Automatic Bottle Filling and Capping Control System

Automatic Bottle Filling and Capping Control System

CHAPTER ONE BACKGROUND OF PROJECT 1.1 Introduction Control Control engine engineeri ering ng has evolv evolved ed overtim overtime. e. In the the past, past, humans humans were were the main main metho method d for cont co ntro roll llin ing g a syst system em.. 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

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

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Computational abilities allow more sophisticated contro

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Trouble shooting aids make programming easier and reduce downtime.

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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  pu  purpose of controlling the output puts 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 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 system It 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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Automatic Bottle Filling and Capping Control System

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 system The 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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Automatic Bottle Filling and Capping Control System

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.  junction. If there there is any difference difference between between the two two responses, responses, the the system system drives the plant, plant, via the actuating signal to make correction. If there is no difference the system does not drive the plant since the plants response is already the desired response. To compared between open loop system & ii

Automatic Bottle Filling and Capping Control 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 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. 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 main objective objective of this this project 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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Automatic Bottle Filling and Capping Control System

1.4 Implementation of project

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Automatic Bottle Filling and Capping Control System

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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Automatic Bottle Filling and Capping Control System

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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Automatic Bottle Filling and Capping Control System

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  machine control. They are capable of storing instructions, such as sequencing, timing, counting, arithmetic, data manipulation and communication, to control machines and processes. ii

Automatic Bottle Filling and Capping Control System

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  Input/output devices  Programming panel or unit

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Automatic Bottle Filling and Capping Control System  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

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Peripheral and external device communication ii

Automatic Bottle Filling and Capping Control System

•

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

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Management of memory

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Communication between programmable controller and other units

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i/o handling of interfaces

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resource sharing

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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  analog/digital (two-bit, multi-bit)  maintained or momentary

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Automatic Bottle Filling and Capping Control System  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 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

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Automatic Bottle Filling and Capping Control System

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.

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 ii

Automatic Bottle Filling and Capping Control System

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 

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Boolean

•

Grafcet

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

2.3 Ladder Logic For 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 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.

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Automatic Bottle Filling and Capping Control System

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.)

Normally open

Normally closed ii

Automatic Bottle Filling and Capping Control System

IIT

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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Automatic Bottle Filling and Capping Control System

Figure 2.4: A Simple Ladder Logic Diagram

2.5 Operation of PLC A PLC works by continually scanning a program. We can think of this scan cycle as consisting of 3 important steps. There are typically more than 3 but we can focus on the important parts and not worry about the others. Typically the others are checking the system and updating the current internal counter and timer values.

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Automatic Bottle Filling and Capping Control System

Figure 2.5 Operation of PLC Step 1-CHECK INPUT STATUS

First the PLC takes a look at each input to determine if it is on or off. In other words, is the sensor  connected to the first input on? How about the second input? How about the third... It records this data into its memory to be used during the next step. St ep 2- EXECUTE PROGRAM

Next the PLC execu tes your progra m o ne instru ction 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 th e ou tputs based on which inpu ts were on durin g the first step and the results of execu ting 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  be ca us e 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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Automatic Bottle Filling and Capping Control System

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 ii

Automatic Bottle Filling and Capping Control System

CHAPTER FOUR  AUTOMATIC BOTTLE FILLING AND CAPPING SYSTEM USING PLC

4.1 Components / Instruments used 4.1.1 Dc motor Motor 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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Automatic Bottle Filling and Capping Control System

4.1.3 Filling level inspection There 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 ii

Automatic Bottle Filling and Capping Control System

 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 actuators Linear 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 Belts There 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 ii

Automatic Bottle Filling and Capping Control System

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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Automatic Bottle Filling and Capping Control System

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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Automatic Bottle Filling and Capping Control System

4.3 Sequence of operation for conveyor System 2 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. 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 LED will light up, indicating that no more bottles shall be placed on the conveyer belt at this ii

Automatic Bottle Filling and Capping Control System

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

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

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Automatic Bottle Filling and Capping Control System

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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Automatic Bottle Filling and Capping Control System

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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Automatic Bottle Filling and Capping Control System

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Automatic Bottle Filling and Capping Control System

Fig 4.4.1 Conveyor System Flow Chart

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Automatic Bottle Filling and Capping Control System

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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Automatic Bottle Filling and Capping Control System

CONCLUSION The 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.

RECOMMENDATION Actually, 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.

REFERENCES

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Automatic Bottle Filling and Capping Control System

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

APENDIX •

PLC programfor automatic bottle filling and capping using lader diagram

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Automatic Bottle Filling and Capping Control System

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Automatic Bottle Filling and Capping Control System

Contents

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Automatic Bottle Filling and Capping Control System

Acknowledgement…………………………………………………………………………………i Table of Contents……………………………………………………….…………………………ii List of figures…………………………………………………………………………………….iv Abstract…………………………………………………………………………………………...v .................................................................................................................................. 1 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 .......................................................................................7 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 fig 2.3 Ladder logic inputs................................................................................16 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

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AUTOMATIC BOTTLE FILLING AND CAPPING SYSTEM USING PLC............................21 4.1 Components / Instruments used .................................................................... 21 4.1.1 Dc motor ................................................................................................... 21 ii