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Page 1: Automatic Bottle Filling and Capping Control System

Automatic Bottle Filling and Capping Control System

CHAPTER ONE

BACKGROUND OF PROJECT

1.1 Introduction

Control engineering has evolved overtime. In the past, humans were the main method for controlling a system.

More recently, electricity has been used for control and early electrical control was based on

relays. These relays allow power to be switched on and off without a mechanical switch. It is

common to use relay to make simple logical control decisions. The development of low

cost computer has brought the most recent revolution, the Programmable Logic Controller (PLC).

The advent of the PLC began in the 1970s, and has become the most common choice for manufacturing

controls.

PLC has been gaining popularity on the factory floor and will probably remain predominant

for some time to come. Most of this because of the advantages:-

Cost effective for controlling complex systems

Flexible and can be reapplied to control other systems quickly and easily

Computational abilities allow more sophisticated contro

Trouble shooting aids make programming easier and reduce downtime.

Reliable components make these likely to operate for years before failure.

Control systems are an integral part of modern society. It consists of subsystems and processes assembled for the

purpose of controlling the outputs of the processes. There are many numerous applications that using control system

around us. A control system provides an output or response for a given input or stimulus. The reason that control

system was built is for power amplification, remote control, convenience of input form; and compensation for

disturbances. Today control systems find widespread application in the guidance, navigation, and control of missiles

and spacecraft’s, as well as planes and ship at sea. The applications also throughout the process control industry,

regulating liquid level tanks, chemical concentrations in vats, as well as thickness of fabricated material.

1.1.1 Open loop systemIt starts with sub system called an input transducer, which converts for the input to that used by the

controller. Then input sometimes called reference, while the output can be called the control

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variable. Other signals, such as disturbances are shown added the controller & process outputs via

summing junctions, which yields the algebraic sum of their input signals using associated sign.

The distinction characteristics of an open loop system is that it cannot compensate for any

disturbances that added to the controller’s driving signals. The output of an open loop system

computed not only by the signals that add to the controller’s commands but also the disturbances

at the output. The system cannot correct for these disturbances & are simply commanded by the

input.

1.1.2 Closed loop systemThe disadvantage of open loop system, namely sensitivity to disturbances an inability to correct

these disturbances, may be over ten in closed loop systems. The input transducer converts the form

of the input to the form used by the controller. An output to the transducer, or sensor, measures the

output response & converts it in to the form used by the controller.

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The first summing junction algebraically adds the signal from the input to the signal from the

output which arrives via the feedback path, the returned path from the output to the summing

junction. In the figure above, output signal is subtracted from the input signal. The result is

generally called the actuating signal.

The closed loop system compensated for disturbances by measuring the output response, feeding

the measurement back through a feedback path, & comparing that response to the input at the

summing junction. If there is any difference between the two responses, the system drives the

plant, via the actuating signal to make correction. If there is no difference the system does not

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drive the plant since the plants response is already the desired response. To compared between

open loop system & closed loop system; closed loop system has the obvious advantage of greater

accuracy than open loop system.

The system are less sensitive to noise, disterbance,in the change in enviroment. Transient response

in steady state eror can be controlled more convinently & with greater flexibility in closed loop

system,often by simply adjutments of gain in the loop & sometimes by redesigning the controller.

in summery, systems that perform the priviously described measurement & correction are called

cosed loop or feedback control system.

1.2 Problem statement

Control system implies direct interaction with physical world. Control system includes sensor and

actuators, the critical pieces needed to ensure that our actuators system can help us manages our

activities and environments in desired ways. The sensor that will be implemented in this project is

infrared sensor. Nowadays, infrared sensor is widely used in daily activities such as for security,

memory detection and other proposes. Infrared sensor consists of two basic part; emitter and

detector. In this project, infrared sensor that is used to detect motion which is the bottle movement

on the conveyor belt. When the infrared sensor detected position bottle, the motor of conveyor will

be stop automatically.

Problem statements in this project are:

To design a closed loop system which can control conveyor by griper sensor?

To make sure that the bottle does not overflow and conveyor must stop as long as sensor is

working.

To design conveyor system which limit the liquid flow into the bottles?

1.3 project objective

The main objective of this project is to apply plc to design automatic bottle filling and capping

control system. The fascination and wide application of plc has motivated to discover more about

plc. The main objective of this project is:

To develop a griper sensor to detect position of bottle.

To build a prototype which are light, low cost, user friendly and with transparent structure?

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1.4 Implementation of project

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Fig 1.5 project flow chart

Last but not least,this thesis will show the final product that has been in chapter six. In this chapter

we will mainly discuss the result analysis, discussions of the result are focussing on the

programming of plc.

Finally this thesis writing will conclude in chapter seven.this chapter high light the important part

of this design and development project during constracting and testing process.

1.5 thesis outline

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In this section, seven chapters will briefly discused.in chapter one the introdussing of

automatically filling bottle system using plc will mainly discuss about the project objective and

scope in order to achieve the desired goal.

After that, chapter two ; litrature review will coverd all explanation about the main type of plc

available and type of plc has been choosen for this project with the reason of selection. Besides,

this chapter wll review other related and background project that have been develop in other

countries for the same purpose.

Chapter three,methadology will decribe about the over all project that has been testified and

successfully operate. Come along with this chapter an explanation about material selection which

is including controller, moto and sensor. In order to design a good project, the descission making

for each electronic programming are briefly discuss in this chapter.

Chaptr four, electrical design, will discuss about electrical compenents used, and the instalations

of electrical compenents on the system.this chapter also discuss the concepts of how the input and

outputs of plc shuold be understood.

After that, programming devlopment will be discussed in chapter five. A systematic aproach of

control system design using plc presented. The machine sequence of operation will be discussed

next. The assignments of input and output are shown in tables.

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CHAPTER TWO

LITRATURE REVIEW

2.1 History of PLC

PLC were first introduced in 1960’s. the primary reason for such adevice was eliminating the large

cost involved in replacing the complicated relation based machine control system.Bedford

associates proposed something called amodular digital controller(MODICON) to major US car

manufacture. Other companies at the time proposed computer based schemes.one of which of

based up on PDP-S. the MODICON OS4 brought the word’s first PLC in to commertial

production.

When aproduction requirements changed so did the control sytem. This becomes very expenssive

when the change is frequent, scincerelays are mechanical device that also have alimited life time

which required strict adhesion to maintenance schedule. Troubleshooting was also quite tedious

when so many relays are involved.

These “new controllers” also had to be easly programmed by maintenance are plant engineers.the

life time had to be long and programming changes easly performance. They also had to servive the

harsh industrial enviroment.

2.2 What is a PLC? A Programmable Logic Controller, PLC is a digital computer used for automation of industrial

processes, such as control of machinery on factory assembly lines. Unlike general-purpose

computers, the PLC is designed for multiple inputs and output arrangements, extended

temperature ranges, immunity to electrical noise, and resistance to vibration and impact. Programs

to control machine operation are typically stored in battery-backed or non-volatile memory. A

PLC is an example of a real time system since output results must be produced in response to input

conditions within a bounded time, otherwise unintended operation will result.

A PLC (i.e. Programmable Logic Controller) is a device that was invented to replace the

necessary sequential relay circuits for machine control. The PLC works by looking at its inputs

and depending upon their state, turning on/off its outputs. The user enters a program, usually via

software, that gives the desired results. PLC are used in many “real world” applications. If there is

industry present, chances are good that there is a plc present. Almost any application that needs

some type of electrical control has a need for a PLC.

A programmable logic controller, commonly known as PLC, is a solid state, digital, industrial

Computer using integrated circuits instead of electromechanical devices to implement control

functions. It was invented in order to replace the sequential circuits which were mainly used for

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machine control. They are capable of storing instructions, such as sequencing, timing, counting,

arithmetic, data manipulation and communication, to control machines and processes.

PLC have many definitions for example: According to NEMA(National Electrical Manufacture’s

Association ,USA),the definition of PLC has been given as “Digital electronic devices that uses a

programmable memory to store instructions and to implement specific functions such as logic ,

sequencing, timing, counting, and arithmetic to control machines and processes.”

Figure below illustrates conceptual diagram of PLC application

Fig 2.1 PLC conceptual application digram

Basic parts of PLC:-

All programmable controllers contain a CPU, memory, power supply, I/O modules, and

programmable devices. Basic parts of the PLC are as follows:-

Processor

Memory

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Input/output devices

Programming panel or unit

Power supply

Those can be shown in block diagram as shown below:

Fig 2.2 basic parts of PLC

Processors module:-

Processor module is the brain of the PLC. Intelligence of the PLC is derived from microprocessor

being used which has the tremendous computing and controlling capability.

Central processing –unit (CPU) performs the following tasks:-

Scanning

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Execution of program

Peripheral and external device communication

Self- diagnostic

Power of PLCs depends on the type of microprocessors being used. Small size PLCs use 8-bit

microprocessors where as higher order controllers use bit-slice microprocessor in order to

achieve faster instruction execute. Modern day PLCs vary widely in their capabilities to control

real world devices, like some processors are able to handle the I/O devices as few as six and

some are able to handle 40000 or more. The no. of input/output control of PLCs depends on

the,hardware, software, overall capacity and memory capability of the PLCs.

The CPU upon receiving instruction from the memory together with feedback on the status of the

I/O devices generates commands for the output devices. These commands control the devices on a

machine or a process. Devices such as solenoid valves, indicator lamps, relay coils and motor

starters and typical loads to be controlled.

The machine or process input elements transmit signal to input modules which in turn, generates

logic signal to the CPU.CPU monitors the input like selector switches, push buttons etc.

Operating system is the main workhouse of the system and hence performs the following tasks:-

Executions of application program

Management of memory

Communication between programmable controller and other units

i/o handling of interfaces

resource sharing

diagnostics

Note:- operating system stored in ROM(non –volatile) memory, whereas application program are

stored in RWM(read-write memory).

There are many types of input modules to choose from. The type of input module selection

depends upon the process, some example of input modules are limit :-switches, proximity switches

and push buttons etc. nature of input classification can be done in three ways, namely:-

low/high frequency

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analog/digital (two-bit, multi-bit)

maintained or momentary

5V/24V/110V/220V switched

Some most industrial power systems are inherently noisy:- electrical isolation is provided between

the input and the processor. Electromagnetic interference (EMI) and radio frequency interference

(RFI) can cause severe problems in most solid state control systems. The component used often to

provide electrical isolation within I/O cards is called an optical isolator or opto-coupler. Typically,

there are 8 to 32 input points on any one input modules. Each input point is assigned a unique

address by the processor.

Output modules:-

Output modules can be used for devices such as solenoids, relays, contractors, pilot lamps and

led readouts. Output cards usually have 6 to 32 output points on a single module. Output cards,

like input cards, have electrically isolation between the load being connected and the PLC.

Analog output cards are a special type of output modules that use digital to analog conversion.

The analog output module can take a value stored in a 12 bit file and convert it to an analog

signal. Normally, this signal is 0-10 volts dc or 4-20ma. This analog signal is often used in

equipment, such as motor-operated valves and pneumatic position control device. Each output

point is identified with a unique address.

Addressing scheme:-

Each I/O device has to be identified with a unique address for exchange of data. Different

manufacturer apply different method to identify i/o devices. One of the addressing schemes may

be “X1 X2 X3 X4 X5” where

X1 = input or output designation fixed by hardware

X2 = i/o rack number in PLC (user designation)

X3 = modules slot number in i/o rack (fixed by hardware)

X4 X5 = terminal number (fixed by hardware)

For example,” 1 2 3 13” implies that input is at rack 2 , module slot no.3 and terminal address

no.13.

Programming unit:-

It is an external, electronic handheld device which can be connected to the processors of the PLC

when programming changes are required. Once a program has been coded and is considered

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finished, It can be burned in to ROM. The contents of ROM cannot be altered, as it is not affected

by power failure. Now a day’s EPROM/EEPROM are provided in which program can be

debugged at any stage. Once the program is debugged, programming unit is disconnected; and the

PLC can operate process according to the ladder diagram or the statement list.

Communications in PLC:-

There are several methods how a PLC can communicate with the programmer, or even with

another PLC. PLCs usually built in communication ports for at least RS232, and optionally for

RS 485, and Ethernet. Mod bus is the lowest common denominator communication protocol.

Others are various field buses such as profibus, interbus-s, foundation field bus, etc.

PLCs are becoming more and more intelligent .in recent years, PLCs have been integrated in to

industrial networks, and all the PLCs in an industrial environment have been plugged in to a

network. The PLCs are then supervised by a control center. There exist many types of networks,

SCADA (supervisory control and data acquisition)

Operation of PLC:-

During program execution, the processor reads all the inputs, and according to control application

program, energizes and de-energizes the outputs. Once all the logic has been solved,

The processors will update all the outputs. The process of reading the inputs, executing the control

application program, and updating the output is known as scan. During the scan operation, the

processor also performs housekeeping tasks. The inputs to the PLCs are sampled by processor and

the contents are stored in memory. Control program is executed, the input value stored in memory

are used in control logic calculations to determine the value of output. The outputs are then

updated. The cycle consisting of reading of inputs, executing the control program, and actuating

the output is known as “scan” and the time to finish this task is known as “scan time”. The speed

at which PLC scan depends upon the clock speed of CPU. The time to scan depends upon

following parameter:-

Scan rate

Length of the program

Types of functions used in the program

Faster scan time implies the inputs and outputs are updated frequently. Due to advance

techniques of ASIC (application specific integrated circuit) within the microcomputer for

specific functions, scan time of different PLCs have reduced greatly.

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As PLCs have developed and expanded, programming languages have developed with them.

Programming languages allow the user to enter a control program into a PLC using an

established syntax. Today’s advanced languages have new, more versatile instructions, which

initiate control program actions. These new instructions provide more computing power for

single operations performed by the instruction itself. In addition to new programming

instructions, the development of powerful I/O modules has also changed existing instructions.

These changes include the ability to send data to and obtain data from modules by addressing the

modules’ locations. For example, PLCs can now read and write data to and from analog

modules. All of these advances, in conjunction with projected industry needs, have created a

demand for more powerful instructions that allow easier, more compact, function-oriented PLC

programs.

The three types of programming languages used in PLCs are:-

Ladder

Boolean

Grafcet

But we are focused on the first type of PLC programming languages

2.3 Ladder LogicFor ease of programming the programmable controller was developed using existing relay ladder

symbols and expressions to represent the program logic, needed to control the machine or process.

The resulting programming language, which used these original basic relay ladder symbols, was

given the name ladder language. Figure below illustrates a relay ladder logic circuit and the PLC

ladder language representation of the same circuit.

The evolution of the original ladder language has turned ladder programming into a more powerful

instruction set. New functions have been added to the basic relay, timing, and counting operations.

The term function is used to describe instructions that, as the name implies, perform a function on

data i.e. handle and transfer data within the programmable controller.

New additions to the basic ladder logic also include function blocks, which use a set of

instructions to operate on a block of data. The use of function blocks increases the power of the

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basic ladder language, forming what is known as enhanced ladder language. The format

representation of an enhanced ladder function depends on the programmable controller

manufacturer; however, regardless of their format, all similar enhanced and basic ladder functions

operate the same way.

Ladder logic is the main programming method used for PLC. As mention before, ladder logic has been

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

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

engineers and trades people was greatly reduce. Modern control systems still include relay, but these are

rarely used for logic. A relay is a simple device that uses a magnetic field to control a switch. Relay are used to let

one power source close a switch for another power source, while keeping isolate.

2.3.1 Ladder Logic Inputs

PLC inputs are easily represented in ladder logic. In Figure shown below there are three types of

inputs shown. The first two are normally open and normally closed inputs.

The IIT (Immediate Input) function allows inputs to be read after the input scan, while the ladder

logic is being scanned. This allows ladder logic to examine input values more often than once

every cycle. (Note: This instruction is not available on the Control Logic processors, but is still

available on older models.)

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Normally open

Normally closed

fig 2.3 Ladder logic inputs

2.3.2 Ladder Logic Outputs

In ladder logic there are multiple types of outputs, but these are not consistently available on all

PLC. Some of the outputs will be externally connected to devices outside the PLC, but it is also

possible to use internal memory locations in the PLC.

2.4 Programming

Programming software CX-Programmer has been utilized in this project. An example of ladder

logic can be seen in Figure 2.5. To interpret this diagram imagines that the power is on the vertical

line on the left hand side, we call this the hot rail. On the right hand side is the neutral rail. In the

figure there are two rungs, and on each rung there are combinations of inputs (two vertical lines)

and outputs (circles). If the inputs are opened or closed in the right combination the power can

flow from the hot rail, through the inputs, to power the outputs, and finally to the neutral rail. An

input can come from a sensor, switch, or any other type of sensor. An output will be some device

outside the PLC that is switched on or off, such as lights or motors. In the top rung the contacts are

normally open and normally closed. This means if input A is on and input B is off, then power will

flow through the output and activate it. Any other combination of input values will result in the

output X being off.

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IIT

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Figure 2.4: A Simple Ladder Logic Diagram

2.5 Operation of PLCA 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.

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Figure 2.5 Operation of PLCStep 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.

After the third step the PLC goes back to step one and repeats the steps continuously. One scan

times defined as the time it takes to execute the 3 steps listed above.

2.6 Time Response

The PLC can only see an input turn on/off when it’s looking. In other words, it only looks at its

inputs during the check input status part of the scan.

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In the diagram, input 1 is not seen until scan 2. This is because when input 1 turned on, scan1 had

already finished looking at the inputs. Input 2 is not seen until scan 3. This is also

because when the input turned on scan 2 had already finished looking at the inputs. Input 3 is

never seen. This is because when scan 3 was looking at the inputs, signal 3 was not on yet. It turns

off before scan 4 looks at the inputs. Therefore signal 3 is never seen by the plc. Now let’s

consider the longest time for an output to actually turn on. Let’s assume that when a switch turns

on we need to turn on a load connected to the plc output.

The diagram below shows the longest delay (worst case because the input is not seen until scan 2)

for the output to turn on after the input has turned on. The maximum delay is thus 2 scan cycles –

1 input delay time.

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CHAPTER THREE

METHODOLOGY

This chapter will mainly discuss about the methodology of the project and also the aspect

or factors that must be taken into consideration during the development process. All this factors

were very important to make sure the project will achieve its objective.

3.1Project Overview

In this section, we will discuss an overall overview of Automatically Filling liquid System Using

PLC project. The introduction to system task will also briefly explain in this chapter. Finally, the

entire decision making will be addressed in this section.

Basically, software design will be used in order to implement this project. In addition, there some

methods must be executed to keep this project implemented successfully. Below block diagram

shows implementation of our project

Figure 3.1 Implementation of project block diagram

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CHAPTER FOUR

AUTOMATIC BOTTLE FILLING AND CAPPING SYSTEM USING PLC

4.1 Components / Instruments used

4.1.1 Dc motorMotor is a small electronic device that can move if the power supply connect. It is a main part to

make the conveyor belt moves perfectly. There are many type of DC Motor at market such as gear DC motor,

motor servo and stepper motor but in this project DC motor will be used because it can spin 360°

continuously. Moreover, it is strong enough to move the trek

4.1.2 Limit switch The limit switches needed to detect the arrival of the bottle to the desired position to do the

processes such as filling and capping. Here we need two limit switches, one to detect the bottle

arrival to the end of the first conveyor belt and the other to detect the bottle arrival to its filling

position. The limit switches are mounted at the edge of the conveyor.

Figure 4.1.2 limit switches

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4.1.3 Filling level inspectionThere are many ways to control the filled liquid level:

• Infrared

• X‐ray

• Gamma rays

• Digital camera

.Filling using weighing cells

Filling using weighing cells

The Sensometic VPGW is a filling system designed for pressure less filling using the gravity

principle. Especially non‐conductive products can be processed ideally with the weighing cells

integrated in the bottle plates. The electro‐pneumatically controlled system enables non‐contact

filling, thus being suitable for microbiologically sensitive products as well. Due to the filling

valves closing towards the top, the product can gently flow into the bottle during closing. Filling

is therefore terminated without deflecting the product jet. As a matter of course, the Sensometic

VPGW is suitable for filling glass containers, cans and plastic bottles. Thanks to the motorized

height adjustment of the ring bowl, this machine can quickly be changed to different container

sizes.

Figure 4.1.3 Weight balance

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Other inspection methods

The following inspection technologies can be used for fill level inspections:

• Infrared

• X‐ray

• Gamma rays

• Digital camera

Our selection would be the weighing cell method (Using Sensomatic VPGW) because of the

following advantages over other methods:

Infinitely adjustable fill quantity

High fill quantity accuracy due to calibratable weighing cells.

Non‐contact filling assuring high microbiological safety.

Product and gas channels free from springs, providing optimum cleaning accessibility.

Weighing cells as a compact and quickly replaceable unit.

4.1.4 Linear actuatorsLinear actuators (Cylinders) used in many parts of the system;

Filling hose actuator: here the actuator moves the hose down until reach the bottle to fill

it. After that, the actuator will move the hose up.

Capping actuator: this actuator moves the capper with suitable speed and force, pressing

the cap against the head of the bottle.

For this purpose of selection, we will consider different suppliers. This will allow for a

comparison to be carried on between the different options available in the market.

Consequently, the optimum option shall be selected.

4.1.5 Conveyer BeltsThere are so many types of conveyor arrangement; some of them

1. Roller Conveyor

2. Belt Conveyor

3. Wheel Conveyor

4. Chain: Flight, Apron, Bucket, Slat

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5. Chute Conveyor

But we are focused on belt conveyor which has two conveyor systems.

The first conveyer belt that carries the bottles to the track to be filled will be made of PVC

(polyvinyl Chloride) to allow for the bottle to slip if it hits the ratchet while another bottle is still

waiting to be grabbed. Also, this will enable us to use a DC motor with relatively small output

power and low speed. The second conveyer belt will be made out of rubber because we need

relatively high coefficient of friction with the bottle to prevent slippage. The motor used here will

be also a DC motor with relatively low speed‐torque capabilities. This is because the load on the

conveyer belt will be low.

4.2 Sequence of operation conveyor System 1

Empty clean plastic bottles are placed in a random manner on a conveyer belt, conveyer belt 1.

The belt will not start until a start button is pressed. Conveyer belt 1has the following arrangement

as shown in figure 4.2. The purpose of this arrangement is to ensure that only one bottle leaves

conveyer belt 1 at a time. This arrangement will be labeled system 1 from now on. As sub‐system

1 detects a bottle at its end, conveyer belt 1 is prompt to stop. This is achieved by sending a

stop_motor1 signal from the PLC to the motor driving conveyer belt 1. Consequently, all bottles

on conveyer belt 1 will be brought to halt. However, the detected bottle at the end of the conveyer

belt 1 will continue to move along the ramp reaching to conveyer belt 2. It is important to note that

both conveyer belt 1 and conveyer belt 2 will have the same steady state speed. This is critical to

avoid tipping any bottle moving from conveyer belt 1 to conveyer belt 2.

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Figure 4.2 end arrangement of conveyer belt 1

At this moment, conveyer belt 1 is at halt and conveyer belt 2 will continue to move, thus

moving the bottles on it through the rest of the system. Conveyer belt 1 will remain at rest until

the bottle on conveyer belt 2 has moved a distance equivalent to the height of the plastic bottle

multiplied by a desired factor of. The importance of this part of the sequence is that it ensures

that if any bottle for any reason tips over, no of the bottle preceding it will tip over resulting in a

domino‐like effect. Therefore, as soon as a bottle leaves conveyer belt 1 and enters conveyer belt

2, a timer starts, and as soon as the timer completes its count, conveyer belt 1 starts to move. A

repetition of this sequence will make sure that bottles moving along conveyer belt 2 will be

separated by a suitable separating distance, allowing for the upcoming processes to be completed

properly. Now, as the bottle moves along conveyer belt 2, it will undergo several processes. The

first process encountered by any bottle on conveyer belt 2 will be the filling process. The system

in charge of filling bottles will be labeled as “filling system”. Figure 4.2.1 provides a schematic

of the main parts and components present in the “filling system”.

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Automatic Bottle Filling and Capping Control System

Figure 4.2.1 main component of filing system

The filling process starts when a bottle is detected by the limit switches shown in Figure 4.2.1.

These limit switches alert the system when a bottle is detected by sending a detection signal to the

PLC. Consequently, the PLC will send a stop_motor1 and stop_motor2 commands to both motor1

and motor 2; controlling conveyer belts 1 and 2 respectively. This will ensure that the bottle

remains stationary while being filled with liquid. Now, a pneumatic actuator will move the filling

arm and head down to an elevation suitable for liquid filling to commence. Then a valve opens,

allowing for the liquid to flow into the bottle. As liquid flows into the bottle, an accurate balance

will continuously measure the weight of the bottle and the liquid filling it. The output from the

balance will serve as an indication of the liquid level present in the bottle. The liquid will continue

to flow until the desired liquid level (1L) is obtained. Figure 4.2.2 provides a schematic of the

arrangement.

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Automatic Bottle Filling and Capping Control System

Figure 4.2.2 schematic of the weighing mechanism arrangement

When the desired level of liquid has been filled into the plastic bottle the balance alerts the system

that the desired level of liquid has been reached. Consequently, the PLC sends a stop liquid signal

to the valve controlling the flow of liquid, thus stopping the flow of liquid to the bottle. After this

is done, the filling arm and head arrangement is retracted and all conveyer belts start moving

again. The second process a bottle has to go through while on conveyer belt 2 is the capping

process. The system in charge of capping the bottles will be referred to as the capping system.

Figure 4.2.3 shows a schematic of the arrangement of the main components of the capping

system.

Figure.4.2.3 Arrangement of the main components of the capping system.

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Automatic Bottle Filling and Capping Control System

The capping process starts when the limit switches detect the entry of a bottle. The detection is

again done though two limit switches fixed on the sides of the track which defines the motion of

the bottles. These limit switches will prompt the PLC to issue a stop motor 1 and stop motor 2

commands to stop both conveyer belts. When the bottle has completely stopped, a pneumatically

actuated gripped is extracted to hold the bottle firm in it position so as to allow for the capping

process to be completed properly. As soon as the gripper extends fully, another pneumatic

actuator extends to push the capping head towards the filled bottle. Push force will result in the

cap being firmly attached to the bottle.

The moment this is done, both pneumatic actuators are retracted, and the PLC issues as start motor

1 and start motor 2 commands; causing both conveyer belts to start moving again. At the end of

the conveyer belt 2, the bottle is transferred to a labeling It is worth noting that both; the filling

and the capping processes, take place concurrently, however on different bottle. In other

words,when a bottle is detected by the filling system, the controller checks if another bottle has

been detected by the capping system. If the capping system has detected a bottle then the capping

process continues. However, if the capping system failed to detect a bottle, then the capping

process does not take place. In either case, the filling process is unaffected by the bottle detection

at the capping system’s side. Furthermore, for this sequence to take place, the separation between

the two systems shall be a multiple of a bottle’s height. Therefore, a suitable separation between

the filling and the capping systems would be twice to three times the height of a bottle. This

separation constitutes a compromise between allowing for enough space between the equipment

with the lowest possible reduction in the production rate. Furthermore, as a safety precaution, as

soon as the start button is pressed, the system will check if the tank has enough milk in it and if the

capping system has enough caps placed in the caps compartment in the capping system.

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4.3 Sequence of operation for conveyor System 2Empty clean plastic bottles are placed in a random manner on a conveyer belt, conveyer belt 1.

The belt will not start until a start button is pressed. As soon as the start button is pressed, the

system makes sure that there is enough milk in the tank and the cap holders have enough caps

installed in them. If either condition is not satisfied the system will not start and an alarm LED

will turn on indicating which condition is not satisfied. In this case, human intervention is

required, where a worker is to go and resolve the problem manually. Once this is done, the

operator is to press the start button once again to start the system. This will start motor 1, which is

responsible for the motion of Conveyer belt 1. Conveyer belt 2 has the following arrangement at

its end:

Figure 4.3: end arrangement at conveyer belt 2

The purpose of this arrangement is to ensure that only one bottle leaves conveyer belt 1 at a time.

Furthermore, as soon as the bottle has been detected and has entered through the ratchet, an alert

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Automatic Bottle Filling and Capping Control System

LED will light up, indicating that no more bottles shall be placed on the conveyer belt at this

moment. The LED will turn off as soon as the bottle starts moving. As the bottle enters the round

track it remains stationary until a gripper grabs it. There are eight gripper arranged in a star‐like

pattern as shown in Figure4.2.1. Each gripper will grab one bottle at point A, and will release it

at point B after being filled and caped. Moreover, each gripper has a liquid filling mechanism, a

cap fitting mechanism and a balance attached to it. This arrangement is illustrated in Figure 4.3.

Figure4.3.1: grippers and round track arrangement

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As soon as the gripper grabs the bottle, a limit switch alerts the system that a bottle has been

grabbed. A pneumatic actuator is used to interchange the position of the filling and the cap fitting

mechanisms. In default position, the actuator is normally retracted. At this actuator position, the

filling mechanism is located straight above the empty bottle. At this moment, the PLC issues a

start filling command. This will open the valve controlling the flow of liquid from the tank to the

bottle, thus allowing liquid to flow into the bottle. Liquid will flow continuously into the bottle

until the desired liquid level is achieved. In our design, we will depend on a balance to

continuously provide an indication of the level of liquid in the bottle. As soon as the balance

signals that the level of liquid in the bottle has reached the desired level1, the PLC issues a stop

filling command. This will close the valve that controls the flow of liquid.

Now, after the filling process has been completed, the PLC issues a start capping command. This

will force the pneumatic actuator to move the filling mechanism away from the bottle and bring

forth the capping mechanism. The capping mechanism consists of a caps holder, a stationary arm

and a capping arm/head. The capping arm/head can move up and down in a controlled manner.

Whenever the capping process starts, the capping arm/head will be forced to move down, pressing

the cap against the bottle. If enough force is applied, the cap will be fitted on the bottle. Once the

above mentioned processes (i.e. the filling and the capping processes) have been completed, the

bottle would have traveled from point A to point B on the circular track. At point B, a second

conveyer belt will move the filled bottle to a different place in the factory, where labeling and

packaging shall take place. It is important to note that we are assuming the level of liquid in the

tank is sufficient to provide for the minimum flow of liquid required for the bottle to be filled and

capped before reaching point B on the circular track.

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Figure 4.3.2: gripper, liquid filling and cap fitting mechanisms, and balance arrangement

4.4 Programming

We start programming with the first conveyor system using flowcharts and ladder diagram as

shown below

4.4.1 Conveyor System Flow Chart:

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A

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Fig 4.4.1 Conveyor System Flow Chart

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A

A

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CHAPTER FIVE

RESULTS AND DISSCUSSIONS

Once the start button is pressed the green light (L1) turns ON and remains ON until stop button is

pressed .As light turns ON out feed motor (M2) starts running. After M2 runs and if either limit

switch (LS) has not signaled or filled bottle condition is fulfilled motor (M1) starts. After limit

switch has signaled timer, T1 gets activated. After T1 gives done (DN) signal and photo eye

detector (PE) is disabled, solenoid valve gets in operation. As PE signals solenoid stops and

buzzer (Q) sounds after which timer, T2 gets enabled which stops the process for the set seconds.

Once the filled bottle condition is activated the cycle starts again.

The ladder diagram was successfully checked in the PLC simulator and all the prescribed

conditions were observed completely.

Conclusion and Recommendation

An Automatic Filling Water System using PLC has been successfully constructed and designed by

applying all the concept of control system at this project. The system that is produced can be

modified to be better if some of the electrical devices and system are upgraded and improved.

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CONCLUSIONThe theory and concept of the automatic filling water system is based on the control system. In

electrical design, the features and functions of the electrical components are required to determine

the system requirement. , the theoretical of the wiring system is required for connecting the inputs

and outputs devices to PLC. In programming design, understandings of the desired control system

and how to use the Ladder Diagram to translate the machine sequence of operation are the most

important parts, because it has direct effect on the system performance. The main aim in this

process is to apply PLC to design automatic filling water system and all objectives in this project

were successfully done as planned. Finally, the basis control system and logic design apply in this

project can be used as a references to design other applications of automation system, and also can

be used as a teaching material for the Industrial Control subject.

RECOMMENDATIONActually, a lot of weakness from the project can be taken as future works so that the improved system will

be better in terms of performance, So that, there are several recommendations or suggestions that we can

take to increase performance in this project. The performance of Automatic Filling Water System can be

increased based on two recommendations which are;

The system that is proposed now is using only one sensor that is griper sensor to detect

position of bottle. It will be better if we add more sensors in this system like a flow sensor

to detect water flow or use level sensor to detect water level. Thus, the system will be more

sensitive as there will be more sensing points

Besides using PLC as controller, the other controller can be used in this future work is like

Microcontroller. However, many factors must be considered like cost, practically and

others.

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REFERENCES

1. Richard A. Cox, Technician’s Guide to Programmable Controllers, 4th edition, Vikash

Publishing House, New Delhi

2.J. R. Hackworth, F.D. Hackworth, Programmable Logic Controllers– Programming

Methods & Applications, Pearson Education, New Delhi

3. J. W. Webb, R A Reis, Programmable Logic Controllers Principle & Applications, 5th

edition, Prentice Hall of India ltd., New Delhi

4. http://www.plcs.net\default.html

5. http://www.sea.siemens.com\step\default.html

6. http://www.seacheng.co.uk\articles\pla\index.html

7. http: //www.omron-ap.com

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APENDIX PLC programfor automatic bottle filling and capping using lader diagram

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Contents

Acknowledgement…………………………………………………………………………………i

Table of Contents……………………………………………………….…………………………ii

List of figures…………………………………………………………………………………….iv

Abstract…………………………………………………………………………………………...v

CHAPTER ONE..........................................................................................................................................1

BACKGROUND OF PROJECT.............................................................................................................1

1.1 Introduction.......................................................................................................................................1

1.1.1 Open loop system.......................................................................................................................1

1.1.2 Closed loop system.....................................................................................................................2

1.2 Problem statement.............................................................................................................................4

1.3 project objective................................................................................................................................4

1.4 Implementation of project..................................................................................................................5

CHAPTER TWO.........................................................................................................................................8

LITRATURE REVIEW..........................................................................................................................8

2.1 History of PLC..................................................................................................................................8

2.2 What is a PLC?..................................................................................................................................8

2.3 Ladder Logic...................................................................................................................................14

2.3.1 Ladder Logic Inputs..................................................................................................................15

2.3.2 Ladder Logic Outputs...............................................................................................................16

2.4 Programming...................................................................................................................................16

2.5 Operation of PLC.............................................................................................................................17

CHAPTER THREE...................................................................................................................................20

METHODOLOGY................................................................................................................................20

3.1Project Overview..............................................................................................................................20

CHAPTER FOUR.....................................................................................................................................21

AUTOMATIC BOTTLE FILLING AND CAPPING SYSTEM USING PLC......................................21

4.1 Components / Instruments used.....................................................................................................21

4.1.1 Dc motor...................................................................................................................................21

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4.1.2 Limit switch............................................................................................................................21

4.1.3 Filling level inspection..............................................................................................................22

4.1.4 Linear actuators........................................................................................................................23

4.1.5 Conveyer Belts.........................................................................................................................23

4.2 Sequence of operation conveyor System 1......................................................................................24

4.3 Sequence of operation for conveyor System 2.................................................................................29

CHAPTER FIVE.......................................................................................................................................35

RESULTS AND DISSCUSSIONS........................................................................................................35

CONCLUSION.....................................................................................................................................36

RECOMMENDATION.........................................................................................................................36

REFERENCES......................................................................................................................................37

APENDIX.............................................................................................................................................38

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