Automatic liquid filling and mixing process using PLC

VISVESVARAYA TECHNOLOGICAL UNIVERSITY
BELAGAVI – 590018
S.D.M. COLLEGE OF ENGINEERING & TECHNOLOGY,
DHARWAD – 580002
(An Autonomous Institution affiliated to Visvesvaraya Technological University, Belagavi – 590018)
Department of Electronics and Communication Engineering
A report on major project entitled
“AUTOMATIC LIQUID FILLING AND MIXING
PROCESS USING PLC”
Conducted by
Mr. Amit Kumar Singh - 2SD13EC007
Mr. Hemant Singh - 2SD13EC031
Mr. Nagmani - 2SD13EC058
Mr. Gaurav Kumar - 2SD12EC035
(8th
Semester B.E)
Under the guidance of
Dr. S. V. Viraktamath
Assistant Professor, Dept. of ECE
Academic year 2016-17

VISVESVARAYA TECHNOLOGICAL UNIVERSITY
BELAGAVI - 590018
S.D.M. COLLEGE OF ENGINEERING & TECHNOLOGY,
DHARWAD – 580002
(An Autonomous Institution affiliated to Visvesvaraya Technological University, Belagavi – 590018)
A report on major project entitled
“AUTOMATIC LIQUID FILLING AND MIXING
PROCESS USING PLC”
Conducted by
Mr. Amit Kumar Singh - 2SD13EC007
Mr. Henant Singh - 2SD13EC031
Mr. Nagmani - 2SD13EC058
Mr. Gaurav Kumar - 2SD12EC035
(8th
Semester B.E)
Under the guidance of
Dr. S. V. Viraktamath
Assistant Professor, Dept. of ECE
Academic year 2016-17

SDM COLLEGE OF ENGINEERING AND TECHNOLOGY, DHARWAD-580002
(An autonomous Institution affiliated to
Visvesvaraya Technological University, Belagavi – 590018)
CERTIFICATE
Certified that this report on the major-project entitled “Automatic Liquid Filling and
Mixing Process using PLC” is a bonafied work carried out by Mr. Amit Kumar Singh
(2SD13EC007), Mr. Hemant Singh (2SD13EC031), Mr. Nagmani (2SD13EC058) and
Mr. Gaurav Kumar (2SD12EC035) students of 8th
semester, Department of Electronics and
Communication Engineering, SDM College of Engineering and Technology under the
Visvesvaraya Technological University, Belagavi during the year 2016-17. The project report
has been approved as it satisfies the academic requirements in respect of Project work prescribed
for the Bachelor of Engineering Degree.
Project Guide Head of the Dept. Principal
Dr. S.V. Viraktamath Dr. G. A. Bidkar Dr. S. B. Vanakudre
Name of the student : Amit Kumar Singh
University Seat Number : 2SD13EC007
Examiner I Examiner II
Signature
with date:
Name:

ACKNOWLEDGMENT
Every project big or small is successful largely due to the effort of a number of
wonderful people who have always given their valuable advice or lent a helping hand. This
report acknowledges all such wonderful people.
We would like to express a deep sense of gratitude and sincere thanks to our guide
Dr. S. V. Viraktamath, Assistant Professor, ECE Department, SDMCET, Dharwad for his
valuable suggestions and guidance in every step of the project.
We express our sincere thanks to Dr. G. A. Bidkar, HOD ECE Department for his
constant guidance and support in extending the needed resources.
We express our gratitude to Dr. S. B. Vanakudre, Principal SDMCET, Dharwad for
all the support and guidance.
We express our deep sense of gratitude to Mr. Himanshu Kumar, Director
INDWELL Institute of Technology, Pune whose guidance, suggestion have contributed
immensely to the evolution of our ideas on the project.
We express our sincere thanks to Prof. D. S. Bhat, HOD Mechanical Engineering
Department and we acknowledge with thanks the kind of timely guidance which we have
received from Mr. R. N. Bagilad, Instructor Machine Shop Lab and Mr. Sri A Sudhindra,
Instructor Bosch Lab Mechanical Engineering Department.
We also thank all the faculty members of ECE Department, SDMCET, Dharwad for
their advice and guidance throughout the project.
We express our sincere thanks to all the non-teaching staff of ECE Department,
SDMCET for all the help.
Last but not the least we place a deep sense of gratitude to all our family members and
friends who have been constant source of inspiration during this project.
Mr.Amit Kumar Singh 2SD13EC007
Mr. Hemant Singh 2SD13EC031
Mr. Nagmani 2SD13EC058
Mr. Gaurav Kumar 2SD12EC035

ABSTRACT
This project is composite of different application which is really well utilised in
present and living environment, this project used in industrial application. Nowadays, the
application of PLC is widely known and used in this digital world. PLC’s application is
obviously applied at the industrial sector. In this project, a discussion about PLC application
will be explained in more details and specified. Whereby a machine that used to prepare
automatic filling and mixing process into bottles is fully controlled by the Bosch Rexroth
IndraLogic PLC, which acts as the heart of the system. The system sequence of operation is
designed by ladder diagram and the programming and visualization of this project is totally
integrated by IndraLogic software. Several electronics and electric devices that usually been
controlled by the PLC are alarm acknowledgement system, blinking bulb, motor for conveyor
system , submersible pump, sensors, selector switch, push button, relays, pneumatic system,
solenoid valve and other devices.

CONTENTS
CHAPTER 1: Industrial Automation………………………………………………..01
1.1: Introduction to Automation…………………………………………….02
1.2: Advantages of Automation……………………………………………..02
1.3: Disadvantages of Automation…………………………………………..02
1.4: Application……………………………………………………………...02
CHAPTER 2: History and Introduction to PLC……………………………………04
2.1: History of PLC…………………………………………………………..05
2.2: Introduction to PLC……………………………………………………..05
2.3: Architecture of PLC……………………………………………………. 06
2.4: Types of PLC…………………………………………………………….06
2.5: Applications of PLC…………………………………………………….,10
2.6: Literature Survey………………………………………………………...11
CHAPTER 3: Working of PLC……………………………………………………...12
3.1: PLC block diagram…………………………………………………….. 13
3.2: PLC scan………………………………………………………………...13
3.3: Switched Mode Power Supply…………………………………………..14
CHAPTER 4: PLC programming language…………………………………………17
4.1: Programming language in PLC………………………………………….18
4.2: Programming by Ladder diagram……………………………………….18
4.3: Generally used instruction symbol for PLC programming……………..19
4.4: Pulse……………………………………………………………………..19
4.5: Timer…………………………………………………………………….20
4.6: Counter………………………………………………………………......22
4.7: Boolean logic design by ladder program………………………………..24
4.8: Different types of PLC Software………………………………………..26
CHAPTER 5: Hardware Components………………………………………………27
5.1: Relay…………………………………………………………………….28
5.2: IR Sensor………………………………………………………………..29
5.3: Submersible pump……………………………………………………....31

5.4: DC Motor……………………………………………………………….32
5.5: Pneumatic Cylinder…………………………………………………......33
5.6: Solenoid Valve………………………………………………………….36
5.7: Capacitive proximity Sensor……………………………………………37
5.8: 2-Way Selector switch………………………………………………….37
5.9: Buzzer…………………………………………………………………..38
5.10: Blinking bulb………………………………………………………….39
5.11: Project block diagram…………………………………………………39
5.12: Hardware setup………………………………………………………..41
5.13: Visualization and project workjng…………………………………….42
Future recommendation……………………………………………………………..44
Conclusion…………………………………………………………………………….44
Reference……………………………………………………………………………...45

LIST OF FIGURES
1.1 PLC Architecture…………………………………………………………………06
1.2 Unitary PLC………………………………………………………………………07
1.3 Modular PLC……………………………………………………………………..07
1.4 Rack mounting PLC……………………………………………………………...08
1.5 Bosch Rexroth PLC……………………………………………………………….09
1.6 Block Diagram…………………………………………………………………....13
1.7 PLC scan………………………………………………………………………….14
1.8 Block diagram of SMPS………………………………………………………….14
1.9 Block diagram of dc to dc converter SMPS……………………………………...15
2.0 Block diagram of ac to dc converter SMPS……………………………………...16
2.1 Ladder diagram…………………………………………………………………..18
2.2 Rising trigger with input and output pulse……………………………………….20
2.3 Falling trigger with input and output pulse………………………………………20
2.4 Timer ON………………………………………………………………………...21
2.5 Timer OFF……………………………………………………………………….21
2.6 Retentive Timer………………………………………………………………….22
2.7 Addressing of Timer……………………………………………………………..22
2.8 Count UP………………………………………………………………………...23
2.9 Count Down……………………………………………………………………..23
3.0 Addressing of Counter…………………………………………………………..24
3.1 AND logic ladder diagram………………………………………………………24
3.2 OR logic ladder diagram………………………………………………………...24
3.3 NOT logic ladder diagram………………………………………………………24
3.4 NAND logic ladder diagram……………………………………………………25
3.5 NOR logic ladder diagram…………………………………………………….. 25
3.6 X-OR logic ladder diagram……………………………………………………..25
3.7 X-NOR logic ladder diagram…………………………………………………...25
3.8 Relay……………………………………………………………………………28
3.9 Internal architecture of relay……………………………………………………28

4.0 Working of relay……………………………………………………………….28
4.1 Bosch Rexroth sensor………………………………………………………….30
4.2 Internal circuit of IR sensor…………………………………………………....30
4.3 Submersible pump……………………………………………………………..31
4.4 DC motor………………………………………………………………………32
4.5 DC motor working…………………………………………………………….33
4.6 Pneumatic Cylinder…………………………………………………………....33
4.7 Internal part of pneumatic cylinder……………………………………………36
4.8 Solenoid valve………………………………………………………………....36
4.9 Capacitive Sensor……………………………………………………………...37
5.0 2-way selector switch………………………………………………………….38
5.1 Buzzer………………………………………………………………………… 38
5.2 Blinking bulb…………………………………………………………………..39
5.3 Project interfacing block diagram……………………………………………..40
5.4 Project hardware setup………………………………………………………...41
5.5 Visualisation…………………………………………………………………..42

Automatic Liquid Filling and Mixing Process Using PLC
Department of Electronics and Communication Engineering, SDMCET, Dharwad-02 Page 1
CHAPTER 1
INDUSTRIAL AUTOMATION

1.1 Introduction to Automation
Automation is the use of control systems such as computers to control industrial
machinery and process, reducing the need for human intervention. In the scope of
industrialization, automation is a step beyond mechanization. Whereas mechanization
provided human operators with machinery to assist them with physical requirements of work,
automation greatly reduces the need for human sensory and mental requirements as well.
Processes and systems can also be automated.
1.2 Advantages of Automation
1. Replacing human operators in tasks that involve hard physical or monotonous work.
2. Performing tasks that are beyond human capabilities of size, weight, endurance etc.
3. Economy improvement: Automation may improve in economy of enterprises, society.
1.3 Disadvantages of Automation
1. Technology limits: Current technology is unable to automate all the desired tasks.
2. Unpredictable development costs: The research and development cost of automating a
process may exceed the cost saved by the automation itself.
3. High initial cost: The automation of a new product or plant requires a huge initial
investment in comparison with the unit cost of the product.
1.4 Application
 Automated video surveillance
Automated video surveillance monitors people and vehicles in real time within a
busy environment. Existing automated surveillance systems are based on the environment
they are primarily designed to observe, i.e. indoor, outdoor or airborne, the amount of
sensors that the automated system can handle and the mobility of sensor, i.e., stationary
camera vs. mobile camera. The purpose of a surveillance system is to record properties
and trajectories of objects in a given area, generate warnings or notify designated
authority in case of occurrence of particular events [1].
 Automated manufacturing
Automated manufacturing refers to the application of automation to produce
things in the factory way. Most of the advantages of the automation technology has its
influence in the manufacture processes. The main advantage are
automated manufacturing are higher consistency and quality, reduced lead times,

simplified production, reduced handling, improved work flow, and increased worker
morale when a good implementation of the automation is made.
 Industrial automation
Industrial automation deals with the optimization of energy-efficient drive
systems by precise measurement and control technologies. Nowadays energy
efficiency in industrial processes are becoming more and more relevant.
Semiconductor companies like Infineon Technologies are offering 8-bit
microcontroller applications for example found in motor controls, general purpose
pumps, fans, and e-bikes to reduce energy consumption and thus increase efficiency.

CHAPTER 2
HISTORY AND INTRODUCTION TO PROGRAMMABLE
LOGIC CONTROLLER (PLC)

2.1 History of PLC
In the 1960's PLC were first developed to replace relays and relay control systems.
Relays, while very useful in some applications, also have some problems. The primary reason
for designing such a device was eliminating the large cost involved in replacing the
complicated relay based machine control systems for major U.S. car manufacturers. These
controllers eliminated the need of rewiring and adding additional hardware for every new
configuration of logic. These, along with other considerations, led to the development of
PLCs. PLC was more improved in 1970’s. In 1973 the ability to communicate between PLCs
was added. This also made it possible to have the controlling circuit quite a ways away from
the machine it was controlling. However, at this time the lack of standardization in PLCs
created other problems [2]. This was improved in the 1980's. The size of PLC was also
reduced then, thus using space even more efficiently. The 90's increased the collection of
ways in which a PLC could be programmed (block diagrams, instruction list, C, etc.).
2.2 Introduction to PLC
 A PLC is an industrial computer control system that continuously monitors the state of
input devices and makes decisions based upon a custom program to control the state of
output devices.
 It is designed for multiple inputs and output arrangements, extended temperature ranges,
immunity to electrical noise, and resistance to vibration and impact.
 They are used in many industries such as oil refineries, manufacturing lines, conveyor
systems and so on, wherever there is a need to control devices the PLC provides a flexible
way to "soft wire" the components together.
 The basic units have a CPU (Central Processing Unit) that is dedicated to run one
program that monitors a series of different inputs and logically manipulates the outputs
for the desired control. They are meant to be very flexible in how they can be
programmed while also providing the advantages of high reliability (no program crashes
or mechanical failures), compact and economical over traditional control systems.
 In simple words, Programmable Logic Controllers are relay control systems put in a very
small package. This means that one PLC acts basically like a bunch of relays, counters,
timers, places for data storage, and a few various other things, all in one small package.

2.3 Architecture of PLC
The PLC give output in order to switch things on or off. The PLC’s output is
proportionally activated according on the status of the system’s feedback sensors and input
terminal which is connected to PLC. The decision to activate output is based on logic
programmes. The logic programme stored in RAM or ROM memory. The PLC also have
same as computer, a CPU, data bus and address busto communicate with external devices
such as programmers, display monitor [3,4]. The next diagram shows a simplified diagram of
PLC’s structure. The central processing unit control everything according to a programme
stored in a memory (RAM/ROM). Everything is interconnected by two buses, the address bus
and data bus. The system must be able and a/d converter. Fig 2.1 shows the PLC architecture.
Fig 2.1: PLC architecture
2.4 Types of PLC
Unitary PLC
A unitary PLC is the more simple type of controller, and contains all of the basic
system components within a single housing, or box. These components typically include the
processor, which runs the software program, in addition to ports for input and output
connections. Unitary PLCs are typically attached directly to the device or application that is
being controlled.
INPUT TERMINAL
OUTPUT TERMINAL
RUN
COMM
ON
RA
M/R
OM
CPU
SOCKETS

Fig 2.2: PLC architecture
A commonly used example of a unitary PLC type is the Micrologix 1000, built by
Allen Bradley. The Micrologix 1000 includes on-board memory for storing programs, 32
digital input and output ports, and a communications port used to program the unit. This
setup is typical of many unitary systems. Fig 2.2 shows the example of Mitsubishi PLC with
various input and output port.
Modular PLC
A modular PLC shown in Fig 2.3 contains several different modules that can be
coupled together to build a customized controller. Typically, a base module contains core
functions such as electrical power regulation, the computer processor, and input connections.
Additional modules, including analog to digital signal converters or additional outputs, can be
added to this core unit as needed. This modular design allows a PLC to be customized and
changed easily.
Fig 2.3: Modular PLC

The Allen Bradley Micrologix 1200 is a commonly used example of the modular PLC
type. This unit is able to handle between 23 and 40 inputs and outputs. The actual number of
connections can be expanded easily by adding modules. This provides a wide range of
flexibility and is typical of a modular PLC.
Rack Mounting PLC
The rack mounting type of PLC is similar to the modular concept, but is implemented
differently. Whereas each module in a modular PLC connects to the base unit directly, a rack
mounting PLC keeps each module separate. All extra modules are connected through a
network, and modules are held in organized racks. This approach allows for larger systems to
be built without becoming overly cluttered and complicated. Modules are well organized on
the rack and can be removed and reinserted as needed. Fig 2.4 shows the rack mounting PLC.
The commercial unit SLC 500 is an industry-standard example of the rack mounting
PLC type. There are essentially no limits on the number of modules that can be added to this
system, each mounted on a standard rack chassis. This setup allows large, scalable
automation solutions to be built and is common in factory settings.
Fig 2.4: Rack mounting PLC

Manufacturers of PLCs
 Allen Bradley PLCs (AB)
 Bosch Rexroth PLCs
 ABB PLCs (Asea Brown Boveri)
 Siemens PLCs
 Omron PLCs
 Mitsubishi PLCs
 Hitachi PLCs
 Delta PLCs
 General Electric (GE) PLCs
 Honeywell PLCs
Bosch Rexroth PLC
The powerful Bosch Rexroth PLC systems set new standards for open automation
with a consistent control, programming and communication design. Whether we are using a
controller or an embedded or industrial PC, we can tackle any job rapidly and cost-
effectively. With state-of-the-art PLC programming according to the IEC-61131-3 standard
as well as new language elements for object orientation, all integrated in the Indra Works
engineering framework, we can achieve our application with a single, uniform software tool.
Fig 2.5: Bosch Rexroth PLC

 High performance with comprehensive functions and numerous interfaces.
 Scalable with the innovative Indra Control L platform.
 Centralized and distributed I/Os.
 Open interfaces for networking via Ethernet or PROFIBUS.
 Simple expansion via function modules (IndraLogic L40).
 Easy integration of HMI solutions.
The Indralogic L plc solutions are based on the scalable Indra control L control
platform. It is available in uniform and compatible system design for our applications in
different performance classes [5,6]. Their compact construction with terminal technology
and simple DIN rail mounting make them suitable for use in every type of automation
environment. The elimination of wearing parts such as batteries and fans permits high
reliability and costs saving in maintenance free design. Starting with the Indra Logic L20
control, an integrated display allows convenient diagnostics and parameterization of the
control without additional hardware. Eight fast inputs and outputs are integrated in the
control at no additional cost.
2.5 Applications of PLC
1. The PLC can be programmed to function as an energy management system for boiler
control for maximum efficiency and safety.
2. In automation of blender recliners
3. In automation of bulk material handling system at ports.
4. In automation for a ship unloaded.
5. Automation for wagon loaders.
6. For blast furnace charging controls in steel plants.
7. In automation of brick molding press in refractory.
8. In automation for galvanizing unit.
9. For chemical plants process control automation.
10.In automation of a rock phosphate drying and grinding system.
11. Modernization of boiler and turbo generator set.

2.6 Literature Survey
DR.A.S.C.S. Sastry, “An automated microcontroller based liquid mixing system”. In
this paper he concluded that the automated microcontroller based liquid mixing system
provides a very satisfactory performance with a minimal percentage error. The utilization of
microcontroller has been accomplished in the form of the at89s51 microcontroller. The
decision to use 3 microcontrollers was based on the elimination of idle time and optimization
of the mixing process. In addition to this the utilization of the various proposed components
such as dispensers, Sensors, Pumps, Relays, DC motor and an input device was also
accomplished[7]. The presented work was published in international journal on computer
science and engineering volume.02, no.08, 2010, 26482651. Shaukat N.PLC Based
“Automatic liquid filling process”, in this paper he concluded that this application of
automation illustrating a PLC based fully automatic untouched liquid filling and mixing
system. The system meets demand of high speed production using least mechanism
requirements. The system has proved to work effectively avoiding unnecessary spill or
wastage of liquids. The system also provides high accuracy and precision in proportion of
liquid filling and mixing. Although proposed system illustrate the mixing process of two
liquids, any number of liquid may be mixed in varying proportions. It is true that the use of
PLC is a costly affair particularly for small industry but it offers many advantage that
overcome its cost [8]. This paper was published in IEEE Multi topic conference, 2002.
Mallaradhya H.M., K.R. PRAKASH, “Automatic liquid filling to bottle of different
height using PLC”. The system has proved to work effectively avoiding unnecessary spill or
wastage of liquids. The system also provide high accuracy and precision in proportion of
liquids mixed. Although proposed system 3 tem illustrates the mixing process of two liquids,
any number of liquids may be mixed in varying proportion. It is true that the use of PLC is a
costly affair particularly for small industry but having many advantage that overcome its cost.
One of the additional feature of proposed system in the use of SCADA, HMI that makes it
controlled through remote location. Complete monitoring of system is possible through
SCADA and intact the process may be stopped or started by SCADA screen. This feature is
particularly very use full in case if some fault occur in system [9]. In proceedings of aece-iraj
international conference, July 2013.

CHAPTER 3
WORKING OF PLC

3.1 PLC Block Diagram
Fig 3.1: Block Diagram
Input module
1. Digital Input
2. Analog Input
Digital Input Devices
1. Push Button
2. Toggle Switch
3. Sensors
Central Processing Unit (CPU)
The CPU is the brain of the system. The CPU is a very microprocessor based
system that replaces control relays, counter, timers and sequencers. A processor
appears only once in a plc and it can be either a one bit (or) a word logic operation.
PLCs with word processors are used when processing text and numerical data,
calculations, gauging, controlling and recording as well as the simple processing of
signals in binary code are required. The CPU accepts (reads) input data from various
sensing devices, executes the stored user program from memory and sends appropriate
commands to control device. A direct current (dc) source is required to produce the
flow level voltage used by the processor and the inputs and outputs modules. The
processor memory module is a major part of the CPU housing. Memory is where the
control plan or program is held or stored in the controller the information stored in the
memory relates to the way the input and output data should be processed [10].
3.2 PLC Scan
1. Input Scan
2. Logic Scan
3. Output Scan

Fig 3.2: PLC scan
Input scan
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, then the second input, then the third and so on. It
records this data into its memory to be used during the next step.
Output scan
Finally the PLC updates the status of the outputs. It updates the outputs based on which
inputs were on during the first step and the results of executing your program during the
second step.
Logic scan
In logic scan PLC scan the program that is dumped in it and change the desired output status.
It takes place from left to right and top to bottom.
3.3 Switched Mode Power Supply (SMPS)
It is widely used in PLC for achieving constant 24 volts DC supply. It provide
continuous supply to the PLC. It is inbuilt in Rexroth-Indralogic PLC. The electronic power
supply integrated with the switching regulator for converting the electrical power efficiently
from one form to another form with desired characteristics is called as Switch-mode power
supply. It is used to obtain regulated DC output voltage from unregulated AC or DC input
voltage.
Fig 3.3: Block diagram of SMPS

1. DC to DC Converter SMPS Working Principle
In a DC-to-DC converter, primarily a high-voltage DC power is directly obtained
from a DC power source. Then, this high-voltage DC power is switched at a very high
switching speed usually in the range of 15 KHz to 50 KHz. And then it is fed to a step-down
transformer which is comparable to the weight and size characteristics of a transformer unit
of 50Hz. The output of the step-down transformer is further fed into the rectifier. This filtered
and rectified output DC power is used as a source for loads, and a sample of this output
power is used as a feedback for controlling the output voltage [11]. With this feedback
voltage, the ON time of the oscillator is controlled, and a closed-loop regulator is formed.
Fig 3.4: Block diagram of dc to dc converter SMPS
DC to DC converter SMPS
The output of the switching-power supply is regulated by using PWM (Pulse Width
Modulation). As shown in the circuit above, the switch is driven by the PWM oscillator, such
that the power fed to the step-down transformer is controlled indirectly, and hence, the output
is controlled by the PWM, as this pulse width signal and the output voltage are inversely
proportional to each other. If the duty cycle is 50%, then the maximum amount of power is
transferred through the step-down transformer, and, if duty cycle decreases, then the amount
of power transferred will decrease by decreasing the power dissipation [12].
Output DC
Input dc
High frequency
switch
Step down
transformer
Rectifier and
filter
Amp
Isolation
Reference
Output
SensorPWM
Oscillator

2. AC to DC Converter SMPS Working Principle
The AC to DC converter SMPS has an AC input. It is converted into DC by
rectification process using a rectifier and filter. This unregulated DC voltage is fed to the
large-filter capacitor or PFC (Power Factor Correction) circuits for correction of power factor
as it is affected. This is because around voltage peaks, the rectifier draws short current pulses
having significantly high-frequency energy which affects the power factor to reduce.
Fig 3.5: Block diagram of ac to dc converter SMPS
AC to DC converter SMPS
It is almost similar to the above discussed DC to DC converter, but instead of direct
DC power supply, here AC input is used. So, the combination of the rectifier and filter,
shown in the block diagram is used for converting the AC into DC and switching is done by
using a power MOSFET amplifier with which very high gain can be achieved. The MOSFET
transistor has low on-resistance and can withstand high currents. The switching frequency is
chosen such that it must be kept inaudible to normal human beings (mostly above 20KHz)
and switching action is controlled by a feedback utilizing the PWM oscillator.
Output dc
Amp
Output sensorIsolation
Reference
PWM
Oscillator
Rectifier and
filter
High frequency switch -15.50 Hz
Input AC
High volt
low freq
Rectifier and
filter
Step down transformer

CHAPTER 4
PLC PROGRAMMING LANGUAGE

4.1 Programming language in PLC
 Instruction List (IL)
 Ladder diagram(LD)
 Function Block Diagram(FBD)
 Sequential Function Chart(SFC)
 Structured Test(ST)
 Continues Function Chart(CFC)
4.1.1 Ladder Diagram (LD)
The Ladder Diagram is also a graphics oriented programming language which
approaches the structure of an electric circuit. Ladder Diagram consists of a series of
networks. Each network consists on the left side of a series of contacts which pass on from
left to right the condition "ON" or "OFF" which correspond to the Boolean values TRUE and
FALSE. To each contact belongs a Boolean variable [14]. If this variable is TRUE, then
condition pass from left to right. Fig 4.1 shows the simple ladder logic diagram with normally
open, normally closed and coil.
Fig 4.1 : Ladder diagram
4.2 Programming by ladder diagram
Ladder logic is a method of drawing electrical logic schematics. It is now a graphical
language very popular for programming Programmable Logic Controllers (PLCs). It was
originally invented to describe logic made from relays. The name is based on the observation
that programs in this language resemble ladders, with two vertical "rails "and a series of
horizontal "rungs" between them. A program in the ladder logic, also called ladder diagram is
similar to a schematic for a set of relay circuits.
The Ladder Diagram is also a graphics oriented programming language which
approaches the structure of an electric circuit. The Ladder Diagram consists of a series of
networks. A network is limited on the left and right sides by a left and right vertical current
line. In the middle is a circuit diagram made up of contacts, coils, and connecting lines.
Each network consists on the left side of a series of contacts which pass on from left
to right the condition "ON" or "OFF" which correspond to the Boolean values TRUE and
FALSE. To each contact belongs a Boolean variable. If this variable is TRUE, then the

condition is passed from left to right along the connecting line. Otherwise the right
connection receives the value OFF.
4.3 Generally used instruction symbol for PLC programming
4.3.1 Input Instruction
1. --[ ]-- This Instruction is Called XIC or Examine If Closed.
ie; If a NO switch is actuated then only this instruction will be true. If a NC switch is
actuated then this instruction will not be true and hence output will not be generated.
2. --[]-- This Instruction is Called XIO or Examine If Open
ie; If a NC switch is actuated then only this instruction will be true. If a NC switch is
actuated then this instruction will not be true and hence output will not be generated.
4.3.2 Output Instruction
1. --( )-- This Instruction Shows the States of Output(called OTE).
ie; If any instruction either XIO or XIC is true then output will be high. Due to high output
a 24 volt signal is generated from PLC processor.
2. --(L)-- Output Latch (OTL)
OTL turns a bit on when the rung is executed, and this bit retains its state when the rung is
not executed or a power cycle occurs.
3. --(U)-- Output Unlatch(OTU)
OTU turns a bit off when the rung is executed, and this bit retains its state when the rung
is not executed or when power cycle occurs.
4.3.3 Rung
Rung is a simple line on which instruction are placed and logics are created
E.g.; ---------------------------------------------
4.4 Pulse
A single vibration or short burst of sound, electric current, light, or other wave. It actives
for only one scan time.
 R-TRIGGER
 F-TRIGGER
4.4.1 R-TRIGGER
Rising Edge asks if a bit just turned from 0 to 1. It gives the output at same time whenever
input turn on.

Fig 4.2: Rising trigger with input and output pulse
4.4.2 F-TRIGGER
Falling Edge asks if a bit just turned from 1 to 0. After releasing switch coil gets
active for one scan time. In industries falling edge trigger is used.
Fig 4.3: Falling trigger with input and output pulse
4.5 Timer
It is an automatic mechanism for activating a device at a preset time. It also used to
indicate how many times someone has done something. Timer has three bit:
1-Scan time
Output
F-trig
1-Scan time
Input
Input
R-trig
Output
1-Scan time
1-Scan time

 EN: Enable bit :
The Timer Enable (EN) bit is set immediately when the rung goes true. It stays set until
the rung goes false.
 TT: Timer timing bit :
The Timer Timing (TT) bit is set when the rung goes true. It stays set until the rung goes
false or the Timer Done (DN) bit is set (i.e. when accumulated value equals preset value).
 DN: Done bit:
The Timer Done (DN) bit is not set until the accumulated value is equal to the preset
value. It stays set until the rung goes false.
4.5.1 Timer is three type:
1. TON 2. TOF 3. RTO
1. TON: Timer On
Counts time base intervals when the instruction is true.
Fig 4.4: Timer on
2. TOF: Timer off
Delay Counts time base intervals when the instruction is false.
Fig 4.5: Timer off
3. RTO: Retentive Timer
This type of timer does NOT reset the accumulated time when the input condition goes false.
Rather, it keeps the last accumulated time in memory, and (if/when the input goes true again)
continues timing from that point.

Fig 4.6: Retentive Timer
 Addressing of timer:
Fig 4.7: Addressing of timer
4.5.2 Table: Status of bits in timer
BIT TON TOF RTO
Name Switch
on
Preset
value=
accumula
ter
value
Switch
off
Switch
On
Switch
off
Preset
value=
accumulate
r
Value
Switch
on
Preset
value=
accumula
ter
Value
Switch
off
EN ON ON OFF ON OFF OFF ON ON OFF
TT ON OFF OFF OFF ON OFF ON OFF OFF
DN OFF ON OFF ON ON OFF OFF ON ON
4.6 Counter
An instruction that stores the accumulated value (ACC) of a PLC timer or counter
zero. An instruction that contains status bits that are used in ladder logic to activate and
deactivate PLC timers and counters when certain conditions become true.
Counter has three bit:

 Count Up bit (CU)
Set When Rung conditions are true and remains set till rung conditions go false or a RES
instruction that has the same address as the CTD instruction is enabled.
 Done bit ( DN)
Set when the accumulated value is => the present value and remains set till the
accumulated value becomes less than the present value.
 Overflow ( OV)
continues counting from there and remains set till a RES instruction that has same address
as the CTD instruction is executed or the count is incremented greater than or equal to
+32,767 with a CTU instruction [15].
Counter is of two type:
1. CTU
2. CTD
1. CTU: Count Up
Increments the accumulated value at each false-to true transition and retains the
accumulated value when the instruction goes false or when power cycle occurs.
Fig 4.8: Count Up
2. CTD: Count Down
Decrements the accumulate value at each false-to true transition and retains the
accumulated value when the instruction goes false or when power cycle occurs.
Fig 4.9: Count Down

Addressing of counter
Fig 4.10: Addressing of timer
4.7 Boolean logic design by ladder program
1. AND logic:
Y0=X0.X1
Fig 4.11: AND logic ladder diagram
2. OR logic:
Y1=X0+X1
Fig 4.12: OR logic ladder diagram
3. NOT logic:
Y3=X0
Fig 4.13: NOT logic ladder diagram

4. NAND logic:
Y0=X0.X1
Fig 4.14: NAND logic ladder diagram
5. NOR logic:
Y1=X0+X1
Fig 4.15 : NOR logic ladder diagram
6. X-OR logic:
Y2=X0 + X1
Fig 4.16: XOR logic ladder diagram
7. X-NOR logic:
Y2=X0 + X1
Fig 4.17: X-NOR logic ladder diagram

4.8 Different type of PLC software
 CoDeSys V2.3
 IndraLogic
CoDeSys V2.3
CoDeSys is a complete development enviromnent for your PLC( CoDeSys stands
for controlled development system) CoDeSys puts a simple approach to the powerful IEC
language at the disposal of the PLC programmer. Use of the editors and debugging functions
is based upon the proven development program environment of a advanced programming
languages ( such as visual C++).
IndraLogic
Indralogic is a complete development enviromnent for your PLC .Indralogic puts a
simple approach to the powerful IEC61131-3 language at the disposal of the PLC
programmer.
Rexroth indralogic based on the CoDeSyes technology of smart software solutions
(3S), due to further development of CoDeSyes and indralogic. It is not allowed to use
CoDeSyes and indralogic simultaneously. The general program compatibility with existing
IEC61131-3 programs will remain unaffected [14].
IndraLogic and CoDeSys version
Indralogic 1.0 based on CoDeSys version 2.3, service pack to for version specific
notes within this documentation. It is always indicated, if the version originates from
CoDeSys or indralogic .If this assignment is missing, the version numers always originate
fromCoDeSys.

CHAPTER 5
HARDWARE COMPONENTS

5.1 Relay
A relay is an electromagnetic switch operated by a relatively small electric current
that can turn on or off a much larger electric current. The heart of a relay is an electromagnet
(a coil of wire that becomes a temporary magnet when electricity flows through it). In our
project we have used relay to turn on motor, pump etc.
Fig 5.1 : Relay diagram Fig 5.2: Internal diagram of relay
5.1.1 Working Principle
Relays are amazingly simple devices. There are four parts in every relay:
1. Electromagnet
2. Armature
3. Spring
4. Set of electrical contacts
The figure 5.3 shows these four parts in action:
Fig 5.3: internal parts of the relay
Here are two simple diagram illustrating how relays use one circuit to switch on a
second circuit.
When power flows through the first circuit
It activates the electromagnet (brown), generating a magnetic field (blue) that attracts
a contact (red) and activates the second circuit. When the power is switched off,
a spring pulls the contact back up to its original position, switching the second circuit off

again. This is an example of a "normally open" (NO) relay: the contacts in the second circuit
are not connected by default, and switch on only when a current flows through the magnet.
Other relays are "normally closed" (NC; the contacts are connected so a current flows
through them by default) and switch off only when the magnet is activated, pulling or
pushing the contacts apart. Normally open relays are the most common.
Here's another animation showing how a relay links two circuits together. It's
essentially the same thing drawn in a slightly different way. On the left side, there's an input
circuit powered by a switch or a sensor of some kind. When this circuit is activated, it feeds
current to an electromagnet that pulls a metal switch closed and activates the second, output
circuit (on the right side). The relatively small current in the input circuit thus activates the
larger current in the output circuit:
 The input circuit (black loop) is switched off and no current flows through it until
something (either a sensor or a switch closing) turns it on. The output circuit (blue loop)
is also switched off.
 When a small current flows in the input circuit, it activates the electromagnet (shown here
as a red coil), which produces a magnetic field all around it.
 The energized electromagnet pulls the metal bar in the output circuit toward it, closing the
switch and allowing a much bigger current to flow through the output circuit.
 The output circuit operates a high-current appliance such as a lampor an electric motor.
5.2 IR Sensor
An infrared sensor is an electronic device that emits in order to sense some aspects of
the surroundings. An IR sensor can measure the heat of an object as well as detects the
motion. These types of sensors measures only infrared radiation, rather than emitting it that is
called as a passive IR sensor. Usually in the infrared spectrum, all the objects radiate some
form of thermal radiations. These types of radiations are invisible to our eyes that can be
detected by an infrared sensor. The emitter is simply an IR LED (Light Emitting Diode) and
the detector is simply an IR photodiode which is sensitive to IR light of the same wavelength
as that emitted by the IR LED. When IR light falls on the photodiode, the resistances and
these output voltages, change in proportion to the magnitude of the IR light receive.

Fig 5.4: Bosch Rexroth sensor
5.2.1 Circuit diagram and working
Fig 5.5: Internal circuitry of IR sensor
An infrared sensor circuit is one of the basic and popular sensor module in
an electronic device. This sensor is analogous to human’s visionary senses, which can be
used to detect obstacles and it is one of the common applications in real time. This circuit
comprises of the following components
 LM358 IC 2 IR transmitter and receiver pair
 Resistors of the range of kilo ohms.
 Variable resistors.
 LED (Light Emitting Diode).
In this project, the transmitter section includes an IR sensor, which transmits
continuous IR rays to be received by an IR receiver module. An IR output terminal of the
receiver varies depending upon its receiving of IR rays. Since this variation cannot be

analysed as such, therefore this output can be fed to a comparator circuit. Here an operational
amplifier (op-amp) of LM 339 is used as comparator circuit.
When the IR receiver does not receive a signal, the potential at the inverting input
goes higher than that non-inverting input of the comparator IC (LM339). Thus the output of
the comparator goes low, but the LED does not glow. When the IR receiver module receives
signal to the potential at the inverting input goes low. Thus the output of the comparator (LM
339) goes high and the LED starts glowing. Resistor R1 (100 ), R2 (10k ) and R3 (330) are
used to ensure that minimum 10 mA current passes through the IR LED Devices like
Photodiode and normal LEDs respectively. Resistor VR2 (preset =5k) is used to adjust the
output terminals. Resistor VR1 (preset =10k) is used to set the sensitivity of the circuit
Diagram.
5.3 Submersible pump
A submersible pump (or sub pump, electric submersible pump (ESP)) is a device
which has a hermetically sealed motor close-coupled to the pump body. The whole assembly
is submerged in the fluid to be pumped. The main advantage of this type of pump is that it
prevents pump cavitation, a problem associated with a high elevation difference between
pump and the fluid surface. Submersible pumps push fluid to the surface as opposed to jet
pumps having to pull fluids. Submersibles are more efficient than jet pumps. A submersible
pump (or sub pump, electric submersible pump (ESP)) is a device which has a hermetically
sealed motor close-coupled to the pump body. The whole assembly is submerged in the fluid
to be pumped.
The main advantage of this type of pump is that it prevents pump cavitation, a
problem associated with a high elevation difference between pump and the fluid surface.
Submersible pumps push fluid to the surface as opposed to jet pumps having to pull fluids.
Submersibles are more efficient than jet pumps.
Fig 5.6: Submersible pump

5.3.1 Working principle
The submersible pumps used in ESP installations are multistage centrifugal pumps
operating in a vertical position. Although their constructional and operational features
underwent a continuous evolution over the years, their basic operational principle remained
the same. Produced liquids, after being subjected to great centrifugal forces caused by the
high rotational speed of the impeller, lose their kinetic energy in the diffuser where a
conversion of kinetic to pressure energy takes place. This is the main operational mechanism
of radial and mixed flow pumps.
The pump shaft is connected to the gas separator or the protector by a mechanical
coupling at the bottom of the pump. When fluids enter the pump through an intake screen and
are lifted by the pump stages. Other parts include the radial bearings (bushings) distributed
along the length of the shaft providing radial support to the pump shaft turning at high
rotational speeds. An optional thrust bearing takes up part of the axial forces arising in the
pump but most of those forces are absorbed by the protector’s thrust bearing.
5.4 DC Motor
This is a device that converts DC electrical energy to a mechanical energy. DC motor
basicallyhavetwowires, andcandirectlypowered from abatteryorother DC power supply. DC motor
also can be power from the driver circuit that can regulate the speed and direction of the motor. The
usual voltages oftheDC motoruseare6Vand 12V. Thecurrent ratingdepends onthemakeoftheconveyor
build for and it is usuallybetween IA and 3A. Varying the voltage input to the motor will varies the speed of
motor accordingly .DC motor has ability to turn at high revolution per minutes (RPM) but has low
torque. The most significant limitation of the DC motor is the low output torque. The speed can be reduced
and the torque increase by adding gear rain to the output shaft. For the purpose of conveyor belt
building,DCmotoristhecheapestcomparetosteppermotororservomotor.
Fig 5.7: DC Motor

5.4.1 Working principle
This DC or direct current motor works on the principal, when a current carrying
conductor is placed in a magnetic field, it experiences a torque and has a tendency to move.
This is known as motoring action. If the direction of current in the wire is reversed, the
direction of rotation also reverses. When magnetic field and electric field interact they
produce a mechanical force, and based on that the working principle of dc motor established.
The direction of rotation of a this motor is given by Fleming’s left hand rule, which states that
if the index finger, middle finger and thumb of your left hand are extended mutually
perpendicular to each other and if the index finger represents the direction of magnetic field,
middle finger indicates the direction of current, then the thumb represents the direction in
which force is experienced by the shaft of the dc motor.
Fig 5.8: DC Motor working
5.5 Pneumatic cylinder
Pneumatics has long since played an important role as a technology in the
performance of mechanical work. It is also being used in the development of automation
solutions. Pneumatic systems are similar to hydraulic systems but in these systems
compressed air is used in place of hydraulic fluid.
Fig 5.9: Pneumatics cylinder

A pneumatic system is a system that uses compressed air to transmit and control
energy. Pneumatic systems are used extensively in various industries. Most pneumatic
systems rely on a constant supply of compressed air to make them work. This is provided by
an air compressor. The compressor sucks in air from the atmosphere and stores it in a high
pressure tank called a receiver. This compressed air is then supplied to the system through a
series of pipes and valves.
The word ‘Pneuma’ means air. Pneumatics is all about using compressed air to do the
work. Compressed air is the air from the atmosphere which is reduced in volume by
compression thus increasing its pressure.
5.5.1 Advantages of pneumatic systems
Pneumatic systems are widely used in different industries for the driving of automatic
machines. Pneumatic systems have a lot of advantages.
 High effectiveness – There is an unlimited supply of air in the atmosphere to produce
compressed air. Also there is the possibility of easy storage in large volumes. The use of
compressed air is not restricted by distance, as it can easily be transported through pipes.
After use, compressed air can be released directly into the atmosphere without the need of
processing.
 High durability and reliability – Pneumatic system components are extremely durable and
cannot be damaged easily. Compared to electromotive components, pneumatic
components are more durable and reliable.
 Simple design – The designs of pneumatic system components are relatively simple. They
are thus more suitable for use in simple automatic control systems. There is choice of
movement such as linear movement or angular rotational movement with simple and
continuously variable operational speeds.
 High adaptability to harsh environment – Compared to the elements of other systems,
compressed air is less affected by high temperature, dust, and corrosive environment, etc.
Hence they are more suitable for harsh environment.
 Safety aspects – Pneumatic systems are safer than electromotive systems because they can
work in inflammable environment without causing fire or explosion. Apart from that,
overloading in pneumatic system only leads to sliding or cessation of operation. Unlike
components of electromotive system, pneumatic system components do not burn or get
overheated when overloaded.

 Easy selection of speed and pressure – The speeds of rectilinear and oscillating movement
of pneumatic systems are easy to adjust and subject to few limitations. The pressure and
the volume of the compressed air can easily be adjusted by a pressure regulator.
 Environmental friendly – The operation of pneumatic systems do not produce pollutants.
Pneumatic systems are environmentally clean and with proper exhaust air treatment can be
installed to clean room standards. Therefore, pneumatic systems can work in environments
that demand high level of cleanliness. One example is the production lines of integrated
circuits.
 Economical – As the pneumatic system components are not expensive, the costs of
pneumatic systems are quite low. Moreover, as pneumatic systems are very durable, the
cost of maintenance is significantly lower than that of other systems.
5.5.2 Limitations of pneumatic systems
Although pneumatic systems possess a lot of advantages, they are also subject to
several limitations. These limitations are given below.
 Relatively low accuracy – As pneumatic systems are powered by the force provided by
compressed air, their operation is subject to the volume of the compressed air. As the
volume of air may change when compressed or heated, the supply of air to the system may
not be accurate, causing a decrease in the overall accuracy of the system.
 Low loading – As the cylinders used in pneumatic systems are not very large, a pneumatic
system cannot drive loads that are too heavy.
 Processing required before use – Compressed air must be processed before use to ensure
the absence of water vapour or dust. Otherwise, the moving parts of the pneumatic
components may wear out quickly due to friction.
 Uneven moving speed – As air can easily be compressed, the moving speeds of the pistons
are relatively uneven.
 Noise – Noise is usually produced when the compressed air is released from the
pneumatic components.
5.5.3 Compressibility of gasses
 Once actuated, compressed air enters into the tube at one end of the piston and hence
imparts force on the piston consequently the piston becomes displaced.
 One major issue engineers come across working with pneumatic cylinders has to do with
the compressibility of a gas.

 Many studies have been completed on how the precision of a pneumatic cylinder can be
affected as the load acting on the cylinder tries to further compress the gas used.
 Under a vertical load, a case where the cylinder takes on the full load the precision of the
cylinder is affected the most.
 A study at the National Cheng Kung University in Taiwan concluded that the accuracy is
about ± 30 nm, which is still within a satisfactory range but shows that the compressibility
of air has an effect on the system
Fig 5.10: Shows internal part of pneumatic cylinder
5.6 Solenoid Valve
Solenoid valves can be individual or in banks (manfolds) and usually are controlled
by 24 V DC. Direct action valves take more current (larger solenoid) but for factor
automation much more popular are piloted valves where solenoid draws very little current
(makes initial small movement of the valve which then allows compressed air to complete
movement). The difference is some 2-4 amp for direct drive solenoid versus some 10-20mA
for piloted value.
Fig 5.11: Solenoid valve

5.7 Capacitive proximity sensor
Capacitive proximity sensors can be used to detect metallic and also non-metallic
targets like paper, wood, plastic, glass, wood, powder, liquid etc. without physical contact.
The capacitive proximity sensor works on the capacitor principle. The main components of
the capacitive proximity Sensor are plate, oscillator, threshold detector and the output circuit.
The plate inside the sensor acts as one plate of the capacitor and the target acts as
another plate and the air acts as the dielectric between the plates.
As the object comes close to the plate of the capacitor the capacitance increases and
as object away the capacitance decreases. The detector circuit checks the amplitude output
from the oscillator and based on that the output switches. The capacitive sensor can detect
any targets whose dielectric constant is more than air.
Fig 5.12: Capacitive Sensor
5.8 2-Way Selector Switch
Selector Switch works on a general principle they contain a simple selector switch on
the front of the panel, and a broad range of potential contact combinations on the inside of the
enclosure. The major difference between the selector switch and the pushbutton is that, while
a pushbutton has a plate that pushes down both contact plungers at the same time a selector
switch has a rotating cam with ridges and flats allowing to actuate the plungers independently
Selector switches are available in 2, 3, or 4-position versions, and are often used when
more than one control option is needed. In general the center position of the selector switch is
the starting composition Left position presses the left plunger in the selector switch. Turning
the selector switch to the right presses down the right plunger.
A 2-way selector switch is used to control the flow of different types of liquid. It
blocks the 2 other path and opens the desired path. For example if we want a green liquid
should flow then we will choose the desired position on selector switch, and if we want
another colour liquid to flow them we will choose another position.

Fig 5.13: 2-Way selector switch
Contact blocks are an integral part of selector switches. The contact block can have
normally open (NO) and/or normally closed (NC) configurations. Single circuits contain a
contact block of either one normally open or one normally closed circuit. For applications
that need only one contact, a single circuit is an efficient, inexpensive way to get the job
done. Dual circuits offer two contacts in a single contact block.
The combinations include
 1 normally open and 1 normally closed contact
 2 normally open contacts
 2 normally closed contacts
 Combinations with special delayed opening or early closing contacts
Dual circuit contact blocks save space in enclosures and add twice the functionality to
a switch because one switch operates two circuits. You can add multiple contact blocks to
increase functionality. For example you can mount 4 dual circuit blocks to 30mm pushbutton
for a total of 8 circuits.
5.9 Buzzer
A buzzer or beeper is an audio signalling device, which may be mechanical,
electromechanical, or piezoelectric. Typical uses of buzzers and beepers include alarm.
Fig 5.14: Buzzer

5.10 Blinking bulb
An incandescent light bulb, incandescent lamp or incandescent light globe is
an electric light with a wire filament heated to such a high temperature that it glows with
visible light (incandescence). The filament, heated by passing an electric current through it, is
protected from oxidation with a glass or quartz bulb that is filled with inert gas or evacuated.
In a halogen lamp, filament evaporation is prevented by a chemical process that redeposits
metal vapour onto the filament, extending its life. Incandescent bulbs are manufactured in a
wide range of sizes, light output, and voltage ratings, from 1.5 volts to about 300 volts. They
require no external regulating equipment, have low manufacturing costs, and work equally
well on either alternating current or direct current. Blinking of bulb is done by PLC program.
It is used to indicate the liquid level in tank.
Fig 5.15: Blinking bulb
5.11 Project interfacing block diagram
The components used in our project can be interfaced using PLC in following manner
as shown in figure 5.16. Here we have interfaced different input components like selector
switch, sensors etc. to the input port of the PLC and different output components like pump,
motor, pneumatic cylinder etc. We have to be careful in interfacing output components
directly to PLC as it cannot drive large current device like pump and motor directly, so to
overcome this we connect large current device through a 24 V relay to PLC. We have used
Bosch Rexroth PLC where SMPS is inbuilt which is used to give continuous supply to PLC.

Fig 5.16: Project interfacing block diagram
Tank1&
tank2
pump
SMPS
24v dc
Start and
stop push
button
Sensor 1
Sensor 2
Sensor 3
Selector
switch
Level
sensors
P
L
C
I
N
P
U
T
O
U
T
P
U
T
Relay
Conveyor
Motor
Tank3
&Tank4
pump
Blinking
bulb
Alarm
Solenoid
valve
Pneumatic
cylinder
Mixing
motor

5.12 Hardware setup
Fig 5.17: Hardware setup of the project

5.13 Visualization and project working
Fig 5.18: Visualization of project
Working procedure
1. When we press start push button tank1 and tank2 pump gets on and its start to fill the
liquid intank3 and tank4 simultaneously, blinking bulb and alarm system acknowledge till
higher level comes in both tank.
2. When higher level comes that time tank1 and tank2 pump gets off and conveyor start
running.
3. In overall functioning whenever liquid comes to the below level that time again blinking
bulb and alarm acknowledge till higher level comes in tank3 and tank4 by tank1 and
tank2 simultaneously.
4. When selector switch is at mid position
1. When selector switch is at mid position sensor1 sense the bottle that time conveyor stops
and tank3 pump gets on which fill the liquid in bottle for 5 sec.
2. After 5sec conveyor automatically starts and filled liquid bottle moves towards sensors2
and when sensors2 sense the bottle that time conveyor stops and tank4 pump gets on and
it fill the liquid in bottle for 5 sec.
3. After 5sec conveyor automatically starts and bottle which is filled with two different
colour liquid moves towards sensor3. When sensor3 sense the bottle that time conveyor
stops and pneumatic gets active through solenoid valve, which mix the liquid for

specified time. After liquid mixing pneumatic cylinder gets off and again conveyor start
which sends the bottle to storage room.
5. When selector switch is at left position
1. When selector switch is at left position that timesensor1only sense the bottle, conveyor
stops and tank2 pump fill the liquid in bottle for 10 sec.
2. After 10 sec conveyor automatically start which sends the filled bottle to store room.
6. When selector switch is at right position
1. When selector switch is at right position that time sensor2 only sense the bottle, conveyor
stops and tank2 pump fill the liquid in bottle for 10 sec.
2. After 10 sec conveyor automatically start which sends the filled bottle to the store room.
7. At any time by pressing stop push button system stops the working.

Future recommendation
1. This project almost meets demand of a small automated industries like pharmaceutical
industries, paint industries, food industries but still there is a place of future advancement
in our present prototype.
2. By the installation of jet nozzle and strong solenoid valve in place of submersible pump
can reduce the time of liquid filling.
3. In present prototype we have not added a system to lift and place the object coming out
after mixing process, this can be done by adding robotic arm to lift and place the object
safely.
4. By installing a counter in store room we can count number of bottles filled by same
colour and different colours and we can also add capping process.
Conclusion
This project implements an application of automation illustrating PLC based fully
automatic untouched liquid filling and mixing system. The system meets the demand of high
speed production using the least mechanism requirements.
The system has proved to work effectively avoiding unnecessary spill wastage of
liquids. The system also provides high accuracy and precision in proportion of liquid filling
and mixing. Although proposed system illustrates the mixing process of two liquids, any
numbers of liquids may be mixed in varying proportion. It is true that the use of PLC is a
costly affair particularly for small industries but it offers advantages that overcome its cost.

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