa to the coast south of El-Aaiun.

ii. The longest conveyor system in an airport is the Dubai International

Airport baggage handling system at 63 km (39 mi). It was installed

by Siemens and commissioned in 2008, and has a combination of traditional belt

conveyors and tray conveyors.

iii. Paddington Bauxite Mine in Western Australian is officially recognized as having

the world's longest and second-longest single belts with a 31-kilometre-long

(19 mi) belt feeding a 20 km (12.5 miles) long belt.

iv. The longest single-belt international conveyor runs from Meghalaya in India to a

cement factory at Chhatak Bangladesh. It is about 17 km long and

conveys limestone and shale at 960 tons/hour, from the quarry in India to the

cement factory (7 km long in India and 10 km long in Bangladesh). The conveyor

was engineered by AUMUND France and Larsen & Toubro. The conveyor is

actuated by three synchronized drive units for a total power of about 1.8 MW

supplied by ABB (two drives at the head end in Bangladesh and one drive at the

tail end in India). The conveyor belt was manufactured in 300-meter lengths on

the Indian side and 500-meter lengths on the Bangladesh side, and was installed

on-site by NILOS India. The idlers, or rollers, of the system are unique in that

they are designed to accommodate both horizontal and vertical curves along the

terrain. Dedicated vehicles were designed for the maintenance of the conveyor,

which is always at a minimum height of 5 meters (16 ft) above the ground to

avoid being flooded during monsoon periods.

Belt conveyor safety system

Conveyors used in industrial settings include tripping mechanisms such as

trip cords along the length of the conveyor. This allows for workers to immediately shut

down the conveyor when a problem arises. Warning alarms are included to notify

employees that a conveyor is about to turn on. In the United States, the Occupational

Safety and Health Administration has issued regulations for conveyor safety and some

are below:

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Food Grade Conveyor Belts

Agriculture Belts

General Purpose Conveyor Belts

Health and Fitness Belts

Packages and Baggage Handling

Recycling Belts

Underground Mining Belts

Wood Product Conveying Belts

2.2.2 DC Series Motor A DC series motor converts electrical energy to mechanical energy. Its principle of

operation is based on a simple electromagnetic law that states that when a magnetic field

is created around current carrying conductor and interacts with an external field,

DC Series Motor Fig 2.2

The key components of a DC series motor are the armature (rotor), stator, commutator,

field windings, axle, and brushes.

The stationary part of the motor, the stator is made up of two or more electromagnet pole

pieces, and the rotor is comprised of the armature, with windings on the core connected

to the commutator. The output power source is connected to the armature windings

through a brush arrangement connected to the commutator. The rotor has a central axle

about which the rotor rotates.

The field winding should be able to support high current because the greater the amount

of current through the winding, the greater will be the torque generated by the motor. So

the winding of the motor is made up of thick heavy gauge wire. Heavy gauge wire does

not allow a large number of turns. The winding is made up of thick copper bars as it helps

in easy and efficient dissipation of heat generated as a result of flow of large amount of

current through winding.

Principle of Operation

An external voltage source is applied across the series configuration of field winding and

armature. So one end of the voltage source is connected to the winding and the other end

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is connected to the armature through the brushes. Initially at the motor start up, with the

voltage source connected to the motor, it draws a huge amount of current because both

the winding and the armature of the motor, both made up of large conductors, offer

minimum resistance to the current path. The large current through the winding yields a

strong magnetic field.

This strong magnetic field provides high torque to the armature shaft, thus invoking the

spinning action of the armature. Thus the motor starts rotating at its maximum speed in

the beginning. The rotating armature in the presence of the magnetic field results in

counter EMF, which limits the current build up in the series combination of armature and

winding.

Thus series motors once started will offer maximum speed and torque but gradually, with

an increase in speed, its torque will come down because of its reduced current. Practically

this is what required from the motors. Due to the high torque provided by the armature,

the load on the shaft is set to rotate initially. Subsequently lesser torque will keep the load

on the move. This further helps in increasing the heat dissipation of the motor. However,

the amount of torque generated by motor is directly proportional to the winding current.

The higher current demands a higher power supply, too

Motor Speed

In DC series motors, a linear relationship exists between the amount of torque produced

and the current flowing through the field windings. The speed of the motor can be

controlled by varying the voltage across the motor, which further controls the torque of

motor.

To increase the speed of the motor, decrease the field current by placing a small

resistance in parallel to the winding and armature. The decrease in current will result in

lowering of magnetic flux and counter EMF, which further hastens the motor’s speed.

To decrease the speed, use an external series resistance along with the field winding and

armature. This will reduce the voltage across the armature with the same counter EMF,

thus resulting in a lower speed of motor.

Unlike DC shunt motors, series motor does not operate at the constant speed. The speed

of the motor varies with change in the shaft load, so speed control of the motor is not

easy to put into practice.

Applications, Advantages and Precautions

Series motors can produce large turning effect, or torque, from a stand still.

These motors have found application in small electrical appliances where high

torque is necessary at start up.

DC series motors are used mainly for industrial applications, e.g. elevator and

pulley and winches systems for carrying heavy loads.

Heavy and magnificent cranes drawing thousands of amperes are driven by this

motor.

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An automobile engine can be started by this motor which draws around 500A of

current.

However, these motors are not suitable where constant speed is required as the

speed of series motors is dependent (varies with load) on load unlike DC shunt

motors whose speed is independent of load.

The construction, designing, and maintenance of these motors is very easy.

Series motors are cost effective as well.

A final advantage of series motors is that they can be used by providing either an

Alternating Current (AC) or Direct Current (DC) power source.

Precautions

Proper care should be taken that a series motor is not operated without any load as

they are totally dependent on shaft loads.

As the armature speed increases, the current through the winding decreases which

further helps in reducing the counter EMF. This reduction fastens the speed of the

armature. As this process continues, the motor speed increases beyond the limit

thus causing devastation to the motor.

Figure 8 dc series motor

What is A GEARBOX?

A gearbox uses mechanical advantage to increase output torque and reduce RPM.

The motor's shaft is feed into the gearbox and through a series of internal gearing

provides the torque and speed conversion. Our gearboxes are available in a variety of

sizes and gear ratios to meet a wide range of torque requirements. The basic design is a

spur gearbox with gear wheels in metal, plastic and combinations of the two materials. A

particular feature is the availability of freewheels and slipping clutches. The gearboxes

are turned by the motor, energy flow is from input to output shaft.

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Figure 9 Motor Gear System

That means, they are not allowed to be driven by the output shaft (for instance turning

manually)

This can lead to damage of some internal components.

Direction of rotation

As a function of the number of stages, the direction of rotation can be either clockwise or

counte clockwise. The direction of rotation of motor gearbox units is generally specified

by the gearbox output shaft.

Figure 10 rotation of motor

Ratio

A gearbox is characterized by its gear ratio i or its time T. Gear ratio i is the ratio of input

speed ne and output speed na. T is the time for one revolution of the output shaft

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Permissible Torque

The lifetime of a gearbox is determined by the load on the gear teeth and the number of

revolutions of the gear wheels. The maximum permissible torque Mn is defined by the

load on the final stage of the gearbox and the stability of the housing. Some gearboxes

have lifetime graphs. It shows the relationship between ratios i and the associated torque

for a fixed period of time, e.g. 1000 or 10000 hours. A conditional parameter is the input

speed (equivalent to motor speed) corresponding to the total number of revolutions of all

gear wheels. In the catalogue we show therefore two curves - for a motor having 250/300

rpm and 500/600 rpm.

For example: Maximum output torque Mx1 is permissible at a ratio of ix1.With smaller

ratios the max. Permissible torque has to be reduced, because otherwise the first stages of

the gearbox would be overloaded.

Example1: The application of motor 1 combined with a gearbox of ratio ix1 leads to an

output torque Mx1 at point A.

The gearbox can transmit this torque, meeting its lifetime.

Fig 2.6

If a ratio of i >ix1 is selected, actual torque would be M > Mx1. However lifetime cannot

be guaranteed, as the operating point now lies above of the lifetime curve.

Efficiency

The number of stages in the gearbox determines the efficiency. With high ratios of i this

factor will decrease below 10%, as the graph below show:

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Figure 11 Efficiency graph

Fig 2.7

Condition for Maximum Mechanical Power

The back emf is equal to half of the applied voltage for maximum gross mechanical

power. It is impossible to achieve this condition practically. Since half of the power input

is wasted as heat in the armature, efficiency will be less than 50 per cent taking account

of other mechanical losses also.

Back EMF

During rotation of the armature, its conductors cut the magnetic flux and emf is induced

in the conductors according to the laws of electromagnetic induction. The direction of

this induced emf can be found by Fleming's right-hand rule and have the direction

opposite to the applied voltage. Therefore, this induced emf is called back emf (Eb)

Rotational Losses of Dc Machines

DC motors have the following rotational losses:

i. Loss due to friction of bearings

ii. The winding loss due to consumption of power by the circulation of air or other

cooling gas in the machine and

iii. Losses in the magnetic core of the machine known as core losses or iron losses.

iv. Core losses are divided into hysteresis loss and eddy current loss.

Let Pr be the rotational loss, Pb be bearing friction loss, Pw be windage loss, Ph be

hysteresis loss, Pe be eddy current loss and Pi be iron or core loss = Ph + Pe.

Let Ta be average torque or internal torque at which the conversion of electromechanical

power takes place, Tsh be useful torque or shaft torque developed at the shaft of an

electric motor and TP be prime mover torque applied at the shaft of a generator.

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Figure 12 DC Series Motor

Chapter #3

3.1 Implementation of Project 1. Block Diagram

2. Electric Circuitry

3. Fabrication of Hardware

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Figure 13 Block Diagram

3.1.1 Implementation of Electric circuitry To drive the complete mechanism of line packaging control system and to interface with

Programmable Logic Controller (PLC) we use the electric circuitry to meet fulfill the required

conditions. Some explanation of devices used in circuit is given below one by one:

Electric Circuits Used For the Project

1) Input Sensor circuit

2) Output Actuator circuit

Basic components of sensor circuit

a) LM-741 (OP-amp)

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b) 24V DC relay

c) LDR (Light dependent resistor)

d) Resistor having various values

e) Diode

f) Transistor(c945)

g) Voltage regulator (7812)

Details and working procedure of Electrical components

3.1.1.1 Operational Amplifier (LM 741)

An operational amplifier (op-amp) is a DC-coupled high-gain electronic

voltage amplifier with a differential input and, usually, a single-ended output.

Figure 14 LM 741 IC

FEATURES Overload Protection on the Input and Output

No Latch-Up When the Common Mode Range is exceeded

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Figure 16 Schematic Diagram LM 741

Connection Diagrams

Figure 15 Connection Diagram of LM 741

SCHEMATIC DIAGRAM

3.1.1.2 Relay

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We are using two types of DC relays

24 V DC Relay for Actuator Circuit

12 V DC Relay for Sensor Circuit

Definition An electrical device, typically incorporating an electromagnet, which is activated by a

current or signal in one circuit to open or close another circuit.

Figure 17 12V DC Relay

Connection Diagram

Figure 18 Connection Diagram of Relay

What is a relay?

We know that most of the high end industrial application devices have relays for their

effective working. Relays are simple switches which are operated both electrically and

mechanically. Relays consist of a n electromagnet and also a set of contacts. The

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switching mechanism is carried out with the help of the electromagnet. There are also

other operating principles for its working. But they differ according to their applications.

Most of the devices have the application of relays.

Why is a relay used?

The main operation of a relay comes in places where only a low-power signal can be used

to control a circuit. It is also used in places where only one signal can be used to control a

lot of circuits. The application of relays started during the invention of telephones. They

played an important role in switching calls in telephone exchanges. They were also used

in long distance telegraphy. They were used to switch the signal coming from one source

to another destination. After the invention of computers they were also used to perform

Boolean and other logical operations. The high end applications of relays require high

power to be driven by electric motors and so on. Such relays are called contactors.

Main Types of DC Relays

NPN Relay Switch Circuit A typical relay switch circuit has the coil driven by a NPN transistor switch, TR1 as

shown depending on the input voltage level. When the Base voltage of the transistor is

zero (or negative), the transistor is cut-off and acts as an open switch. In this condition no

Collector current flows and the relay coil is de-energized because being current devices,

if no current flows into the Base, then no current will flow through the relay coil.

If a large enough positive current is now driven into the Base to saturate the NPN

transistor, the current flowing from Base to Emitter (B to E) controls the larger relay coil

current flowing through the transistor from the Collector to Emitter.

For most bipolar switching transistors, the amount of relay coil current flowing into the

Collector would be somewhere between 50 to 800 times that of the required Base current

to drive the transistor into saturation. The current gain, or beta value ( β ) of the general

purpose BC109 shown is typically about 290 at 2mA (Datasheet).

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NPN Relay Switch Circuit

Figure 3.6

Note that the relay coil is not only an electromagnet but it is also an inductor.

When power is applied to the coil due to the switching action of the transistor, a

maximum current will flow as a result of the DC resistance of the coil as defined

by Ohms Law, (I = V/R). Some of this electrical energy is stored within the relay

coil’s magnetic field.

When the transistor switches “OFF”, the current flowing through the relay coil decreases

and the magnetic field collapses. However the stored energy within the magnetic field has

to go some where and a reverse voltage is developed across the coil as it tries to maintain

the current in the relay coil. This action produces a high voltage spike across the relays

coil that can damage the switching NPN transistor if allowed to build up.

So in order to prevent damage to the semiconductor transistor, a “flywheel diode”, also

known as a freewheeling diode, is connected across the relay coil. This flywheel diode

clamps the reverse voltage across the coil to about 0.7V dissipating the stored energy and

protecting the switching transistor. Flywheel diodes are only applicable when the supply

is a polarized DC voltage. An AC coil requires a different protection method, and for this

an RC snubber circuit is used.

Features Very small size with light weight. Various coil sensitivity types are available.

Plastic sealed type is available for washing protective.

Wide operation coil voltage range.

Specifications

Max. 100mΩ at initial value.

Contact Resistance Test Current: 1A, Open Circuit Test Voltage: 6VDC.

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By using Voltage Drop Method.

Contact Capacity 2 Amps at 120VAC Cosφ=1.

2 Amps at 24VDC L/R=0.

Operate Time 5m Sec. Max.

Release Time 3m Sec. Max.

COIL SPECIFICATION AT 20 Table 1 Coil Specification of Relay

Nominal Nominal Coil Power Pull-In Drop-Out

Max.

Coil Allowable

Voltage Current Resistance Consumption Voltage Voltage

Sensitivity Voltage

(VDC) (mA) (Ω±10%) (W) (VDC) (VDC)

(VDC)

3 120 25

5 71.4 70

ST-D

6 60 100 Abt. 0.36

75% 5% 130%

9 40 225 Max. Min.

12 30 400

24 15 1,600

3 66.7 45

5 40 125

ST-T

6 33.3 180 Abt. 0.20

75% 5% 130%

9 22.5 400 Max. Min.

12 16.7 720

24 8.3 2,880

3 50.0 60

5 29.9 167 80% 5%

ST-L 6 25.0 240 Abt. 0.15 130%

Max. Max.

9 16.7 540

12 12.5 960

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3.1.1.3 Transistor C945

A C945 transistor is a type of negative-positive-negative (NPN) bipolar junction transistor.

Typically, circuits where a low-current, high-speed transistor is required will employ a

transistor such as the C945 transistor. Circuits such as a small-signal amplifier or a high-

speed switching circuit might employ one or more C945 transistors. A C945 transistor can be

used in several types of electronic circuits, but it is best suited for use in low-power

applications.

Figure 19 C945

Bipolar junction transistors contain three semiconductor regions: the collector, the base and

the emitter. An NPN bipolar junction transistor — such as the C945 — contains a base

region that is doped with positive, or P-type, semiconductor material, along with collector and

emitter regions that are doped with negative, or N-type, semiconductor material. This

configuration allows the C945 transistor to conduct electric current between the collector and

emitter regions when voltage is applied to the transistor’s base region.

Configuration of pins

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Table 3.2

Table 2 Electrical Characteristics of Transistor

Figure 20 Collector Current vs Vce

Figure 3.8

Total Power Dissipation vs Ambient Temperature Collector Current vs

Collector to Emitter Voltage

3.1.1.4 LDR (Light dependent resistor)

A photo resistor or light dependent resistor or Cadmium Sulfide (CdS) is a resistor whose

value resistance decreases with increasing incident light intensity. It can also referred to a

Photoconductor.

A photo resistor is made of a light resistance semiconductor. If light falling on the device

is of high enough frequency. Photons absorbed by the semiconductor give bound

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electrons enough energy to jump into the conduction band. The resulting free electron

and it hole partner conduct electricity thereby lowering resistance.

Applications

Auto flash for cameras

Industrial control

Photoelectric control

Photo switch

Room light control

Photo lamp

Photo musical I.C.

Electronic toys

Circuit Diagram

Electrical characteristics TA = 25°C. 2854°K tungsten light source

Table 3 Electrical Characteristics of LDR

Parameter Conditions Min. Typ. Max. Units

Cell resistance 1000 lux - 400 - Ω

10 lux - 9 - kΩ

Dark resistance - 1.0 - - MΩ

Dark capacitance - - 3.5 - pF

Rise time 1 1000 lux - 2.8 - Ms

10 lux - 18 - Ms

Fall time 2 1000 lux - 48 - Ms

10 lux - 120 - Ms

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Figure 3.9 Figure 21 Dimension of LDR

Features Wide spectral response Low cost Wide ambient temperature range.

Dimensions

Light memory characteristics Light dependent resistors have a particular property in that they remember the lighting conditions in which they have been stored. This memory effect can be minimised by storing the LDRs in light prior to use. Light storage reduces equilibrium time to reach steady resistance values.

Spectral Reponse

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3.1.1.5 Voltage Regulator (7812)

We are using a 7812 voltage regulator which converts input 24V to output 12V. We are

using 12v DC relay to operate our sensor circuit.

Figure 22 Voltage Regulator 7812

Advantages

78xx series ICs do not require additional components to provide a constant,

regulated source of power, making them easy to use, as well as economical and

efficient uses of space. Other voltage regulators may require additional

components to set the output voltage level, or to assist in the regulation process.

Some other designs (such as a switched-mode power supply) may need

substantial engineering expertise to implement.

78xx series ICs have built-in protection against a circuit drawing too much power.

They have protection against overheating and short-circuits, making them quite

robust in most applications. In some cases, the current-limiting features of the

78xx devices can provide protection not only for the 78xx itself, but also for other

parts of the circuit.

Disadvantages

The input voltage must always be higher than the output voltage by some

minimum amount (typically 2.5 volts). This can make these devices unsuitable for

powering some devices from certain types of power sources (for example,

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powering a circuit that requires 5 volts using 6-volt batteries will not work using a

7805).

As they are based on a linear regulator design, the input current required is always

the same as the output current. As the input voltage must always be higher than

the output voltage, this means that the total power (voltage multiplied by current)

going into the 78xx will be more than the output power provided. The extra input

power is dissipated as heat. This means both that for some applications an

adequate heat sink must be provided, and also that a (often substantial) portion of

the input power is wasted during the process, rendering them less efficient than

some other types of power supplies. When the input voltage is significantly higher

than the regulated output voltage (for example, powering a 7805 using a 24 volt

power source), this inefficiency can be a significant issue

Individual devices in the series TS7805 linear voltage regulator in a TO-220 variant package with electrically isolated

tab.

There are common configurations for 78xx ICs, including 7805 (5 volt), 7806 (6 volt),

7808 (8 volt), 7809 (9 volt), 7810 (10 volt), 7812 (12 volt), 7815 (15 volt), 7818

(18 volt), and 7824 (24 volt) versions. The 7805 is common, as its regulated 5 volt supply

provides a convenient power source for most TTL components. Each device in this series

has minimum input voltage to be maintained to get regulated output.

Less

comm

on are

lower

-

power

versions such as the LM78Mxx series (500 mA) and LM78Lxx series (100 mA) from

Part Number Output Voltage (V) Minimum Input Voltage (V)

7805 +5 7.3

7806 +6 8.3

7808 +8 10.5

7810 +10 12.5

7812 +12 14.6

7815 +15 17.7

7818 +18 21.0

7824 +24 27.1

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National Semiconductor. Some devices provide slightly different voltages than usual,

such as the LM78L62 (6.2 volts) and LM78L82 (8.2 volts) as well as STMicroelectronics

L78L33ACZ (3.3 volts)

Features

Output Current up to 1A

Output Voltages of 5, 6, 8, 9, 10, 12, 15, 18, 24

Thermal Overload Protection

Short Circuit Protection

Output Transistor Safe Operating Area Protection

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Project hardware

Figure 23 Assembly of conveyors

Figure 24 Assembly 2

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Figure 25 Omron PLC

Figure 26 Interfacing Circuit

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Chapter 4

Simulation Results

Ladder Logic programming

Figure 27 Ladder logic code

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Explanation

In above ladder logic:

Inputs:

1. Box detector sensor

2. Counter input

3. Emergency switch

Outputs:

1. Stop the box conveyor

2. Stop the product conveyor

3. Counter output

Other instructions:

1. Timer

2. Counter

3. Interlock

Name of

instruction

Input/output Status Address of I/O

Box detector

sensor Input N/C 0.02

Counter input Input N/O 0.03 Emergency switch Input N/O 0.04 Stop the box

conveyor Output N/C 1.00

stop the product

conveyor Output N/O 1.01

Counter output Output N/O 1.02 Timer Input/output N/O T0001 Counter Input/output N/O C0000

Table 4 Instructions used in code

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Simulation Results:

In normal operation status box detection sensor (0.02) is ON (normally close N/C). And

stop the box conveyor (1.00) is in OFF status (N/C). When 0.02 turns ON the 1.00 also

turns ON and PLC sends a signal and turns OFF the box conveyor motor. At same while

0.02 turns ON the product conveyor (1.01). The sensor on the edge of product conveyor

acts as counter input (0.03) and sends signal to PLC and counts the products falling from

product conveyor. When counter reaches its preset value then it stops the product

conveyor (1.01) again and same time it starts the box conveyor (1.00) and same process

occurs when next box reaches in front of box detection sensor. The emergency switch

(0.04) is actually interlocking instruction. So when 0.04(N/C) is at logic 1 all ladder logic

stops and retain its condition. When 0.04 is at logic on then all ladder logic is operated

normally. Timer (T1) is for security gap.

Basic commands used in PLC ladder logic

AND

AND is used for a normally open bit connected in series. AND cannot be directly connected to the bus

bar, and cannot be used at the beginning of a logic block. If there is no immediate refreshing

specification, the specified bit in I/O memory is read. If there is an immediate refreshing specification,

the status of the Basic Input Unit's input terminal is read.

AND NOT

AND NOT is used for a normally closed bit connected in series. AND NOT cannot be directly

connected to the bus bar, and cannot be used at the beginning of a logic block. If there is no immediate

refreshing specification, the specified bit in I/O memory is read. If there is an immediate refreshing

specification, the status the Basic Input Unit's input terminals is read.

Instruction mnemonic function

AND AND Takes a logical AND of

status of the specified

operand bit and the current

execution condition.

AND NOT AND NOT Reverses the status of the

specified operand bit and

takes a logical AND with

the current execution

condition

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OR/OR NOT

OR

OR is used for a normally open bit connected in parallel. A normally open bit is configured to form a

logical OR with a logic block beginning with a LOAD or LOAD NOT instruction (connected to the

bus bar or at the beginning of the logic block). If there is no immediate refreshing specification, the

specified bit in I/O memory is read. If there is an immediate refreshing specification, the status of the

Basic Input Unit's input terminal is read.

l OR NOT

OR NOT is used for a normally closed bit connected in parallel. A normally closed bit is configured to

form a logical OR with a logic block beginning with a LOAD or LOAD NOT instruction (connected

to the bus bar or at the beginning of the logic block). If there is no immediate refreshing specification,

the specified bit in I/O memory is read. If there is an immediate refreshing specification, the status of

the Basic Input Unit's input terminal is read.

Instruction Mnemonic Function

OR OR Takes a logical OR of

ON/OFF status of specified

operand and the current

execution condition.

OR NOT OR NOT Reverses the status of the

specified bit and takes a

logical OR with the current

execution condition.

Table 4.3(OR/OR NOT)

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TIM/TIMX

Instruction Mnemonic Function code Function

Hundred-MS Timer TIM/TIMX 550 TIM or

TIMX(550)

operates a

decrementing timer

with units of 0.1-s. Table 5 Timer

Function

When the timer input is OFF, the timer specified by N is reset, i.e., the timer's PV is reset

to the SV and its Completion Flag is turned OFF.

• When the timer input goes from OFF to ON, TIM/TIMX (550) starts decrementing the

PV. The PV will continue timing down as long as the timer input remains ON and the

timer's Completion Flag will be turned ON when the PV reaches 0.

• The status of the timer's PV and Completion Flag will be maintained after the timer

times out. To restart the timer, the timer input must be turned OFF and then ON again or

the timer's PV must be changed to a non-zero value (by MOV (021), for example).

• The setting range for the set value (SV) is 0 to 999.9 s for TIM and 0 to 6,553.5 s for

TIMX (550).

• The timer accuracy is -0.01 to 0 s.

Note The timer accuracy for CS1D CPU Units is 10 ms + the cycle time. The timer

accuracy for unit version 4.1 of the CJ1-H-R is -0.1 to 0 s.

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CNT/CNTX

Instruction Mnemonic Function code function

COUNTER CNT/CNTX 546 CNT/CNTX(546)

operates a

decrementing

counter Table 6 Counter

Table 4.5(Counter)

Counter:

N: Counter Number

The counter number must be between 0000 and 4095 (decimal).

S: Set Value

BCD: #0000 to #9999

Binary: &0 to &65535 (decimal) or #0000 to #FFFF (hex

Function

• The counter PV is decremented by 1 every time that the count input goes from OFF to ON. The

Completion Flag is turned ON when the PV reaches 0.

• Once the Completion Flag is turned ON, reset the counter by turning the reset input ON or by using

the CNR (545)/CNRX (547) instruction. Otherwise, the counter cannot be restarted.

• The counter is reset and the count input is ignored when the reset input is ON. (When a counter is

reset, its PV is reset to the SV and the Completion Flag is turned OFF.)

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OUT/OUT NOT

Instruction Mnemonic Function code Function

OUTPUT OUT ---- Output the

result(execution

condition) of the

logical processing

and output it to the

specified bit

OUTPUT NOT OUT NOT ---- Reverses the result

(execution condition)

of the logical

processing, and

outputs it to the

specified bit.

Table 4.6(OUT/OUT NOT)

OUT

If there is no immediate refreshing specification, the status of the execution condition (power flow) is

written to the specified bit in I/O memory. If there is an immediate refreshing specification, the status

of the execution condition (power flow) is also written to the Basic Output Unit's output terminal in

addition to the output bit in I/O memory.

OUT NOT

If there is no immediate refreshing specification, the status of the execution condition (power flow) is

reversed and written to a specified bit in I/O memory. If there is an immediate refreshing specification,

the status of the execution condition (power flow) is reversed and also written to the Basic Output

Unit's output terminal in addition to the output bit in I/O memory.Table 4.7(SET/RESET)

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IL/ILC

Instruction Mnemonic Function code Function

INTERLOCK IL 002 Interlocks all

outputs between

IL(002) and

ILC(003) when the

execution condition

for IL(002) is OFF.

INTERLOCK

CLEAR

ILC 003 Indicates the end of

the interlock range. Table 7 Interlock instruction

Function

When the execution condition for IL (002) is OFF, the outputs for all instructions

between IL (002) and ILC (003) are interlocked. When the execution condition for IL

(002) is ON, the instructions between IL (002) and ILC (003) are executed normally.

Instruction Mnemonic Function

SET SET SET turns the operand bit

ON when the execution

condition is ON. After this,

the specified contact will

remain ON regardless of

ON/OFF of the input

condition.

RESET RSET RSET turns the operand bit

OFF when the

execution condition is ON.

After this, the specified

contact will remain OFF

regardless of ON/OFF of

the input condition.

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Conclusion We started the project with the objectives mentioned in the project statement and

achieved all of them. We have implemented the interfacing of DC Series Motors with

Programmable Logic Controller. After doing work on this project and having hand

experience of PLC, we have become a good familiar with the use of PLC.

It is concluded that PLC is a simple and useful machine in the industry because of its

easy languages.

In industries many types of processes are being controlled through PLCs, DCS and

SCADA systems. Packaging processes, bottle filling, packets filling etc. are some

examples which are controlled by PLCs.

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Recommendations After all experience and interaction with PLC we recommend some steps for the future

team who wants to proceed in this field

1. Soft start and soft stop concepts of motor should be used for vanishing inertia if

load (boxes or products) are heavy.

2. HMI and SCADA system can be used for monitoring of all processes at distance.

3. An extra sensor at the product conveyor that prevent the product conveyor from

moving without load i.e. when products shortage occurs after some seconds

product conveyor should stop automatically for prevention of energy loss.

4. Pressure sensor or weight sensor may also be used for box so we can also detect

products on the basis of pressure/weight.

5. Manual placement of objects may be replaced with robotic arm for automatic

boxes and products placement.

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APPENDIX

PLC: Programmable Logic Controller

SCADA: Supervisory Control and Data Acquisition

IL: Inter lock

ILC: Inter lock Clear

TIM: Timer

CNT: Counter

IC: Integrated Chip

N/O: Normally Open

N/C: Normally Close

DCS: Distributed Control System

HMI: Human Machine Interface

BMS: Batch Management System

MES: Manufacturing Execution System

LIMS: Laboratory Information Management System

EMF: Electromagnetic Force

Op-Am: Operational Amplifier

LDR: Light Dependent Resistance

LED: Light Emitting Diode

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References

[1]Image Courtesy, Awn Muhammad

[2]DC Series Motors, http://zone.ni.com/devzone/cda/ph/p/id/53

[3]Series Motors, http://www.tpub.com/content/neets/14177/css/14177_58.htm

[4]Bright Hub: Understanding Shunt-Wound DC Motors

[5]Series DC Motor, http://www.lmphotonics.com/DCSpeed/series_dc.htm

[6]Bright Hub: Build a DC Motor Speed Controller Circuit

[7]LM78XX Series Voltage Regulator:www.DatasheetCatalog.com

[8]C945 Transistor(NPN):http://www.HZ-DZ.NET

[9] C945 Transistor(NPN):http://www.weitron.com.tw

[10] http://www.ece.com.tw/product-list.php?uID=6&cID=11 (relay)

[11]http://www.oxforddictionaries.com/definition/english/relay

[12]http://electronics.howstuffworks.com/relay.htm (working of relay)

[13]http://www.ti.com/lit/ds/symlink/lm741.pdf (LM-741 OP-AMP)