1. WATER DRAINING AND FILLING CONTROL
USING PLC AND SCADA
by
Jawad Ur Rasul
IS/92013/BSC/EE/A_09/M
Fazal Ur Rehman
IS/92009/BSC/EE/A-09/M
Muhammad Nasir Yousaf
IS/92017/BSC/EE/A-09/M
A Report submitted to the
Department of Electrical Engineering
in partial fulfillment of the requirements for the degree of
BACHELOR OF SCIENCE IN ELECTRICAL ENGINEERING
Federal Urdu University of Arts, Science, and Technology
Islamabad, 44000, Pakistan
<July, 2013>
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4. CERTIFICATE OF APPROVAL
It is certified that the final year project’s work titled “Water Draining And Filling
Control Using PLC And SCADA” is carried out by Muhammad Nasir Yousaf Reg.
No IS/92017/BSC/EE/A-09/M, Fazal Ur Rehman Reg. No. IS/92009/BSC/EE/A-
09/M and Jawad Ur Rasul Reg. No. IS/92013/BSC/EE/A-09/M under the supervision
of Engr. Hamayun Aziz Khan, at Federal Urdu University of Arts Science and
Technology, Islamabad. It is fully adequate, in scope and in quality, as a thesis for the
degree of MS of Electronic Engineering.
Supervisor: -------------------------
Engr. Hamayun Aziz Khan
Lecturer
Dept. of Electrical Engineering
Federal Urdu University of Arts., Science., and Technonolgy., Islamabad
Internal Examiner: ----------------------------
xyz
Professor
Dept. of Electrical Engineering
Federal Urdu University of A., S., and T., Islamabad
External Examiner: ----------------------------
ABC
Associate Professor
Dept. of Electrical Engineering
Federal Urdu University of A., S., and T., Islamabad
Head of Department: ----------------------------
Dr. Zamin Ali Khan
Dept. of Electrical Engineering
Federal Urdu University of A., S., and T., Islamabad
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5. ACKNOWLEDGMENT
If ocean turn into ink and all of the wood becomes pens, even the praises of ALLAH
ALMIGHTY cannot be expressed. First and for most, praise and thanks to ALLAH Subhanaho
Wataala, the most Merciful, the most Gracious, without Whose help no work can be
accomplished successfully. We also offer our humble thanks to the last Prophet Muhammad
( Sallallho Alaihe Wa Alaihe Wasallam), Who is the a source of guidenance and knowledge for
the humanity.
We feel great pleasure in express our profound thanks to our teacher and supervisor Engr.
Hamayun Aziz Khan (Department of Electrical, Federal Urdu University of arts, science and
technology, Islamabad) for his keen interest, constant encouragement and supervision and
sympathetic attitude. His encouraging behavior enabled us in broadening my capabilities in the
field of electrical and in other aspects of life. We are also grateful to Engr Tahir Sarwar (Lab
Engr FUUAST, Islamabad for his kind direction, inspiring guidance and invaluable discussion
throughout the project.
Special thanks are due to Engr. Ibrar Aziz (Lab Engr FUUAST, Islamabad) for his valuable
support during the project and Engr. Faisal Baig (Lab Engr FUUAST, Islamabad) for his moral
and manual help throughout this project work.
We would like to acknowledge all my lab fellows who were always very helpful during our
studies.
We owe all our academic success to our affectionate parents, our loving brothers and caring
sisters for their prayers, caring behavior and encouraging attitude.
Finally we feel it our duty to express our sincere and deepest regards for all of our family
members especially to our parents who left no stone unturned in arranging for our needs and
educational requirements.
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6. DECLARATION
It is declared that the work entitled “Water draining and filling control using Plc and
Scada” presented in this report is an original piece of my own work, except where otherwise
acknowledged in text and references. This work has not been submitted in any form for another
degree or diploma at any university or other institution for tertiary education and shall not be
submitted by us in future for obtaining any degree from this or any other University or
Institution.
Muhammad Nasir Yousaf
IS/92017/BSC/EE/A_09/M
Fazal Ur Rehman
Reg. No. IS/92009/BSC/EE/A_09/M
Jawad Ur Rasul
Reg. No. IS/92013/BSC/EE/A_09/M
July 2013
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9. 1.1 Problem Statement:
The aim of this project is to design a PLC Based Water Supplying SCADA System that monitors
the water distribution among the different areas of a locality; through a centralized remote
location. So that this system would have minimum human dependency and maximum
automation to save time , errors and off course money.
1.2 Solution Statement:
The above mentioned Water Supplying SCADA System would be developed through PLC
(Programmable Logic Controllers). All the inputs of the system would come to PLC and PLC
performs the desired operations using SCADA (supervisory control and data acquisition) and
updates the particular outputs to perform our desired operations.SCADA would also control all
the operations of Water Supplying System present at remote location through PLCs. This whole
system is based on SCADA which performs the most of monitoring part of this whole system. In
fact not only the monitoring part but it will also send action commands to PLC to control this
water supplying system from a remote location that is your system is installed at some field
location and SCADA is controlling all the processes far away from that field location.
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10. 1.3 Project Description:
1.3.1 Objectives:
We are aiming to build the prototype of such control automation that will meet the requirements
of modern water supply system. PLC will be introduced to give perfect automation. The main
reasons of selecting this project is to have monitoring plus control the every stage of water
supply system from a centralized location and also to minimize the number of labor cost required
for troubleshooting and service by giving it automatic control.
1.3.2 Future Scope of the Project:
The current water supply systems in Pakistan are old and traditional systems in which there is
more labor cost, wastage of water and these are un-reliable systems, but SCADA & PLC based
water supply system will take over these issues.This is a pure industrial project and its scope is
huge mainly in water supplying departments, water purification plants, boilers and in every field
where we have to supply water or any other liquid (off course with some modifications). For
example in Pakistan this system can be very useful for CDA(Capital Development Authority),
WASA (Water and Sanitation Agency), DWM (Department of Water Management) NWFP
e.t.c.
1.3.3 Required Modules / Equipment:
Liquid level detectors to translate complete knowledge about Underground & Overhead Tanks,
Digital valve, water pumps, PLC having enough I/Os channel to handle all the inputs & outputs
of the System, InduSoft software for interpretation of the process & for Supervisory Control as
well.
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11. 1.4 Field Instruments:
Field Instruments are the instruments (sensors , motors , pumps e.t.c) which are installed in the field near the
system that send data (input) to the PLC and PLC will act according to this received data from the field
instruments. Field instruments collect all the information of the system and send this information to PLC in the
form of Analogue or Digital inputs. These field instruments could be sensors, actuator, pumps e.t.c. In our
project the field instruments are:
1.4.1 Level Detectors:
Level Detectors are used to sense the level of liquid (water in our case). For this purpose different types of
detectors are used that can be digital and analogue.
1.4.1.1 Analogue Water Level Sensors:
For point to point liquid level detection a wire gauge is used that moves with the level of water and a
potentiometer is used that changes the output voltage accordingly to varying water level. This is called analogue
sensor as it produces voltage in the analogue manner for example 0V for the low level, 2.5V for the mid , 5 V
for the maximum upper level.
Fig. 1.1
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12. 1.4.1.2 Digital Water Level Sensors:
Digital water level sensor are those sensors that works on the discrete value i.e. 0 and 1 .1 represent the
presence of water and 0 represent absence of water vice versa. This can be achieved by :
1.4.1.2.1 Simple Water Shorting Method:
In the simple water shorting method, different levels of water are indicated by shorting them with rising water
level. In our project we used this type of sensor instead of buying costly ready made level sensor. We designed
and made them ourself . For this purpose we used metals rod of different length.the longest rod is taken as a
reference and other rods for any desired level of water.As we know water is conducting medium for electricity,
So the current flows in the water which comes in contact with metal rods placed one above the other .when
water level rises up current starts flowing from reference rod into those rods which touches the water level that
can be used to trip a relay to give us digital output or can be directly used to power up LEDs and give signal to
PLC.
We used 2 such sensors in our project that is 1 for the ground tank (low, mid and high levels) and
1 for the overhead tank (low, mid and high levels).
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13. Fig. 1.2
1.4.1.2.2 Infrared Water Level Sensors:
The infrared water level sensors are those that uses infrared beam is used for level detection .TX-
RX (Transmitter Receiver) IR LEDs are used for that purpose and a simple circuit with relays for
digital output.It give a digital signal when the beam path between transmitor and receiver is cut-
off by water.
Fig. 1.3 (a) Fig. 1.3 (b) Fig. 1.3 (c)
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14. Circuit diagram is shown below
Fig. 1.3 (d)
1.4.2 Water Pump:
Water Pump is used to pump (supply) the water from one location to another location.
In our project we had to supply water from ground tank to overhead tank and for this purpose we
used water pumps locally called as “submersible water pump ” used in fish aquarium tanks. The
electrical specifications of this water pump is:
Voltage Current Flow Rate
24 V D.C 1.5 A 2100 ml/min
Table 1.1
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15. Fig. 1.4
1.4.3 Solenoid Valve:
A solenoid valves or electrical valves are electromechanical valve for use with liquid or gas.
The valve is controlled by an electric current from plc through a solenoid, that the flow is
switched on or off. A solenoid valve consist of two main parts: the solenoid and the valve. The
solenoid changes electrical energy into mechanical energy which, then, closes or opens the valve
mechanically.we used three valves one main valves and other for sectors.By using PLC we can
control whole city valves.
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16. Fig. 1.5 (a)
Fig. 1.5 (b)
We used three Solenoid Valves shown below to supply water from overhead tank to two
different locations.
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17. 1.4.3.1 Specifications of Solenoid Valves:
No.
Voltage
(A.C) Orifice Pipe Size
Pressure
(Max.) Temperature
1 220V/110V 15 mm 1/2" 10 kg/cm² -5 ºC----85 ºC
2 220V/110V 15 mm 1/2" 10 kg/cm² -5 ºC----85 ºC
3 220V/110V 15mm 1/2" 10kg/cm² -5 ºC----85 ºC
Table 1.2
1.4.3.2 Working of a Solenoid Valve:
The media controlled by the valve, intake valve through the opening (part 2 in the picture above).
The media should at the start (9), solenoids valve before continuing to flow into the outlet (3).
The diaphragm is opened and closed by the plunger (7).solenoid hydraulic valve.
Fig. 1.6
The valve shown above a valve normally closed. NC valves use a spring (8),Air treatment units
push the end of the piston at the beginning of the exposure. The sealant on top of the piston to
hold the media to the opening created by the plunger of an electromagnetic field of the coil
increases.
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19. 2.1 Control
2.1.1 PLC (Programmable Logic Controller)
A programmable logic controller (PLC) or programmable controller is a digital computer used
for automation of electromechanical processes, such as control of machinery on factory assembly
lines, amusement rides, or light fixtures, water supplying systems and many more such industrial
processes. PLCs are used in many industries and machines. Unlike general-purpose computers,
the PLC is designed for multiple inputs and output arrangements, extended temperature ranges,
immunity to electrical noise, and resistance to vibration and impact.
Fig. 2.1 (a) Fig. 2.1 (b)
2.1.1.1 Brief History of PLC
The PLC was invented in response to the needs of the American automotive manufacturing
industry. Before the PLC, control, sequencing, and safety interlock logic for manufacturing
automobiles was accomplished using hundreds or thousands of relays, cam timers, and drum
sequencers and dedicated closed-loop controllers. The first PLC, designated the 084 because it
was Bedford Associates' eighty-fourth project. Early PLCs were designed to replace relay logic
systems. These PLCs were programmed in "ladder logic”
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20. 2.1.1.2 Ladder Logic
The basic programming language of PLC is called Ladder Logic. The name given because in this
a programmer develops the logic of the control system in sequence of a ladder. Ladder Logic is
much simple and easier as compared to other programming languages. Figure given below shows
an example of simple programe in ladder logic.
2.1.1.3 Modern PLCs
Modern PLCs can be programmed in a variety of ways, from ladder logic to more traditional
programming languages such as BASIC and C. Another method is State Logic, a very high-level
programming language designed to program PLCs based on state transition diagrams.
More recently, PLCs are programmed using application software on personal computers. The
computer is connected to the PLC through Ethernet, RS-232, RS-485 or RS-422 cabling. The
programming software allows entry and editing of the ladder-style logic. As PLCs became more
advanced, methods were developed to change the sequence of ladder execution, and subroutines
were implemented. This simplified programming and could also be used to save scan time for
high-speed processes; for example, parts of the program used only for setting up the machine
could be segregated from those parts required to operate at higher speed.
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21. 2.1.1.4 Communication
PLCs usually communicate through 9-pin RS-232, and EIA-485 or Ethernet(optionally). Modbus
and BACnet are normally used for communications protocols. Other options include various
fieldbuses such as DeviceNet or Profibus are also used for communication protocols.Now
modern PLCs are able to communicate on a network of some other system, i.e. computer
running a SCADA (Supervisory Control And Data Acquisition) system or web browser. SCADA
has been explained in the monitoring part of this chapter.
2.1.1.5 Types of PLC
Depending on the number of I/Os , storage memory , processing speed and size there are many
types and brands of PLC. Some of the brands are:
Fatek , Mitsubishi , Allen Bradely, Omron , Siemens e.t.c
In our project we used Fatek PLC of model number FBs-24-MC
2.1.1.6 Tri Super PLC , T100MD2424+
Description of Tri Super PLC , T100MD2424+ we used is:
Place of Origin USA
Brand Name Tri Super PLC , T100MD
Model Number Tri Super PLC , T100MD2424+
Specifications are :
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22. • 8 Analog I/O
- 6 x iA-10 bits,0-5 v
- 2 x 0A -8 bit ,0-5 v
• 24 Digital Outputs
-includes 2 x PWM 10A @24VDC,
-include 2 x stepper motor pulse outputs.
• 24 Digital Inputs (24V NPN)
-include special inputs such as interrupts,
High-speed encoders and etc.
• Expandable using EXP4040 & EXP1616R.
• Dimension: 7.05"(L)x 4.5"(W) x 0.8"(H)
• Optional DIN-rail mounting kit for easy installation.
Figure given below shows PLC we used:
Fig. 2.2
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24. 2.2 Manual Control
In addition with automation , manual control has also been given to our water supplying system.
This manual control is given keeping in mind the failure of automation in any case . So that this
system would not stop in case of failure of automatic control. Then an operator will keep an eye
on the water levels of both underground and overhead tanks, he will manually ON/OFF motor
pump , solenoid vales , alarms e.t.c . For this purpose a main control panel has been included in
this project for the operator. This control panel consists of :
• Emergency Stop Button: This button has been introduced to protect the whole system
and human lives in case of emergency. So that our whole system would be shut down
with a single button. For example in case of fire , short circuiting e.t.c
• Auto / Manual Switch: This switch is used to make our system fully automatic or
manual when require.
• 0ne toggle switch:- this is used for automatic distribution of water supply depending on
our program according to need of user.
• Three Toggle Switches: To ON / OFF solenoid vales these swiches are used.
• One push button: To ON / OFF the water pumps.
• LED Indicator: To show the water levels in the tanks LED water level indicator have
been introduced. In this 6 LEDs are used for each tank (Green for the upper level ,
Yellow for the mid level and Red for the Low level).
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25. 2.3 Monitoring
Most of the monitoring part of our project has been performed by SCADA.
2.3.1 SCADA (Supervisory Control And Data Acquisition)
SCADA stands for Supervisory Control And Data Acquisition, is computer system for gathering
and analyzing real time data. SCADA systems are used to monitor and control a plant or a
machine in an industry and a process for example water and waste control, telecommunications, ,
energy, oil and gas refining and transportation. In our project SCADA performs vital role to
monitor and control the system.
2.3.2 Components of SCADA
A SCADA system usually consists of the following subsystems:
• A human–machine interface or HMI is the apparatus which presents process data to a
human operator, and through this, the human operator monitors and controls the process.
• A supervisory (computer) system, gathering (acquiring) data on the process and sending
commands (control) to the process.
• Remote terminal units (RTUs) connecting to sensors in the process, converting sensor
signals to digital data and sending digital data to the supervisory system.
• Master Terminal Unit (MTU)
• Programmable logic controller (PLCs) used as field devices because they are more
economical, versatile, flexible, and configurable than special-purpose RTUs.
• Communication infrastructure connecting the supervisory system to the remote terminal
units.
• Various process and analytical instrumentation
Fig. 2.3
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26. 2.3.3 Brief History of SCADA
SCADA systems became popular in the 1960’s as the need to monitor and control remote
equipment grew. Early SCADA systems used mainframe technology and required human
operators to make action decisions and maintain the information systems. Because this increased
the human labor cost, early SCADA systems were very expensive to maintain. Today, SCADA
is generally much more automated, and consequently more cost-efficient.
2.3.4 DCS (Distributed Control System)
There are many systems that are used for similar purpose as SCADA e.g DCS , ICS(Industrial
Control System). These are generally called Distributed Control Systems (DCS). The functions
are same , the difference is in their ranges. DCS are typically effective within a confined area
like a factory complex. Thus the communication is carried out through a Local Area Network
(LAN).
Fig. 2.4
DCS networks have their limitations. They cannot cover large territories. This is where SCADA
comes in handy. However the communication systems are not as reliable as a LAN.
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27. 2.3.5 Comparison of SCADA and DCS
DCS SCADA
Close loop system (dependent upon the same
vendor’s PLC and HMI.
Open loop system (PLC and HMI of any
vendor can be used with SCADA)
Local Area Network (LAN) based. Both Local Area Network (LAN) and Wide
Area Network (WAN) based.
Rag relay system (consists of hundereds and
thousands of relays to control the system)
PLC based.
Table 2.2
2.3.6 Remote Terminal Unit (RTUs)
These are devices deployed in the field at specific sites and locations. RTU’s gather information
locally from the sensors to report back to the SCADA master unit. RTU’s can also issue control
commands to the control relays it communicates with.
2.3.7 Master Terminal Unit (MTU)
SCADA master units are the main, user-end component of the entire SCADA monitoring
system. They are also sometimes referred to as the SCADA HMI (Human-Machine Interface).
The master provides the central processing capability for the SCADA system. Master units
connect the human operators to the system with a browser interface that allows the system
operator to respond to data gathered from all parts of the network.
2.3.8 Generations of SCADA Systems
2.3.8.1 First Generation :“Monolithic”
With the passage of time SCADA was developed. Thus SCADA systems were independent
systems with no connectivity to other systems. The communication protocols used were often
proprietary at that time. The first-generation SCADA system was redundant since a back-up
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28. mainframe system was connected at the bus level and was used in the event of failure of the
primary mainframe system.
2.3.8.2 Second Generation :“Distributed”
The processing was distributed across multiple stations which were connected through a LAN
and they shared information in real time. Each station was responsible for a particular task thus
making the size and cost of each station less than the one used in First Generation. The network
protocols used were still mostly proprietary, which led to significant security problems for any
SCADA system that received attention from a hacker.
2.3.8.3 Third Generation :“Networked”
This is the current generation of SCADA. Due to the usage of standard protocols and the fact that
many networked SCADA systems are accessible from the Internet, the systems are potentially
vulnerable to remote cyber-attacks. On the other hand, the usage of standard protocols and
security techniques means that standard security improvements are applicable to the SCADA
systems, assuming they receive timely maintenance and updates.
2.3.9 Hierarchy of SCADA system implementation
The hierarchy of SCADA system could be implemented through following three layers:
Layer-1: Field instruments collect real time data from industrial environment and thus located
at the first level of interfacing.
Layer-2: PLCs / Controllers then provide interface between HMI and field instruments.
Layer-3: HMI application for SCADA system implementation.
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29. Hierarchy of SCADA system implementation
Fig. 2.5
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Field
Instruments
Controllers
HMI
31. 3.1 Communication Media and its types
Early SCADA network communicates over radio, modem or dedicated serial lines. Today the
trend is to put SCADA data on Ethernet and IP over SONET. For security reasons, SCADA data
should be kept on closed LAN/ WANs without exposing sensitive data to the open Internet.
3.1.1 Basic Functions performed by Communication Media
Communications bring RTU’s information from the various plants to a central location. The
communication medium can also occasionally return instructions to the RTUs. In internal
communication between server-client and server-server is in general on publish-subscribe and
event-driven basis and uses a TCP/IP protocol while data serevers are communicated PLCs;
either directly or via networks or fieldbuses
3.1.2 Types of Medium
• Private Medium
• Public Medium
• Others Medium
3.1.3 Private Media
Private mediums are owned, licensed, operated and serviced by the user. It includes following
options:
3.1.4 Wireless
1. Spread Spectrum Radio (SSR)
This media type is license-free and available to the public in the 900 MHz and 5.8 GHz
bands. SSR modems generally have built in error correction, encryption and other
features that make them a reliable, secure and long-lasting solution for network
communication.
2. Microwave Radio (MR)
Microwave radio transmits at high frequencies through parabolic dishes mounted on
towers. This media uses point-to-point and line of sight technology.
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32. 3. VHF / UHF Radio
Good for up to 30 miles, VHF / UHF radio is an electromagnetic transmission with
frequencies of 175 MHz-450 MHz-900 MHz received by special antennas
.
3.1.5 Public Media
Public medium is a communication service that the customer pays for a monthly or per time or
volume as use. It includes:
3.1.6 Telephone Company
1. Switched Lines
Public Switch Telephone Networks (PSTN) and generally switched telephone network
(GSTN) are dial-up voice and data transmission networks furnished by your local
telephone company.
2. Private Leased Lines (PLL)
PLL are permanently connected 24 hours a day between two or more locations and used
for analog data transmission.
3. Digital Data Service (DDS)
DDS is a private leased line with a spectral bandwidth used to transfer data at higher
speed and lower error rate.
4. Cellular
This service is equivalent to switched line services over landlines.
3.1.7 Other Media Types
1. Wi-Fi-SMR
Wi-Fi equipment utilizes broadband with high data rates and is used in a “time-share”
basis. This media generally requires advanced protocols like TCP / IP.
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33. 2. Satellite-Geosynchronous / LE
Geosynchronous Satellites use high frequency transmission received by parabolic dish
antennas. Low Earth Orbit (LEO) satellites hand off signals to other satellites for
continous coverage.
3.2 Communication Architecture of SCADA
Figures below shows the communication architecture of SCADA:
Fig. 3.1 (a) Fig. 3.1 (b)
For understanding the communication architecture of SCADA first we know the protocols of
communication:
• HART (Highway Addressable Remote Transducer)
• Fieldbus Standards
3.3 HART Protocol
The HART (Highway Addressable Remote Transducer) Protocol is the global standard for
sending and receiving digital information across analog wires between smart devices and control
or monitoring system. More specifically, HART is a bi-directional communication protocol that
provides data access between intelligent field instruments and host systems. Because most
automation networks in operation today are based on traditional 4-20mA analog wiring, HART
technology serves a critical role because the digital information is simultaneously communicated
with the 4-20 mA signal.Figure shows HART master /slave communication.
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34. HART master /slave communication
Fig. 3.2 (a)
The communication speed for HART signalling is 1.2 kbps. HART uses Frequency Shift Keying
(FSK) to encode digital information on top of the 4-20 mA analog signal as shown below:
Fig. 3.2 (b)
3.4 Fieldbus Protocol
Fieldbus is the name of a family of industrial computer network protocols used for real-time
distributed control. It is a way to connect instruments in a manufacturing plant. Fieldbus works
on a network structure which typically allows daisy-chain, star, ring, branch, and tree network
topologies. Previously computers were connected using RS-232 (serial connections) by which
only two devices could communicate. This would be the equivalent of the currently used 4-20
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35. mA communication scheme which requires that each device has its own communication point at
the controller level, while the fieldbus is the equivalent of the current LAN-type connections,
which require only one communication point at the controller level and allow multiple
(hundreds) of analog and digital points to be connected at the same time. This reduces both the
length of the cable required and the number of cables required.
Commonly used standards of fieldbuses
1. PROFIBUS
The Process Field Bus (PROFIBUS) is a fieldbus protocol. Of the two PROFIBUS variants,
decentralized peripherals and process automation (DP and PA), PROFIBUS DP is commonly
used for sensor operation and actuators through a centralized controller in discrete manufacturing
and process control.
2. Modbus
Modbus is an open, royalty-free serial communications protocol developed for programmable
logic controller (PLC) applications. Modbus allows many devices to connect to the same
network, such as interfacing a supervisory computer with a remote terminal unit (RTU) in
supervisory control and data acquisition (SCADA) systems.
3. Interbus
INTERBUS is a serial bus system which transmits data between control systems (e.g., PCs,
PLCs, VMEbus computers, robot controllers etc.) and spatially distributed I/O modules that are
connected to sensors and actuators (e.g., temperature sensors, position switches).
4. LonWorks
LonWorks (local operation network) is a networking platform specifically created to address the
needs of control applications. It is used for the automation of various functions within buildings
such as lighting and HVAC.
5. Safety BUS p
Safety BUS p is a standard for safe field bus communication within factory automation. The
main use of Safety BUS p is the communication of data with safety relevant content. Safety
BUS p is found where the data integrity and timely delivery of data is required for the protection
against risks. In this respect risks may affect life or health, but as well the protection of valuables
or machinery.
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36. Fig. 3.3
3.5 PLC Communication
Communication Module
Communication module of PLC provides Ethernet connection (Fast Ethernet, Industrial
Ethernet) to the network. PLCs still provide Serial based connectivity that is relatively slow (RS
232 , RS485)
Ethernet / Modem
Used for communication with remote computers. Takes input from encoder and tracks
position. This allows encoder changes that are much faster than the PLC scan.
ASCII Modem
Adds a serial port for communicating with standard serial port RS-232.
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38. 4.1 Flow Diagram of the Project:
Block Diagram
Fig. 4.1
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Distribution
Unit
Main
Water
Stream
Undergrou
nd Tank
PLC
HMI
(SCADA)
Input
s
Output
s
Overhead
Tank
39. 4.2Equipment Used
• Ground Tank
A plastic bucket has been used for the ground tank as shown in the figure below. This ground
tank consist of infrared water level sensor to measure 3 levels (low, mid and high) , two 12V
D.C water pumps to pump the water to the overhead tank. This ground tank stores the water
and also supply to overhead tank when needs. Follwing are specifications of ground tank:
Height Width Diameter Radius Storage
Capacity
60 cm 40 cm 20 cm 40 cm 19.5 liters
Table 4.1
• Overhead Tank
Similar but small plastic bucket has been used as overhead tank as shown in the figure below.
This overhead tank consist of infrared water level sensor to measure 3 levels (low, mid and
High) , Two 220V A.C Solenoid Valves to supply water to two different locations. Following
Are the specifications of overhead :
Height Width Diameter Radius Storage
Capacity
35 cm 25 cm 12.5 cm 25 cm 12 liters
Table 4.2
• PLC
Tri super PLC of model number T100Md 2424. has been used for this project as shown in figure
below. Specifications of this PLC has already been explained in details.
The inputs ( 24 ) are from X0 to X23.
The outputs (24) are from Y0 to Y23.
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40. Fig 4.2
All the other equipment has been already explained in chapter 2.
4.3Input / Output Configuration of PLC
Before mentioning the Ladder Logic Programming of our project it is necessary to know about
the I/O configuration. The I/Os have been allocated in the following sequence:
4.3.1 Inputs
• X0 = Ground tank’s low level sensor
• X1 = Ground tank’s high level sensor
• X2 = Overhead tank’s low level sensor
• X3 = Overhead tank’s high level sensor
• X4 = Solenoid Valve 1 (Toggle Button)
• X5 = Solenoid Valve 2 (Toggle Button)
• X6 = Water Pump (Toggle Button)
4.3.2 Outputs
• Y0 = Ground Tank’s low level indicator (3 red LEDs 6V D.C)
• Y1 = Ground Tank’s High level indicator (3 green LEDs 6V D.C)
• Y2 = Overhead Tank’s low level indicator (3 red LEDs 6V D.C)
• Y3 = Overhead Tank’s high level indicator (3 green LEDs 6V D.C)
• Y4 = 12V D.C Water Pump
• Y5 = 12V D.C Beep (For the indication of Low level of either of the two tanks)
• Y6 = 12V D.C Buzzer (For the indication of High level of either of the two tanks)
• Y7 = Solenoid Valve 1 (220 V A.C)
• Y8 = Solenoid Valve 2 (220 V A.C)
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41. 4.4 Ladder Logic Language
We programmed our PLC with Ladder Logic Language. It is symbolic language in which we use
different ladders of symbols to represent input, output, timers, counters e.t.c
4.4.1 Inputs and outputs.
In ladder logic inputs are called contacts and outputs are called coils.
With just the Normally Open Contact and Normally Open Coil - a surprising array of basic
logical conditions can be represented.
Normally Open Contact. This can be used to represent any input to the control logic - a
switch or sensor, a contact from an output, or an internal output.
When "solved" the referenced input is examined for an ON (logical 1) condition. If it is ON, the
contact will close and allow power (logic) to flow from left to right. If the status is OFF (logical
0), the contact is Open, power (logic) will NOT flow from left to right.
Normally Open Coil. This can be used to represent any discrete output from the control
logic.
When "solved" if the logic to the left of the coil is TRUE, the refrenced output is ON (logical 1).
Solving a Single Rung
Suppose a switch is wired to Input1, and a light bulb is wired through Output1 in such a way that
the light is OFF when Output1 is OFF, and ON when Output1 is ON.
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42. When Input1 is OFF (logical 0) the contact remains open and power cannot flow from left to
right. Therefore, Output1 remains OFF (logical 0).
When Input1 is ON (logical 1) then the contact closes, power flows from left to right, and
Output1 becomes ON (the light turns ON).
Another set of basic contacts and coils that can be used in Ladder Logic are the Normally Closed
Contact and the Normally Closed Coil. These work just like their normally open counterparts -
only in the opposite.
When "solved" the referenced input is examined for an OFF condition. If the status is OFF
(logical 0) power (logic) will flow from left to right. If the status is ON, power will not flow.
When "solved" if the coil is a logical 0, power will be turned on to the device. If logical 1,
power will be OFF.
4.1.2 Timers and Counters:
• Simple Timers
A timer is simply a control block that takes an input and changes an output based on time. There
are two basic timer types which is define below.( - On-Delay Timer and the Off-Delay Timer.
On-Delay Timer – On delay timer takes an input, waits a the specific amount of time, then
turns ON an output i.e. allows logic to flow after the delay.
Off-Delay Timer – Off delay timer takes turns ON an output and keeps that output ON until the
set amount of time has passed, then turns it OFF the logic.
A simple example of PLC Ladder Logic Application:
Consider the following circuit and PLC program:
When the pushbutton switch is unactuated (unpressed), no power is sent to the X1 input of
the PLC. Following the program, which shows a normally-open X1 contact in series with a
Y1 coil, no "power" will be sent to the Y1 coil. Thus, the PLC's Y1 output remains de-
energized, and the indicator lamp connected to it remains dark.
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43. Fig. 4.3
If the pushbutton switch is pressed, however, power will be sent to the PLC's X1 input. Any and
all X1 contacts appearing in the program will assume the actuated (non-normal) state, as though
they were relay contacts actuated by the energizing of a relay coil named "X1". In this case,
energizing the X1 input will cause the normally-open X1 contact will "close," sending "power"
to the Y1 coil. When the Y1 coil of the program "energizes," the real Y1 output will become
energized, lighting up the lamp connected to it:
Fig. 4.4
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44. 4.5 Ladder Logic of Our Project:
The ladder logic used in our project is shown below
:
Fig. 4.5 (a)
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46. 4.6 Explanation of our ladder logic and project implementation:
The input X0 is ground tank’s low level sensor and when is will be ON it will activate the output
Y0 which trips a 12V D.C relay to provide 6V D.C supply to 2 red LEDs indicating about the
low water level. X1 is ground tank’s high level sensor and when both X0 and X1 will be ON it
will activate the outputs Y0 and Y1. Y1 trips another 12V D.C relay to provide 6V D.C supply to
3 green LEDs indicating about the high water level. (Due to the low number of I/Os in our PLC
the mid level sensor will directly trip a 12V relay to provide voltage to 3 yellow LEDs).
Similarly X2, X3 and Y2, Y3 are the inputs and outputs of overhead tank and will work the same
way as ground tank’s sensors. Now when both X0, X1 or X2, X3 (Normally open) are connected
in parallel when they will be activated (either ground tank or overhead tank becomes full) then
output Y4 will be ON for 5 seconds and this Y4 will trip relay to provide 12V D.C supply to
Buzzer that is when either of the tank will be full the buzzer will sound for 5 seconds. To give 5
sec. ON time we placed a 5 sec. up timer, it will reset (OFF) buzzer after 5 sec.
In the same normally closed X0, X1 and X2, X3 will activate Y5 for the 5 sec. to ON a 12V D.C
beep, which will sound for the 5 sec. to indicate the empty state of either of the tanks. X2 and X3
are further connected in series having output Y6 at the end and normally closed Y6 in parallel
with X3 (latching), Y6 is connected to relay that will provide 15V D.C to two Water Pumps.
Water pump will remain ON as long as water level in the overhead tank will not reach the high
level.
At the end X4 and X2 are connected in series having output Y7 at the end. X4 is the input from a
toggle switch/button and Y6 is connected to relay to provide 220V A.C to solenoid valve 1.
When switch will be pressed and overhead tank will have at least low water level then the
solenoid valve 1 will be ON as long as switch will be pressed. In the same way solenoid valve 2
will act. X5 is the input from another toggle switch/button and will activate Y8 which is the
solenoid valve 2.
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47. 4.7 Hardware Implementation
The implementation of our project’s hardware is as following:
Buzzer
Relay
Panel
Fig. 4.5
Fig. 4.6
4..8 Main Relay Panel
All the outputs from PLC go to the main relay panel . From here these outputs trip the
corresponding relays to provide voltage to output devices (Motor pump, LEDs, Solenoid Valves,
Buzzer, Beep). 8 Relays (12V D.C) have been added to this panel shown in the figure below:
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220 v AC
Solenoid
Valves
220 V A C Motor
Pump
24V D.C LEDs
beep
24 V
Led indicator of
level
PLC
X0 X1 X2 X5
Y0 Y7
Overhead Tank
Solenoid Valves
Manual Control Panel
Ground
Water Pump
Sensor
Relay
Panel
Level sensor
48. Fig. 4.7
4.9 Solenoid Valves with pipes setup
Solenoid Valves have already been explained in detail, below is the figure of our real
solenoid valves.
Fig. 4.8
4.10 LED Water Level Indicator
The LED water level indicators for ground tank and overhead tank gets the output voltage
supply from main relay panel. These are shown below:
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53. 5.1 Software Results
The SCADA of our system is based on Open Control developed Solutions. This SCADA has
been interfaced through Serial Communication. With the help of this SCADA our system can
be controlled from a remote location, having Tanks level indicators, status of solenoid valves,
motor pump, Buzzer and beep. Plus three buttons have been added for the manual control of
Solenoid valves and one button for the manual control of water motor pump. We tested the
results of our software that were according to our goal.
5.2 Hardware Results
This is a simple prototype of water supplying system which can be implemented in the real
life with the slight changes in the hardware equipment, for example to be implemented in the
real life there would be bigger solenoid valves having large opening ( minimum 2"), more
powerful water pumps would be required that will supply the water from real underground
tank to a real overhead tank as shown below:
Fig. 5.1
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55. 6.1Why we used SCADA ?
We used SCADA for our project’because of the following facts:
• Open loop system (PLC of any vendor can be used with SCADA)
• Both Local Area Network (LAN) and Wide Area Network (WAN) based.
6.2 Why we used PLC instead of microcontroller ?
We used PLC to give automatic control to our project because:
• PLC is intended for industries environment (temperature range).
• PLC is simple and easier to program (i.e. simple framework and language) and
configure communications.
• It is easier to debug as it uses on-line debugging.
• Standard industrial communications and compatibility with other PLCs.
6.3 Minimum Human involvement :
Minimum human involvement and maximum automation will reduce time, cost and errors in
water supplying system as all the things are automatic so it will reduce the number of
operators to control the system. Only one operator is required to keep an eye on the SCADA
based computer screen and control the system manually when need.
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57. 7.1 Book References
Chatha, Andrew. (1994). Fieldbus: The Foundation for Field Control Systems Control
Engineering, May, 47–50.
Furness, Harry. (1994). Digital Communications Provides... Control Engineering,
January, 23–25.
Loose, Graham. (1994). When Can The Process Industry Use Fieldbus? Control and
Instrumentation, May, 63–65.
Powell, James and Henry Vandelinde (2009), An introduction to PROFIBUS for Process
Automation' www.measuremax.ca.
O'Neill, Mike (2007). Advances in Fieldbus, Process Industry Informer, January, 36–37.
N.P. Mahalik; P.R. Moore (1997) Fieldbus technology based, distributed control in
process industries: a case study with LonWorks Technology
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58. 7.2 Websites
http://www.designworldonline.com/articles/2280/155/CIP-Safety-on-SERCOS-
Specification.aspx
http://www.echelon.com/support/documentation/manuals/transceivers/005-0154-01D.pdf
http://global.ihs.com/doc_detail.cfm?document_name=CEA-852.1 IP Tunneling Protocol
(USA)
http://www.lonmark.org/membership/directory/ Directory of LonMark International
Member Companies
http://global.ihs.com/doc_detail.cfm?document_name=CEA-709.1 Protocol Standard
(USA)
http://www.tioni.com.au/news.html (PLC)
http://www.cn-lida.com/news/Solenoid-valve--The-working-principle-of-solenoid-
valve.html (solenoid valve working peinciple)
http://www.festivalchannel.com/magazine/read/modern-day-western-wedding-dresses-
_2019.html (solenoid valve specs)
http://www.tri-plc.com/t100md2424.htm (PLC specification).
http://autohome.com.my/automation/plc/super-plc/m-series (PLC specification).
http://www.hartcomm.info/protocol/about/aboutprotocol_what.html (HART)
http://www.dpstele.com/dpsnews/techinfo/scada/scada_knowledge_base.php?rf=2
(SCADA)
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