PLC SCADA training report

A SUMMER TRAINING REPORT

On

PLC-SCADA AND AUTOMATION

Submitted in partial fulfilment of requirements for the award ofBachelors of Technology

InElectrical and Electronics Engineering

2012-2016

Submitted ToEr. PAWAN PUNIA-HOD,EEE

Submitted ByJASKAWAL SINGH-12ETSEX009

Saraf Institute of Engineering & Technology Hanumangarh, Rajasthan

Session 2012-16 [PLC , SCADA & AUTOMATION REPORT]

CERTIFICATE

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ABSTRACT

An Industrial SCADA and PLC system is used for the

development of the controls of machinery. This report

describes the SCADA & PLC systems in term of their

architecture, their interface to the process hardware, the

functionality and the application development facilities they

provide.

Some attention is also paid to the industrial standards to which

they abide their planned evolution as well as the potential

benefits of their use.

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CANDIDATE’S DECLARATION

I hereby declare that the work presented in this report entitled

“PLC-SCADA & Automation”, submitted in EEE Department

of Saraf Institute of Engineering and Technology, affiliated to

Rajasthan Technical University, Rajasthan, is an authentic

record of my own work carried out during my degree under the

guidance of Er. Pawan Punia (HOD, EEE Deptt.)

The work reported in this has not been submitted by me for

award of any other degree or diploma.

Signature of Candidate:

Jaskawal singh

12ETSEX009

This is to certify that the above statement

made by the candidate is correct to the best of my knowledge.

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Er. Pawan Punia (HOD,EEE Deptt.)

ACKNOWLEDGEMENT

It gives me immense pleasure to express my deepest sense of

gratitude and sincere thanks to my highly respected and

esteemed guide Er. Pawan Punia (HOD EEE Deptt.) S.I.E.T,

Hanumangarh for their valuable guidance, encouragement

and help for completing this work. Their useful suggestions

for this whole work and co-operative behavior are sincerely

acknowledged.

I would like to express my sincere thank to Mr. Manoj

Sharma, Founder, C.E.O & C.T.O ,Kaizen Robeonics

Research Pvt. Ltd. for

giving me this opportunity to undertake this training.

At the end I would like to express my sincere thanks to all my

friends and others who helped

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me directly or indirectly during this project work.

. TABLE OF CONTENTS CHAPTER NO. TITLE PAGE NO.

TITLE PAGE........................................i

CERTIFICATE....................................ii

ABSTRACT..........................................iii

CANDIDATE’S DECLARATION....iv

ACKNOWLEDGEMENT...................v

TABLE OF CONTENTS....................vi

LIST OF FIGURES.............................ix

LIST OF TABLES................................x

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1. AUTOMATION....................................11 1.1 Introduction to automation.....................12 1.2 Block diagram of automation.................14 1.3 Application.............................................14 1.4 Advantage and Disadvantage.................18 1.5 Automation tools....................................20 1.6 Limitation of automation........................21

2. CONTROLLER.....................................22

2.1 What are Controllers.............................232.2 Types of Controllers.............................23

.

CHAPTER NO. TITLE PAGE NO.

2. 2.2.1 PID Controllers..................................23

2.2.2 CNC Controller..................................25

2.2.3 PC based Controller..........................27

2.2.4 PLC based Controller.......................29

2.2.5 DCS..................................................30

3. PLC....................................................... 31 3.1 Introduction to PLC..............................32 3.2 History and Origin................................35 3.3 PLC Vendors.........................................36 3.4 Block diagram.......................................37 3.5 Major components of a PLC................37 3.6 Classification of PLC............................38 3.7 PLC operation.......................................39

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3.8 Scan Cycle.............................................39 3.9 Circuit isolation in PLC.........................41 3.10 Sinking and Sourcing concept.............43 3.11 Communications..................................43 3.12 Programming Language......................46. 3.13 Ladder logic .......................................47 3.14 Timers ................................................49 3.15 Compare instructions..........................50 3.16 Counter................................................52 3.17 Compute/Math ...................................53 3.18 Move/Logical .....................................54 3.19 Softwares.............................................56

CHAPTER NO. TITLE PAGE NO.

4. SCADA.....................................................59

4.1 Introduction to SCADA...............................60

4.2 What SCADA can do for you......................61

4.3 SCADA software.........................................62

4.4 Functionality...............................................63

4.5 Automation.................................................70

4.6 Application Development...........................71

4.7 Application of SCADA...............................72

4.8 Communication ..........................................76

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CONCLUSION....................................77

REFERENCES....................................78

LIST OF FIGURES

S NO. NAME PAGE NO.

01. Block Diagram of Automation.................1402. Block diagram of PID Controller...............2503. Computer Numerically Controlled.............2704. Allen Bradley PLC....................................3205. Block diagram of PLC...............................3706. Scan Cycle of a PLC..................................4007. Circuit Diagram of PLC.............................4208. Sinking and Sourcing Concept...................4309. Ethernet Cable............................................4410. PMO2 Cable...............................................45

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11. Trending.....................................................6412. Alarm Handling..........................................6513. Logging and Archiving...............................6614. SCADA Systems........................................75

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LIST OF TABLES

S NO. NAME PAGE NO.

01. PLC Vendors.........................................36

02. Allen Bradley Data File Description.....57

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Chapter - IAutomation

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1.1 Introduction to Automation

Automation is the use of control systems such as

computers to control industrial machinery and processes,

reducing the need for human intervention. In the scope of

industrialization, automation is a step beyond mechanization.

Whereas mechanization provided human operators with

machinery to assist them with the physical requirements of

work, automation greatly reduces the need for human sensory

and mental requirements as well. AutomationIs Basically The

Use Of Control Systems (Such As Numerical Control,

Programmable Logic Control, And Other Industrial Control

Systems), In Concert With Other Applications Of Information

Technology (Such As Computer-Aided Technologies [CAD,

CM, Cax]), To Control Industrial Machinery And Processes,

Reducing The Need For Human Intervention. In The Scope

Of Industrialization, Automation Is A Step Beyond

Mechanization. Whereas Mechanization Provided Human

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Operators With Machinery To Assist Them With The

Muscular Requirements Of Work, Automation Greatly

reduces The Need For Human Sensory And Mental

Requirements As Well. Processes And Systems Can Also Be

Automated.

Automation Plays An Increasingly Important Role In The

Global Economy And In Daily Experience. Engineers Strive

To Combine Automated Devices With Mathematical And

Organizational Tools To Create Complex Systems For A

Rapidly Expanding Range Of Applications And Human

Activities. Specialized Hardened Computers, Referred To As

Programmable Logic Controllers (Plcs), Are Frequently Used

To Synchronize The Flow Of Inputs From (Physical) Sensors

And Events With The Flow Of Outputs To Actuators And

Events. This Leads To Precisely Controlled Actions That

Permit A Tight Control Of Almost Any Industrial Process.

Human-Machine Interfaces (HMI) Or Computer Human

Interfaces (CHI), Formerly Known As Man-

MachineInterfaces, Are Usually Employed To Communicate

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With Plcs And Other Computers, Such As Entering And

Monitoring Temperatures Or Pressures For Further

Automated Control Or Emergency Response.

1.2. Block diagram of automation

FIG:01

1.3. Applications Automated video surveillance:

The Defense Advanced Research Projects Agency (DARPA) started the research and development of automated visual surveillance and monitoring (VSAM) PAGE

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http://en.wikipedia.org/wiki/DARPA


program, between 1997 and 1999, and airborne video surveillance (AVS) programs, from 1998 to 2002. Currently, there is a major effort underway in the vision community to develop a fully automated tracking surveillance system. Automated video surveillance

monitors people and vehicles in real time within a busy environment. Existing automated surveillance systems are based on the environment they are primarily designed to observe, i.e., indoor, outdoor or airborne, the amount of sensors that the automated system can handle and the mobility of sensor, i.e., stationary camera vs. mobile camera. The purpose of a surveillance system is to record properties and trajectories of objects in a given area, generate warnings or notify designated authority in case of occurrence of particular events.

Automated highway systems: As demands for safety and mobility have grown and technological possibilities have multiplied, interest in automation has grown. Seeking to accelerate the development and introduction of fully automated vehicles and highways, the United States Congress authorized more than $650 million over six years for intelligent transport systems (ITS) and demonstration projects in the 1991Intermodal Surface Transportation Efficiency Act (ISTEA). Congress legislated in ISTEA that “the Secretary of Transportation shall develop an automated highway and vehicle prototype from which future fully automated intelligent vehicle-highway systems can be developed. Such development shall include PAGE

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http://en.wikipedia.org/wiki/United_States_Secretary_of_Transportation

http://en.wikipedia.org/wiki/Intelligent_transport_system

http://en.wikipedia.org/wiki/Intelligent_transport_system

http://en.wikipedia.org/wiki/United_States_Congress


research in human factors to ensure the success of the man-machine relationship. The goal of this program is to have the first fully automated highway roadway or an automated test track in operation by 1997. This system shall accommodate installation of equipment in new and

existing motor vehicles.Full automation commonly defined as requiring no control or very limited control by the driver; such automation would be accomplished through a combination of sensor, computer, and communications systems in vehicles and along the roadway. Fully automated driving would, in theory, allow closer vehicle spacing and higher speeds, which could enhance traffic capacity in places where additional road building is physically impossible, politically unacceptable, or prohibitively expensive. Automated controls also might enhance road safety by reducing the opportunity for driver error, which causes a large share of motor vehicle crashes. Other potential benefits include improved air quality (as a result of more-efficient traffic flows), increased fuel economy, and spin-off technologies generated during research and development related to automated highway systems.

Automated manufacturing :Automated manufacturing refers to the application of automation to produce things in the factory way. Most of the advantages of the automation technology has its influence in the manufacture processes.

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The main advantages of automated manufacturing are higher consistency and quality, reduced lead times, simplified production, reduced handling, improved work flow, and increased worker morale when a good implementation of the automation is made.

Home automation:Home automation (also called domotics) designates an emerging practice of increased automation of household appliances and features in residential dwellings, particularly through electronic means that allow for things impracticable, overly expensive or simply not possible in recent past decades.

Industrial automation :Industrial automation deals with the optimization of energy-efficient drive systems by precise measurement and control technologies. Nowadays energy efficiency in industrial processes are becoming more and more relevant. Semiconductor companies like Infineon Technologies are offering 8-bit microcontroller applications for example found in motor controls, general purpose pumps, fans, and ebikes to reduce energy consumption and thus increase efficiency.

Agent-assisted Automation : Agent-assisted Automation refers to automation used by call center agents to handle customer inquiries. There are PAGE

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two basic types: desktop automation and automated voice solutions. Desktop automation refers to software programming that makes it easier for the call center agent to work across multiple desktop tools. The automation would take the information entered into one tool and populate it across the others so it did not have to be entered more than once, for example. Automated voice solutions allow the agents to remain on the line while

disclosures and other important information is provided to customers in the form of pre-recorded audio files. Specialized applications of these automated voice solutions enable the agents to process credit cards without ever seeing or hearing the credit card numbers or CVV codes.

The key benefit of agent-assisted automation is compliance and error-proofing. Agents are sometimes not fully trained or they forget or ignore key steps in the process. The use of automation ensures that what is supposed to happen on the call actually does, every time.

1.4. AdvantagesThe main advantages of automation are:

Increased throughput or productivity.

Improved quality or increased predictability of quality.

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Improved robustness (consistency), of processes or product.

The following methods are often employed to improve productivity, quality, or robustness.

Install automation in operations to reduce cycle time. Install automation where a high degree of accuracy is

required. Replacing human operators in tasks that involve hard

physical or monotonous work.[3]

Replacing humans in tasks done in dangerous environments (i.e. fire, space, volcanoes, nuclear facilities, underwater, etc.)

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. For example, when an enterprise invests in automation, technology recovers its investment; or when a state or country increases its income due to automation like Germany or Japan in the 20th Century.

Reduces operation time and work handling time significantly.

Frees up workers to take on other roles. Provides higher level jobs in the development, deployment,

maintenance and running of the automated processes.

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http://en.wikipedia.org/wiki/Japan

http://en.wikipedia.org/wiki/Germany

http://en.wikipedia.org/wiki/Automation#cite_note-2


DisadvantagesThe main disadvantages of automation are:

Security Threats/Vulnerability: An automated system may have a limited level of intelligence, and is therefore more susceptible to committing errors outside of its immediate scope of knowledge (e.g., it is typically unable to apply the rules of simple logic to general propositions).

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. Automation toolsEngineers can now have numerical control over automated devices. The result has been a rapidly expanding range of applications and human activities. Computer-aided technologies (or CAx) now serve the basis for mathematical and organizational tools used to create complex systems. Notable examples of CAx include Computer-aided design (CAD software) and Computer-aided manufacturing (CAM software). The improved design, analysis, and manufacture of products enabled by CAx has been beneficial for industry. PA

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http://en.wikipedia.org/wiki/Computer-aided_manufacturing

http://en.wikipedia.org/wiki/Computer-aided_manufacturing

http://en.wikipedia.org/wiki/Computer-aided_design

http://en.wikipedia.org/wiki/Computer-aided_design

http://en.wikipedia.org/wiki/Computer-aided_technologies

http://en.wikipedia.org/wiki/Computer-aided_technologies

http://en.wikipedia.org/wiki/Numerical_control

http://en.wikipedia.org/wiki/Plant

http://en.wikipedia.org/wiki/Product_(business)

http://en.wikipedia.org/wiki/Research_and_development


Information technology, together with industrial machinery and processes, can assist in the design, implementation, and monitoring of control systems. One example of an industrial control system is a programmable logic controller (PLC). PLCs are specialized hardened computers which are frequently used to synchronize the flow of inputs from (physical) sensors and events with the flow of outputs to actuators and events. An automated online assistant on a website, with an avatar for enhanced human.

Human-machine interfaces (HMI) or computer human interfaces (CHI), formerly known as man-machine interfaces, are usually employed to communicate with PLCs and other

computers. Service personnel who monitor and control through HMIs can be called by different names. In industrial process and manufacturing environments, they are called operators or something similar. In boiler houses and central utilities departments they are called stationary engineers. Different types of automation tools exist:

DCS - Distributed Control System HMI - Human Machine Interface SCADA - Supervisory Control and Data Acquisition PLC - Programmable Logic Controller

Instrumentation

Motion control

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http://en.wikipedia.org/wiki/Motion_control

http://en.wikipedia.org/wiki/Instrumentation

http://en.wikipedia.org/wiki/Programmable_Logic_Controller

http://en.wikipedia.org/wiki/Supervisory_Control_and_Data_Acquisition

http://en.wikipedia.org/wiki/Human_Machine_Interface

http://en.wikipedia.org/wiki/Distributed_Control_System

http://en.wikipedia.org/wiki/Human%E2%80%93computer_interaction

http://en.wikipedia.org/wiki/Human%E2%80%93computer_interaction

http://en.wikipedia.org/wiki/Human-computer_interaction

http://en.wikipedia.org/wiki/Avatar_(computing)

http://en.wikipedia.org/wiki/Automated_online_assistant

http://en.wikipedia.org/wiki/Sensor

http://en.wikipedia.org/wiki/Programmable_logic_controller

http://en.wikipedia.org/wiki/Industrial_control_systems

http://en.wikipedia.org/wiki/Industrial_process

http://en.wikipedia.org/wiki/Machinery

http://en.wikipedia.org/wiki/Industry

http://en.wikipedia.org/wiki/Information_technology


Robotics

1.6. Limitations to automation Current technology is unable to automate all the desired

tasks. As a process becomes increasingly automated, there is less

and less labor to be saved or quality improvement to be gained. This is an example of both diminishing returns and the logistic function.

Similar to the above, as more and more processes become automated, there are fewer remaining non-automated processes. This is an example of exhaustion of opportunities.

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http://en.wikipedia.org/wiki/Robotics


Chapter – IIControllers

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2.1. What Are Controllers?

In control theory, a controller is a device which monitors and

affects the operational conditions of a given dynamical system.

The operational conditions are typically referred to as output

variables of the system which can be affected by adjusting

certain input variables.

For example, the heating system of a house can be

equipped with a thermostat (controller) for sensing air

temperature (output variable) which can turn on or off a

furnace or heater when the air temperature becomes too low

or too high.

2.2. TYPES OF CONTROLLERS

There are many types of controllers. Some of them are as

follows:

2.2.1 PID Controllers PA

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A proportional–integral–derivative controller (PID controller)

is a generic control loop feedback mechanism (controller)

widely used in industrial control systems.

PID controller attempts to correct the error between a

measured process variable and a desired set point by

calculating and then outputting a corrective action that can

adjust the process accordingly and rapidly, to keep the error

minimal.

The PID controller calculation (algorithm) involves three

separate parameters; the proportional, the integral and

derivative values. The proportional value determines the

reaction to the current error, the integral value determines the

reaction based on the sum of recent errors, and the derivative

value determines the reaction based on the rate at which the

error has been changing. The weighted sum of these three

actions is used to adjust the process via a control element such

as the position of a control valve or the power supply of a

heating element.PA

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FIG:02

2.2.2 Computer Numerically Controlled (CNC)

Computer Numerical Control (CNC) controllers, working as a

brain for manufacturing automation, are high value-added

products counting for over 30% of the price of machine tools.

CNC technology is generally considered as a measure for the

level of manufacturing technology of a nation. Often referred

to as "The Flower of Industrial Technology", the development

of CNC technology depends upon the integration of

technologies from computer, hardware, machining, and other

industries, and requires strategic long-term support, mostly on

a governmental level.

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Today, computer numerical control (CNC) machines are

found almost everywhere, from small job shops in rural

communities to Fortune 500 companies in large urban areas.

Truly, there is hardly a facet of manufacturing that is not in

some way touched by what these innovative machine tools can

do.

The most basic function of any CNC machine is automatic,

precise, and consistent motion control. Rather than applying

completely mechanical devices to cause motion as is required

on most conventional machine tools, CNC machines allow

motion control in a revolutionary manner. All forms of CNC

equipment have two or more directions of motion, called axes.

These axes can be precisely and automatically positioned

along their lengths of travel. The two most common axis types

are linear (driven along a straight path) and rotary (driven

along a circular path).PA

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FIG:03

2.2.3 PC Based Controllers

The days of the PC being used just for visualization and

production data acquisition in control and automation

applications is rapidly becoming a thing of the past.

The PC is now increasingly recognized as an open and

powerful hardware platform, which can provide effective and

reliable control, with no requirement for additional processors

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or complex hardware additions. Traditional automation

and control systems typically comprise a number of hardware

and software elements; a PC for process visualization, hard

PLCs with coprocessor cards, coprocessor PLCs, I/O via field

bus, motion control via parallel cabling and a selection of

software operating systems and programming languages.

PC-based controller system is often used in the factory

where it resists the adverse environmental factors such as

dustiness and extreme temperature. Under this condition, PC-

based controller system must meet the requirements of

reliability, durability, strong vibration, and extreme

temperature. Since industrial products do not require high

level of math functions, appropriateness is much more

important than the performance.PC-based system is also used

in the medical care industry.

The disadvantages of this approach being high hardware

and software costs, complexity of system design and build plus,

in many applications, limited functionality.

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2.2.4 Programmable Logic Controllers (PLC)

Programming Logic Controller or PLC as it is universally

called is the “work horse” of industrial automation. The PLC,

being a microprocessor based device, has a similar internal

structure to many embedded controllers and computers. They

consist of the CPU, Memory and I/O devices. These

components are integral to the PLC controller. Additionally

the PLC has a connection for the Programming and

Monitoring Unit, Printer and Program Recorder.

Basically PLC is used for following applications in industry:

1) Machine controls.

2) Packaging, loading uploading and weighing.

3) Palletizing.

4) Material handling and similar Sequential task

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2.2.5 Distributed Control System (Dcs)

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

central in location (like the brain) but are distributed

throughout the system with each component sub-system

controlled by one or more controllers. The entire systems of

controllers are connected by a network for communication and

monitoring.

DCS is a very broad term used in a variety of industries, to

monitor and control distributed equipment like Electrical

power grids and electrical generation plants, Environmental

control systems, Traffic, water management systems, Oil

Refining plants, chemical, Pharmaceutical manufacturing,

Dry cargo and bulk oil carrier ships.Distributed control

systems (DCS) use decentralized elements or subsystems to

control distributed processes or complete manufacturing

systems.

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Chapter – III

Programmable Logic Controller (PLC)

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3.1. Introduction to PLCA PLC is an industrial computer or control system that continuously monitors the state of input devices and makes decisions based upon a custom program to control the state of output devices.

FIG:04

A programmable logic controller (PLC) or programmable

controller is a digital computer used for automationof

electromechanical processes, such as control of machinery on

factory aassembly lines, amusement rides, or lighting fixtures.

PLCs are used in many industries and machines. Unlike

general-purpose computers, the PLC is designed for multiple PAGE

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inputs and output arrangements, extended temperaure ranges,

immunity to electrical noise, and resistance to vibration and

impact. Programs to control machine operation are typically

stored in battery-backed or non-volatile memory. A PLC is an

example of a real time system since output results must be

produced in response to input conditions within a bounded

time, otherwise unintended operation will result.

A PLC (i.e. Programmable Logic Controller) is a device that

was invented to replace the necessary sequential relay circuits

for machine control. The PLC works by looking at its inputs

and depending upon their state, turning on/off its outputs. The

user enters a program, usually via software, that gives the

desired results.

PLCs are used in many "real world" applications. If

there is industry present, chances are good that there is a plc

present. If you are involved in machining, packaging, material

handling, automated assembly or countless other industries

you are probably already using them. If you are not, you are

wasting money and time. Almost any application that needs

some type of electrical control has a need for a plc.

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PLC controllers are low cost, compact, versatile units based on

the standard microprocessor architecture used in the control

of machines or processes. They are designed for ease of

programming and maintenance. The plc systems replace the

old relay logic control systems in automated manufacturing

and are designed to provide an easy and efficient replacements

for the bulky relay logic controllers. The PLC, also known as

programmable controller (PC) is defined by the National

Electrical Manufacturers Association (NEMA) in 1978 as:

"A digitally operating electronic apparatus which uses a

programmable memory for the internal storage of instructions

for implementing specific functions, such as logic, sequencing,

timing, counting and arithmetic, to control through digital or

analog input/output, various types of machines or process".

They essentially operate by detecting the on/off (logic) or

analog inputs and depending on the control programs - the

ladder diagrams - outputs of the same type (usually logic) are

produced.

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In PLC implementation, field wiring between the logic

elements remains unaltered, but there are no more hard wired

connections between the devices. Instead, the connections are

stored in computer memory. This allows the programming of

these connections, which is in turn made easier as they are

entered in ladder logic.

PLC systems have considerable advantages over the old relay

logic systems. They include:

1. all the capabilities of the earlier systems,

2. dramatic performance increase over the relay logic systems

3. greater reliability

4. little maintenance due to no moving parts

5. no special programming skills required by maintenance

personnel

6. physical size of the PLC system is much smaller than the

conventional relay based logic

7. and most importantly much lower cost

3.2. History and Origin• Developed to replace relays in the late 1960s PAGE

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• PLC began in the 1970s, and has become the most common choice for manufacturing controls.

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

•

The PLC was invented in response to the needs of the American automotive manufacturing industry (primarily General motors).

• Costs dropped and became popular by 1980s

• Now used in many industrial designs.

3.3. PLC Vendors

S.NO Company Country

1. Allen Bradley USA

2. Seimens Germany

3. ABB(Asia Brown Bravery) USA

4. GE Fanuc USA

5. Mitsubhishi Japan

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6. OMRON Japan

7 MOORE Japan

8. L&T(Larson and Turbo) India

3.4. Block Diagram of PLC

FIG:05

3.5. Major Components of a Common PLCPOWER SUPPLY Provides the voltage needed to run the primary PLC components.

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I/O MODULES Provides signal conversion and isolation between the internal logic- level signals inside the PLC and the field’s high level signal. The I/O interface section of a PLC connects it to external field devices. The main purpose of the I/O interface is to condition the various signals received from or sent to the external input and output devices. Input modules convert’s signals from discrete or analog input devices to logic levels

acceptable to PLC’s processor. Output modules converts signal from the processor to levels capable of driving the connected discrete or analog output devices.

PROCESSOR Provides intelligence to command and govern the activities of the entire PLC systems.

PROGRAMMING DEVICE Used to enter the desired program that will determine the sequence of operation and control of process equipment or driven machine.

3.6. CLASSIFICATION OF PLC

Based on physical assembly-1. Compact - In these types of PLC the number of input and output is fixed and these are very purpose specified.

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2. Modular - In this type of PLC the input and output modules are used and thus the number of the I/O ports is variable n depend upon the number of slots available and modules used. Based on number of I/O ports-1. Small-It covers units with up to 128 I/O’s and memories up to 2 Kbytes. These PLC’s are capable of providing simple to advance levels or machine controls.

2. Medium- has up to 2048 I/O’s and memories up to 32 Kbytes.3. Large- the most sophisticated units of the PLC family. They have up to 8192 I/O’s and memories up to 750 Kbytes. can control individual production processes or entire plant.

3.7. PLC OperationBasic Function of a Typical PLC

Read all field input devices via the input interfaces, execute the user program stored in application memory, then, based on whatever control scheme has been programmed by the user, turn the field output devices on or off, or perform whatever control is necessary for the process application.

This process of sequentially reading the inputs, executing the program in memory, and updating the outputs is known as scanning.

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3.8. Scan CycleWhile the PLC is running, the scanning process includes the following three phases, which are repeated continuously as individual cycles of operation

FIG:06

PHASE 2Program

Execution

PHASE 3Output

Scan

PHASE 1Read Inputs

Scan

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PHASE 1 – Input Status scan

A PLC scan cycle begins with the CPU reading the status of its inputs.

PHASE 2– Logic Solve/Program Execution

The application program is executed using the status of the inputs.

PHASE 3– Output Status Scan

An output status scan is then performed, whereby the stored output values are sent to field output devices. The cycle ends byupdating the outputs. As soon as Phase 3 are completed, the entire cycle begins again with Phase 1 input scan. The time it takes to implement a scan cycle is called SCAN TIME. The scan time composed of the program scan time, which is the time required for solving the control program, and the I/O update time, or time required to read inputs and update outputs. The program scan time generally depends on the amount of memory taken by the control program and type of instructions used in the program. The time to make a single scan can vary from 1 ms to 100 ms.

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3.9. Circuit Isolation in PLC

In PLC, isolation is provided using optocoupler in its internal circuit that’s why it is also known as optical isolation. Optical isolation means that there is no real electrical connection between the input device and the processor. This eliminates any possibility of the unwanted (high surge or malfunctioned) input line voltage from coming in contact with and damaging the low voltage DC section of the Processor.

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FIG:07

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3.10. Sinking and sourcing concept Sinking Concept (NPN)- When the current direction

of any signal is inwards to the PLC input or output port it is known as the Sinking.

Sourcing Concept (PNP) - When the current direction of any signal is outwards to the PLC input or output port it is known as the Sourcing ..

FIG:08

3.11. Communications :PLC can communicate or connected to PC through Ethernet,RS-232,RS-422 or RS-485 cabling.

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Ethernet

Ethernet introduced in 1980.Ethernet divide a stream of data into individual packets called frames. Each frame contains source & destination address & error checking data so that damaged data can be detected & re-transmitted. Data rates were periodically increased from the original 10 megabits per sec to 100 gigabits per sec

FIG:09 Ethernet cable

RS-232

It can transfer-20000 bits per second. It is commonly used in computer for serial port RS-232 port has feature of a personal computer for connected to modems,printer,mice,UPS & other PA

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peripheral device. PM02 cable is used for this type of communiction.it has 9 pin on PC side and 8 pin on PLC side.

FIG:10 PM02 cable

RS-485

RS-485 can be used effectively over long distances. it can transfer-35M bits per second up to 10 meter 100 Kbits/sec 1200 meter.

RS-422

It can transfer-10 Million bits per second. It can used as long as 1500 meter.

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3.12. Programming Languages Ladder Diagram (LD)

Functional block Diagram (FBD)

Sequential Functional Chart (SFC)

Structured Text (ST)

Instruction List (IL)

Ladder Diagram- It is a graphical programming language. Initially programmed with simple contacts that simulated the opening and closing of relays, Ladder Logic Programming has been expanded to include such functions as counters, timers, shift registers, and math operations.Function Block Diagram – A graphical language for depicting signal and data flows through re-usable function blocks. FBD is useful for expressing the interconnection of control system algorithms and logic.Sequential Function Chart – A method of programming complex control systems at a more highly structured level. A SFC program is an overview of the control system, in which the basic building blocks are entire program files. Each program file is created using one of the other types of PA

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programming languages. The SFC approach coordinates large, complicated programming tasks into smaller, more manageable tasks. Structured Text – A high level text language that encourages structured programming. It has a language structure (syntax)

that strongly resembles PASCAL and supports a wide range of standard functions and operators.Instruction List – A low level ‘assembler like’ language that is based on similar instructions list languages found in a wide range of today’s PLC. The language which we used in the PLC for writing any logic is Ladder language.

3.13. Ladder LogicLadder logic is a method of drawing electrical logic schematics. It is now a graphical language very popular for programming Programmable Logic Controllers (PLCs). It was originally invented to describe logic made from relays. The name is based on the observation that programs in this language resemble ladders, with two vertical "rails" and a series of horizontal "rungs" between them.

Generally Used Instructions & symbol For PLC Programming

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Input Instruction

This Instruction is Called XIC or Examine If Closed.

i.e.; If a NO switch is actuated then only this instruction will be true. If a NC switch is actuated then this

instruction will not be true and hence output will not be generated.

This Instruction is Called XIO or Examine If Open

i.e.; If a NC switch is actuated then only this instruction will be true. If a NC switch is actuated then this instruction will not be true and hence output will not be generated.

Output Instruction

This Instruction is called OTE and shows the States of Output.

i.e.; If any instruction either XIO or XIC is true then output will be high. Due to high output a 24 volt signal is generated from PLC processor.

Retentive output instruction

OTL (output latch):If the rung is true, turns ON a bit and it remains ON even the PA

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rung gets false. The bit stays ON until the rung containing an OUT with same address goes true.

OTU (output unlatch ):If the rung is true, turns OFF a bit. The bit stays OFF until the rung containing an OTL with

same address goes true and the rung containing OUT with same address remains false.

3.14. Timers1. TON-

This is an ON timer , in this we set the time base and can give the time delay.

2. TOF

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This is an OFF timer, here we need to enable as well as disable the timer.

3. RTO-

This is called Retentive Timer On, here the timer is not reset once we disable it, so we need to use the RES (reset) function. This timer can be paused easily.

3.15. Compare instructions: 1. LIM (limit test):

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The Rung goes true when test value in between lower and higher limit.

2.EQU (Equal):

The rung goes true, when source A equal to source B.

3.NEQ (Not Equal):

4.LES (Less Than):PA

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5.GRT(Greater Than):

6.LEQ( Less Than or Equal):

7.GEQ( Greater Than or Equal):

3.16. Counters

1. CTU-

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This is Counter Up, here we set the preset and whenever the signal is given the accumulator is increased, to reset the counter we have to use RES.

2. CTD-

This is Counter down, here DN bit is on initially and as the accumulator decreases and becomes less than preset it becomes off.

RESET Function-

This function is used to reset the counters and the timers.

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3.17. Compute / Math:1.ADD (Addition):

When the rung goes true, value stored in source A is added with value stored in Source B and the resulted value is stored in Destination.

2.SUB (Subtraction):

3.MUL (Multiplication):

4.DIV (Division): PAGE

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5.SQR (Square Root):

3.18. Move/Logical:1. MOV (Move):

When rung goes true the value stored in source move to destination.

2.AND (Bitwise Logical AND):

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When the rung goes true, value stored in source A is Logically ANDed with value stored in Source B and the resulted value is stored in destination.

3.OR (Bitwise Logical OR):

4.XOR (Bitwise Logical NOR):

5.NOT(Bitwise Logical NOT): PAGE

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6.CLR(Clear):

When rung goes true, then destination becomes empty.

3.19. Software for PLCFor Allen Bradley(Micro) :-

Simulator: - Logix Pro

Communication software: - Rslinx classic

Programming software: - Rslogix500 OR Rslogix Microstarter Lite

Allen Bradley Data File Description

File

#

Type Description

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O0 Output This file stores the state of output

terminals for the controller.

I1 Input This file stores the state of input

terminals for the controller.

S2 Status This file stores controller operation

information useful for troubleshooting

controller and program operation.

B3 Bit This file stores internal relay logic.

T4 Timer This file stores the timer accumulator

and preset values and status bits.

C5 Counter This file stores the counter accumulator

and preset values and status bits.

R6 Control This file stores the length, pointer

position, and status bits for control

instructions such as shift registers and

sequencers.

N7 Integer This file is used to store bit information

or numeric values with a range of -32767

to 32768.

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Chapter – IVSCADA

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4.1. Introduction to SCADA SCADA stands for supervisory control and data acquisition. As

the name indicates it is not a full control system, but rather

focuses on the supervisory level. As such , it is a purely

software package that is positioned on the top of hardware to

which it is interfaced in general via programmable logic

controllers (PLC’s ), or other commercial hardware modules.

S- supervisory (we can see process on monitor)

C- control(when setup is complete we can also control the

process )

A- and

D- data( database can also be saved in plc or pc memory)

A- acquisition

SCADA programs are used in industrial process control

applications for centralized monitoring and recording of

pumps, tank levels, switches, temperatures etc. SCADA systems

are also referred to as HMI (Human Machine Interfaces), or

the less politically correct MMI (Man Machine Interfaces).

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A SCADA program normally runs on a PC and

communicates with external instrumentation and control

devices. Communications methods can be via direct serial

link, radio, modem, field bus or Ethernet links. If a mixture of

instruments with differing communication interfaces and

protocols need to be connected, then converters can be used.

SCADA is often used on remote data acquisition systems

where the data is viewed and recorded centrally.

It’s an optional device used in automation for continuous

monitoring.

4.2. What SCADA can do for you:

SCADA is not a specific technology, but a type of application. SCADA stands for SupervisoryControl and Data Acquisition — any application that gets data about a system in order to controlthat system is a SCADA application.A SCADA application has two elements:1. The process/system/machinery you want to monitor a control — this can be a powerPlant, a water system, a network, a system of traffic lights, or anything else.

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2. A network of intelligent devices that interfaces with the first system through sensors andControl outputs. This network, which is the SCADA system, gives you the ability toMeasure and control specific elements of the first system.

A SCADA system usually consists of the following subsystems:

1. 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 (compute) system, gathering (acquiring) data on the process and sending commands (control) to the process.

2. Remote terminal units(RTUs) connecting to sensors in the process, converting sensor signals to digital data and sending digital data to the supervisory system.

3. 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.

4.3. SCADA software:-

Allen Bradley – RSView 32

Wonder ware – InTouch

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Siemens – Win CC

4.4. Functionality

4.4.1 Access Control

Users are allocated to groups, which have defined

read/write access privileges to the process parameters in the

system and often also to specific product functionality.

4.4.2 Trending

The products all provide trending facilities and

one can summarize the common capabilities as follows:

1) the parameters to be trended in a specific chart can be

predefined or defined online

2) A chart may contain more than 8 trended parameters

or pens and an unlimited number of charts can be

displayed (restricted only by the readability)

3) Real-time and historical trending are possible, although PAGE

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generally not in the same chart

FIG:11

4) Historical trending is possible for any archived parameter

5) Zooming and scrolling functions are provided

6) Parameter values at the cursor position can be displayed

The trending feature is either provided as a separate

module or as a graphical object (ActiveX), which can then

be embedded into a synoptic display. XY and other statistical

analysis plots are generally not provided.

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4.4.3 Alarm Handling

Alarm handling is based on limit and status checking and

performed in the data servers. More complicated expressions

(using arithmetic or logical 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 (e.g., the acknowledgement),

and multiple alarm priority levels (in general many more

than 3 such levels) are supported.

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FIG:12

4.4.4 Logging And Archiving

The terms logging and archiving are often used to

describe the same facility. However, logging can be thought

of as medium-term storage of data on disk, whereas archiving

is long-term storage of data either on disk or on another

permanent storage medium. Logging is typically performed

on a cyclic basis, i.e., once a certain file size, time period or

number of points is reached the data is overwritten. Logging of

data can be performed at a set frequency, or only initiated PAGE

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if the value changes or when a specific predefined event

occurs. Logged data can be transferred to an archive

once the log is full.

FIG:13

The Logged data is time-stamped and can be filtered when

viewed by a user. The logging of user actions is in general

performed together with either a user ID or station ID. There

is often also a VCR facility to play back archived data.

4.4.5 Networking

1. In many application, we have to use more than one

SCADA software / operator stations. This can be achieved

by taking the SCADA node on network.

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2. In many cases Ethernet TCP/IP is commonly used for

networking.

3. In certain cases the SCADA software use propriety

networking protocols for networking.

4.4.6 Device Connectivity

1. Every control hardware has its own communication

protocol for communicating with different hadrware /

software. Some of the leading communication protocol

include Modbus, Profibus, Ethernet, Dh +, DH 485,

Devicenet, Control net

2. The SCADA software needs device driver software for

communication with PLC or other control hardware.

3. More the driver software available better is the device

connectivity. Most of the SCADA software used in the

industry have connectivity with most of the leading

control system.

4.4.7 Database Connectivity PAGE

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1. In many plants, it is important to download the real-time

information to the MIS. In this case the database

connectivity is must.

2. Many SCADA software don’t have their own database.

Hence for storage and reporting they use third party

database like MS Access or SQL.

4.4.8 Script

1. Script is a way of writing logic in SCADA software. Every

SCADA software has its own instructions and way of

writing program.

2. Using scripts, one can develop complex applications. You

can create your own functions to suit the process

requirement. execution. PAGE

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3. Various types of scripts make project execution simpler

for programmer.

4.4.9 Report Genertion

One can produce reports using SQL type queries to the

archive, RTDB or logs. Although it is sometimes possible to

embed EXCEL charts in the report, a "cut and paste"

capability is in general not provided. Facilities exist to be able

to automatically generate, print and archive reports.

4.5 AUTOMATION

The majority of the products allow actions to be

automatically triggered by events. A scripting language

provided by the SCADA products allows these actions to be

defined. In general, one can load a particular display,

send an Email, run a user defined application or script

and write to the RTDB.

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The concept of recipes is supported, whereby a

particular system configuration can be saved to a file and

then re-loaded at a later date .Sequencing is also supported

whereby, as the name indicates, it is possible to execute a more

complex sequence of actions on one or more devices.

Sequences may also react to external events. Some of the

products do support an expert system but none has the

concept of a Finite rate Machine (FSM).

4.6 Application Development

4.6.1 Configuration

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

SCADA stands for Supervisory Control and DataAcquisition PAGE

75


— any application that gets data about a system in order to

control that system is a SCADA application.

A SCADA application has two elements:

1. The process/system/machinery you want to monitor a

control — this can be a power plant, a water system, a

network, a system of traffic lights, or anything else.

2. A network of intelligent devices that interfaces with the first

system through sensors and control outputs. This network,

which is the SCADA system, gives you the ability to measure

and control specific elements of the first system.

The development of the applications is typically done

in two stages. First the process parameters and associated

information (e.g. relating to alarm conditions) are defined

through some sort of parameter definition template

and then the graphics, including trending and alarm

displays are developed, and linked where appropriate to

the process parameters. The products also provide an

ASCII Export/Import facility for the configuration data

(parameter definitions), which enables large numbers of PAGE

76


parameters to be configured in a more efficient manner using

an external editor such as Excel and then importing the data

into the configuration database.

On-line modifications to the configuration database and

the graphics are generally possible with the appropriate level

of privileges.

4.7 Applications Of SCADA

We can use SCADA to manage any kind of equipment.

Typically, SCADA systems are used to automate complex

industrial processes where human control is impractical —

systems where there are more control factors, and more fast-

moving control factors, than human beings can comfortably

manage.

Around the world, SCADA systems control.

4.7.1 Electric Power Generation, Transmission

And Distribution PAGE

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Electric utilities use SCADA systems to detect current flow and

line voltage, to monitor the operation of circuit breakers, and

to take sections of the power grid online or offline.

4.7.2 Water And Sewage

State and municipal water utilities use SCADA to monitor and

regulate water flow, reservoir levels, pipe pressure and other

factors.

4.7.3 Building, Facilities And Environment

Facility managers use SCADA to control HVAC, refrigeration

units, lighting and entry systems.

4.7.4 Manufacturing

SCADA systems manage parts inventories for just-in-time

manufacturing, regulate industrial automation and robots,

and monitor process and quality control. PAGE

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4.7.5 Mass Transit

Transit authorities use SCADA to regulate electricity to

subways, trams and trolley buses; to automate traffic signals

for rail systems; to track and locate trains and buses; and to

control railroad crossing gates.

4.7.6 Traffic Signals

SCADA regulates traffic lights, controls traffic flow and

detects out-of-order signals.

SCADA systems provide the sensing capabilities and the

computational power to track everything that’s relevant to

your operations

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FIG:14- SCADA SYSTEMS

4.8. Communications

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Between Rsview32 and Micrologix :- Communication between Review 32 SCADA and Micrologix PLC done with Direct Driver. For this First of all communicate PC with PLC and then go to Rsview32 and make channel, after this go to node and make a node with Direct Driver.

Between Rsview32 and EXCEL:-

Communication between Rsview 32 SCADA and EXCEL done with DDE.

Between Intouch and Micrologix: -

Communication between Intouch SCADA and Micrologix PLC done with DDE.

Between Intouch and EXCEL:

-Communication between Intouch SCADA and EXCEL also done with DDE.

CONCLUSION

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All the different languages have the function of providing the

easy programming, program modification and allowing the

user the choice of a most appropriate language for a particular

application. In this way the ease of use and maximum

functionality is achieved without placing any constraints on

the possible application of a PLC system. The standardization

of the PLC languages and the programming styles has meant

that the common set of languages, the subject of this report, is

supported by all the manufacturers of the PLC systems.

Together with all the other advantages the PLC systems have

over the relay logic systems, they have assumed a dominant

position once held by the relay logic controllers in the field of

process and automated manufacturing control. SCADA

systems have made substantial progress over the recent

years in terms of functionality, scalability, performance and

openness such that they are an alternative to in house

development even for very demanding and complex

control systems as those of physics experiments. PA

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REFRENCES:

[1] Madhuchhanda Mitra and Samarjit Sen

Gupta,“Programmable Logic Controllers and Industrial

Automation”,penram International publishing (India) Pvt.

Ltd.,Third Edition.2005

[2] Stuart A. Boyer, “Scada:Supervisory Control and Data

Acquisition”,2nd Edition, April 2006

[3] S.Brian Morriss, “Programmable Logic Controllers”

Prentice Hall Publication, Eighth Edition, July 1999.

[4]Nebojsa Matric, “Introduction to PLC Controllers”,

http://www.aarkstore.com/reports/Home-Automation-

Solutions-and-Business-Issues-2009-18434.html

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