plc and scada report

Training Report on Industrial Automation

Chapter-1

Introduction to Institution

Advance Technology, Chandigarh

Advance Technology, Chandigarh is an ISO 9001:2008 Certified Company deals in the field of

Hardware Development, Embedded Products Development, Security & Surveillance and

Engineers Training Programs. Advance Technology is the mission, which is working for the

promotion of latest technologies in India & Abroad. To achieve our goal, we have made

coloration with a number of institutions and firms. Advance Technology deals in three different

domains, first is development, second is industrial automation and third is education. Advance

Technology an Embedded Design House. Advance Technology offer various Technical

Education solutions, Products & Development tools to Engineering colleges, Universities,

research organizations. We also offer the business of providing Technical education solutions

& development tools to the educational & industrial customers. Advance Technology has

developed a number for private as well government organizations.

Geeta Institute of Management and Technology, Kurukshetra

Geeta Institute of Management and Technology (A Unit of Geeta Education Trust) offers

M.Tech, B.Tech, MBA & MCA programs for which the institute has created excellent

infrastructure in terms of physical, Human and Information resources. The institute has also tie

up with leading corporate house for training, development and placement of students. Its vision

is to become a top institution in engineering and management with departments as centres of

excellence, imparting high quality education and providing ambience for growth of

professionals as excellent human beings as well. GIMT has an Open door policy to ensure

transparency in administration and also encourages faculty in their research projects and

organizes orientation programmes for them from time to time. The institute has Scholarship

schemes for meritorious students and has implemented Fee - concession for economically

weaker students. Our Motto is "Blend Knowledge with Technology & Technology with

Perfection".

Geeta Institute of Management & Technology, Kurukshetra


Chapter-2

Introduction of Automation

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 labour; 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. 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,

electronic and computers, usually in combination. Complicated systems, such as modern

factories, airplanes and ships typically use all these combined techniques

2.1 Industrial Automation

Fig.2.1 Automation used in industry

Industrial automation is the use of control systems, such as computers or robots, and

information technologies for handling different processes and machineries in an industry to



replace a human being. It is the second step beyond mechanization in the scope of

industrialization.

2.2 Advantages and Disadvantages of Industrial Automation

Lower operating cost: Industrial automation eliminates healthcare costs and paid leave and

holidays associated with a human operator. Further, industrial automation does not require

other employee benefits such as bonuses, pension coverage etc. Above all, although it is

associated with a high initial cost it saves the monthly wages of the workers which leads to

substantial cost savings for the company. The maintenance cost associated with machinery used

for industrial automation is less because it does not often fail. If it fails, only computer and

maintenance engineers are required to repair it.

High productivity

Although many companies hire hundreds of production workers for a up to three shifts to

run the plant for the maximum number of hours, the plant still needs to be closed for

maintenance and holidays. Industrial automation fulfils the aim of the company by

allowing the company to run a manufacturing plant for 24 hours in a day 7 days in a week

and 365 days a year. This leads to a significant improvement in the productivity of the

company.

High Quality

Automation alleviates the error associated with a human being. Further, unlike human

beings, robots do not involve any fatigue, which results in products with uniform quality

manufactured at different times.

High flexibility

Adding a new task in the assembly line requires training with a human operator, however,

robots can be programmed to do any task. This makes the manufacturing process more

flexible.

High Information Accuracy

Adding automated data collection, can allow you to collect key production information,

improve data accuracy, and reduce your data collection costs. This provides you with the



facts to make the right decisions when it comes to reducing waste and improving your

processes.

High safety

Industrial automation can make the production line safe for the employees by deploying

robots to handle hazardous conditions.

Disadvantages of Industrial Automation

High Initial cost

The initial investment associated with the making the switch from a human production line

to an automatic production line is very high. Also, substantial costs are involved in training

employees to handle this new sophisticated equipment.

Chapter-3



Programmable Logic Controller (PLC)

3.1 Need of Programmable Logic Controller (PLC)

Before PLCs came into existence; sequencing, safety interlock logic for manufacturing,

and other controls were accomplished using physical relays, timers, and dedicated closed-loop

controllers. A relay is a simple device that uses a magnetic field to control a switch .When a

voltage is applied to the input coil; the resulting current creates a magnetic field to control a

switch. When a voltage is applied to the input coil, the resulting current creates a magnetic

field. The magnetic field pulls a metal switch (or reed) towards it and the contacts touch,

closing the switch. The contact that closes when the coil is energized is called Normally

Open(NO).The Normally closed (NC) close when the input coil is not energized and open

when the input coil is energized. But the control industries were looking forward to eliminate

the high costs associated with inflexible, relay controlled systems. The specifications required a

solid-state system with computer flexibility which must be able to

(1) Survive in an industrial environment,

(2) Be easily programmed and maintained by plant engineers and technicians, and

(3) Be reusable.

Such a control system would reduce machine downtime and provide expandability for the

future.

Some of the initial specifications included the following:-

• The new control system had to be price competitive with the use of relay systems.

• The system had to be capable of sustaining an industrial environment.

• The input and output interfaces had to be easily replaceable.

• The controller had to be designed in modular form, so that subassemblies could be

removed easily for replacement or repair.

• The control system needed the capability to pass data collection to a central system.

• The system had to be reusable.



• The method used to program the controller had to be simple, so that it could be easily

understood by plant personnel.

The first programmable controllers:-

By 1969 the first programmable controller was developed. These early controllers met the

original specifications and opened the door to the development of a new control technology.

The first PLCs offered relay functionality and replaced the original hardwired relay logic ,

which used electrically operated devices to mechanically switch electrical circuits. They met

the requirements of modularity, expandability, programmability, and ease of use in an

industrial environment. These controllers were easily installed, used less space, and were

reusable. The controller programming, although a little tedious, had a recognizable plant

standard: the ladder diagram format. By 1971 PLC had spread to other automation industries

such as food and beverage, metals and manufacturing, pulp and paper.

3.2 Programmable Logic Controller (PLC)

Programmable Logic Controller (PLC) has become increasingly popular as control tools

for industrial applications. Because of their power, flexibility, and ease of use they have wide

acceptance by design engineers, operators and maintenance personnel.

3.3 Historical Notes on PLC

The first PLC was built by hand at Bedford Associates. It has a special configuration of a

computer for specific application. The PLC language was developed when it was available for

commercial use. In 1969, General Motors (a large auto manufacturer) purchased the first PLC.

The features of the original PLC are still found today on most PLC units. In 1969, a capacity

of 256 words memory was more than adequate but later PLC was expanded to 1000 words

machine. It had a non-interrupt structure and a l6-bit word length, and was a dedicated

machine. Its input and output channels were directly accessible by user software. Seeking a

language that would be compatible with industry, the developer decided to use ladder listing, a

language started in Germany and known throughout the world by people of all language.

Another hurdle the original PLC designers faced involved the type of memory. Vendors were



attempting to sell high speed, highly susceptible memory planes, but the application called for

slow memories with big cores, as they had to be immune to electrical interference. Core

memory initially solved the problem. The early machines with 1000 words had a relatively low

speed, and it could not do arithmetic -only relay logic. The most difficult part of the design

involved the logic solver. When the program first started, the logic solver and the PLC

consisted of a computer and memory, input-output devices. But, the computer~ had difficulty

in executing ladder logic quickly. Another early challenge was the Input-Output (I/O) modules,

which had to be reliable and directly connected to the program. Much effort was expended in

designing the I/O structure, including its VO cards and input sensors and output triads for

driving 110V devices. The objective was to have the user perceive the PLC as a device just as

reliable as relays but substantially easier to program and start-up.

3.4 Introduction to PLC

Most manufacturing processes require a sequence of operation in order to produce a

product. The sequence control can be done either manually or with some type of controller.

Until 1960’s, the processes operations was usually performed using a bank of relays uniquely

wired to perform the particular task. Thus, the use of relay logic is known very well in most

industries. The relay logic is difficult to troubleshoot and modify. This forced to develop more

reliable and standardized system. The availability of the semiconductors and the problems

faced by process control engineers, resulted in the development of the electronic programmable

logic controller (PLC). The PLC was developed to use ladder diagram of relay logic which was

well known in the industries. This reduced the technician's program development time with

minimum training. For example, unlike numerical control (NC) and computer numerical

control (CNC) units which are used to control position, the PLC is used for sequence control.

3.5 Definition of PLC

In 1978, the National Electrical Manufacturers Association (NEMA) released a Standard

for programmable logic controllers after four years of work by a Committee made up of

representatives from programmable logic controller manufacturers. NEMA standard ICS3 -

1978, part ICS3-304, defined a programmable logic controller as "A digitally operating

electronic apparatus which was 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 I/O modules, various types of machines or processes. A

digital computer which is used to perform the functions of a programmable logic controller is

considered to be within this scope. Excluded are drum and similar mechanical type sequencing

controllers. Based on NEMA definition, there are probably more than 50 control products,

manufactured in the world that could be called a programmable logic controller

Fig.3.5 Internal Diagram of PLC

3.6 PLC Architecture

The architecture of PLC is similar to general purpose microcomputer. However PLC

has other advantages:


Processor

Module

System

Po

wer

Supp

ly

I/O M

odules

I/O M

odules

I/O M

odules

I/O M

odules

I/O M

odules

Central Processing Unit


(1) They are rugged solid-state equipment that can endure the industrial environment;

(2) they have no moving parts, which eliminates maintenance problem and

(3) In an era of intense pressure on profit margins, they are cost-effective. Moreover,

PLC technology does not require production management and maintenance personnel

to learn a computer language.

The PLC has two main sections: a central processing unit (CPU) and an I/O interface

section (Fig. 1.l). The CPU is further divided into three components: the processor, memory

system, and system power. The basic element of a programmable controller is shown in the

Fig. 4.5.

Fig 3.6: Main Parts of Programmable Logic Controller

The processor modules are being developed using latest microprocessors / micro

controllers. The processor module contains the microprocessor / microcontroller, its supporting

circuitry and its memory system. Some processor modules are having a dedicated math

processor module to perform the complicated mathematical function. It is intended to increase

processor speed of the PLC.

3.6.1 The CPU

The processor module scans the I/O channels and updates the corresponding memory

location at fixed intervals. The main function of the processor is to analyze the data coming



from shop floor through input modules, make decisions based on the user's defined control

program, and return signals back through output modules to the shop floor devices.

Processors of most of the PLCs available today are capable of performing the following

wide verities of task:

a) Relay logic

b) Latches

c) Timing

d) Count

e) ASCII interface

f) Proportional integral derivative (Pill) loops

g) Shift register

h) Data high way communications

i) Arithmetic

j) Comparison

k) Computer interface

l) Matrix manipulation

m) Binary coded decimal (BCD)

n) Binary conversion

0) Analog data manipulation

p) Variety of other peripherals like printers, display unit

3.6.2 Memory System

The memory system in the processor module has two parts –

(1) System memory and

(2) Application memory.

The collection of control program, which controls the activities of PLC on execution of

the user's control program, driver for communication with peripherals devices and other

activities, are stored in the system memory area. Normally it is stored in read-only memory

devices. A scratch pad memory area is included in the system memory area for temporary

storage of data for interim calculation of control. The application memory is divided into data

table area and user program area. The I/O status data, variables or preset values, flag values



and other data are stored in data table area. The data table is the one where data is monitored,

manipulated and changed for control purpose. The user program area is the one where the

programmed instructions, entered by the user, are stored as an application control program.

3.6.3 System Power Supply

The system power supply provides the voltages needed to run the processor modules,

memory system, I/O circuits etc. The battery power is also provided to retain the content of

memory in the processor modules in case of power failure.

3.6.4 I/O Interfaces

The I/O interfaces are of modular type. They can be plugged in and out of the system.

The field signals are connected to PLC through I/O modules. The main purpose of the I/O

modules is to condition the various field signals. The Input modules convert the field signal to

digital signal acceptable to the PLC's processors. The output modules convert the processors'

signal (digital signal) to capable of driving various output devices.

I/O modules are housed in the same racks or panels that house the other components of

the PLC system. If there is no room for additional I/O modules in the main frame master rack,

the additional I/O modules can be housed in local I/O rack which can be placed-up several

thousand feet from main rack. The remote I/O rack may also be used to communicate I/O

information and to diagnose status of remote field devices. Every I/O module in a PLC system

has its own address and these addresses are used to access to the I/O devices through user's

program. A data communications network may be connected to the PLC processor module to

allow communications to other control systems or computer networks.

3.6.5 Programming Devices

The programming devices are used for programming the application software, editing

and troubleshooting the software. The on-line /off-line programming is also possible with PLC.

PLC programs are typically written in a special application on a personal computer and then

downloaded by a direct-connection cable or over a network to the PLC. The program is stored


Program Programming Device

I/O Modules

Output Device

InputDevice


in the PLC either in battery-backed-up RAM or some other non-volatile flash memory. Often, a

single PLC can be programmed to replace thousands of relays.

Fig 3.6.5: Basic elements of programmable logic controller

3.7 PLC Operating Cycle

3.7.1 Input Scan

Each cycle begins with an input status scan. The specific memory locations are reserved

for input channels called input status table / input process image. Scanning of inputs is carried

out as a single step, uninterrupted by other operation, to provide a clear snap shot of the state of

the process at a given instant.

3.7.2 Program Execution



Next, the user program is executed using available feedback status and input signals

and the results are stored in a reserved portion of the memory location meant for output status

table or output program image.

3.7.3 Output Scan

In course of output scan the output values are sort to output field devices. Depending on

the PLC design, this process of updating the output devices may be done at the end of program

execution or updated immediately upon execution of its corresponding logic statement in the

user program. Normally output status table / output process image is updated upon execution of

user program. On each scanning the stored output values are sort to field output devices.

3.7.4 Memory Word -Zero

In most of PLCs a period of housekeeping or overhead operations is performed called

memory word-zero time. These overhead functions include diagnostic checks on the PLC as

well as service of peripheral devices such as loader / terminals and communications interfaces.

As soon as these tasks are completed, the entire cycle begins again with another input status

scan. The time it takes to implement a scan cycle is called scan time. The scan time is

composed of the program scan time, which is the time required for execution of 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 the type of instructions used in the program. The time to make a single scan can typically

vary from 16ms to 200ms.

3.8 PLC Software

3.8.1 Software Used

RSLOGIX-500

3.8.2 Program Structure



A programmable controller's program comprises the system program (or operating

system) and the application program the system program comprises all statements and

declarations for internal functions (such as data backup in the event of a power failure). The

system program is an integral part of the programmable controller, and the user cannot modify

it in any way. The application program (also called user program) comprises all user-

programmed statements and declarations for the processing of signals used to control a process.

The application program is subdivided into sections. Sectioning is arbitrary, and is the user's

responsibility.

3.8.3 Program Organization

In order to scan the application program cyclically, the system program invokes cyclic

program block. The organization of a program determines which user-written blocks are to be

processed, and in what order. This is done by calling the required blocks conditionally or

unconditionally in the cyclic program blocks. It is recommended that the order in which the

blocks are called in the cyclic program blocks represent the process-related or function-related

subdivision of the plant or process.

3.9 PLC Programming

Early PLCs, up to the mid-1980s, were programmed using proprietary programming

panels or special-purpose programming terminals, which often had dedicated function keys

representing the various logical elements of PLC programs. Programs were stored on cassette

tape cartridges. Facilities for printing and documentation were very minimal due to lack of

memory capacity. More recently, PLC programs are typically written in a special application

on a personal Computer then downloaded by a direct-connection cable or over a network to the

PLC. The very oldest PLCs used non-volatile magnetic core memory but now the program is

stored in the PLC either in battery-backed-up RAM or some other non-volatile flash memory.

Early PLCs were designed to be used by electricians who would learn PLC programming on

the job. These PLCs were programmed in "ladder logic", which strongly resembles a schematic

Diagram of relay logic, Modern PLCs can be programmed in a variety of ways, from ladder

logic to more traditional programming languages such as BASIC and C. Another method is

State Logic, a Very High Level Programming Language designed to program PLCs based on



State Transition Diagrams. The PLC is primarily used to control machinery. A program is

written for the PLC which turns on and off outputs based on input conditions and the internal

program. In this aspect, a PLC is similar to a computer.

3.9.1 Ladder logic

Ladder logic is a method of drawing electrical logic schematics. It is now a graphical

language very popular for programming Programmable Logic Controllers (PLCs). It was

originally invented to describe logic made from relays. The name is based on the observation

that programs in this language resemble ladders, with two vertical "rails" and a series of

horizontal "rungs" between them. A program in ladder logic, also called a ladder diagram, is

similar to a schematic for a set of relay circuits. An argument that aided the initial adoption of

ladder logic was that a wide variety of engineers and technicians would be able to understand

and use it without much additional training, because of the resemblance to familiar hardware

systems. (This argument has become less relevant given that most ladder logic programmers

have a software background in more conventional programming languages, and in practice

implementations of ladder logic have characteristics — such as sequential execution and

support for control flow features — that make the analogy to hardware somewhat imprecise.)

Ladder logic is widely used to program PLCs, where sequential control of a process or

manufacturing operation is required. Ladder logic is useful for simple but critical control

systems, or for reworking old hardwired relay circuits. As programmable logic controllers

became more sophisticated it has also been used in very complex automation systems. Ladder

logic can be thought of as a rule-based language, rather than a procedural language. A "rung"

in the ladder represents a rule. When implemented with relays and other electromechanical

devices, the various rules "execute" simultaneously and immediately. When implemented in a

programmable logic controller, the rules are typically executed sequentially by software, in a

loop. By executing the loop fast enough, typically many times per second, the effect of

simultaneous and immediate execution is obtained. In this way it is similar to other rule- based

languages, like spreadsheets or SQL. However, proper use of programmable controllers

requires understanding the limitations of the execution order of rungs.

—( )— A regular coil, energized whenever its rung is closed.

—(\)— A "not" coil, energized whenever its rung is open.



—[ ]— A regular contact, closed whenever its corresponding coil or an input which

controls it is energized.

—[\]— A "not" contact, closed whenever its corresponding coil or an input which

controls it is not energized

The "coil" (output of a rung) may represent a physical output which operates some device connected to the programmable controller, or may represent an internal storage bit for use elsewhere in the program.

3.10 Industrial applications

There are numbers of industrial applications of plc some of these are:

Continuous Bottle-filling system Batch mixing system Speed control of dc motor 3-stage air conditioning system Control of planar machine Automatic frequency control of Induction heating Air Flow Sensor Position Sensor


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CHAPTER-4

SCADA

4.1 Meaning of 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 top of hardware to which it is interfaced, in general via

Programmable Logic Controllers (PLCs), or other commercial hardware modules. SCADA

systems are used not only in industrial processes: e.g. steel making, power generation

(conventional and nuclear) and distribution, chemistry, but also in some experimental facilities

such as nuclear fusion. The sizes of such plants are range from a few 1000 to several 10

thousands input/output (I/O) channels. However, SCADA systems evolve rapidly and are now

penetrating the market of plants with a number of I/O channels of several 100 K: we know of

two cases of near to 1 M I/O channels currently under development.

SCADA systems used to run on DOS, VMS and UNIX; in recent years all SCADA

vendors have moved to NT and some also to Linux.



Fig 4.1.: Scada system

4.1.1 Architecture

This section describes the common features of the SCADA products that have been

evaluated at CERN in view of their possible application to the control systems of the LHC

detectors [1], [2].



Fig.4.1.1: Architecture of SCADA

4.1.2 Hardware Architecture

One distinguishes two basic layers in a SCADA system: the "client layer" which caters for

the man machine interaction and the "data server layer" which handles most of the process data

control activities. The data servers communicate with devices in the field through process

controllers. Process controllers, e.g. PLCs, are connected to the data servers either directly or

via networks or field buses that are proprietary (e.g. Siemens H1), or non-proprietary (e.g.

Profibus). Data servers are connected to each other and to client stations via an Ethernet LAN.

The data servers and client stations are NT platforms but for many products the client stations

may also be W95 machines.

4.2 Communications:

4.2.1 Internal Communication



Server-client and server-server communication is in general on a publish-subscribe and

event- driven basis and uses a TCP/IP protocol, i.e., a client application subscribes to a

parameter which is owned by a particular server application and only changes to that parameter

are then communicated to the client application.

4.2.2 Access to Devices

The data servers poll the controllers at a user defined polling rate. The polling rate may be

different for different parameters. The controllers pass the requested parameters to the data

servers. Time stamping of the process parameters is typically performed in the controllers and

this time-stamp is taken over by the data server. If the controller and communication protocol

used support unsolicited data transfer then the products will support this too. The products

provide communication drivers for most of the common PLCs and widely used field-buses,

e.g., Modbus. Of the three field buses that are recommended at CERN, both Profibus and

World flip are supported but CAN bus often not [3]. Some of the drivers are based on third

party products (e.g., Applica cards) and therefore have additional cost associated with them.

VME on the other hand is generally not supported. A single data server can support multiple

communications protocols: it can generally support as many such protocols as it has slots for

interface cards. The effort required to develop new drivers is typically in the range of 2-6

weeks depending on the complexity and similarity with existing drivers, and a driver

development toolkit is provided for this. As PLCs became more advanced, methods were

developed to change the sequence of ladder execution, and subroutines were implemented. This

simplified programming and could also be used to save scan time for high-speed processes;

parts of the program used, for example, only for setting up the machine could be segregated

from those parts required to operate at higher speed.

4.2.3 Interfacing

The provision of OPC client functionality for SCADA to access devices in an open and

standard manner is developing. There still seems to be a lack of devices/controllers, which

provide OPC server software, but this improves rapidly as most of the producers of controllers

are actively involved in the development of this standard. OPC has been evaluated by the

CERN-IT-CO group.

The products also provide



• An Open Data Base Connectivity (ODBC) interface to the data in the archive/logs, but not to

the configuration database,

• An ASCII import/export facility for configuration data,

• A library of APIs supporting C, C++, and Visual Basic (VB) to access data in the RTDB, logs

and archive. The API often does not provide access to the product's internal features such as

alarm handling, reporting, trending, etc.

The PC products provide support for the Microsoft standards such as Dynamic Data Exchange

(DDE) which allows e.g. to visualize data dynamically in an EXCEL spreadsheet, Dynamic

Link Library (DLL) and Object Linking and Embedding (OLE).The configuration data are

stored in a database that is logically centralized but physically distributed and that is generally

of a proprietary format. For performance reasons, the RTDB resides in the memory of the

servers and is also of proprietary format. The archive and logging format is usually also

proprietary for performance reasons, but some products do support logging to a Relational Data

Base Management System (RDBMS) at a slower rate either directly or via an ODBC interface.

4.2.4 Scalability

Scalability is understood as the possibility to extend the SCADA based control system by

adding more process variables, more specialized servers (e.g. for alarm handling) or more

clients. The products achieve scalability by having multiple data servers connected to multiple

controllers. Each data server has its own configuration database and RTDB and is responsible

for the handling of a sub-set of the process variables (acquisition, alarm handling, archiving).

4.2.5 Redundancy

The products often have built in software redundancy at a server level, which is normally transparent to the user. Many of the products also provide more complete redundancy solutions if required.

4.3 Functionality:

4.3.1 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.

4.3.2 Human Machine interface (HMI)

The products support multiple screens, which can contain combinations of synoptic

diagrams and text. They also support the concept of a "generic" graphical object with links to

process variables. These objects can be "dragged and dropped" from a library and included into

a synoptic diagram. Most of the SCADA products that were evaluated decompose the process

in "atomic" parameters (e.g. a power supply current, its maximum value, its on/off status, etc.)

to which a Tag-name is associated. The Tag-names used to link graphical objects to devices can

be edited as required. The products include a library of standard graphical symbols, many of

which would however not be applicable to the type of applications encountered in the

experimental physics community. Standard windows editing facilities are provided: zooming,

re-sizing, scrolling... On-line configuration and customization of the MMI is possible for users

with the appropriate privileges. Links can be created between display pages to navigate from

one view to another.

4.3.3 Trending

The products all provide trending facilities and one can summarize the common

capabilities as follows:

• The parameters to be trended in a specific chart can be predefined or defined on-line • 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) • real-time and historical trending are possible,

although generally not in the same chart.

4.4 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. It is generally possible to group alarms and to



handle these as an entity (typically filtering on group or acknowledgement of all alarms in a

group). Furthermore, it is possible to suppress alarms either individually or as a complete

group. The filtering of alarms seen on the alarm page or when viewing the alarm log is also

possible at least on priority, time and group. However, relationships between alarms cannot

generally be defined in a straightforward manner. E-mails can be generated or predefined

actions automatically executed in response to alarm conditions.

4.5 Logging/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 if the value changes or when a specific predefined event occurs. Logged data

can be transferred to an archive once the log is full. 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.

4.6 Report Generation

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.

4.7 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. 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.

4.8 Application & Development in SCADA

4.8.1 Configuration

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 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.

However, many of the PC tools now have a Windows Explorer type development studio. The

developer then works with a number of folders, which each contains a different aspect of the

configuration, including the graphics.

The facilities provided by the products for configuring very large numbers of parameters are

not very strong. However, this has not really been an issue so far for most of the products to-

date, as large applications are typically about 50K I/O points and database population from

within an ASCII editor such as Excel is still a workable option. On-line modifications to the

configuration database and the graphics are generally possible with the appropriate level of

privileges.

4.8.2 Development Tools

The following development tools are provided as standard:

• A graphics editor, with standard drawing facilities including freehand, lines, squares

circles, etc. It is possible to import pictures in many formats as well as using predefined

symbols including e.g. trending charts, etc. A library of generic symbols is provided that can be

linked dynamically to variables and animated as they change. It is also possible to create links

between views so as to ease navigation at run-time. • A data base configuration tool (usually

through parameter templates). It is in general possible to export data in ASCII files so as to be



edited through an ASCII editor or Excel. • A scripting language • An Application Program

Interface (API) supporting C, C++, VB

4.8.3 Evolution

SCADA vendors release one major version and one to two additional minor versions once

per year. These products evolve thus very rapidly so as to take advantage of new market

opportunities, to meet new requirements of their customers and to take advantage of new

technologies. As was already mentioned, most of the SCADA products that were evaluated

decompose the process in "atomic" parameters to which a Tag-name is associated. This is

impractical in the case of very large processes when very large sets of Tags need to be

configured. As the industrial applications are increasing in size, new SCADA versions are now

being designed to handle devices and even entire systems as full entities (classes) that

encapsulate all their specific attributes and functionality. In addition, they will also support

multi-team development. As far as new technologies are concerned, the SCADA products are

now adopting:

• Web technology, ActiveX, Java, etc. • OPC as a means for communicating internally between

the client and server modules. It should thus be possible to connect OPC compliant third party

modules to that SCADA product.

Chapter-5

5.1 ELECTRICAL DRIVES

Drives are employed for systems that require motion control – e.g. transportation system,

fans, robots, pumps, machine tools, etc. Prime movers are required in drive systems to provide

the movement or motion and energy that is used to provide the motion can come from various



sources: diesel engines, petrol engines, hydraulic motors, electric motors etc. Drives that use

electric motors as the prime movers are known as electrical drives

There are several advantages of electrical drives:

a. Flexible control characteristic – This is particularly true when power electronic

converters are employed where the dynamic and steady state characteristics of the motor can be

controlled by controlling the applied voltage or current.

b. Available in wide range of speed, torque and power

c. High efficiency, lower noise, low maintenance requirements and cleaner operation

d. Electric energy is easy to be transported.

Fig.5.1: Electrical Drives

A typical conventional electric drive system for variable speed applications employing multi-

machine system. The system is obviously bulky, expensive, inflexible and requires regular

maintenance. In the past, induction and synchronous machines were used for constant speed

applications – this was mainly because of the unavailability of variable frequency supply. With

the advancement of power electronics, microprocessors and digital electronics, typical electric

drive systems nowadays are becoming more compact, efficient, cheaper and versatile – this is

shown in Figure 2. The voltage and current applied to the motor can be changed at will by

employing power electronic converters. AC motor is no longer limited to application where



only AC source is available, however, it can also be used when the power source available is

DC or vice versa

Fig.5.1.1: Electric drive system employing power electronic converters

5.2 Components of Electrical Drives

The main components of a modern electrical drive are the motors, power processor, control

unit and electrical source. These are briefly discussed below.

5.2.1 Motors

Motors obtain power from electrical sources. They convert energy from electrical to

mechanical - therefore can be regarded as energy converters. In braking mode, the flow of

power is reversed. Depending upon the type of power converters used, it is also possible for the



power to be fed back to the sources rather than dissipated as heat. There are several types of

motors used in electric drives – choice of type used depends on applications, cost,

environmental factors and also the type of sources available. Broadly, they can be classified as

either DC or AC motors: DC motors (wound or permanent magnet) AC motors:

Induction motors – squirrel cage, wound rotor

Synchronous motors – wound field, permanent magnet

Brushless DC motor – require power electronic converters

Stepper motors – require power electronic converters

Synchronous reluctance motors or switched reluctance motor – require power electronic converters

5.2.2 Power processor or power modulator

Since the electrical sources are normally uncontrollable, it is therefore necessary to be

able to control the flow of power to the motor – this is achieved using power processor or

power modulator. With controllable sources, the motor can be reversed, brake or can be

operated with variable speed. Conventional methods used, for example, variable impedance or

relays, to shape the voltage or current that is supplied to the motor – these methods however are

inflexible and inefficient. Modern electric drives normally used power electronic converters to

shape the desired voltage or current supplied to the motor. In other words, the characteristic of

the motors can be changed at will. Power electronic converters have several advantages over

classical methods of power conversion, such as :

• More efficient – since ideally no losses occur in power electronic converters

• Flexible – voltage and current can be shaped by simply controlling switching functions of the

power converter

• Compact – smaller,

• Compact and higher ratings solid–state power electronic devices are continuously being

developed – the prices are getting cheaper.

Converters are used to convert and possibly regulate (i.e. using closed-loop control) the

available sources to suit the load i.e. motors. These converters are efficient because the

switches operate in either cut-off or saturation modes



Several conversions are possible:

AC to DC DC to AC DC to DC AC to AC

5.2.3 Control Unit

The complexity of the control unit depends on the desired drive performance and the type

of motors used. A controller can be as simple as few op-amps and/or a few digital ICs, or it can

be as complex as the combinations of several ASICs and digital signal processors (DSPs). The

types of the main controllers can be: • analog - which is noisy, inflexible. However analog

circuit ideally has infinite bandwidth. • digital – immune to noise, configurable. The bandwidth

is obviously smaller than the analog controller’s – depends on sampling frequency •

DSP/microprocessor – flexible, lower bandwidth compared to above. DSPs perform faster

operation than microprocessors (multiplication in single cycle). With DSP/microp., complex

estimations and observers can be easily implemented.

5.2.4 Source

Electrical sources or power supplies provide the energy to the electrical motors. For high

efficiency operation, the power obtained from the electrical sources need to be regulated using

power electronic converters Power sources can be of AC or DC in nature and normally are

uncontrollable, i.e. their magnitudes or frequencies are fixed or depend on the sources of

energy such as solar or wind. AC source can be either three-phase or single-phase; 3-phase

sources are normally for high power applications

There can be several factors that affect the selection of different configuration of electrical drive system such as:

a) Torque and speed profile - determine the ratings of converters and the quadrant of operation required.

b) Capital and running cost – Drive systems will vary in terms of start-up cost and running

cost, e.g. maintenance.

c) Space and weight restrictions –

d) Environment and location



5.3 Comparison between DC and AC drives

5.3.1 Motors

• DC require maintenance, heavy, expensive, speed limited by mechanical construction

• AC less maintenance, light, cheaper, robust, high speed (esp. squirrel–cage type)

5.3.2 Control unit:

• DC drives: Simple control – decoupling torque and flux by mechanical commutator – the

controller can be implemented using simple analog circuit even for high performance torque

control –cheaper.

• AC drives, the types of controllers to be used depend on the required drive performance –

obviously, cost increases with performance. Scalar control drives technique does not require

fast processor/DSP whereas in FOC or DTC drives, DSPs or fast processors are normally

employed.

5.3.3 Performance:

• In DC motors, flux and torque components are always perpendicular to one another thanks

to the mechanical commutator and brushes. The torque is controlled via the armature current

while maintaining the field component constant. Fast torque and decouple control between flux

and torque components can be achieved easily.

• In AC machines, in particular the induction machines, magnetic coupling between phases

and between stator and rotor windings makes the modeling and torque control difficult and

complex. Control of the steady state operating conditions is accomplished by controlling the

magnitude and the frequency of the applied voltage; which is known as the scalar control

technique. This is satisfactory in some applications. The transient states or the dynamics of the

machine can only be controlled by applying the vector control technique whereby the

decoupling between the torque and flux components is achieved through frame transformations.

Implementation of this control technique is complex thus requires fast processors such as

Digital Signal Processors (DSPs).

5.4 Overview of AC and DC drives



The advancement in electric drive system is very much related to the development in the

power semiconductor devices technology. The introduction of the Silicon-Controlled Rectifier

(SCR) in 1957 has initiated the application of solid state devices in power converters. The

development of the electrical drives systems can be divided into three stages. Before power

semiconductor devices were introduced: AC drives were used for fixed speed operation.

Generating an AC voltage with variable frequency was only possible by using rotary

converters, which are bulky and inflexible. Although it is possible to use variable voltage with

fixed frequency sources to control the speed of AC motors, the efficiency of the drive system

will be very poor especially at low speeds. On the other hand, variable DC supply can be

produced using multi-machine configuration and hence could be used to control the armature

voltage of the DC motors. Consequently, DC drives are widely used for variable speed

operation, whereas AC machines were used mainly for fixed speed applications.

After power semiconductor devices were introduced in 1950s although self turnoff devices

(Bipolar Junction Transistor – BJT) were available in the 1950s their voltage ratings were too

low which make them inappropriate to be used in power circuit. Silicon-Controlled Rectifier

(SCR) was introduced in 1957. The higher ratings of SCR compared to the solid state transistor

at that time, has made it possible for it to be used in static frequency converters or inverters.

Speed control with AC motor can be performed because variable frequency AC supply can be

generated using inverters. However, since the switching frequency of an SCR was low which

require commutation circuit in order to turn off; square wave inverters were mainly used in AC

drive system. In early 1960s, the improvement in the fabrication of BJT along with the

introduction of pulse width modulation (PWM) control technique has significantly contributed

to the improvement in the AC motor drives. Transient torque control to some extent was nearly

achieved to the expense of a very complex algorithm with numerous approximations. The true

high performance torque control similar to DC drives was still not achievable due to the

complex magnetic coupling between phases in the stator and rotor of the AC machines.

Nevertheless, DC drives were gradually being replaced with AC drives in medium performance

variable speed applications. Applications requiring precise and fast torque control were still

dominated by DC drives. After semiconductor devices were introduced in 1980s In 1972,

Prof. Blashke published his approach of AC motor control, to what is now known as Field

Oriented Control (FOC) or vector control. FOC control basically transformed the control of AC

motors to the one similar to DC motor control. In other words, the high performance torque

control can be achieved using AC motors. This is possible through complex frame



transformations and algorithm. However not until in the early 80s, where faster

microprocessors were available, the algorithm used for FOC was not practically realizable. In

1980s, increasing number of applications utilizing FOC control could be found in industries.

Applications which were previously possible only with DC drives were gradually being

replaced with FOC of AC drives. It was predicted that the AC drives will eventually replace the

DC drives in the near future.

5.5 Connection of Electric Drives

5.5.1 There are 3 mode of connection.

1. Keypad mode

Fig. 5.5.1: Keypad of Electrical Drive

2. 2-wire mode



Fig.5.5.2: 2-wire connection3. 3-wire mode

Fig.5.5.3: 3-wire connection

5.6 Programming Parameter



5.6.1 Input Parameter

Parameter Code Description

P101 Motor NP voltage

P102 Motor NP frequency

P103 Motor O.L. current

P104 Minimum Frequency

P105 Maximum frequency

P106 Start source

P107 Stop Mode

P108 Speed reference

P109 Acceleration time

P110 Deceleration time

5.6.2 Display parameter

Code Description

D001 Output frequency

D002 Command frequency

D003 O/P current

D004 O/P voltage

D005 DC bus voltage

D006 Drive status

D007 Fault display

D008 Fault display

D009 Fault display

D0010 RPM display

Chapter-6



Projects Done

6.1 Automatic lift control

In this I design a model of lift control in which I shows how a lift works. In this model we

use PLC, relays, dc gear motor, sensors & switches. All plays very important role. We

upload a program in PLC which is formed in ladder logic.

Fig. 6.1 program for automatic lift control

Switches are used to calling or going the lift upward or downward and sensors are used to

sense the present position of lift.Dc gear motor used to rotate the pully in which lift is fixed.

6.2 Automatic bottle filing plant



In this project we design a program for a bottle filing plant. In which we used a conyer

belt, motor, valve, sensors & internal timer of PLC. Sensors used as switch which sense

the position of bottle it used where bottle have to be stopped. Timer is used to count the

time for which valve is open to fill the bottle.

Fig. 6.2 Automatic bottle filing plant

6.3 Blinking of 2 lamps



In this we design a program for blinking of 2 lamp simultaneously. We blink a both lamp

simultaneously with a 5seconds time delay. First lamp 1 is glow for a first 5seconds and lamp 2

is off then in another 5seconds lamp 1 off and lamp 2 is glow.

Fig. 6.3 blinking of 2 lamps

6.4 Paint mixing plant



In paint mixing plant we mix the two different paints for making one by combining both

paint. After combining both a new color of paint is formed. For mixing of paints we use a tank

which is filled by two different colors of paints which is filling by two valves. And sensors are

used to measure the paint level in the tank. After filling the tank mixing motor is ON for

10seconds and then valve 3 is open for taking off the paint from the tank.

Fig. 6.4 Paint mixing plant

CONCLUSION



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. Automation provides 100% accuracy all time. So the failures and mismatch in production completely eliminates. It makes the system’s efficiency higher than manual as well as It controls wastages.. So the overall savings increases. It provides safety to human being. By that industry can achieves the safety majors and ISO and OHSAS reputation. It makes the operation faster than manual which causes higher production and proper utilization of utilities. It increases the production by which the cost of each product decreases and industry profit increases. It provides smooth control on system response. It provides repeatability, so that the same kinds of products are easier to manufacture at different stages without wasting time. It provides quality control, so that the products become reliable which improves industrial reputation in market. It provides integration with business systems. It can reduce labor costs, so the final profit increases. Industrial automation is very compulsory need of industries in today’s scenario to meet market competition

REFERENCES



[1] A.Daneels, W.Salter, "Technology Survey Summary of Study Report", IT-CO/98-08- 09, CERN, Geneva 26th Aug 1998.

[2] A.Daneels, W.Salter, "Selection and Evaluation of Commercial SCADA Systems for the Controls of the CERN LHC Experiments", Proceedings of the 1999 International Conference on Accelerator and Large Experimental Physics Control Systems, Trieste, 1999, p.353.

[3] G.Baribaud et al., "Recommendations for the Use of Fieldbuses at CERN in the LHC Era", Proceedings of the 1997 International Conference on Accelerator and Large Experimental Physics Control Systems, Beijing, 1997, p.285.

[4] D. Kandray, Programmable Automation Technologies , Industrial Press, 2010.

[5] W. Bolton, Programmable Logic Controllers, Fifth Edition, Newnes, 2009.

[6] http://www.surecontrols.com/what-is-industrial-automation/


http://www.surecontrols.com/what-is-industrial-automation/

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