146136344 industrial automation summer training report plc scada hmi instrumentation shamsher

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Project Report on “Industrial Automation” Submitted in partial fulfillment of the Requirement for the degree of Bachelor of Technology in Mechanical Engineering Under Guidance of: Submitted By: Mr. Praveen Chugh Md.Shamsher Ansari (Associate Professor) 93059 ME-A (8 th SEM)

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Project Report on Industrial Automation

Submitted in partial fulfillment of the Requirement for the degree of

Bachelor of Technology


Mechanical Engineering

Under Guidance of: Submitted By:

Mr. Praveen Chugh Md.Shamsher Ansari

(Associate Professor) 93059

ME-A (8th SEM)

Session 2009-2013

Department of Mechanical Engineering

Shri Ram College of Engineering & Management, Palwal

Affiliated to Maharishi Dayanand University, Rohtak (Haryana).

Declaration of Originality and Compliance of Academics Ethics

I/We hereby declare that this project will contain literature survey and original work by undersigned candidate/candidates, as part of their B.Tech (Mechanical) studies.

All Information for the project will be obtained and presented in accordance with academic rules and ethical conduct.

I/We also declare that, as required by these rules and conduct, I/We will be fully cited and referenced all material and results that are not original to this work.

(Signature of on the job guide with date)(Signature of Students with date)

Mr. Praveen Chugh Md.Shamsher Ansari

(Training Guide) 93059



This training report is a genuine works by Mr. Md Shamsher Ansari, B.tech final yr, from Shri Ram college of engg & mangt. The report was made under my supervision, and I express my delight on it Successful completion. I also very happy to have offered her guidance whenever it was required.

I wish her successful in all her future endeavors.

Mr. Surinder Kumar Md Shamsher Ansari

(HOD Mechanical) 930559

ME-A (8th SEM)



I am thankful to the Institute Prolific for providing necessary facility to carry out my training successfully. Id also like to thank Er. Arun sing(M.E) and Er. Miss lofa (E.E), for enduring support and guidance throughout the training I am very grateful to the whole control and instrumentation Department for their support and guidance. Also, I am highly obliged to the head of our training and placement cell Who provided me such a great opportunity to do my summer training in a reputed institute like.

Prolific Systems & technologies pvt.ltd

ISO 9001-2008 Certified Company

Mr. Praveen ChughMd. Shamsher Ansari

(Internal Guide) 93059

ME-A (8th SEM)



It gives me an immense pleasure to submit this report as a part of practical training of 4 Months .Practical training is the most important part of the engineering studies.

During the course of the training a trainee learns to correlate both the practical problem to the possible theoretical knowledge or solution .This training record is prepared on the basis of my own experience gained during my practical training. On the basis of information collected and guidance provide I had prepared a comprehensive training report. This report contain the history,

Introduction, quality policy and description op PLC, SCADA, HMI, instrumentations

Md Shamsher Ansari


ME-A (8th SEM)



Table of Content



Page No.








Example of automation

8 to 9

Types of automation, industrial automation

10 to 13


Programmable logic controller PLC

Introduction, Relay


History of PLC, Advantages

14 to 15

Inside PLC, CPU, RAM, ROM, EEPROM, I/P Module

16 to 17

Output Module. Sensor, Actuator

18 to 19

Number system, decimal, binary

19 to 20

Converting binary to decimal, Bits, byte words.logic1, logic0

21 to 22

BCD, Hexadecimal, communication

23 to 24

PLC operation, Programming PLC, Ladder logic, Example

24 to 30





System concept


Tags, types of Tags, classification of tags

32 to 33

Alarm, System components, Salient features

34 to 35

Benefits SCADA/HMI, Recommend




Introduction, types, difference between

35 to 36


Instrumentation, Application of automation, plc SCADA

37 to 39










General Abbreviation

PLC: Programmable logic controllers.

SCADA: Supervisory control and data acquisition.

I/P: Input

O/P: Output.

T-On: On timer.

T-Off: Off timer.

M: Memory Bits.

Q: Output in program.

MW: Memory words.

NO: Normally open.

NC: Normally closed.

DCS: Distributed Control System.

HMI: Human machine interference.

VFD: Variable Frequency Drive.

MD: Memory Double Word.

MB: Memory Byte

XIC: Examine If Closed

XIO: Examine If Open




Automation is the use of control system such as computers to control industrial machinery & process, reducing for need for human intervention. In the scope of industrialization,

Automation is a step beyond mechanization. whereas mechanization provided human operators with machinery assist them with physical requirement of work, automation greatly reduces the need for human sensory and mental requirements as well. Process and system can also be automated.

Example of automation

Automatic machine tools to process parts- CNC m/c

Industrial robots

Automatic material handling

Feedback control system



Automatic Material Handling Conveyors.

Industrial Robots

feedback control systems



Fixed automaton

Programmable automation

Flexible automation

Fixed automation

Fixed automation refers to the use of custom-engineered (special purpose) equipment to automated a fixed sequence of processing or assembly operations. This is also called hard automation.

The primary drawbacks are the large initial investment in requirement and the relative flexibility.

Programmable automation

In programmable automation, the equipment is designed to accommodated a specific class of product changes and the processing or assembly operation can be changed by modifying the control program.

Flexible automation

In flexible automation, the equipment is designed to manufacture a variety of products or parts and very little time is spend on changing from one product to another . A flexible manufacture various combination of products according to any specified schedule.



Monitoring & controller

Field instrument

Intelligent controller


Field instrument

This type of instrument mainly used to get the feedback any type of process carried our so they mainly plant used

Sensors, Transducer, Transmitter

Proximity Sensor.

Intelligent controller

This device are basically micro control based or micro controller device mainly intelligent controller are:

Programmable logic controller (PLC)

PID Controller

Distributed controller system (DCS)

Computer Numerical controller (CNC





Monitoring and controller

This type of device to control whole plant just in a setting in control room, so mainly control device are

Supervisory Control & Data Acquisition (SCADA)

Human Machine interface (HMI)


600 Series touch screen HMI.



A PLC is a solid device designed to perform the function previously accomplished by components such as electromechanical relay, drums switch, mechanical timers /counter etc. for the control and operation of manufacturing process equipment and machinery. Even thought the electromechanical relay (control relay, pneumatic timer relay, etc ) have served well for many generations, often under adverse conditions, the

ever increasing sophistication and complexity of modern processing equipment requires faster acting, more reliable functions that electromechanical relays or timing devices cant offer.

What is relay?

A relay is an electromechanical switch, operated by passing current through a coil wire wound around a steel core, which act as an electromagnet pulling the switch contact down or break a circuit



The first programmable logic controller were designed and developed by Modicon as a relay replacer for GM and landis.

This controller eliminated the need for rewiring and adding additional for each new configuration of logics.

The new system drastically increased the functionality of the control while reducing the cabinet space that housed the logic.

The first PLC, model 084, was invented by Dick Morley in 1969.

The first commercial successful PLC, the 184, was introduced in 1973 and was designed Michael Greenberg.


PLC not only capable of performing the same tasks as hard-wired control, but are also capable of many more flexible application. In addition, the PLC program and electronic communication lines replace much of the interconnecting wires require hardwire control. Therefore, hard wiring, thought still required to connect field device, is less intensive. This also makes correcting errors and modified the application easier.

Some of the additional advantages of PLCs are as follow

Smaller physical size than hard-wire solutions

Easier and faster and to make changes.

PLCs have integrated diagnostics and override functions

Diagnostics are centrally available

Application can be immediately documented


Application can be duplicated faster and less expansively

Speed in operation


Online/ offline modifications

PhotographshowingseveralinputandoutputmodulesofasingleAllen-Bradley PLC.



The Central processing Unit (CPU), contains and internal program that tells the PLCs how to perform the following functions:

Execute the control instructions contained in the users

Programs. This program is store in nonvolatile memory,

Meaning that the program will not be lost if power is removed.

Communicate with other device, which can include I/O

Device, programming device, networks and even other PLCs

Performs housekeeping activities such as communication, internal diagnostic, etc.


The microprocessor or processor module is the brain of PLC system. It consists of the microprocessors, memory integrate circuits, and circuits necessary to store and retrieve information from memory. It also includes communication ports to the other peripherals, other PLCs or programming terminals. Todays processors vary widely in their capabilities to control the real world devices. Some control as few as 6 inputs and

outputs (I/O) and other 40,000 or more. One processor can be control more than one process or manufacturing line. Processors are often linked together in order to provide continuity throughout the process.


RAM or Random Access Memory is a volatile memory that would lose its information if power were removed. This is why some processors units incorporate a battery back-up. This type of RAM normally used CMOS or Complementary Metal Oxide Semiconductor. CMOS RAM is used for storage of the users program (ladder logic diagrams) and storage memory.



ROM or Read only memory is a non volatile memory. This means you dont need external power source to keep information. In this type of memory, information can be read, but not changed. For these reason the manufacture sometimes calls this firmware. It is placed their for the internal use and operation of processors units.


EEPROM or Electrically Erasable programmable Read Only Memory is usually an add-on memory module that is used to back of the main program in COSMOS RAM of the processors. Can be programmed to load the EEPROMs program to RAM is lost or corrected.


There are many types of input module to choose form. These type of module used is dependent upon what real world input to the PLCs is desired. Some example input are limit switches, electric eyes, and pushbuttons. DC input, such as thumbwheels switches, can be used to enter integer values to the manipulated by the PLC, DC input cards are used for this application. Since most industrial power systems are inherently noisy, electrical isolation is provided between the input and the processor. Electromechanical interference (EMI) and radio frequency interference (RF) can be cause severe problems in most solid state control systems. The component used most often to provide electrical isolation within I/O cards is called an optical isolator. The wiring of an input is not complex. The object is to get a voltage at a particular point on the card. Typically there are 8 to 32 input points on any one input module. Each point will be assigned a unique address by the processor. Analog input modules are special cards that use analog to digital conversion (A to D) to sense variables such as temperature, speed, pressure and position. The external device normally is connect to a controller (transducer) producing an electrical signal the analog input card can interpret. This signal is usually 4 to 20 Ma or 0 to 10 volts.



Output modules can be used for ac or dc devices such as solenoids, relay, contractor, pilot lamps, and LED readouts. Output card usually have from 6 to 32 outputs on a signal module. The output device within the cards provides the connection from the user power supply to the load. Usually silicon controlled rectifier (SCR), triac, or dry contact relay are use for this purpose. Individual output are rated most often at 2 to 3 amperes. Output cards, like input cards have electrical isolation between the load being connected and the PLC. Analog output cards are a special type of output modules that use digital to analog conversion (D to A). The analog output module can be take a value store in a 12 bit file and convert it to an analog signal. Normally this signal is 0-10 volts dc or 4 to 20 Ma. This analog signal is often used in equipment such as motor operated valves and pneumatic position control device.


A sensor is a device that converts a physical condition into an electrical signal for use by the PLC. Sensors are connected are input of a PLC. A pushbutton is one example of sensors that is connected to the PLC input. An electrical signal is sent from the pushbutton to the PLC indicating the condition (open/closed) of the pushbutton contacts.

Pushbutton (Sensors)




Actuators convert an electrical signal from the PLCs into a physical condition. Actuators are connected to the PLC output. A motor starter is one example of actuator that is connected to the PLC output. Depending on the PLC signal the motor starter will either start or stop motor.



Actuator (Starter)


Since PLCs is computer it stores information in the form of on or off conditions (1 to 0), refers to as binary digits (bits). Sometimes binary digits are used individually and sometimes they are used to represent numerical valves.


Various number system are used by PLCs. All number systems have the same three characteristic:




The decimal system, which is commonly used in everyday life, has the following characteristic:

Ten digits 0,1,2,3,4,5,6,7,8,9

Base 10

Weights 1, 10, 100, 1000



The binary system is used by programmable controllers. The binary system has the following characteristic:

Two digits 0,1

Base 2

Weights power of base 2 (1, 2, 4, 8, 1, 6)

In the binary system 1s 0s are arranged into columns. Each column is weights. The first column has a binary weight of 2(.

This is equivalent to decimal 1. This is referred to as the least significant bit. The binary weight is double with each succeeding column. The next column, for example, has a weight of 2^1which is equivalent to decimal 2. The decimal value is double in each successive column. The number in the far left hand column is referred to as the most significant bit. In this example, the most significant bit has a binary weight of 2^7. This is equivalent to decimal to 128.



The following steps can be used to interpret a decimal number from a binary value.

1. Search from least to most significant bit for 1s .

2. Write done the decimal representation of each column containing a 1.

3. Add the columns values.

In the following example, the fourth and fifth columns from the right containing a 1.The decimal values of the fourth column from the right is 8, and the decimal value of the fifth column from the right is 16. The decimal equivalent of this binary number is 24. The sum of all the weighted columns that contains a 1is the decimal number that the PLC has stored


Each binary piece of data is a bit. Eight bits make of one byte.

Two bytes, or 16 bits, make of one word.



Programmable controllers can only understand a single that that is on or off (present or not present).the binary system is a system in which there are only two numbers, 1 and 0.

Binary 1 indicates that a signal is present, or the switch is on.

Binary 0 indicates that a signal is present, or the switch is off.

BCD (Binary-coded decimal)

Binary-coded decimal (BCD) are the decimal number where the each digit is represented by a four-bit binary number. BCD is commonly used with input and output devices. Thumbwheel stitch is one example of an input device that uses BCD. The binary number are broken into group of four bits, each group representing decimal equivalent. A four-digit thumbwheel switch, like the one show here, would control 16 (4*4) PLC inputs.



Hexadecimal is another system used in PLCs. The hexadecimal has the following characteristic:

16 digits 0,1,2 ,3,4,5,6,7,8,9,A,B,C,D,E,F

Base 16, weights power of base 16(16, 256, 4096..)

The ten digits of the decimal system are used for the first ten digits of the hexadecimal system. The first six letter of the alphabet are used for the remaining six digits.

A=10, B=11, C=12, D=13, E=14, F=15

The hexadecimal system used in PLCs because it allows the statues of large number of binary bits to the represented in a small space such as on a computer screen or programming device display. Each hexadecimal digit represented the exact of the four binary bits. To convert a decimal number to a hexadecimal number the decimal number is divided by the base of 16.

To convert decimal 28, for example, to hexadecimal

Decimal 28 divided by 16 is 1 with a remainder 12. Twelve is equivalent to C in hexadecimal. The hexadecimal equivalent of decimal 28 is 1c.

The decimal value of a hexadecimal is obtained by multiplying the individual hexadecimal digits by the base 16 weight and the adding the results. In the following example the hexadecimal number 2B is converted to its decimal equivalent

Of 43.



There are several methods to communicate between a PLC and programmer or even between two PLCs. Communications between a PLC and a programmer (PC or Hand held) are provided by the makers and you only have to plug in a cable from your PC to the programming port on the PLC. The communication can be RS232, RS485 or TTY. Communication between two PLCs can be carried out by dedicated links supplied/ programmed by the makers (RS232 etc) or via outputs from one PLC to the input on another PLC. The direct link method of communication can be as a simple as, if an output on the PLC is on then the corresponding input on the second PLC will be on and then this input is used within on the program on the second PLC


There are four basic steps in the operation of all PLCs. Which continually take place in a repeating loop.

Input scan

Program scan

Output scan


Input Scan

Detect the state of all input device that are connect to the PLCs.

Program Scan

Execute the user create program logic. 24


Energize or de-energize all output devices that are connect to the PLCs.


This step includes communication with program terminals, internal diagnostic etc.


First the PLC takes a look at each input to determine if is on or off. In other words, is the sensors connected to the first input on? Then second input? Then the third so onit

record this data into its memory to be used during the next step.


Next PLC executes your program one instruction at a time.

Maybe the program says that if the first input was on then it should on the first output. Since it is already knows which input are on/off from the previous step it will be able to decide whether the first output should be turn on based on state of first input. It will store the execution result for use during the next step.


Finally the PLC updates the state of the outputs. It update the outputs base on which inputs were on during the first step and the result of executing your program during the second step. Based on the example of step 2 it would now turn on the first output because the first input was on and your program said to turn on the first output when this condition is true.

After the third step the PLC goes back to step one and repeats the step continuously. One scan time is defined as the time is takes to execute the 3 steps listed below.



Various languages are used for programming of PLCs.

Ladder Diagram ( LD)

Ladder diagram is a graphic programming language derived from the circuit diagram of directly wired relay control. The ladder diagram contains contact rails to the left the right of the diagram, these contact rails are connected to switching elements (normally open/ normally closed contacts) via current path and the coil elements.


In the function block diagram, the function and blocks are represented graphically interconnected into networks. The function block diagram originates from the logic diagram for the design of electric circuits.



The sequential function chart is language resource for the structuring of sequence- oriented control programs. The element of the sequential function charts are steps, transition, alternative and parallel branching. Each step represents a processing state of a control program, which is active or inactive. A step consists of action which identical to the transition, are formulated in the IEC 1131-3 languages. Action themselves can again contain sequence structure. The feature permits the hierarchical structure of the control program. The sequential Function Chart therefore an excellent tool for the design and structuring of control programs.


Ladder Logic, Ladder programs is the most common programming language used to program a PLC.

Ladder Logic was one of the first programming approaches used in PLCs because it borrowed heavily from the relay diagram that plant electricians already knew.

The symbols used in relay ladder Logic consists of a power rail to the left, a second power rail to the right. The logic of each circuit (or rung) is solved to the left to right. The symbols of these diagram look like a ladder with two side rails and circuits that resemble rungs on ladder.

The picture above represented single rung of ladder

If input is on (or true)- power (logic) completes the circuits from the left rail- and output turns ON(or true)

If output is off (or false)- then the circuit is not complete and logic does not follow to the right- and output 1 is OFF

There are many logic symbols available in ladder logic-includes

Timers , counter , Math, and Data moves such that any logical condition or control loop can be represented in ladder Logic. With just hand full of basics symbols a normally open contact, normally closed contact, normally open coli, normally close coils, timer, counter most logical conditions can be represented.


With just the normally open contact and normal 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 reference input is examined for an ON (Logic1) condition. if it is ON, contact will closed and allow power (logic) to flow from left to right. If the state is off (logic 0).then contact is open, power (logic) will NOT from left to right.

Normally open coil

This can be used to represent any discrete output from the control logic

When solve if the logic to left of the coil is TRUE, the referenced OUT is ON (logic1)


Suppose a switch is wired to input, and a light bulb is wired through output 1 in a such way that the light is OFF when output1 is off and ON when output1is ON.

When input1 is OFF (logic 0) the contact remaining open and power cant flow from left to right, therefore,Output1 remain off (logic 0)

When input is ON (logic 1) then the contact close, power flows from left to right, and output1 becomes ON (the right turns ON)



The AND isa basic fundamental logic condition that iseasy to directly represent in Ladder Logic.

Suppose a switch is wired to Switch1, a second switch is wired toSwitch2, and a light bulb is wired through Light1 in such a way that the light is OFF when Light1 is OFF, and ON when Light1 is ON.In order for Light1 to turn ON, Switch1 must be ON, AND Switch2 must be ON.

If Switch1 is OFF, power (logic) flow from the left rail, but stops at Switch1. Light1 will be OFF regardless ofthe state of Switch2.

If Switch1 is ON, power makes it to Switch2. If Switch2 is OFF, power cannot flow any further to the right, and Light1 is OFF.

If Switch1 is ON, AND Switch2 is ON - power flows to Light1 solving its state to ON.


The OR is a logical that is easy to represent in ladder diagram

Suppose a switch is wired to switch 1, second switch is wired to switch 2, and the light bulb is wired through a light1 in such a way the light is OFF when light is OFF, and ON when light is ON. In this instance, we want to the light to turn ON if either switch1 OR switch is ON.

If switch1 is ON - power flow to Light1 turning it ON.

If switch2 turn is ON power flows through the switch2 contact, and up the rail to light1- turning it ON.

If switch1 AND Switch2 are ON- light1 is ON.

The only way Light1 is OFF is if Switch1 AND Switch2 are OFF.



First consider a hardwired approach

The following line diagram illustrate how a normally open and a normally closed pushbutton might be connected to control a three -phase AC motor as shown above figure.

In this example , a motor starter coil (M) is wired in series with a normally open, momentary start pushbutton, a normally closed , momentary stop pushbutton , and normally closed overload relay (OL) contacts.

Momentarily pressing the start push button complete the path for current flow and energies the motor starter (M). This close the associated M and Ma (auxiliary contact located in the motor starter ) contacts. When the start button is released, current

Continues to flow through the stop button and the Ma contacts, and the M coil remains energized. The motor will run until the normally closed stop button is pressed, unless the overload relay (OL) contacts open . when the stop button is pressed, the path for current is interrupt , opening the associated M and Ma contacts and the motor stop. 30



SCADA is not a specific technology, but a type of application

SCADA stands for Supervisory Control And Data Acquisition any application can gets data about a system in order to control the system is a SCADA application it is a purely software package that is positioned on top of hardware to which it is interfaced , in general via Programmable logic controller (PLCs), or other commercial hardware modules.

In other words

SCADA: the term refers to a large scale, distributed measurement (and control) system. SCADA are used to monitor or to control chemical, physical or transport process.

SCADA it is refers to an industrial control system a computer system monitoring and controlling process. The process can be industrial, infrastructure or facility describe below

Industrial process: it is includes those of manufacturing, production, power generation, fabrication, and refining and process may be in continuous, batch, repetitive or discrete or modules.

Infrastructure process: it may be public or private and water treatment and distribution, wastewater collection, and treatment, oil and gas pipelines, electric power transmission and distribution, and large communication systems.

Facility Process: it is occur both in public facilities and private ones, including building, airports, ship and space station. The monitor and control HVAC, access and energy consumption

A SCADA system usually consists of following subsystem

A Human Machine interface (HMI) is the apparatus which present process data to human operator, and through this, the human operator monitor and control the process.

A supervisory (computer) system, gathering (acquiring) data on the process and sending commands.

Remote terminal unit (RTU) connection to sensors in the process and converting sensors signals to digital data and sending digital data to the supervisory system.

Programmable Logic Controller (PLC) used as field devices because they are more economical, versatile, flexible configurable than special purpose -RTUs.

Communication infrastructure connection the supervisory system to the Remote Terminal Unit. 31

Systems Concepts

The terms SCADA usually refer to a central system that monitors and controls a complete site. The bulk of the site control is actually performed automatically by a Remote Terminal Unit (RTU) or by a programmable Logic controller (PLC). Host control functions are almost always restricted to basic site over- ride or supervisory level capability.

EX: A PLC may control the flow of cooling water through part of an industrial process, but the SCADA system may allow operators to change the set points for the flow, and enable alarm condition, such as loss of flow and high temperature, to be displayed and recorded. The feedback control loop passes through the RTU or PLC while the SCADA system monitors the overall performs of the loop.


It is logical name of a variable or object that be used in our animation of a plant.

Tags are two types

System defined Tags

User defined tags


System defined tags

It is represent the system value in the SCADA it is represented by dollar sing $

User defined tags

This tag are defined by the user or programmer

Except (A,S) are not defined.


it is used for graphical representation of process

Two types

Real times trends

Historical Times trends

Classification of tags

Direct tags

Indirect tags

Direct tags

These tags are directly used by the programmer to represent the value of plant or variable

Indirect tags

These tags are used by the another tags to show or represent the value of plant or variable

Direct tags

Memory tags : these tags having no connection with process the plant.



An important part of most SCADA implementation is alarm handling. The system monitors whether certain alarm conditions are satisfied, to determine when an alarm event has occurred. Once alarm event has been detected, one or more action are taken (such as the activation or remote SCADA operators are informed) in many case, a SCADA operate may have to knowledge the alarm event, these may be deactivate some alarm indicators whereas other indicators remain active until thealarm conditions are cleared. Alarm conditions can be explicit - for example, an alarm point is a digital status point that has either the value NORMAL or ALARM that is calculated by aformula based on the values inother analogue and digital points- or implicit: the SCADA system might automatically monitor whether the value in an analogue point lies outside high and low limit values associated with that point. Examples of alarm indicators include a siren, a pop-up box on a screen, or a colored or flashing area on a screen (that might act in a similar way to the "fuel tank empty" light in a car); in each case, the role of the alarm indicator is to draw the operator's attention to the part of the system 'in alarm' so that appropriate action can be taken. In designing SCADA systems, care is needed in coping with a cascade of alarm events occurring in a short time, otherwise the under lying cause (which might not be the earliest event detected) may get lost in the noise. Unfortunately, when used as a noun, the word 'alarm' is used

rather loosely in the industry; thus, depending on context it might mean an alarm point, an alarm indicator, or an alarm event.


The three components of a SCADA system are:

1. Multiple Remote Terminal Units (Also knows as RTUs or outstation)

2. Central control Room with host computer (s)

3. Communication infrastructure

Remote Terminal Unit (RTU)

The RTU connects to physical equipment and read status dada such as the open/close status from a switch or a valve, read measurements such as pressure, flow, voltage or a valve, or setting the speed of a pump. The RTU can read digital status data or analogue measurement dada, and send out digital commands or analogue.


Salient feature of modern SCADA system

1. User- friendly (X-windows/graphic) interface.

2. Automatic control.

3. Off-line processing.

4. Integrated environments.

5. Extensive Historical data manipulation.

6. Extremely high data throughput

7. On-line complex electrical network analysis.

8. Real time supply/ demand- side economic calculations.

9. Automatic voltages and power factor correction.

10.Distributed processing power.

Benefits HMI/SCADA

1. Powerful monitoring and control over your production

2. Ease of use for New and experienced users.

3. Robust connectivity to other software, system and devices

4. True client /server Architecture for ease Scale ability

5. Powerful thin client technology.

6. Sophisticate Alarm and trending.

SCADA Recommended

1. LAN /WAN support

2. Import from multiple PLC system

3. Support for low bandwidth operation.

4. Secure & flexible.

5. Low CPU & memory requirements.

6. Drives work on Rs232, 422, 485, TCP/IP.

7. Unlimited number of tags (tags support 80 char).

8. Graphic (transparent color support, advanced animation without coding, import graphic window bitmap Auto Cad, fax image.

9. Supervision

10. Controlling

11. Dada collection

12. Interface of PLCs

13. Alarm.

Human Machine Interface (HMI)


HMI is the smallest form of SCADA which is used for monitoring and controlling and it is combination of hardware and software.


Human machine Interface:

The HMI/SCADA industry was essentially out of a need for user friendly front-end to a control system containing programmable logic controller (PLC). While a PLC does provide automated, preprogrammed control over a process, they are usually distributed across a plant, making a difficult to gather data from them manually. additionally, the PLC information are usually in crude user-unfriendly format. The HMI/SCADA gather information from the PLCs via some form of communication method, and combines and formats the information. Since the early1990s the role of SCADA system in large civil engineering solutions has changed, requiring them to perform more operations automatically. A sophisticated HMI may also be linked to a database to provide instant trending diagnostic data, scheduled maintenance procedures, logistic information, detail schematics for a particular sensors or machine, expert system troubleshooting guides.

Since about 1998 , virtually all major PLC manufacture have offered integrated HMI/SCADA system, many of them using open and non proprietary communication protocols.

Types of HMI

1. Keypad

2. Touch screen

3. Keypad + touch screen

Difference between SCADA and HMI


It is software

It is work at low temperature

Screen ratio of SCADA is large

Local and Remote control

Data base connectivity is possible

Range of SCADA


it is combination of s /w and h/w

it is work at high temperature & low

Screen ratio of HMI is Low i.e 6 inch

LAN area Control

Data base connectivity is not possible

Range of HMI is 100m



Instrumentation is a branch of engineering electric (science) which is used for measurement of process parameters and electric parameters it include, flow meter, thermocouple, level instrument etc.


It is device which converted one form of engineering into another form of energy.


It is transducer which converted one form of energy into measurable form of energy.

Types of sensors

1. Flow meter

2. Pressure sensors

3. Ambient meter


It is a device which is used for the transmission of signal over long distance so generally used for transmitter.


Electric power generation, transmission and Distribution.

Manufacturing industries.

Mass transit & whether management system

Traffic signals.

Cement and petrochemicals industries.

Automobiles industries


Application for PLC in substation automation & SCADA

There are many applications for PLC for substation automation, distribution automation & SCADA system. As utility engineers become more familiar with capability of PLCs and PLC manufactures develop a new substation specific products. The number and type of potential applications continues to increase.

RTU (Remote terminal Unit) emulation & replacement

Alarm reduction & intelligent messaging

Utilize existing SCADA protocols

Ethernet, TCP/IP

Multiprotocol, DNP 3.0, Modbus plus

Analog & Discrete I/O

Protection & control

Protective relay interface/ intrection

Automatic switching

Automatic transfer schemes

Circuit breaker control &interlocking

Feeder automation & fault recovery

Automatic service restoration

Emergency load Shedding

Station HMI- Graphic user interface (GUI)

Remote control

Demand control



This report has discussed the role that programmable logic controller have in efficient design and control of mechanical process. Also discussed was the understanding,

AUTOMATION, SCADA, HMI, Instrumentation and the programming involved with it. Finally, the report has discussed as complete Automation, like a , relay, Components, history.

Programmable Logic Controller, history, advantages. Inside PLC etc

PLC components, understanding Ladder logic, example

SCADA: this section contains basic introduction of SCADA, features, Recommended, Tags, Trends

Difference between SCADA & HMI.

HMI: This section contains basic HMI, types of HMI, introduction.



Pollet, Jonathan, SCADA Security Strategy, Plant data Technology, August 8, 2002









Study material by Prolific automation system pvt. Ltd.

Study material by Futronix automation pvt. ltd.

Programmable logic by John. R . Hockwarth


Programmable logic by L.N.Bryan

controllers E.A.Bryan

Programmable logic by W.Batton


Automatic manufacturing by Hugh Jack

System with PLC

Communication technology guidelines for SCADA system, power delivery by Marihart, D.J