सुविचार

विक्रम संवत...........२०७५
मास..............माघ
पक्ष..............कृष्ण
तिथि............दशमी
वार..............बुधवार
दिनांक...........३०-१-२०१९

🙏🏽 💐 वंदे मातरम् 💐

सुविचार:▶ " दूसरों को क्षति पंहुचाकर अपनी भलाई कि हमें आशा नहीं करनी चाहिए।"

सुविचार

विक्रम संवत...........२०७५
मास..............माघ
पक्ष..............कृष्ण
तिथि............नवमी
वार..............मंगलवार
दिनांक...........२९-१-२०१९

🙏🏽 🚩 जय सिया राम 🚩

सुविचार:👉 " जैसे आचरण की हम दूसरों से अपेक्षा रखते है, वैसा ही आचरण हम दूसरों के प्रति करे।"

सुविचार

विक्रम संवत...........२०७५
मास..............माघ
पक्ष..............कृष्ण
तिथि............अष्टमी
वार..............सोमवार
दिनांक........... २८-१-२०१९

🙏🏽 🌺 🕉 नम: शिवाय 🌺

               सुविचार
                  👇
 
" सुन्दर आचरण, सुन्दर देह से अच्छा है।"

Gantantra Divas Ki Shubhkamna

Desh Ke Samvidhan, Samprabhuta,& Samman Ke Prti Hum Sada Sajag & Tatstha Rahe, Esi Aasha Ke Sath Tumko 70 ve Gantantra Divas Ki Shubhkamna.
"BHARAT MATA KI JAY"

We wish you a " A Very Happy 70th Republic Day 2019" for everyone.

सुविचार

" आचरण अच्छा हो तो मन में अच्छे विचार ही आते हैं।"

             👆
          सुविचार

🙏🏽 🌼 शुभम मंगल 🌼

*आप सभी को गणतंत्र दिवस की शुभकामना* 🚩🙏🏽👏

विक्रम संवत...........२०७५
मास..............माघ
पक्ष..............कृष्ण
तिथि............षष्टी
वार..............शनिवार
दिनांक........... *२६-१-२०१९*

सुविचार

विक्रम संवत...........२०७५
मास..............माघ
पक्ष..............कृष्ण
तिथि............पंचमी
वार..............शुक्रवार
दिनांक...........२५-१-२०१९

🙏🏽 🌷 सुप्रभातम् 🌷

सुविचार:👉 " चरित्र एक वृक्ष है, मान एक छाया।
हम हमेशा छाया की सोचते हैं, लेकिन असलियत तो वृक्ष ही है।"

सुविचार

विक्रम संवत...........२०७५
मास..............माघ
पक्ष..............कृष्ण
तिथि............चतुर्थी
वार..............गुरुवार
दिनांक...........२४-१-२०१९

🙏🏽 🌻 भारत माता की जय 🌻

सुविचार:➡ " अच्छी आदतों से शक्ति की बचत होती है, अवगुण से बर्बादी।"

सुविचार

विक्रम संवत...........२०७५
मास..............माघ
पक्ष..............कृष्ण
तिथि............तृतीया
वार..............बुधवार
दिनांक...........२३-१-२०१९

🙏🏽 🍁 वंदे मातरम् 🍁

सुविचार:⏩ " हम बर्फ़ के समान विशुद्ध रहे और हिम के समान स्थिर तब भी लोक निन्दा से नहीं बच पायेगे।"

सुविचार

विक्रम संवत...........२०७५
मास..............पौष
पक्ष..............शुक्ल
तिथि............पूर्णिमा
वार..............सोमवार
दिनांक...........२१-१-२०१९

🙏🏽 🌸 हर हर महादेव 🌸

सुविचार:↔ " आत्मा की शक्ति संपूर्ण विश्व के हथियारों को परास्त करने की क्षमता रखती है।"

सुविचार

विक्रम संवत...........२०७५
मास..............पौष
पक्ष..............शुक्ल
तिथि............त्रयोदशी
वार..............शनिवार
दिनांक...........१९-१-२०१९

🙏🏽 🌺 शुभम मंगल 🌺

सुविचार:▶ " हम स्वयं को बदल दे तो भाग्य स्वयं ही बदल जायेगा।"

Programming Logic Controller (PLC) REPORT

CONTENTS

S.No.		TOPIC	Page No.
Certificate			i
			ii
Overview Of The Industry
			iii
Practical Training Evaluation Form
			iv
Acknowledgement			v
Preface			vi
List of contents			vii
List of figure			viii
Chapter 1 : INDUSTRIAL AUTOMATION			1-5
1.1		Introduction	1-2
1.2		Industrial automation	2-3
	1.2.1  PLC		3
	1.2.2  SCADA		3
	1.2.3  HMI		3
	1.2.4  ANN		4
	1.2.5  DCS		4
	1.2.6  PAC		4
1.3		Advantages of Automation	4
1.4		Disadvantages of Automation	5
1.5		Limitations of  Automation	5
1.6		Application of Automation	5
Chapter 2 : PLC ( PROGRAMMABLE  LOGIC
CONTROLLER)			6-21
2.1	Introduction To PLC		6
2.2	Development And History		7-8
2.3	Features Of  PLC		9-10
2.4	Architecture Of  PLC		10-15
2.5	Sourcing  And Sinking		15

2.6	Working Of PLC			15-18
2.7	Classification Of PLC			18-19
	2.7.1 On Basis Of  I/O Modules			19
	2.7.2	On Basis Of	Application Range	19
	2.7.3	On Basis Of	Application	19
2.8	Application Of  PLC			19-20
2.9	Advantages Of  PLC			21
2.10	Disadvantages Of  PLC			21

	Chapter 3 : SCADA (SUPERVISORY CONTROL  AND
	DATA	ACQUISITION) SYSTEM	22-36
3.1	What Is SCADA?		22
3.2	Fields Where SCADA Can Be Used		22
3.3	How Does SCADA Works?		23
3.4	Why SCADA?		24
3.5	Architecture Of  SCADA		25
3.6	Components Of  SCADA		25-26
	3.6.1  HMI (Human Machine Interface )		25
	3.6.2  SC (System Concepts)		26
	3.6.3  RTU (Remote Terminal Units)		26
	3.6.4  PLC (Programmable Logic Control)		26
	3.6.5	Supervision Station	26
3.7	Features And Their Functionality		27-31
	3.7.1	Dynamic Process Graphics	27
	3.7.2	Alarm Summary And Alarm History	27-28
	3.7.3	Real  Time Trend And Historical Time Trend	28
	3.7.4	Security	28
	3.7.5	Data Connectivity	29-30
	3.7.6	Device Connectivity	30
	3.7.7	Scripts	30
	3.7.8	Recipe Management	30
	3.7.9	Networking	31

	3.7.10	Data Acquisition	31
	3.7.11	Operator Interface	31
3.8	Developers Of  SCADA		31
3.9	Working With Intouch SCADA Scripts		32
3.10	Components Of SCADA(Sensors)		33-34
3.11	Application Of  SCADA		34-36
3.12	Advantages Of SCADA		36
3.13	Disadvantages Of SCADA		36
	Chapter 4 :  CONCLUSION		37-38
	References		39

List of figure

1.	Figure 1.1 Automatic bottle filling plant	6
2.	Figure 2.1 PLC	10
3.	Figure 2.2 Basic PLC architecture	11
4.	Figure 2.3 Internal structure of CPU	12
5.	Figure 2.4 Ladder logic diagram of logic gates	13
6.	Figure 2.5 Opto-isolator	14
7.	Figure 2.6 Sinking and sourcing	15
8.	Figure 3.1 Control panel of SCADA	22
9.	Figure 3.2 Working of SCADA	23
10.	Figure 3.3 Architecture of SCADA	24
11.	Figure 3.4 Symbols in SCADA	27
12.	Figure 3.5 Real time and historical trends	28
13.	Figure 3.6 Data connectivity	29
14.	Figure 3.7 Script writing in SCADA	32
15.	Figure 3.8 Different kinds of sensors	34
16.	Figure 4.1 Fields where automation is used	37

1

CHAPTER 1

INDUSTRIAL AUTOMATION

1.1 INTRODUCTION

As the name suggest “Automation” means to perform automatic operations by means
of different kinds of machines.
Automation means self -move “auto” and "motion”
Automation is the use of control systems and information technologies to reduce the
need for human work in the production of goods and services. In the scope of
industrialization, automation is a step beyond mechanization.
Automation or automatic control, is the use of various control systems for operating
equipment such as machinery, processes in factories, boilers and heat treating ovens,
switching in telephone networks, steering and stabilization of ships, aircraft and other
applications with minimal or reduced human intervention. Some processes have been
completely automated.
The biggest benefit of automation is that it saves labor, however, it is also used to save
energy and materials and to improve quality, accuracy and precision.
The term automation, inspired by the earlier word automatic (coming
from automaton), was not widely used before 1947, when General Motors established
the automation department.[1] It was during this time that industry was rapidly
adopting feedback controllers, which were introduced in the 1930s
Automation has been achieved by various means including mechanical, hydraulic,
pneumatic, electrical, electronics and computers, usually in combination. Complicated
systems, such as modern factories, airplanes and ships typically use all these
combined techniques.
In the automation system we include PLC, SCADA, HMI, DRIVE and all industrial
sensors and motors.

1

The main component of an industrial automation system are-

□       Process Controller (People)

□       Control System(Technical System)

FIG 1.1: Industrial Automation Process

□       Computer and Communication System

□       Sensors

By combination of above all processes an industrial automation system is created which can implement any kind of process.

1.2 INDUSTRIAL AUTOMATIONTOOLS

Current technology is unable to automate all the desired tasks, unpredictable development costs. The research and development cost of automatic a process is difficult to predict accurately beforehand. Since this cost can have a large impact on profitability, it's possible to finish automating process only to discover that there's no economic advantage in doing so. Initial costs are relatively high. The automation of a

2

new product required a huge initial investment in comparison with the unit cost of the product, although the cost of automation is spread in many pr oduct batches. The automation of a plan t required a great initial investment too, although this cost is spread in the product s to be produced. Automation tools differen t types automation tools exist:

1.2.1 PLC - Programmable Logic Controller–

It is a digital comput er used for automation of electromechanic al process such as control of machinery on the factory assembly lines, amusement rides, or lighting fixtures PLCs are us ed in many industries and machines. Unlike general-purpose computers, the PLC is designed for multiple inputs and output arra ngements.

1.2.2 SCADA - Super visory Control and Data Acquisition–

SCADA (supervisory control and data acquisition) is a type o f industrial control system (ICS). Industrial control system are computer controlled s ystems that monitor and control industrial processes that exists in the physical world . SCADA systems historically distinguish themselves from other ICS systems be being large scale processes that can include multiple sites, and large distance.

1.2.3 HMI- Human Machine Interface-

Human Machine inter face is the part of the machine that handles the Human-machine interaction. Membrane Switches, Rubber Keypads and Touch scre ens are examples of that part of the Human Machine interface which we can see and tou ch.

3

1.2.4 ANN -Artificial neural network–

An artificial neural network is a computational simulation of a biological neural network. These models mimic the real life behavior of neurons and the electrical messages they produce between input (such as from the eyes or nerve endings in the hand), processing by the brain and the final output from the brain (such as reacting to light or from sensing touch or heat). There are other ANNs which are adaptive systems used to model things such as environments and population.

1.2.5 DCS - Distributed Control System–

A distributed control system(DCS) refers to a control system usually of a manufacturing system, process or any kind of dynamic system, in which the controller elements are not in location (like a brain) but are distributed throughout the system with each component sub-system controlled by one or more controllers. It is a computerized control system used to control the production line in the industry.

1.2.6 PAC- (Programmable Automation Controller) Instrumentation Motion control Robotics-

Programmable automation controller or PAC a relatively new name coined for small, local control systems. The name is derived largely from the popular PLC or Programmable Logic Controller. One major difference between the PLC and PAC is the programming interface. Most PLCs are programmed in a graphical representation of coils and contacts called Ladder Logic. Most of the PACs are programmed in a modern programming language such as C or C++.

1.3 ADVANTAGES OF AUTMATION-

•      Replacing human operators in tasks that involve hard physical or monotonous work.

•      Replacing humans in tasks done in dangerous environments.

•      Performing tasks that are beyond human capabilities of size, weight, speed, endurance, etc.

•      Economy improvement: Automation may improve in economy of enterprises, society or most of humanity.

4

1.4 DISADVANTAGES OF AUTOMATION -

•       Security threats vulnerability: An automated system may have a limited level of intelligence, and is therefore more susceptible to committing errors of its immediate scope of knowledge.

•       Unpredictable/excessive development costs: the research and development cost of automating a process may exceed the cost saved by the automation itself.

•       High initial cost: the automation of a new product or plant typically requires a very large initial investment in comparison with the unit cost of the product, although the cost of automation may be spread among many products and over time.

1.5 LIMITATIONS OF AUTOMATION-

•       Current technology is unable to automate all the desired tasks.

•       As a process becomes increasingly automated, there is less labor to be saved or quality improvement to be gained.

•       Similar to the above, as more and more processes become automated, there are fewer remaining non-automated processes.

1.6 APPLICATIONS OF AUTOMATION-

•       Automated retail- food and drink, stores

•       Automated mining

•       Automated video surveillance

•       Automated high way systems

•       Automated waste management

•       Automated manufacturing

•       Home automation

•       Industrial automation

5

CHAPTER 2

PLC (Programmable Logical Controller)

2.1 INTRODUCTION OF PLC

A PROGRAMMABLE LOGIC CONTROLLER (PLC) is an industrial computer control system that continuously monitors the state of input devices and make 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. Almost any production process can greatly enhanced using this type of control system, the biggest benefit in using a PLC is the ability to change and replicate the operation or process while collecting and communicating vital information. Another advantage of a PLC is that it is modular. i.e. you can mix and match the types of input and output devices to best suit your application.

Fig.: 2.1 PLC

6

2.2 DEVELOPMENT AND HISTORY

Before the PLC, control, sequencing, and safety interlock logic for manufacturing automobiles was mainly composed of relays, cam timers, drum sequencers, and dedicated closed-loop controllers. Since these could number in the hundreds or even thousands, the process for updating such facilities for the yearly model change- over was very time consuming and expensive, as electricians needed to individually rewire the relays to change their operational characteristics.

Digital computers, being general-purpose programmable devices, were soon applied to control of industrial processes. Early computers required specialist programmers, and stringent operating environmental control for temperature, cleanliness, and power quality. Using a general-purpose computer for process control required protecting the computer from the plant floor conditions. An industrial control computer would have several attributes: it would tolerate the shop-floor environment, it would support discrete (bit-form) input and output in an easily extensible manner, it would not require years of training to use, 
an it would permit its operation to be monitored. The responsetimeofanycomputersystemmustbefastenoughtobeusefulforcontrol;

the  required  speed  varying  according  to  the  nature  of  the  process.^[1]  Since many

industrial processes have timescales easily addressed by millisecond response times, modern (fast, small, reliable) electronics greatly facilitate building reliable controllers, especially because performance can be traded off for reliability.

In 1968 GM Hydra-Metric (the automatic transmission division of General Motors issued a request for proposals for an electronic replacement for hard-wired relay systems based on a white paper written by engineer Edward R. Clark. The winning proposal came from Bed ford Associates of Bed ford, Massachusetts. The first PLC, designated the 084 because it was Bed ford Associates' eighty-fourth project, was the result. Bed ford Associates started a new company dedicated to developing, manufacturing, selling, and servicing this new product: Mod-icon, which stood for Modular Digital Controller. One of the people who worked on that project

was Dick Morley,  who is  considered  to  be the  "father" of  the PLC.  The Mod-icon

brand was sold in 1977 to Gould Electronics, and later acquired by German Company AEG and then by French Schneider Electric, the current owner. These PLCs

7

were programmed in "ladder logic", which strongly resembles a schematic diagram of relay logic.

This program notation was chosen to reduce training demands for the existing technicians. Other early PLCs used a form of instruction list programming, based on a stack-based logic solver.

Modern PLCs can be programmed in a variety of ways, from the relay-derived ladder logic to programming languages such as specially adapted dialects of BASIC and C. Another method is State Logic, a very high-level programming language designed to program PLCs based on state transition diagrams.

Many early PLCs did not have accompanying programming terminals that were capable of graphical representation of the logic, and so the logic was instead represented as a series of logic expressions in some version of Boolean format, similar to Boolean algebra. As programming terminals evolved, it became more common for ladder logic to be used, for the aforementioned reasons and because it was a familiar format used for electromechanical control panels. Newer formats such as State Logic and Function Block (which is similar to the way logic is depicted when using digital integrated logic circuits) exist, but they are still not as popular as ladder logic

In 1969 Gould Modicon developed the first PLC. Hardware CPU controller, with logic instructions, 1K of memory and 128 I/O points

• 1974 - Use of several processors within a PLC

• 1976- Remote input/output systems introduced

• 1977 - Microprocessors-based PLC introduced

• 1980 - Intelligent I/O modules developed enhanced communications facilities.

• 1983 - low-cost small PLC' introduced

• 1985 on - Networking of all levels of PLC, computer and machine using SCADA software.

8

2.3 FEATURES OF PLC

PLC control system is that it regards PLC as control key component, utilize special I/O module to form hardware of control system with a small amount of measurement and peripheral circuit, to realize control to the whole system through programming.

2.3.1 HIGH RELIABILITY

Strong anti-interference quality and very high reliability are the most important features of PLC. In order to make PLC work stably in strong interferential circumstance. Many techniques are applied in PLC. Software control instead of relay control mode can decrease faults which are brought about by original electric contact spot outside working badly. Industrial grade components made by advance processing technology can resist interference's, and self-diagnosis measures of watchdog circuit for protecting memory can improve performance of PLC greatly.

2.3.2 FLEXIBILITY

There are several programming languages for PLC including ladder diagram, SFC, STL, ST and so on. If operator can master only one of programming languages, he can operate PLC well. Every who want to use PLC has a good choice. Based on engineering practice, capacity and function can be expanded by expanding number of module, so PLC has a good flexibility.

2.3.3 QUALITY OF STRONG EASY OPERATION

It is very easy to edit and modify program for PLC by computer offline or online. It is very easy to find out where the fault lie by displaying the information of fault and function of Self Diagnosing Function, and all these make maintenance and repair for PLC easier. It is very easy to configure PLC because of modularization, standardization, serialization of PLC

9

2.3.4 EASY PROGRAMMING AND MODIFICATION

Programming in PLCs is easier in terms of coding and logic designing. In comparison to embedded system and micro-controllers it is easier to program a PLC and also modification of logical design of PLCs is easier. Since it is very user friendly and contains various function blocks so working with PLCs has its own advantages in various fields.

2.3.5 LONGER-LIFE

PLCs are free from problem of ageing due to their rugged construction and static relays have longer life. Since heating effect is lesser in case of PLCs the reduction in efficiency and performance is no more a problem either.

2.3.6   VAST APPLICATION

Application of PLCs is vast and they can be used in and of application in various industries from power plant to manufacturing and from controlling to security they serves many purposes in a single build that ultimately is an advantage and saves space and complexity of system is reduced to a large extent.

All these features add up and create an ultimate system which assures a high performance in terms of accuracy, efficiency and productivity in all the industrial and controlling processes carried out in various fields like industries, power plants, controlling station and other concerning areas.

2.4 ARCHITECTURE

It consists of a central processing unit (CPU) containing the system microprocessor, memory, and input/output circuitry. The CPU controls and processes all the operations within the PLC. It is supplied with a clock with a frequency of typically between 1 and 8 MHz’s. This frequency determines the operating speed of the PLC and provides the timing and synchronization for all elements in the system. The information within the PLC is carried by means of digital signals. The internal paths along which digital signals flow are called buses. In the physical sense, a bus is just a

10

number of conductors along which electrical signals can flow. It might be tracks on a printed circuit board or wires in a ribbon cable.

Fig .: 2.2 Basic PLC architecture

The CPU uses the data bus for sending data between the constituent elements, the address bus to send the addresses of locations for accessing stored data and the control bus for signals relating to internal control actions. The system busies used for communications between the input/output ports and the input/output unit.

2.4.1 CPU

The internal structure of the CPU depends on the microprocessor concerned. In general they have:

O    An arithmetic and logic unit (ALU) which is responsible for data manipulation and carrying out arithmetic operations of addition and subtraction and logic operations of AND, OR, NOT and EXCLUSIVE-OR.

O    Memory, termed registers, located within the microprocessor and used to store information involved in program execution.

O    A control unit which is used to control the timing of operations.

11

Fig.:2.3 Internal structure of CPU

                                                            

The CPU itself has a few different operating modes.

•       Programming Mode.

•       Run Mode.

•       Stop Mode.

•       Reset Mode

BASIC INTRODUCTION ABOUT GATE WITH LADDER LOGIC PROGRAMMING:-

Fig.:2.4 Ladder logic diagram of logic gates

2.4.2 The buses

The buses are the paths used for communication within the PLC. The information is transmitted in binary form, i.e. as a group of bits with a bit being a binary digit of 1 or 0, i.e. on/off states. The term word is used for the group of bits constituting some information. Thus an 8-bit word might be the binary number 00100110. Each of the bits is communicated simultaneously along its own parallel wire. The system has four buses:

□       Data Bus

□       Address Bus

□       Control Bus

□       System Bus

13

2.4.3 Memory

There are several memory elements in a PLC system:

□          System read-only-memory (ROM) to give permanent storage

□          Random-access memory (RAM) for the user's program.

□          Random-access memory (RAM) for data.

□           Possibly, as a bolt-on extra module, erasable  and  programmable  read-only-

memory (EPROM) for ROMs that can be programmed and then the programmed permanent.

The programs and data in RAM can be changed by the user. All PLCs will have some amount of RAM to store programs that have been developed by the user and program data. However, to prevent the loss of programs when the power supply is switched off, a battery is used in the

PLC to maintain the RAM contents for a period of time. After a program has been developed in RAM it may be loaded into an EPPROM memory c hip, often a bolt-on module to the PLC, an d so made permanent .

2.4.4 Input/ Output U nit

The input/output unit provides the interface between the system an d the outside world, allowing for connections to be made through input/output chann els to input devices such as sensors and output devices such as motors and solenoids. It is also through the input/output unit that programs are entered from a program panel. Every input/output point has a unique address which can be used by the CPU.

The input/output channels provide isolation and signal condition in g functions so that sensors and actuators can often be directly connected to them wit hout the need for other circuitry. Electrical isolation from the external world is usually by means of opt isolators (the term opto-coupler is also often used).

Fig.:2.5Optoisolator

14

2.5 SOURCING ANDSINKING

The terms sourcing and sinking are used to describe the way in which d.c. devices are connected to a PLC. With sourcing, using the conventional current flow direction as from positive to negative, an input device receives current from the input module, i.e. the input module is the source of the current.

If the current flows from the output module to an output load then the output module is referred to as sourcing. With sinking, using the conventional current flow direction as from positive to negative, an input device supplies current to the input module, i.e. the input module is the sink for the current.

If the current flows to the output module from an output load then the output module is referred to as sinking.

Fig.: 2.6 Sinking and sourcing

2.6 WORKING OF PLC

The operation of a programmable controller is relatively simple. The input/output (I/O)systemisphysicallyconnectedtothefielddevicesthatareencounteredinthe

15

Machine or that are used in the control of a process. These field devices may be discrete or analog input/output devices, such as limit switches, pressure transducers, push buttons, motor starters, solenoids, etc. The I/O interfaces provide the connection between the CPU and the information providers (inputs) and controllable devices (outputs).

During its operation, the CPU completes three processes:

□       It reads, or accepts, the input data from the field devices via the input interfaces.

□It executes, or performs, the control Program stored in the memory system.

 □It writes, or updates, the output devices via the output interfaces.This process of sequentially reading the inputs, executing the

 Program in memory, and updating the outputs is known as scanning.

A PLC program is generally executed repeatedly as long as the controlled system is running. The status of physical input points is copied to an area of memory accessible to the processor,some times called the"I/O Image Table".The programisthenrun

from its first instruction rung down to the last rung. It takes some time for the Processor of the PLC to evaluate all the rungs and update the I/O image table with the status of outputs. This scan time may be a few milliseconds for a small program or on a fast processor, but older PLCs running very large programs could take much longer (say, up to 100 MS) to execute the program. If the scan time were too long, the response of the PLC to process conditions would be too slow to be useful.

As PLCs became more advanced, methods were developed to change the sequence of ladder execution, and subroutines were implemented. This simplified programming

16

2.6.1 Connection of PLC

Allen Bradley PLC

2.7 CLASSIFICATION OFPLC

Although PLCs have vast fields of application and are used in many processes but still They have to be classified in order to find out the suitability and compatibility of the system and process which we are to follow or for the application for which we use it. We have various parameter for classification of PLCs.

2.7.1 On Basis of I/O Modules

a)      Discrete I/O Module- It provides the field connection between field device and CPU which transmits and receives discrete signals.

b)     Analog I/O Module- Analog input modules are used where continuous signal such as temperature, pressure are to be detected.

Analog output module is used where continuous current and voltage signal is required in output.

2.7.2    On The Basis Of Application Range

a)      Micro PLCs- Up to 32I/O.

b)     Small PLCs- 32 to 128 I/O.

c)      Medium PLCs- 128 to 1024I/O.

d)     Large PLCs- 512 to 4096I/O.

e)      Very Large PLCs- 1024 to 8192I/O.

2.7.3    On the Basis of Application

a)      Safety PLCs- They are designed with some form of logic processing redundancy and monitoring as well as input and output self-checking. As you may have guessed, these cost more, roughly 30% higher than the standard fare and are use in high risk situations.

b)     PAC or Programmable Automation Controllers- They are essentially the tops of the PLC food chain. They are very powerful in terms of processing speed, extensibility, programming and communications.

c)      OEM PLCs- They are generally without a case or enclosure and therefore suited to fit inside a product that is mass produced, for instance a washing

19

2.8 APPLICATIONS OFPLC

PLC is a very versatile device and its application area are very broad. It can be used as a controller as well as a security equipment and most importantly it automates all the processes and reduces the manual labor to a large extent. Some of very highly demanding application of PLC are-

2.8.1     Application in Security-PLCs can be used in various security processes to avoid severe losses and avoid large or minute accidents in power stations and Grid sub stations. They can be used in commercial security too by a little bit of modification in programming and circuitry.

PLC based security systems are more reliable, efficient and are accurate to a large extent (depending upon the accuracy and precision of sensors). Although they are costlier but still they can be used for large buildings with easy application and reduced risks.

2.8.2     Controlling Applications-PLCs are primarily used as controllers for various industrial and commercial processes. The relay system in PLC is used to control various analog and digital signals and gives controlled output according to the programming given to it in the system.

For controlling operation sensors are used to provide input signal and PLC cpu processes the signal accordingly so that the output can be controlled and a regulated desired output is achieved.

2.8.3     Industrial Application-PLCs have very vast industrial application below we

have some examples-

20

INDUSTRY	APPLICATION
Manufacturing	□ complete manufacturing system
Industry	□ silo feeding control system
Travel Industry	□ Escalator  operation,  monitored  safety  control
	System
	□ Lift operation, monitored safety control system

2.9 ADVANTAGES OFPLC

2.9.1  Flexibility:  One  single  Programmable  Logic  Controller  can  easily run  many

machines.

2.9.2    Correcting Errors: In old days, with wired relay-type panels, any program alterations required time for rewiring of panels and devices. With PLC control any change in circuit design or sequence is as simple as retyping the logic. Correcting errors in PLC is extremely short and cost-effective.

2.9.3    Space Efficient: Today's Programmable Logic Control memory is getting bigger and bigger this means that we can generate more and more contacts, coils, timers, sequencers, counters and so on. We can have thousands of contact timers and counters in a single PLC. Imagine what it would be like to have so many things in one panel.

2.9.4 Low Cost: Prices of Programmable Logic Controller’s vary from few hundreds to few thousands. This is nothing compared to the prices of the contact and coils and timers that you would pay to match the same things.

2.9.5 Testing: A Programmable Logic Control program can be tested and evaluated in a lab. The program can be tested, validated and corrected saving very valuable time.

2.9.6 Visual observation: When running a PLC program a visual operation can be seen on the screen. Hence troubleshooting a circuit is really quick, easy and simple.

2.9.7 Pre-Defined Function Blocks: Pre-defined function blocks provides user an opportunity to avoid extra programming for the specific functions. In PLC we have functions like timer, counter, add, sub, RTO are pre-defined

2.10    DISADVANTAGES OF PLC

1         It is a tedious job when replacing or bringing any changes to it.

2 Skillful work force is required to find its errors. 3 Lot of effort is put to connect the wires.

20

CHAPTER3

SCADA

(SUPERVISORY CONTROL AND DATA ACQUISITION)

3.1 WHAT IS SCADA?

SCADA is an acronym for Supervisory Control and Data Acquisition, which is a computer system for gathering and analyzing real-time data. Such systems were first used in the 1960s. The SCADA industry was essentially born out of a need for a user-friendly front-end to a control system containing PLCs (programmable logic controllers). SCADA networks enable remote monitoring and control of an amazing variety of industrial devices, such as water and gas pumps, track switches, and traffic signals.

One of the key processes of SCADA is the ability to monitor an entire system in real time. This is facilitated by the data acquisitions including meter reading and checking statuses of sensors that are communicated at standard intervals depending on the system.

Fig.: 3.1 Control panel of SCADA

3.2 FIELDS WHERE SCADA CAN BE USED

SCADA can be used to manage many kinds of equipment. Typically, SCADA systems are used to automate complex industrial process where human control is impractical. Around the world, SCADA system control are used in the following industries:

3.2.1    Manufacturing: SCADA systems manage parts inventories for JIT manufacturing.

3.2.2     Buildings,  facilities  and  environments:  facility  managers  use  SCADA  to  control

HVAC.

22

3.2.3   Electrical power generation, transmission and distribution: electric utilities are SCADA systems to detect current flow and line voltage, to monitor the operation of circuit breakers.

3.2.4   Water and sewage: state and municipal water utilities use SCADA to monitor and regulate water flow, reservoir levels, and pipe pressure .

3.2.5   Mass transit: transit authorities use SCADA to regulate electricity to subways, trams and trolley buses; to automate traffic signals for rail system s .

3.2.6   Traffic signals: SCADA regulates traffic lights, controls traffic flow and detects out-

of-order signals.

3.3 HOW DOES SCADAWORK?

A SCADA network consists of one of more Master Terminal Units (MTUs), which are utilized by operators to monitor and control a large number of Remote Terminal Units (RTUs). The MTU is often a computing platform, like a PC, which runs SCADA software. The RTUs are generally small dedicated devices that are hardened for outdoor use and industrial environments.

As we saw earlier, there are several parts of a working SCADA system A SCADA system usually includes signal hardware , controllers, networks, user interface(HMI), communications equipment and software.

23

3.4 WHY SCADA?

SCADA systems are an extremely advantageous way to run and monitor processes. They are great for small applications, such as climate control, but they can be effectively used in large applications such as monitoring and controlling a nuclear power plant or mass transit system.

SCADA can come in open and non-proprietary protocols. Smaller systems are extremely affordable and can either be purchased as a complete system or can be mixed and matched with specific components. Large systems can also be created with off-the-shelf components. SCADA system software can also be easily configured for almost any application, removing the need for custom software development.

SCADA is acronym that denotes Supervisory Control and Data Acquisition. SCADA is a control system with applications in managing large-scale, automated industries operations. Factories and plants, water supply systems, nuclear and conventional power generator systems etc are a few examples. The SCADA systems, nuclear and conventional power generator etc.

3.5 ARCHITECTURE OFSCADA-

Fig.: 3.3 Architecture of SCADA

3.5.1     First generation: “Monolithic”-in the first generation, computing was done by mainframe computers. Networking did not exist at the time SCADA was

24

Developed. Thus SCADA systems were independent systems with no connectivity to other systems. Wide Area Networks were later designed by RTU vendors to communicate with the RTU. The communication protocols used were often proprietary at that time. The first-generation SCADA system was redundant since a back-up mainframe system was connected at the bus level and was used in the event of failure of primary mainframe system.

3.5.2    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.

3.5.3    Third generation: “Networked”- 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 timely maintenance and updates

3.6       COMPONENTS OFSCADA-

3.6.1          A human- machine interface or HMI- HMI is the apparatus which presents process data to human-machine interface or HMI is the apparatus which presents process data to a human operator, and through which the human operator controls the process. An HMI is usually linked to the SCADA system’s databases and software programs, to provide trending, diagnostic data, and management information such as scheduled maintenance procedures, logistics information, detailed schematics for a particular sensor or machine and expert-system troubleshooting guides. The HMI system usually presents the information to the operating graphically, in the form of a mimic diagram. This means that the operator can see a schematic representation of the plant being controlled.

25

3.6.2	System concepts- A supervisory (computer) system, gathering (acquiring) data
	on the process and sending commands (control) to the process. The term SCADA
	usually  refers  to  centralized  systems  which  monitor  and  control  entire  sites,  or
	complexes  of  systems  spread  out  over  large  areas.  Most  control  actions  are
	performed automatically by RTUs or by PLCs. Host control functions are usually
	restricted to basic overriding or supervisory level intervention.
3.6.3	Remote  terminal  units  (RTUs)  -  RTU  used  to  connecting  sensors  in  the
	process, converting sensor signals to digital data and sending digital data to the
	supervisory system. The RTU connects to physical equipment. Typically, an RTU
	converts  the  electrical  signals  from  the  equipment  to  digital  values  such  as  the
	open/closed status from a switch or a valve, or measurements such as pressure, flow,
	voltage or current. By converting and schematic these electrical	signals out	to
	equipment the RTU can control equipment, such as opening or closing a switch		or
	a valve, or setting the speed of a pump. It can also the flow of a l i q u i d .
3.6.4	Programmable logic controller (PLCs) - PLC is a solid state device or
	mini industrial  computer that  performs discrete or  sequential logics in a  factory
	environment. It was originally developed to replace mechanical relay, timers, and
	counters. PLCs are successfully used to execute complicated control operations. Its
	purpose to monitor crucial parameters & adjust process operation accordingly. It is a
	digital  computer  used  for  automation  of  electromechanical  processes,  such  as
	control of machinery on factory assembly lines, amusement rides, or light fixtures.
	PLCs are used in many industries and machines.
3.6.5	Supervisory  station-  communication  infrastructure  connects  the  supervisory
	system  to  the  remote  terminal  units.  The  term  supervisory  station  refers  to  the
	servers  and  software  responsible  for  communicating  with  the	field  equipment

(RTUS, PLCs, etc.), and then to the HMI software running on workshops in the control room, or elsewhere. In smaller SCADA systems, the master station may be composed of a single PC. In larger SCADA systems, the master station may include multiple servers the multiple servers will often be configured in adual-

26

Redundant or hot-standby formation providing continuous control and monitoring in the event of a server failure.

3.7      FEATURES & THEIRFUNCTIONALITY-

3.7.1    Dynamic process Graphic – it should resemble the process mimic SCADA should have good library of symbols so that develop the mimic as per required. When operator sees the screen he should know what’s going in plant. By this feature, graphic develop which can resemble the plant. The graphics can include reactors, valve, pumps, agitators, conveyors as well as other equipment and machinery used in the plant. The status of the equipment running / stopped can be shown using different colors /animation.

Typically the SCADA software will have many ready to use symbols for proper representation which can be used in any type of industry.

3.7.2    Alarm summary & Alarm history – A SCADA system must be able to

detect, display and log alarms and events. When there are problems the SCADA system must notify the operators to take corrective a action. Alarms and event must be recorded so that engineers and programmers can review the alarm to determine what caused the alarm and prevent them happening again .

27

More complicated expressions can be developed by creating derived parameters on which status or limit checking is then performed. The alarms are logically handled centrally, i.e. the information only exists in one place and all users see the same status, and multiple alarm priority levels are supported.

3.7.3    Real time trend & Historical time trend – The trends play very important

role in the process operation. If batch fails or the plant trips then historical trend data used and do the analysis. Better look of the representing parameters through the trends in graphical form the trend plots the value with reference to the time .

Real-time data will plot the real –time value for fixed period of time while historical data will have historical data stored value which can be viewed on demand. Depending upon the storing capacity of the hard-disk one can specify the no of days the data can be stored.

3.7.4    Security (Application Security) – Allocated certain facilities or features to the operator, process people, engineering dept. & maintenance dept. for example operators should only operate the system, not be able change the application. The

28

Engineers should access to changing the application. The eng ineers should access for securing the application by avoiding unauthorized a c c e ss .

Depending upon the access level given the operator/ engineer s allowed to do the task. in most of the cases, the operators are allowed only to operate the plant while maintenance eng ineers can do the application modifications. The security can be given for individu al as well as for groups.

3.7.5    Database con nectivity – in manufacturing units go for Enterprise Resource Planning (ERP) or management Information System (MIR). One can produce reports using SQL type queries to the archive, RTDB or logs. Although it is sometimes possible to conn ect embed EXCEL charts in the report. Facilities exist to be automatically gen erated, print and archive reports. It is important to download the real-time information to the MIS.

In this case the database connectivity is must. Much SCADA software doesn’t have their own database. Hence for storage and reporting they use third party database like MS Access or SQL.

3.7.6    Device connectivity – There are hundreds of automation hardware manufacturer like Modicon, Seimens, Allen Bradley, Yokogawa, ABB. There are own communication protocol. SCADA s/w should have connectivity to the different hardware used in automation. It should not happen that for Modicon buy one software & for seimens another one.

The software like Aspic or Wonderware has connectivity to almost all hardware used in Automation. Every control hardware has its own communication protocol for communicating with different hardware / software. Some of the leading communication protocol include Modbus, Profibus, Ethernet, DH +, DH 485, Device net, Control net.

3.7.7    Scripts – the majority of the products allow actions to be automatically triggered by events. Scripting languages provided by the SCADA products allow these actions to be defined. The concepts of receipts is supported, whereby a particular system configuration can be saved a file and then re-loaded at a later date. Sequencing is also supported, it is possible to execute a more complex sequence of actions on one or more devices. Sequences may also react to external events. Scripts is a way of writing logic in SCADA software. Every SCADA software has its own instructions and way of writing program.

3.7.8    Recipe management – it is an additional feature. Most of the plants are manufacturing multi products. When Different product to manufacturing, then recipe of that particular get locked. The same plant for manufacturing different

30

Product range. For example an oil blending plant can manufacture power oil, transformer oil, and automobile oil.

It is the facility used for maintains various recipes of different products and implement it on the process. The recipe can be stored in a single server and it can be fetched by any client server from any area to run the process .

3.7.9    Networking – in an application, we have to use more than one SCADA software operator stations. This can be achieved by taking the SCADA node on network. Ethernet TCP/IP is commonly used for networking.

3.7.10  Data Acquisition – SCADA must be able to read data from PLCs and other hardware and then to analyze and graphically present that data to the user. SCADA systems must be able to read and write multiple sources of d a t a .

3.7.11  Operator Interface– A SCADA system collects all of the information about a process. The SCADA systems then need to display this data to the operator so that they can comprehend what is going on with process

3.8  Developers of SCADA

1.      Wonderware :Intouch

2.      Allen Bradly : RSview

3.      Siemens :winCC

4.      Intelution :iFix

5.      KPIT :ASTRA

6.      Modicon :Vijeocitect

31

3.9 Working with Intouch SCADA Script:-

Fig.:3.7 Script writing in SCADA

32

3.10 Component of SCADA (SENSOR):-

3.10.1 What are sensors?

A sensor is a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat, motion, moisture, pressure, or any one of a great number of other environmental phenomena. The output is generally a signal that is converted to human-readable display at the sensor location or transmitted electronically over a network for reading or further p ro ces s i ng .

Here are a few examples of the many different types of s e n s o rs :

In a mercury-based glass thermometer, the input is temperature. The liquid contained expands and contracts in response, causing the level to be higher or lower on the marked gauge, which is human-readable.

An oxygen sensor in a car's emission control system detects the gasoline/oxygen ratio, usually through a chemical reaction that generates a voltage. A computer in the engine reads the voltage and, if the mixture is not optimal, readjusts the b a l a n c e .

Motion sensors in various systems including home security lights, automatic doors and bathroom fixtures typically send out some type of energy, such as microwaves, ultrasonic waves or light beams and detect when the flow of energy is interrupted by something entering its path.

Classification based on property is as given below:

·                Temperature - Thermostats, thermocouples, RTD’s, IC and many m o r e .

·          Pressure   -   Fiber   optic,   vacuum,   elastic   liquid   based   manometers,    LVDT,

e l e c t r o n i c .

·                Flow - Electromagnetic, differential pressure, positional displacement, thermal mass,etc.

·                Level Sensors - Differential pressure, ultrasonic radio frequency, radar, thermal displacement,etc.

·                Proximity and displacement - LVDT, photoelectric, capacitive, magnetic, ultrasonic.

·                Biosensors - Resonant mirror, electrochemical, surface Plasmon resonance, Light addressablepotentio-metric.

·                Image - Charge coupled devices,CMOS

·                Gas and chemical - Semiconductor, Infrared, Conductance, Electrochemical.

·                Others - Moisture, humidity sensor, Speed sensor, mass, Tilt sensor, force, viscosity.

33