HAWASSA

DEPART MENT OF ELECTRICAL AND

COMP ENGINERIG
STREM: industrial control
HOSTING COMPANY; MOHA SOFT DRINKS INDUSTRY S.C.
HAWASSA MILLENNIUM PEPSI COLA PLANT
PREPARED BY: ID/N

NEAWY KIFLU R/0907/05

ZELALEM ZELEKE R/

ADVISOR: ABDU

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Contents
Declaration ..................................................................................................................................................... 4
Acknowledgement .......................................................................................................................................... 5
1.1Introduction ............................................................................................................................................... 7
1.2 Back ground of Hawassa millennium Pepsi Cola plant............................................................................ 7
1.2.1 Brief history ....................................................................................................................................... 7
1.2.2 Mission of the company .................................................................................................................... 8
1.2.3 Vision of the company ....................................................................................................................... 8
1.2.4 Objectives of the company ................................................................................................................ 8
1.3 The main customers or end users of its products or service ..................................................................... 9
CHAPTER TWO .......................................................................................................................................... 10
2.1 The organization and work flow of the company ................................................................................... 10
2.1.1 Organization of Hawassa millennium Pepsi cola plant ................................................................... 10
2.1.6 PRODUCTION FLOW ................................................................................................................... 13
CHAPTER –THREE.......................................................................................................................................... 14
2. OVERALL INTERNSHIP EXPERIENCE ...................................................................................................... 14
Power distribution .................................................................................................................................... 14
I. Control system .................................................................................................................................. 15
c) Variable frequency drives ................................................................................................................. 16
2.1 Working section in the company .......................................................................................................... 17
II. Sugar and syrup preparation room.................................................................................................... 18
III. Water treatment room ................................................................................................................... 18
IV. Cooling room ................................................................................................................................ 18
V. Air compression room ...................................................................................................................... 18
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VI. Co2 facility room............................................................................................................................. 18

VII. Boiler room...................................................................................................................................... 18
2.2 THE MAIN OPERATIONAL SECTIONS & PROCESS FLOW IN MOHA..................................................... 18
2.3. Automatic bottle filler machine......................................................................................................... 25
2.3.1. Packer machine .............................................................................................................................. 28
2.4 Main PLC Parts .................................................................................................................................. 35
3.1.3.1 In terms of improving practical skills ........................................................................................... 36
3.1.3.2 In terms of upgrading theoretical knowledge ............................................................................... 36
3.1.3.3 In terms of improving interpersonal communication skill............................................................ 36
3.1.3.4 In terms of improving team playing skill ..................................................................................... 37
3.1.3.5 In terms of improving leadership skill .......................................................................................... 37
3.1.3.6 In terms of understanding about work ethics related issues ......................................................... 38
CHAPTER FOUR ............................................................................................................................................. 40
3.1 TOTAL OBSERVATION IN THE COMPANY ........................................................................................... 40
3.2 Problems observed in the company ..................................................................................................... 40
3.5 Statement of problem........................................................................................................................... 40
3.6 Methodology of the Project.................................................................................................................. 41
3.7 Used symbols and their description ....................................................................................................... 49
3.8 Results and simulation .......................................................................................................................... 51
CHAPTER FIVE

4.1 CONCULSIN AND RECOMMENDATION

4.10 CONCULSION

4.1.1 Recommendation to the hosting company....................................................................................... 56

4.1.2 Recommendation to the university .................................................................................................. 56
References .................................................................................................................................................... 57

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Declaration
We would like to declare that we have successfully completed a four month
internship program at a company called MOHA soft drinks industry at Hawassa
millennium plant. we have stayed from late October 2016 to 31 January 2017 in
internship program. It is obvious that wollo university kombolch institute of
technology, school of electrical and computer engineering is established sustainable
network with private and public sectors to create better linkage between
industrial Companies. During this internship time we have improved our theoretical
and practical skills.

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Acknowledgement
First of all we would like to express our gratitude and appreciation to our advisors Mr. abdu
whose help, suggestions and encouragement helped us to coordinate and conduct this
internship project and report. And also we would like to say thanks to wollo University and
specially School of Electrical and computer engineering for giving us this opportunity to
build up ourself in industrial internship program and to have practical knowledge. our last
thanks goes to the MOHA soft drinks factory Hawassa Millennium Pepsi cola plant whose
cooperation and guidance were great.

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CHAPTER ONE

1.1 Introduction
The internship is the way through which students are exposed to the practical work. The objective
of this internship is to allow students to practice or to change their theoretical knowledge to
practical skill. It also helps students to adopt themselves real work environment. This report is intended
to be used as an introductory text for the execution and maintenance of some electrical materials that
used in the company. It is mainly about Hawassa millennium Pepsi cola plant description, its control
system, power distribution etc which found in Hawassa town. This report gives update information about
the maintenance work of the company like motor winding.

So much of this report focuses on plant overall description, power distribution, control system etc.
In specific the internship program holds that, how students change their theoretical knowledge into
practice and testing students what they have learned so far and acquaints them with practical ideas
of classroom situation from their perspective. And also the students learn how they pass the
challenges though the works .Finally this report gives some suggestion and recommendation to the
department and to the host company.

1.2 Back ground of Hawassa millennium Pepsi Cola plant

1.2.1 Brief history

MOHA soft drinks Industry S.C was established on May 15, 1996 acquiring Nifas Silk Plant,
TekleHaimanot, Gonder plant and Dessie plant from the Ethiopia privatization Agency with paid
capital of Birr 108,654,000.

The Company currently has seven operating units including summit plant, Bure plant, and the
recently inaugurated Hawassa plant in the Southern Nations & Nationalities people’s Region. The
major products of MOHA Soft Drinks Industry S.C. are: Pepsi Cola, Miranda Orange, 7-
Up,Mirinda Tonic, Miranda Apple (all Pepsi Brands), and Kool (BureKool and Tossa bottled water
products).The Annual Turn-over of the company has reached to Birr 556 million and sales stands at
an average annual growth rate of 12%.

Hawassa Millennium Pepsi Cola plant is found in the southern region of Ethiopia and SNNPRS on
the southern edge of Hawassa city. It is licensed under MOHA soft drinks industry as 7th Plant
of its sister companies. In 1999 the foundation of the plant was laid and completed the whole
building as well as more advanced technology machinery erection done and in august

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2007 it started production. The plant was inaugurated on September 03/2007and started producing
its licensed products for its customers officially.

1.2.2 Mission of the company

 Striving to reach, maintain and expand our national market leadership through
optimal customer service and exceed the expectation of our customers for our
existing and new products in both quality and quantity.
 Treating and serving all customers with respect, sensitivity and fairness.
 Fulfilling non alcoholic need of the society

1.2.3 Vision of the company

 To insure competitiveness of the company through sustained innovation of its

infrastructure and work toward it based on well-managed and led organization for
achieving best quality and high volume products and be recognized as profitable and
growth oriented company.
 To see Pepsi Cola being the biggest soft drinks industry in the country and remain
dominant in the market share.

1.2.4 Objectives of the company

The business purposes of MOHA soft drinks industry S.C. as stipulated in the memorandum
of association are:
 To manufacture, buy, sell, bottle, distribute and otherwise deal in non-alcoholic
beverages and the ingredients there of Ethiopia and elsewhere.
 To manufacture, sell, and distribute carbon dioxide.
 To invest in other business enterprises, to establish and manage in Ethiopia or
abroad, such subsidiaries, branches or agencies as may be deemed desirable.
 And generally to carry on and engage in other activities which the company may
deem necessary incidental or related to the attainment of the above purpose.
1.2.5 Main Products or Services of the Company
This company holds majorities of the market share in soft drinks industry in the country. With an
expansion and replacement of absolute machinery, production capacities of the plants have
increased substantially. A significant growth over the years of production, sales, and profitability
due to reorganization of operations has been achieved. Productivity has improved tremendously
with major cost savings and insured a regular supply of high quality products. It has also succeeded

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in reaching new market areas across the country. The products of the company are designed to give
the benefit and satisfaction to the customers with an affordable price. And products of this company
are listed below.

They are:
 Pepsi
 Miranda orange
 Miranda apple
 Miranda tonic
 7-up
 Carbon-dioxide
The company has to-date paid more than a million Birr as excise and sales tax to the government. It
provides many jobs for citizens out of which some of them are new employment opportunities.
MOHA has been successfully implementing its social obligation by way of sponsoring different
events and supporting initiatives. It has contributed some million of Birr for victims of natural
disaster. It has also backed initiatives and supports HIV/AIDS victims in the company. MOHA is
well known for its multifaceted participation in community activities.

1.3 The main customers or end users of its products or service

Hawassa Pepsi Cola being distributing the products for local customers directly from southern
region (Hawassa, Hossana, Arbaminch, Dilla, etc.) and some parts of Oromia region (Shashemene,
Zeway, Meki, Borena, Bale, etc.).And indirectly delivers the products from the company to the
customers as follows:

Manufacturers Distributers Retailers customers

Fig 1 block diagram of product flow

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CHAPTER TWO

2.1 The organization and work flow of the company

2.1.1 Organization of Hawassa millennium Pepsi cola plant

Hawassa millennium Pepsi cola plant is a well structured and adequately staffed organization
capable of satisfy customers need by producing high quality soft drinks like Pepsi, Miranda orange,
Miranda apple, Miranda tonic and 7-up. The company uses the combined knowledge and
experience of personnel, from Engineers to skilled workers, for consistent quality of the product.
The qualified, well-trained and committed workforce also enables it to uphold production
schedules, even under adverse circumstances.

All the achievements of the company have been made possible by the dedicated efforts of executives and
qualified personnel. The organization of Hawassa millennium Pepsi cola plant works for a long time in a
day. That is from Monday to Saturday in a week (6 days) and Sunday is maintenance and sanitation day. In
a day it works time is 24 hours and sometime 18 hours and therefore the workers have overtime payment.

Employees at Hawassa millennium Pepsi cola plant are working towards continuing success with
the help of a committed leadership and highly motivated workforce by enduring close relationships
with clients and alliance partners. The Company is highly increasing its manpower in all levels of
responsibility and professional practice pertaining to production work. This has created a relaxed
and easy handling of a number of maintenance problems at a time.

2.1.2 Training of the company

Hawassa millennium Pepsi cola plant has internal and external training.

 Internal training: - that is given to staff member in different time different places. For
instance, workshop practices in different part of our country.
 External training: - that is given to selected individual outside of the country.

The company at least gives internal and external training but it has lack of on job training program
for employees to upgrade their performance.

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2.1.3 Work structure of the company

Plant General Manager

Sales Technical Production Food safety & Store &

Human Finance
Quality control Procurement
Manager
Resource Manage Manager Manager
Manager Manager
manager

Personnel General Area Production Store &

accounts supervisor Food safety & procurement
supervisor supervisor
supervisor quality control supervisor
supervisor

General
Territory
Service Cost &
supervisor Mechanical
supervisor budget Programmer Electrical
supervisor supervisor
supervisor

Fig 2 Structure of the company

2.1.4 Employee Information of the company

-It has 302 regular and irregular workers. The number of worker is stated with their education level
(position) in the following table.

Educational background No. of male No. of female Total

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MSc.& BSc. 26 5 31
TVET &Diploma 61 38 99
Grade 9-10 52 22 74
Grade 1-8 45 19 64
Uneducated 20 14 34
Table 1 the number and position of workers

2.1.5 Major Duty Assigned and orientation

The major duty assigned to performed in the company were, to see and observe the whole process
of the product from the start to the end, the work flow in technical and production section and
identify the problem of the company like:-electrical problem troubleshooting and its maintenance,
and material uses in general.

We were oriented that

the rules and regulations of the company

work ethics and safety rules should be taken under our internship and production line
as well
punctuality and being alert and eager to know new ideas from our seniors
Electrical workshop and hand tools we are going to use.
Being sociable and cooperative with the staff (team work) and etc.

Our supervisor helped us at different way to succeed our intern in stayed time. He gave us
suggestion and comment at daily activities and asks us questions on daily activities depend up on
our intern. So at this time we developed knowledge and confidence practical skill. He also frankly
discuses socially and challenges us by technical and management system.

The knowledge that we develop to succeed in daily duty was:-

 The best quality we developed in our internship was tolerance on tracing malfunctioned
electrical lines and technical observation to overcome challenges.
 Programmable logic control(PLC) increase the production rate and decrease man power as
we compare with older type of controlling system which is mostly used by
electromechanical systems
 We are familiar with many electrical types of equipment and how they operate and
maintaining different electrical equipments.

We also developed the working environment and social behaviors.

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2.1.6 PRODUCTION FLOW

The following explanation illustrates the production flow diagram and process flow of the company

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Figure 3. BLOCK DIAGRAM OF PROCESS FLOW IN MOHA

CHAPTER –THREE

2. OVERALL INTERNSHIP EXPERIENCE

Power distribution
Hawassa millennium Pepsi cola plant gets Input 15kv from EEPCO which is step-down by two
transformers to 380-415AC.There is also stand by generator from main which used when power
interruption occurred. Then the voltage described above go to LV (low voltage) room which
sophisticated and the voltage to all machines are distributed ,since the power(voltage) and current is
in phase in any power system but here the current lag the voltage because of inductive load. So, it
needs compensation, that means the current and voltage are become in phase by a capacitor using as
power factor corrector. The power factor is about 0.97.

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EEPCO 15KV

Generator

2 Step-down 1100 KVA

Transformers

Motorized change over CB

Main breaker

LV Room

Fig 4 Power distribution of sub-breaker

Different the company

I. Control system
The power
The control systemflow to different
of the companyroom like,microprocessor,
are PLC, production room, boiler
VDF areroom etc.used.
mostly

a) Actuator
 Electrical actuator
 Pneumatic actuator
 Hydraulic actuator

b) Sensors

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The plant has different type of photo electric (P.E) cell that are used to detect the presence of bottles
and to control the speed of the conveyor belt. There are also different types of proximity sensors
transmitter they install to perform their purpose. There are also different types of temperature
sensors (transmitter) these are:

 Resistance thermometry
 Temperature sensors
 Mercury thermometer
 Level sensor
 Weight detector
 Flow sensor

Since the company control system mostly used PLC and VFD. We will tried to discuss them as
follows:

c) Variable frequency drives

There are many and diverse reasons for using variable speed drives. In general, variable speed
drives are used to:

 Match the speed of a drive to the process requirements

 Match the torque of a drive to the process requirements
 Save energy and improve efficiency

The needs for speed and torque control are usually fairly obvious. Modern electrical VFDs can be
used to accurately maintain the speed of a driven machine to within ±0.1%, independent of load,
compared to the speed regulation possible with a conventional fixed speed induction motor, where
the speed can vary by as much as 3% from no load to full load. The benefits of energy savings are
not always fully appreciated by many users. These savings are particularly apparent with pumps
and fans, where load torque increases as the square of the speed and power consumption as the cube
of the speed. Substantial cost savings can be achieved in some applications. The general wiring

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diagram of a load with variable frequency drive includes the power supply, protection devices, the
frequency drive itself, the motor and the load.

Fig 5 wiring diagram of VFD

In actual diagrams, the variable frequency drives includes particularly the following modules

 The rectifier module where AC is converted to DC

 The DC link module where the rectified DC is smoothened by a capacitors and inductors
 The pre-charge module where the capacitor is pre-charged by a DC power before the actual
power is connected to protect it from damaging.
 The inverter module where the DC is converted back to AC of variable frequency

The controller module which controls the proper functionality of the drive and monitors the drive
for any undesired status e.g. over voltage, ground fault, over temperature etc.

2.1 Working section in the company

The Working section we have been working in it is known as production room. The section that
we have been interred. The first place we were interred in the production department to practice
in the Internship program. The production room of the company held different production
section where different operational procedure is made by each section. Such as

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II. Sugar and syrup preparation room

III. Water treatment room

IV. Cooling room

V. Air compression room

VI. Co2 facility room

VII. Boiler room

2.2 THE MAIN OPERATIONAL SECTIONS & PROCESS FLOW IN MOHA

The following description are mainly to shows the patterns of the working process of different
sections of the factory .Thus the explanations here indicated are taken from practical involvement
and observation from the internships point of view. Therefore, the production process is fully part
of these sections which influences directly the productivity level of the factory. Hence, operational
system elaborations are made for each section as follows.

2.2.1 IN FEED SECTION

The reception section (in feed section) of the factory has storage area where this section holds the
empty bottle with its cases. These empty bottle and cases are returned and stored in this section
after the sales of the product in the market. Since these bottles and cases are coming from the
regions of Addis Ababa area after the consumers consume/used the fluid part it is full of dirt, some
users may use the bottle for different purpose (like for oil, gas) and the cases are expected to be
washed by highly pressurized hot water and the bottle have long processes of washing system.

2.2.2 CASE WASHER

The case washer is a cleaning machine that cleans case. There are two partitioned spaces where
cases are treated. It is by lightly warm caustic soda (600C) and soft water with a temperature of 250c
.The desirable amount of heat is regulated by heat regulator those heat is transferred through

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conduction system with steam pipe that comes from the boiler room. These machines consist of
spraying nozzles which is used to accelerate the flow of water .This machine have 6 drive motor
those motors drives the conveyers which is stainless steel it also has pump motor is used to pump
water that comes from the water treatment room .

Figure 4.Diagram of case washer machine

2.2.3 BOTTEL WASHER

The bottle washer is a bottle cleaning machine with a capacity of cleaning 27500 bph (bottle per
hour) and this washing machine has different zones in order to treat those bottles. It uses a total
power of 31.43 Kilowatt. The bottles are assembled for transportation by using steel bar called
carriage. Totally it has 440 holes and about 33in a row. The machine used to sanitize the bottle by a
caustic soda and also has diaphragm valve that control the temperature of the caustic acid by using
pressure that comes from the compressor. There are some mechanical components which are used
to drive carriage like servo drive which are used to drive chain gear box used for transmitting
power, shaft, gear and chain and electrical components like proximity sensors, limit switches. The
washer machine consists of seven different section:-

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 Pre heating and intermediate spray. This means treated water comes into the machine and the
bottle moves by means of conveyor where it is lifted and got into carriage. Then the bottle in the
carriage get sprayed by spray jet (nozzles) with fresh water and is affected by cam shaft or
engine shaft (there are 2 spray jets in each steps) in each from down and upside through small
holes from both sides. The power used in this step is 3.0KW.
 Caustic 1. In this step the bottles sinks in a chemical called caustic soda boiled with
temperature of 70-74 degree Celsius. This is controlled by diaphragm valve which senses the
temperature from the boiler in the form of steam. Thus the diaphragm monitors the temperature
range to be in between 70-74 degree Celsius where if it goes out of the range it opens and closes
the valve by a pressure that comes from the compressor. The power used in this step is 5.5KW.
 Caustic 2.This section is the same as caustic 1, here we use caustic soda having the
conductivity range of 100-120ms/cm which is the same for both caustic 1 & caustic 2.The most
important thing in this step is more water is used to clean the bottles.
 Zone 1.Warm water: In this section the bottle passes through the water which is not very hot but
moderate one which is heated by conduction system via steam comes from boiler. The
temperature of the water in this zone is nearly 49.8degree Celsius.
 Zone2.In this zone the bottles get sprayed by spray jet before it gets rinsed. Here the water
temperature is approximately between 370c-42 0C.
 Zone 3. Finally the bottles washed by clean and treated water that comes from water treatment
section.

Inspection section

In the inspection section the washed bottles are inspected in order to check any untreated bottle
which the inspection includes properly unwashed bottle and a bottle that cannot be used for specific
kind of product through light screening. It is just to ensure the safety of the work in processes. The
company has its own program on the inspectors to check up their eyes three months.

Draining residuals

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Remnant beverage is emptied in to a collection pan. The remnants are discharged separately
from the machine.

Pre-cleaning

Pre-cleaning follows remnants beverage emptying. This flushes out any impurities clinging to
the bottoms of bottles. Rough impurities such as drinking straws, cigarette butts, crown corks,
etc. are deposits in a collection pan together with residue from rinsing bottles.

A special method of water control removes all residue out of the machine via a filler/discharge
belt into a waste collection receptacle.

Pre- heating 1

Pre-heating of bottles and bottle supporting units such as bottle pockets, carriers and chain is
carried out by submerging and filling. Empting of the water is carried out in a separate
discharging basin to avoid strong contamination of the following spraying zones. The glass
debris resulting from glass breakage in the submerged zone of pre-heating 3 are collected in a
cullet and discharged on the supplying side after daily emptying of the bath.

Pre-heating 2

Pre-heating of bottles and supporting unites is carried out by a flushing system constituted of
outer and inner flushing devices fitted at given intervals to ensure optimal spraying. The medium
to be sprayed is cleaned in a filtering system to the bath to protect the spraying pipes from
contamination.

AUTOMATIC LEVEL CONTROL

The machine is equipped an automatic filling control to keep the level of caustic in the submersion
baths at the personified level. The current level of caustic in the bath is measured by a pressure
sensor mounted in the drain box of the submersion bath and forwarded to the PLC. The PLC
regulates the filling level.

 Drain box
 Pressure sensor

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 Caustic bath side wall

 Over safety switch(float switch)
 Caustic cascade
 MAX level during operation and with flush off running
 Filling level during automatic filling with fresh water and settled caustic

Figure 5: External structure of bottle washer machine

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Figure 6, Controlling Board and Internal structure of washer machine

2.2.4 CONVEYER
A conveyor system is a common piece of mechanical handling equipment that moves materials
from one location to another. Conveyors are especially useful in applications involving the
transportation of heavy or bulky materials. Conveyor systems allow quick and efficient
transportation for a wide variety of materials, which make them very popular in the material
handling and packaging industries. Many kinds of conveying systems are available, and are used
according to the various needs of different industries.

Figure 2.3: conveyor machine

MOHA uses chain conveyors (floor and overhead as well. After the bottles are well washed and dry
they under go to the filler by the help of conveyor. In the accelerating conveyor zone gaps and
accumulation are detected by automatic swiches(sensors) which is used to transmit data to PLC.
The PLC determines the required conveyor speed.

2.2.5 Para mix

Is the machine which controls the processing and preparing the product mix such as Pepsi cola,
mirinda orange, mirinda tonic, 7 up, and mirinda apple The system is working with
cooperatively with a digital computer listed for automation of electromechanical process, such as
control of machineries on the factory which is called PLC (programmable logic control).The
PLC is accountable for the control of components like actuators for valves, pumps, drives and
pipes. Three components come through the pipe these are the water, the syrup and CO2. Both
syrup and water tank consists of circulation pump. A circulation pump is used to circulate the
water throughout the tank. Circulation pump works side by side with the vacuum pump. The mix
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creates bubble and the bubbles are not needed for the product as a result vacuum pump is used to
extracts the CO2 and gases.

2.2.6 Process of making beverage (Para mix)

The processes of making the soft drinks in the company have three tanks namely, water tank,
syrup tank and final product tank (buffer tank). In the water tank there is a system which
separates the water from other gases and eliminated by the help of vacuum pump motor .Then
the water go to mixer pump. The mixing pump is an induction motor with two in late and one
out late which mix the syrup with water. The water and syrup are carefully combined by
sophisticated machines, called proportions, which regulate the flow rate and ratio of the liquids.
The vessels are pressurized with carbon dioxide to prevent aeration of the mixture. The rate of
proportionally of water and syrup is 1:5 respectively. After it mix the product should be cool to
be carbonated. The cooling system is the combination of ammonia, water and glycol. The Glycol
cools the beverage by conduction (with the contact of product pipe and glycol pipe). After the
beverage cooled it mix with carbon dioxide.

Carbonation is generally added to finished product, though it may be mixed into the water at an
earlier stage. The temperature of the liquid temperature must be carefully controlled since carbon
dioxide solubility increase as the liquid temperature decrease. The amount of carbon dioxide
pressure used depends on the type of soft drink. For instance, fruit drinks required far less
carbonation than mixer drink, such as tonics, which are meant to be diluted with other liquids.
The beverage is slightly over-pressured with carbon dioxide to facilitate the movement into
storage tanks and ultimately to the filler machine. After this process the product pass to final
product tank (buffer tank).

In the final product tank there is a sampler which take a sample and check whether there
is a shortage of syrup or shortage of water. If there is a shortage of syrup or shortage of water the
sampler command the dozing pump to open, the function of a dozing pump is to balance the
beverage and to reach to its required state. If there is excess of water it opens the syrup tank and
feed the required amount of syrup or if there is an excess of syrup the dozing pump open the
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water tank and feed until it reaches to its required state. All of beverage production is function
by the help of PLC and programs. There are sensors, float switch, 7 motors and solenoid coils.

Figure 7: Control diagram of Production process

2.3. Automatic bottle filler machine

Filler is a machine which is used to fill the bottles with the drinks that has been prepared in the
Para mix. The automatic filling machine is the most reliable, accurate, more complicated and
cost effective liquid filling machine .It has 66 nozzles more of the function is controlled by PLC
and it fill 24000 bottles/hr. It is unyieldingly connected with the Para mix and the crowner cork
section. It also has bowl pressure, the bowl level, the bowl litter, capacity, mode filler, bottle
counter, and the temperature. These all things have their own purpose. The various filling
process are selected at the operator panel. First the drink is stored in the bowl and above this
drink carbon dioxide gas will be placed, and then when the empty bottles are transported by the
in feed conveyor through the in feed worm gear which pushes the bottles in sequenced manner
and indeed star of the preparation table and positioned to the filling process then the bottles are
pressed against the filling valve by a lifting element called piston (lifting cylinder).

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- 1 bottle carrier
- 2 retraction roller
- 3 Air reaches ring line
- 4 drain screw
- 5 guide

Figure 2.5: lifting cylinders

The piston will perceive the existence of the bottles during the lifting process. If the bottle is
present the process is started and the bottle is filled. The corresponding filling valve remains
closed if the bottle is missing or when filling is finished, the switch pinion forces the spring
carrying the flow control valve to close and hence flow of product to the bottle stops.

The pressing elements have the task of pressing bottles up tight against the filler element. There
are also 99 filling valves called vents and expanding tubes, where these tubes have small holes
that are used to transport the gas as well as the drinks in the inside and outer side respectively. In
this section theCO2should be filled first in the bottles in order to balance the temperature and the
pressure as well. When the fluid (drink) poured into the bottle the gas occupying the remaining
vacant space of the bottle goes up to the returned gas media through the vent tube in the ring
tank. The length of the return air tube determines the filling level in the bottle, this is because
filling terminates when the product in the bottle reaches the bottom edge of the return air tube.
After the filling process has been completed the gas and water valves are mechanically closed by
means of cam shaft. Then the filled bottle will be sealed and conveyed.

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Filling principles (filling machine operational procedures)

 Centering of the bottle: alignment of the bottles to the filling valve

 Positioning of the bottles: the bottles pushed by the bottle lift, comes into contact with
the centering cup and placed in the working position.
 Pre- pressuring: the air valve opens for a very short time, thus allowing CO2 to entering
the bottle
 Evacuation: by closing the air valve, the mixture of residual air and from the pre-
pressuring is sucked.
 Filling: the product from the ring tank starts to flow into the bottle by flowing over the
radiation collar into the bottle internal wall surface at the same time the gas return to the
filling bowl.

Fill ending: When product is reaches the tips of the filling tube. It blocks the filling by interrupting
the return of the gas to the filling bowl filling terminates when the product in the bottle reaches the
bottom edge of the return air tube. When filling is finished, the switch pinion forces the spring
carrying the flow control valve to close and hence flow of product to the bottle stops.

 Decompression: Closing the filling valve, the gas remaining in the neck of the bottle is
ejecting by pressing pushing button.
 Releasing of bottles: it is performed by discharge star.
 Capping: it is done by Crowner upper it consists of capper closure, crown feed, sorter,
vibrator, magnetic belt conveyor, sealing

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Figure 8 Filling machine

2.3.1. Packer machine

After the bottles properly filled they undergo to packer machine with the help of conveyor. The
company packer machine is a type of high speed, Automatic Operational mode. It has 96 nozzles
which sack the bottles and put in to the cart. The packer is capable to excellently perform sorting
and order-picking tasks. The inclusion of servo motors, cog belts and continuous path control
induces the drive equipment of Inn pack PPZ with highest modernity and efficient. The machine
is robust and robotic. The controlling system of the packer is either machine control or by pass.

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Figure 9 Back side of packer machine

Figure
10 Front of packer machine

There are changeover program for the tank in which the bricks is placed. In short way it means
cleaning internal part. There are two steps

TOFROM PEPSI MIRINDA MIRINDA 7-UP TONIC

ORANGE APPLE

PEPSI 3-STEPS RINSE 5-STEPS RINSE

MIRINDA 5-STEPS 3-STEPS 5-STEPS 3-STEPS

ORANGE

MIRINDA 5-STEPS 3-STEPS 5-STEPS 3-STEPS

APPLE

7-UP 3-STEPS RINSE RINSE 3-STEPS

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TONIC 3-STEPS 3-STEPS 3-STEPS 3-STEPS

Table 11 Cleaning internal part

From the above table we see changeover CIP matrix of MOHA Factory:

1. The 3 steps

 First rinse by 50OC- 60OC water for 10-15 minutes

 Cleaning by 50OC -60OC using caustic soda for 20 minutes and the concentration of this
soda should be in between 0.5%-2%.
 Rinse by 38OC -OC water for 10-15 minutes then checking for the absence of chemicals.
2. The five steps

 Cleaning by 50OC -60OC using caustic soda for 20 minutes and the concentration of this
soda should be in between 0.5%-2%.
 Rinse by 38OC -OC water for 10-15 minutes then checking for the absence of chemicals
 Sanitize either by hot water at 80OC for 15 minutes or chlorine at 100ppm PH
concentration for 20 minutes

2.3.2 Air compressors

Is the device that generates air pressure Air is drawn in from the atmosphere and compressed air to an
intermediate pressure the compressor has receiver tank which is used as storage reservoir for compressed
air the receiver allows the compressed air an opportunity to cool. This compressor also has an air drier that
ensures the removal of water from the tank and Daberator (which is used to filter air). Compression is
accomplished by the reciprocating movement of a piston with in a cylinder. This motion fills the cylinder
and compressed air.

2.3.3 Sugar Room and Syrup Preparation

The syrup preparation process and the sugar dissolving process are the most significant process
for the company. There are different tankers used for the process:-

 Sugar Dissolving tank

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The sugar is added to Sugar Dissolving tank through screw conveyer then the jet mixer (Agitator
motor) mixes the sugar with treated water. The Dissolving tank also consists circulation motor
which is used to prevent the sugar from settling. Around the Dissolving tank there is a steam
pipe in order to melt the sugar through conduction. Activated Carbon is added to the tank in
order to clean the sugar then we wait for 25 minute. Additionally, we use High flow (sylatten)
for 5 minutes for better cleanness if the sugar we used in the process is produced in Ethiopia.
The temperature of the Dissolved sugar becomes 800c.

 Filter AID Mixed tank

Here, the sylattenis mixed with water by mixer motor then goes to filter press or filter
sheet in order to form sylatten sheet.
 Slattern sheet: - which is used to filter the dissolved sugar. After filtration the dissolved
sugar goes to Chiller .The CO2 is added to it in order to push the remnant sugar.
 Chiller (Heat exchanger):- is used to cool down the temperature of the dissolved sugar by
conduction with water. The temperature of the sugar becomes 25 0C.
 Filter Bag:-Finally, the Dissolved sugar filtered with filter bag and goes to Syrup Tank in
Syrup Preparation Room.
 Syrup Room:-This room contains six Syrup Tanks and one Dissolving Tank. Here in the
Dissolving Tank we use Agitator motor in order to mix the Flavor and different Dray
Component. Then pump motor suck and take the mixed component to the Syrup Tank
and it is mixed with Dissolved Sugar by Agitator motor.

2.3.4 Cooling system

The refrigeration or the cooling system of the plant consists of components where the actions
take place such as compressor, condenser, evaporator expansion valve, oil separator, heat
exchanges and intermediate tank. The system is protected against high and low pressure by
means of pressure switch which stops the compressor in the case of pressure disturbance. First
ammonia are working below ambient pressure is compressed in the form of steam gas towards
the four stage compressor and it will be pushed by means of reciprocating piston towards as the

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filtrate tank. Through pipe which consists of an oil separator, an oil lubrication. This plays a
significant role for the cooling system of mechanical parts inside the compressor. The
compressor generates the pressure difference between high and low pressure. The oil discharge
is regulated by the solenoid valve which is working automatically. After the oil separator, the
steam formed by ammonia will be sent toward the condenser which contains the breathing
apparatus that is responsible for cooling water over ammonia pipe and then ammonia will
change its state and returned by another pipe through expansion valve which throttles the
ammonia liquid under high pressure to the evaporator. The evaporator is part of a system in
which cooling is taking place. It comprises the heat exchanger which receives glycol water inlet
and glycol water outlet. And the evaporator is responsible to transfer the cooling media of
ammonia to the glycol water by conduction.

The glycol in and out recirculation from the intermediate tank towards the evaporator and
vice versa are transmitted through consumer pump and chiller pump. The other vital component
the major role in the manufacturing plant is the heat exchanger.

2.3.5 Water treatment room

The water treatment is a process performed in reverse osmosis process. The first section in this
room is Multimedia sand Filter (MMF), here the Tank initially contains Sand then the raw water
and limited amount of FeSO4 is added to it. Then the water goes to Intermediate Storage Tank by
using pump motor and chlorine is added to it in order to kill Micro Organism. From the storage
Tank the water goes to Membrane for filtration system. Before the water enters the membrane
Sodium Meta bi sulfate is used to remove chlorine then we use Caustic Soda (so as to adjust PH)
and Anti scalene (used to remove scale or rust).After that the water goes to Product tank and
chlorine is added to it .Finally, the water is treated with Carbon Filter (to remove carbon),
Polisher (to remove carbon) and CCP (Ultraviolet lamp).Then the treated water goes to water
Tank.

The soft water used in washer and boiler is also prepared in this room. The softener gets the
water from the water Reservoir. Here we use sand for filtration and zeolite is used to change
hard water to soft water.

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Figure 1.9: Control diagram of water treatment room

2.3.6 Steam boiler

The principle of the function of steam boiler is fully automatic where the operation is effected by
switching on the step switch of oil furnace and by putting by the switch of the boiler feed pump
“automatic”. Steam pressure, oil furnace and height of water level are regulated automatically.
Thermal energy is transported to the water inside the boiler body by means of heating. The water
grows warmer and vaporizes the steam so the pressure in the boiler rises. As soon as the working
pressure is a trained, the pressure governor cuts of heating. The pressure governor will connect
up the furnace again. There only small quantities of steams are required; the furnace has not to
switch on and cuts of itself permanently. The burners inside the boiler have two stages regulation
system on the switch board. According to steam needed stage 1, stage 2 or both stage1 and
stage2.

Initially the furnace oil is soft, so we should have to soften it by increasing the
temperature. Then, the softener oil goes to the master oil pump, which is a 3-phase heater. Inside

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the master oil pump we have a solenoid or resistor in order to heat the furnace oil so as to make
it suitable for spray. Here the solenoid valve is electrically energized and controlled by Photo
cell sensor (is used to indicate the presence of spark). The spark plug or Electrodes are very
essential to spill the furnace oil. For the spark formation we use to electrodes and each electrodes
are connected with a high voltage of 14,000V.To generate this high voltage step up transformer
is used.

2.3.7 CO2 facility room

CO2 facility process is one of the significant utility sections which is prepared inside the CO 2
room which is controlled by observing the pressure gauge on the top side of CO 2tanker. The
desired and well prepared gas is transported via to the filler machine through a transmission
pipe. The filler machine is responsible to pressurize and mix with the soft drink. This is an
accomplished after the co2 gas and product components are correctly checked by using a control
system known as PLC.
d) Programmable logic controllers (PLCs)

Programmable logic controllers are used extensively in diverse industrial applications ranging from
machining to automated assembly. They were designed to replace the necessary sequential relay
circuits for machine control. PLCs have been gaining popularity on the factory floor and will
probably remain predominant for some time to come. Other areas of application of PLCs are
industrial automation and control of industrial equipment. Most of this is because of the advantages
they offer.
 Cost effective and flexible
 Computational abilities
 Troubleshooting aids
 Reliable components

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e) Main PLC Parts

PLCs are often defined as miniature industrial computers that contain hardware and software used
to perform control functions. A PLC consists of five modules;

Central processing unit (CPU)/processor

Input module
Output module
Power supply module
Programming unit
Small PLC is modular including the CPU, inputs and outputs in one module. On the other hand
larger PLCs comprise of different modules listed above.

3.1.3 Benefits gained from the internship

Internship program is a method of letting the students to assume themselves as a potentially
responsible workman for a particular work by assigning them to actively participating in production
control as well as maintenance in industrial company. And such trends help us to have valuable
work experience. Internship programs are also potentially valuable to company. Unfortunately,
some companies continue to regard interns as little more than a free source of labor to catch up on
filing and other tedious office tasks. But many business owners and managers realize that internship
programs can provide them with an early opportunity to gauge the talents of a new generation of
workers and, in many cases, sell themselves as a quality place for students to begin their careers
after they graduate.
In this internship we could observe what the outside industrial world looks like more than we know
when we were at school. When we were at the school we learned or take many theoretical lessons
even difficult to understand theoretically. So in this internship we get good opportunity to solve
these difficulties. Because those things which were theoretically difficult to understand, were not
hard to understand when we learned practically.

The overall benefits of the intern ship are not limited to the practical skill only. We would like to
group the overall benefits that we have been gained in terms of different categories such as:-
 improving practical skill
 upgrading theoretical knowledge
 improving interpersonal communication skill
 improving team playing skill
 improving leadership skill

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 understanding about work ethics related issues

 entrepreneurship skill
3.1.3.1 In terms of improving practical skills
As it’s commonly practiced, most of the courses were taken in the class dealt with the theoretical
side of engineering. Some lecturers took the initiative and tried to illustrate the practical part of this
field by displaying different graphic images in their lecture or suggested materials in the laboratory.
That was more or less illustrative or even took us to the company to show what the actual
engineering look like. But these trials were fruitless and failed to give us the clear picture. Although
this visits helped us get a little more familiar with the tangible part, they were simply not enough.
This internship program was exactly what we needed to nurture the lack of practical skills we had.
Generally as an internship student we’re responsible to handle the following tasks.

 Troubleshooting and maintenance

 Electrical/electronics, control and automation systems.
 Variable frequency drives
 Winding of electrical motor
 Single phase induction motor winding
 Three phase induction motor winding
 Replacing electrical protective device when they failed
 Making simple installation like electrical light installation
 Seeing how to read tag number from electrical material and relate it with the wiring diagram
 Identifying cause of motor failure

3.1.3.2 In terms of upgrading theoretical knowledge

This internship program provided us broadening our intellectual knowledge and practical skills. The
work we did was mostly related to most courses that we have taken in the class room, especially
power electronics, machine, process control etc. During class time before the internship, we mainly
discussed PLC, control system, motor winding, application of power electronics and electric drives
etc. we covered here application of power electronics like convertor and inverter, PLC, motor
winding.

3.1.3.3 In terms of improving interpersonal communication skill

Interpersonal communication is usually defined by communication scholars in numerous ways,

usually describing participants who are dependent upon one another and have a shared history. It
can involve one on one conversations or individuals interacting with many people within a society.
It helps us understand how and why people behave and communicate in different ways to construct

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and negotiate a social reality. While interpersonal communication can be defined as its own area of
study, it also occurs within other contexts like groups and organizations.

For any person communication is an important way of learning, which can be defined formally as
the act, process, or experience of gaining knowledge or skills. Cool communication is important in
the real industrial world and it can appear in different forms as speaking, writing, and listening.
Production is team work, which is performed by not only by one person rather than cooperation
with other. This success couldn’t be achieved without developing good communication skill.

Company that we have been involved has different people with various back ground came together.
They are varying in educational level, economic situations, cultural backgrounds and etc. Since the
aim of the company is to accomplish the work in good way, we need to have good communicative
skills.

During our internship we have improved our communication skill by communicating starting from
daily labor to project manager learning different type of production terms.

3.1.3.4 In terms of improving team playing skill

At times, when different individuals come together to work for common goals of the company for
increasing productivity, the most important point is just reaching an agreement from different points
on the work to be done. In general a person with good team playing skill will upgrade the
following;

 To share ideas with colleagues openly and willingly

 To become more confidence on tasks
 To give attention other’s idea
 To treat others in a respectful and supportive manner
 To accept advices and technical supports
 To demonstrate reliability
 To increase the ability of active participant
 To help and co-operate with others
 To give comment to the team
 To become a problem solver on time

3.1.3.5 In terms of improving leadership skill

No much place of responsibility was given to me to lead any task. As such, we have not got full
benefits from leadership skills during our stay in the company. But from observations of the leader

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of the company leading the workers, if we are in the position of leadership, we understood from the
internship to give relevant and important solutions to the problems and should be active to manage
those individuals whom we are leading.

In terms of improving leadership skills we offered the followings;

 To become accurate and more sure on our judgment

 To know ourselves and to make self improvement
 To give technical support
 To become more responsible in actions
 To increase our work states
 To plan, schedule and to prepare all necessary materials
3.1.3.6 In terms of understanding about work ethics related issues

Work ethics include not only how one feels about their job, career or vocation, but also how one
does his/her job or responsibilities. This involves attitude, behavior, respect, communication, and
interaction; how one gets along with others. Work ethics demonstrate many things about whom and
how a person is. Work ethics involve such characteristics as honesty and accountability. Essentially,
work ethics break down to what one does or would do in a particular situation. The begging
question in a situation involves what is right and acceptable, and above board, versus what is
wrong, underhanded, and under the table.

In our period of internship we understand what work ethics, one of ethics is punctuality. To be
punctual is duties of every worker so that they could achieve their task with the time given and we
have been punctual. Other work ethics is to be anti corruption which not taking thing that benefited
us in illegal way.

Some of the work ethics includes;

 Punctuality
 Office disciplines
 Reliability
 Honesty
 Cooperation
 Avoiding potential or apparent conflict of interests

From this perspective, I’ve gained a valuable lesson that transparency and carefulness are two very
important work ethics one needs to abide and live by.

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CHAPTER FOUR
3.1 TOTAL OBSERVATION IN THE COMPANY
We have worked our internship for four months in Moha soft drinks. During the time of internship
we have observed the overall processing of the company starting from its management up to the
final output product and its shop such as Mechanical shop and Electrical shop. In the first two
weeks we visit these shops. Then after we have observed all the process of the company, we have
selected the Electrical shop and electrical application area because when we observed in the first
two weeks we have identified some problems in the Electrical application and some problem attract
our intention. After we identified the problems we tried to give some recommendations and
suggestion about that problem

3.2 Problems observed in the company

problem on manual inspection of full bottles

problem on empty bottle inspection & rejection system
Problem on manual removing of burned copper wire from motors
These problems have a greater impact and are the major reason for excess down time and quality
related problems that exist in the production line of soft drink. Especially the copper wire removing
is the major problem it have a great in increasing the profitability of the company.

3.3 Short summary of the project

The company uses human power to clean cooper wire coil and all varnish epoxy, paint and
insulation from motors system so it needs a special simple application. Also they are very costly
regarding with labor power and time spending then we try to reduce this very costly boring system
into simple manner. The project contains a simple electrical equipment simulation that is used to
rewind motors

3.5 Statement of problem

Generally the company uses to remove the material from motor by hand this is slow and
expensive often damaging to parts and unsafe for working. Not only did it solve safety it helped
rebuilders dramatically Increase production capacity efficiency and quality so the Automatic
controls regulated by temperature of stator core safety and economically strips stators and parts
without any damage to aluminum or “T” frames addition to the system the labor power is not
enough guarantees as we see. We try to reduce this tedious and large man power company system
into a simple and applicable automatic electrical system

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3.6 Objective of the project

The main objective of this project is to integrate the hard wired control system of rewind of motor
by using oven to PLC control system.
3.6 1 Main objective
 To make the system simple and moderate
 To reduce maintenance cost
 To reduce motor hold up time.
 To reduce property (stator) loss
 To save wastage of time
 To make the work more flexible

3.6.2 Specific objective

 To be familiar with PLC
 To identify different parts of some control systems

37 Methodology of the Project

For this project work we follow the following methodology7

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Figure 2 methodology of the project

What is PLC?

 History

Programmable Logic Controllers were discovered by the automotive industry to substitute the re-
wiring of the machine’s control panel.

Prior to the invention of PLC, automobiles were manufactured using plenty of relays, cam timers,
and closed loop controllers. The electricians had to re-wire every part of the machine daily which
was time consuming and highly expensive on the financial front.

Later in the year 1968, a request for an electronic device for the hard-wired relay systems was made
by GM hydromantic. Bedford Associates won the proposal and started a new company to develop,
fabricate, sell, and service this new launched product. The first PLC launched was designated 084
as it was the eighty fourth projects of Bedford Associates. Dick Morley worked on this project and
is being considered as the Father of PLC. In the year 1977, the brand invented by Modicon was sold
to Gould Electronics. The Gould Electronics later sold it to German Company AEG which was later
taken over by French Schneider Electric.

The first 084 model of PLC was revealed in North Andover, Massachusetts at the Modicon
headquarters.

The manufacturing industry is one of the largest users of PLC.

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Initially industries used relays to control the manufacturing processes. The relay control panels had
to be regularly replaced; it consumes lot of power and it was difficult to figure out the problems
associated with it. To sort these issues, Programmable logic controller (PLC) was introduced.

 PLC

Programmable Logic Controller (PLC) is a digital computer used for the automation of various
electro-mechanical processes in industries. These controllers are specially designed to survive in
harsh situations and shielded from heat, cold, dust, vibrations, noise, humidity, and moisture etc.
PLC consists of a microprocessor which is programmed using the computer language.

The program is written on a computer and is downloaded to the PLC via cable. These loaded
programs are stored in non – volatile memory of the PLC. During the transition of relay control
panels to PLC, the hard wired relay logic was exchanged for the program fed by the user. A visual
programming language known as the Ladder Logic was created to program the PLC.

Fig3.1 controlling screen

 PLC Hardware

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The hardware components of a PLC system are CPU, Memory, Input/Output, Power supply unit,
and programming device. Below is a diagram of the system overview of PLC.

Fig 3.2 plc. Hardware components

 CPU – Keeps checking the PLC controller to avoid errors. They perform functions including
logic operations, arithmetic operations, computer interface and many more.
 Memory – Fixed data is used by the CPU. System (ROM) stores the data permanently for
the operating system. RAM stores the information of the status of input and output devices,
and the values of timers, counters and other internal devices.
 I/O section – Input keeps a track on field devices which includes sensors, switches.
 O/P Section - Output has a control over the other devices which includes motors, pumps,
lights and solenoids. The I/O ports are based on Reduced Instruction Set Computer (RISC).
 Power supply – Certain PLCs have an isolated power supply. But, most of the PLCs work at
220VAC or 24VDC.
 Programming device – This device is used to feed the program into the memory of the
processor. The program is first fed to the programming device and later it is transmitted to
the PLC’s memory.

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 System Buses – Buses are the paths through which the digital signal flows internally of the
PLC. The four system buses are:
1. Data bus is used by the CPU to transfer data among different elements.
2. Control bus transfers signals related to the action that are controlled internally.
3. Address bus sends the location’s addresses to access the data.
4. System bus helps the I/O port and I/O unit to communicate with each other
 Working of PLC (Programmable Logic Controller)

The Programmable logic controller functions in three steps.

Fig3.3. Working steps of plc.

1. Input scan: The state of the input is scanned which is connected externally. The
inputs include switches, pushbuttons, and proximity sensors, limit switches,
pressure switches. Ideally, they are transformers and not relays.
2. Program scan: The loaded program is executed to carry out the function
appropriately.
3. Output scan: The input sources have a control over the output ports to energize
or de-energize them. The outputs include solenoids, valves, motors, actuator, and
pumps. Depending on the model of PLC, these relays can be transistors, triacs or
relays.
 Advantages of PLC
 PLCs can be programmed easily which can be understood clearly well.

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 They are fabricated to survive vibrations, noise, humidity, and temperature.

 The controller has the input and output for interfacing.
 Disadvantages of PLC
 It is a tedious job when replacing or bringing any changes to it.
 Skilful work force is required to find its errors.
 Lot of effort is put to connect the wires.
 The holdup time is usually indefinite when any problem arises.

The STEP 7 Standard Package

The standard package matches the graphic and object oriented operating philosophy of Windows
and runs under the operating systems MS Windows XP Professional (simply Windows XP below),
MS Windows Server 2003 and MS Windows 7 Business, Ultimate and Enterprise

 Functions of the standard package

The standard software supports you in all phases of the creation process of an automation task, such
as:

 Setting up and managing projects

 Configuring and assigning parameters to hardware and communications
 Managing symbols
 Creating programs, for example, for S7 programmable controllers
 Downloading programs to programmable controllers
 Testing the automation system

 Applications in STEP 7

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The STEP 7 Standard package provides a series of applications (tools) within the software:

Fig3.4 S7 standard package

 You do not need to open the tools separately; they are started automatically when you select
the corresponding function or open an object.

Circuit design

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Used symbols and their description

1. ---( ). This symbol represents the Output Coil it works like a coil in a relay logic diagram. If
there is power flow to the coil the bit at location <address> is set to "1". If there is no power
flow to the coil, the bit at location <address> is set to "0". An output coil can only be placed at
the right end of a ladder rung.
2. ---| |---. This symbol represents the Normally Open Contact. It is closed when the bit value
stored at the specified <address> is equal to "1". When the contact is closed, ladder rail power
flows across the contact and the result of logic operation = "1".
3. ---| / |---. This symbol represents the normally closed Contact. It is closed when the bit value
stored at the specified <address> is equal to "0". When the contact is closed, ladder rail power
flows across the contact and the result of logic operation = "1".

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4.
S_PULSE (Pulse S5 Timer) starts the specified timer if there is a positive
edge at the start (S) input. A signal change is always necessary in order to
enable a timer. The timer runs as long as the signal state at input S is "1", the longest
period, however, is the time value specified by input TV. The signal state at output Q is "1"
as long as the timer is running. If there is a change from "1" to "0" at the S input before the
time interval has elapsed the timer will be stopped. In this case the signal state at output Q
is "0". The timer is reset when the timer reset (R) input changes from "0" to "1" while the
timer is running. The current time and the time base are also set to zero. Logic "1" at the
timer's R input has no effect if the timer is not running.

The current time value can be scanned at the outputs BI and BCD. The time value at BI is binary
coded, at BCD it is BCD coded. The current time value is the initial TV value minus the time
elapsed since the timer was started.

5. S_PEXT (Extended Pulse S5 Timer) starts the specified timer if there is

a positive edge at the start (S) input. A signal change is always necessary
in order to enable a timer. The timer runs for the preset time interval specified at input TV
even if the signal state at the S input changes to "0" before the time interval has elapsed. The
signal state at output Q is "1" as long as the timer is running. The timer will be restarted ("re-
triggered") with the preset time value if the signal state at input S changes from "0" to "1"
while the timer is running. The timer is reset if the reset (R) input changes from "0" to "1"
while the timer is running. The current time and the time base are set to zero.

The current time value can be scanned at the outputs BI and BCD. The time value at BI is binary
coded, at BCD is BCD coded. The current time value is the initial TV value minus the time elapsed
since the timer was started.

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6. SR (Set-Reset Flip Flop) is set if the signal state is "1" at the S input, and
"0"at the R input. Otherwise, if the signal state is "0" at the S input and "1"at
the R input, the flip flop is reset. If it is "1" at both inputs, the order is of primary
importance. The SR flip flop executes first the set instruction then the reset instruction at the
specified <address>, so that this address remains reset for the remainder of program scanning.
Otherwise, if the signal state at the specified <address> is "1", the contact is opened. When the
contact is opened, power does not flow across the contact and the result of logic operation (RLO) =
"0".

Otherwise, if the signal state at the specified <address> is "0", the contact is open. When the contact
is open, power does not flow across the contact and the result of logic operation (RLO) = "0".

7. CMP? I (Compare Integer) can be used like a normal

contact. It can be located at any position where a normal
contact could be placed. IN1 and IN2 are compared
according to the type of comparison you choose. If the
comparison is true, the RLO of the function is "1". It is linked to the RLO of the whole rung by
AND if the box is used in series, or by OR if the box is used in parallel.

Results and simulation

In this project simulation we have got the following results

1. When the system is running in manual mode of operation

The oven coil got energy and it starts to melt the copper wire that is found inside the
motor until the manual stop pushbutton is pressed.
When the manual stop pushbutton is pressed, the oven stops the burning off process
and automatically the fun coil is energized and it starts to cool down the oven up to
the set point is reached.
2. When the system is running in auto (timer) mode of operation

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 The oven coil got energy and it starts to melt the copper wire that is found inside the
motor until the timer set point is reached.
 When the timer set point is reached, the oven stops the burning off process and
automatically the fun coil is energized and it starts to cool down the oven up to the
set point is reached.
3. When the system is running in auto (sensor) mode of operation
 The oven coil got energy and it starts to melt the copper wire that is found inside
the motor until the sensor set point is reached.
 When the sensor set point is reached, the oven stops the burning off process and
automatically the fun coil is energized and it starts to cool down the oven up to the
set point is reached

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CHAPTER FIVE

4.1 Conclusion and Recommendation

5.1 Conclusion

From four months (one semester) in internship program, we have concluded that it gives real practical skills
and make students being familiar to the out6side industries world. Truly, it prepared us to pay special
attention in all practical activities that will be carried out in the company. Because, of little error or mistake
can leads to large failure in the production process if it is not carried in the correct procedure. Also this
program allows us to make and develop professional contacts for our future time and it helps us to know
maintenance terms and working standards. Finally, the benefits we offered from the program are: work
ethics and team playing skills, Upgrading control and power concepts that we have been seen in the class.

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4.1.1 Recommendation to the hosting company

In these four month internship semester we have got the chance to see something not good and
affect the company’s quality and hinder its growth and efficiency. And we think they need our
recommendation. And we would like to recommend on some of them.

 Lack of spare part for machine and its components

 The motor winder waste a lot of time and labor force when the motor is rewind, since no
winding machines in electrical workshop
 The CO2 plant must produce in its maximum capacity to satisfy the necessity of CO2 gas to
company and its customers by maintain its failed part
 The company engineer must trained on each machine, especially on hard wired control
system and PLC in order to maintain the machines as soon as it failed
 The company should use Industrial Internet, to solve electrical problem that is beyond
ability of the company’s engineer by communicating with other engineer or by getting
online maintenance.

4.1.2 Recommendation to the university

Depending on our work from the very beginning to the end we would like to recommend the
following important points
 There is lack of coordination between university industrial linkage and host companies
 The university should arrange some practical visit in some courses. Because it helps the
students to easy understand what they are learnt in laboratory and lecture class. In this
internship we saw how it is easy to understand on practical work.
 The university should have some contact with the host companies the students are assigned
to facilitate some coordination and to help the students what they have to know
 The department should send the student to the host company on time for this internship
program
 Finally the budget allocation for this internship program is not enough for the students to
spend in this program.
Therefore the university should reconsider the program rule and law by taking the above
recommendation under consideration

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References

1. Hawassa millennium Pepsi cola plant company’s profile, like electrical manual
2. A text book of electrical machine II by U.A.Bakshi and M.V.Bakshi
3. Training manual on PLC by Mengesha Mamo Addis Ababa University at May 2009
4. htt://www.krones.com

Oral data gained from the Electrical supervisor4.1.1 Recommendation to the hosting
company
In these four month internship semester we have got the chance to see something not good and
affect the company’s quality and hinder its growth and efficiency. And we think they need our
recommendation. And we would like to recommend on some of them.

 Lack of spare part for machine and its components

 The motor winder waste a lot of time and labor force when the motor is rewind, since no
winding machines in electrical workshop
 The CO2 plant must produce in its maximum capacity to satisfy the necessity of CO2 gas to
company and its customers by maintain its failed part
 The company engineer must trained on each machine, especially on hard wired control
system and PLC in order to maintain the machines as soon as it failed
 The company should use Industrial Internet, to solve electrical problem that is beyond
ability of the company’s engineer by communicating with other engineer or by getting
online maintenance.

4.1.2 Recommendation to the university

Depending on our work from the very beginning to the end we would like to recommend the
following important points
 There is lack of coordination between university industrial linkage and host companies
 The university should arrange some practical visit in some courses. Because it helps the
students to easy understand what they are learnt in laboratory and lecture class. In this
internship we saw how it is easy to understand on practical work.
 The university should have some contact with the host companies the students are assigned
to facilitate some coordination and to help the students what they have to know
 The department should send the student to the host company on time for this internship
program
 Finally the budget allocation for this internship program is not enough for the students to
spend in this program.

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Therefore the university should reconsider the program rule and law by taking the above
recommendation under consideration

References

5. Hawassa millennium Pepsi cola plant company’s profile, like electrical manual
6. A text book of electrical machine II by U.A.Bakshi and M.V.Bakshi
7. Training manual on PLC by Mengesha Mamo Addis Ababa University at May 2009
8. htt://www.krones.com
9. Oral data gained from the Electrical supervisor
10.

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