Scada Based Plc

download Scada Based Plc

of 51

Transcript of Scada Based Plc

  • 7/30/2019 Scada Based Plc

    1/51

    SCADA

    BASED POWER CONTROL SYSTEM

    USING PLC

    TABLE OF CONTENTS

    1. INTRODUCTION

    1.1 Introduction

    1.2 Why SCADA

    1.3 Challenges and Applications

    1.4 Research Issues

    1.4.1 Flexible Communication Architecture1.4.2 Open And Interoperable Protocols

    1.4.3 Smart remote terminal units

    1.5 Potential Benefits Of SCADA

    1.6 Cyber Security for SCADA

    1.6.1 SCADA Security

    1.6.2 Commodity Infrastructure

    1.6.3 Network Architecture

    1.6.4 Confidentiality

    1.6.5 Authentication

    1

  • 7/30/2019 Scada Based Plc

    2/51

    1.6.6 Lack of Session Structure

    2. SYSTEM DEVELOPMENT

    2.1 Block Diagram

    2.2 Main components of project

    2.2.1 Switch Mode Power Supply

    2.2.2 Power Relays2.2.2.1 Physical Size And Pin Arrangement

    2.2.2.2 Coil Voltage

    2.2.2.3 Coil Resistance

    2.2.2.4 Switch Ratings (Voltage and Current)

    2.2.2.5 Switch Contact Arrangement (SPDT, DPDT

    etc)2.2.3 Serial Interface (RS232)

    2.2.3.1 RS232 Serial Cable Layout

    2.2.3.2 RS232 Serial Connector Pin Assignment

    2

  • 7/30/2019 Scada Based Plc

    3/51

    3 PROGRAMABLE LOGIC CONTROLLER (PLC)

    3.1 Hardware Overview

    3.2 PLCs Input And Outputs Terminals

    3.3 Horizontal View of PLC

    3.4 Vertical View of PLC

    3.5 Wiring Diagram of PLC

    3.6 Connection of computer with PLC

    3.7 Principles of Machine Control

    3.8 DH-485 Network

    3.9 Principles of Machine Control

    3.9 Memory Features of Micrologix 1000 PLC

    3.10 Processing Features of Micrologix 1000 PLC

    3.11 Operating Cycle of PLC

    3.12 Software Features of Micrologix 1000 PLC

    3.13 System Requirements for Micrologix 1000 PLC

    3.14 Power Distribution

    3.15 Preventing Excessive Heat

    4. SOFTWARE IMPLEMENTATION

    5. CONCLUSION

    3

  • 7/30/2019 Scada Based Plc

    4/51

    CHAPTER 1INTRODUCTION

    1.1 INTRODUCTION

    Using powerful technologies, based on experience of

    qualified personal, SCADA (Supervisory Control And Data

    Acquisition) applications are created as a main tool for performing

    management, required by technical reengineering of an industrial

    company. In modern manufacturing and industrial processes,

    mining industries, public and private utilities, leisure and security

    4

  • 7/30/2019 Scada Based Plc

    5/51

    industries, control systems are often needed to connect equipment

    and systems separated by large distances. These systems are used

    to send commands, programs and receives monitoring information

    from these remote locations. SCADA refers to the combination of

    control systems and data acquisition. In the early days of data

    acquisition, relay logic was used to control production and plant

    systems. With the advent of the CPU (Central Process Unit) and

    other intelligent electronic devices, manufacturers incorporated

    digital electronics into relay logic equipment. The PLC

    (Programmable Logic Controller) is still one of the most widely

    used control systems in industry.

    1.2 WHY SCADA ?

    SCADA provides several unique features that make it a

    particularly good choice

    for many control problems. The features are as follows:

    the computer control primary equipments, record an store a

    very large amount of data from process

    the operator can incorporate real data simulations into the

    system

    the operator is assist by computer that recommend actions to

    keep the system safety

    5

  • 7/30/2019 Scada Based Plc

    6/51

    many types of data can be collected from the RTUs (Remote

    Terminal Unit), this creates online the image of the system.

    1.3 CHALLENGES AND APPLICATIONS

    Supervisory Control And Data Acquisition (SCADA)

    systems have been widely used in industry applications. Due to

    their application specific nature, most SCADA systems are heavily

    tailored to their specific applications. For example, a remote

    terminal unit (RTU) that monitors and controls a production well

    in an oilfield is only connected with a few sensors at the well it

    resides. The RTU usually collects sensor data at pre-defined

    intervals , and only sends data back when being polled by a central

    data server. A user can only access the data in one of the two ways:

    directly connecting to the RTU in the field or reading from the data

    server in the control room. A major drawback of typical SCADA

    systems is their inflexible, static, and often centralized architecture,

    which largely limits their interoperability with other systems. For

    example, in a SCADA system developed for oil and gas fields, the

    RTUs are usually places at production wells and injection wells.

    However, there are many other places, such as pipeline, tanks, etc.,

    that have valuable data but are too expensive (e.g., cable

    6

  • 7/30/2019 Scada Based Plc

    7/51

    requirement) to deploy more RTUs. In such cases, sensor networks

    are a perfect solution to extend the sensing capability of the

    SCADA system. However, it is difficult to integrate sensor

    networks with current SCADA systems due to their limited

    interoperability. We identify that enabling such interoperability is

    an important task for future SCADA systems.

    Another drawback of the current SCADA systems is their

    limited extensibility to new applications. In the above oilfield

    monitoring example, a user in the field can only access a sensors

    data by physically going to that well and connecting to its RTU. If

    the company wants to extend its SCADA system by

    adding a safety alarm system, it will be very difficult to add

    the new application.

    The original application only monitors well production at

    predefined intervals or on demand. The new application requires

    7

  • 7/30/2019 Scada Based Plc

    8/51

    real-time interaction between sensors and mobile users in the field.

    The RTUs that detect a safety problem need to proactively report

    the problem without waiting. The rigid design of current RTUs

    makes it hard to extend the SCADA from one application to

    another.

    Deploying a SCADA system in a large field is very

    expensive If the SCADA system is interoperable with new

    technologies, such as sensor networks, and extensible for new

    applications, it will be able to significantly improve the

    productivity at a minimal cost.

    1.4 RESEARCH ISSUES

    This section identifies major research issues to enable

    interoperability and extensibility of future SCADA systems. We

    roughly classify them in three categories:

    Flexible communication architecture,

    Open and interoperable protocols, and

    Smart remote terminal units.

    1.4.1 Flexible Communication Architecture

    Current SCADA systems are essentially a centralized

    communication system, where the data server polls each remote

    8

  • 7/30/2019 Scada Based Plc

    9/51

    terminal unit (RTU) to collect data. There is no data sharing and

    forwarding between different RTUs. Usually these RTUs only

    communicate with the data server. This communication

    architecture is not flexible to interact with other systems, such as

    the embedded sensor networks and mobile users in the field.

    Designing a flexible communication architecture is one of the key

    factors to enable interoperability and extensibility.

    1.4.2 Open And Interoperable Protocols

    We suggest that SCADA systems should adopt the use

    of Internet technologies for networking, rather than proprietary or

    link-level approaches. collect and manipulate different types of

    sensor data. It also includes how to discover and configure sensors.

    An open protocol should be extensible to support various types of

    sensors. These protocols should also address what types of data

    should be transmitted and to whom. For example, raw data are

    only sent to data server for archival. Status summaries will be sentto managers and engineers, while emergency safety alarms should

    be broadcast to all field operators.

    9

  • 7/30/2019 Scada Based Plc

    10/51

    1.4.4 Smart remote terminal units

    Remote terminal units play an important role in the new

    communication architecture we described above. They serve as

    bridge points to sensor networks as well as access points to mobile

    users in the field. They respond to users queries and collect data

    from specific sensors. These RTUs should be smart enough to

    perform preliminary data processing. The first reason is to validate

    the data collected from different sensors. Sensors can give false

    values due to various reasons. It is important to validate them

    before use them to make important decisions. For example, in

    oilfield monitoring, a false sensor reading may result in a mistaken

    decision to shut in a well and lose production. The RTU is in a

    good position to validate sensor readings by cross checking from

    adjacent sensors.

    Another reason of requiring smart RTUs is that they are

    important in changing the reactive operation to proactive

    operation. Current SCADA systems mainly operate in the reactive

    mode, where data are usually sent in response to the data servers

    polling.

    10

  • 7/30/2019 Scada Based Plc

    11/51

    In a new class of applications, detection needs to be done in

    real time, and events need to be reported immediately, such as

    pipeline leakage, or H2S detection. Intelligent algorithms will run

    on these smart RTUs to process data in real time.

    Finally, these RTUs need to be smart enough to protect data

    from unauthorized access and altering. Access control and security

    measures need to be installed to protect the sensing system from

    attackers and ensure data integrity.

    1.5 POTENTIAL BENEFITS OF SCADA

    The benefits one can expect from adopting a SCADA system

    for the control of experimental physics facilities can be

    summarized as follows:

    a rich functionality and extensive development facilities. The

    amount of effort invested in SCADA product amounts to 50 to

    100 p-years!

    the amount of specific development that needs to be performed

    by the end-user is limited, especially with suitable engineering.

    reliability and robustness. These systems are used for missioncritical industrial processes where reliability and performance

    are paramount. In addition, specific development is performed

    11

  • 7/30/2019 Scada Based Plc

    12/51

    within a well-established framework that enhances reliability

    and robustness.

    technical support and maintenance by the vendor.

    For large collaborations, as using a SCADA system for their

    controls ensures a common framework not only for the

    development of the specific applications but also for operating the

    detectors. Operators experience the same" look and feel" whatever

    part of the experiment they control. However, this aspect also

    depends to a significant extent on proper engineering.

    1.6 CYBER SECURITY FOR SCADA

    Cyber security for SCADA Systems provides a high-level

    overview of this unique technology, with an explanation of eachmarket segment. Cyber security for SCADA Systems is suitable

    for the non-technical management level personnel as well as IT

    12

  • 7/30/2019 Scada Based Plc

    13/51

    personnel without SCADA experience. The security issues with

    SCADA systems as follows :

    Traditionally SCADA systems were designed around

    reliability and safety. Security was not a consideration. However,

    security of these systems is increasingly becoming an issue due to:

    increasing reliance on public telecommunications networks

    to link previously separate SCADA systems is making them

    more accessible to electronic attacks;

    increasing use of published open standards and protocols, in

    particular Internet technologies, expose SCADA systems to

    Internet vulnerabilities;

    the interconnection of SCADA systems to corporate

    networks may make them accessible to undesirable entities;

    lack of mechanisms in many SCADA systems to provide

    confidentiality of communications means that intercepted

    communications may be easily read;

    lack of authentication in many SCADA systems may result in

    a system users identity not being accurately confirmed.

    1.6.1 SCADA Security

    The majority of SCADA systems have useful lifetimes

    ranging from 15 to 30 years. In most instances the underlying

    protocols were designed without modern security

    13

  • 7/30/2019 Scada Based Plc

    14/51

    requirements in mind. The rapid advance of technology and the

    changing business environment is driving change in SCADA

    network architecture, introducing new vulnerabilities to legacy

    systems.

    The current push towards greater efficiency, consolidated

    production platforms and larger companies with smaller staffing

    levels is leading to changes in SCADA systems which are raising

    many questions about security.

    In summary, these involve:

    an increasing reliance on public telecommunications

    networks to link previously separate SCADA systems;

    increasing use of published open standards and protocols, in

    particular Internet technologies; and

    the interconnection of SCADA systems to other business

    networks to enhance the amount, detail and timeliness of

    information available to management.

    1.6.2 Commodity Infrastructure

    The changes in SCADA systems have exposed them to

    vulnerabilities that may not have existed before. For example, the

    14

  • 7/30/2019 Scada Based Plc

    15/51

    switch from using leased telecommunications lines to public

    infrastructure i.e. Public CDMA and GSM networks, the use of

    commodity computers running commodity software and the

    change from proprietary to open standards have meant that

    vulnerabilities have been introduced into SCADA systems.

    1.6.3 Network Architecture

    Effective network design which provides the appropriate

    amount of segmentation between the Internet, the companys

    corporate network, and the SCADA network is critical to risk

    management in modern SCADA systems. Network architecture

    weakness can increase the risk from Internet and other sources of

    intrusion.

    1.6.4 Confidentiality

    Generally, there are no mechanisms in SCADA to provide

    confidentiality of communications. If lower level protocols do not

    provide this confidentiality then SCADA transactions are

    communicated in the clear meaning that intercepted

    communications may be easily read.

    15

  • 7/30/2019 Scada Based Plc

    16/51

    1.6.5 Authentication

    Many SCADA systems give little regard to security, often

    lacking the memory and bandwidth for sophisticated password or

    authentication systems. As a result there is no mechanism to

    determine a system users identity or what that user is authorized

    to access. This allows for the injection of false requests or replies

    into the SCADA system.

    1.6.6 Lack of session structure

    SCADA systems often lack a session structure which, when

    combined with the lack of authentication, allow the injection of

    erroneous or rogue requests or replies into the system without any

    prior knowledge of what has gone on before.

    16

  • 7/30/2019 Scada Based Plc

    17/51

    CHAPTER 2

    SYSTEM DEVOLPMENT

    2.1 BLOCK DIAGRAM

    The block diagram of the SCADA based power controlsystem is shown:

    17

  • 7/30/2019 Scada Based Plc

    18/51

    Figure 2.1 Block Diagram Of the SCADA and PLC

    based control system

    2.2 Main components of project are as follow:

    1. SMPS (+24 VDC)

    18

  • 7/30/2019 Scada Based Plc

    19/51

    2. RELAYS ( 24 VDC, 50/60Hz)24 VDC, 50/60Hz)

    3. Serial Interface (RS-232)

    4. PLC (6/4)

    5. COMPUTER

    2.2.1 SWITCH MODE POWER SUPPLY (SMPS)

    The picture of SMPS used is shown below and their features

    are as follows:

    High efficiency, high reliability,

    AC input range selected by switch

    100% full load burn-in test.

    Protections: Short circuit/ Over load/

    Over voltage Fixed switching frequency

    at 25KHz.

    Dimensions: 199*110*50mm

    L*W*H

    Figure 2.2.1 Physical

    Structure Of SMPS

    Point to note for selecting a SMPS.

    19

    SMPS (+24VDC)SMPS (+24VDC)

    Inputs 115 AC (2.4A) , 230AC (4.5A)Inputs 115 AC (2.4A) , 230AC (4.5A)

    Outputs +24V (4.5A)Outputs +24V (4.5A)

  • 7/30/2019 Scada Based Plc

    20/51

    1. All parameters NOT specially mentioned are measured at

    230VAC input, rated load and 25*C of ambient temperature.

    2. Ripple & noise are measured at 20MHz of bandwidth by using a

    12twisted pair-wire terminated with a 0.1 & 47 parallel

    capacitor.

    3. Each output can within current range. But total output power

    cant exceed rated load.

    4. The power supply is considered a component which will be

    installed into a final equipment. The final equipment must be re-

    confirmed that it still meets EMC directives.

    2.2.2 POWER RELAYS

    The coil of a relay passes a relatively large current, typically

    7a for a 24V relay, but it can be as much as 100mA for relays

    designed to operate from lower voltages. Most ICs (chips) cannot

    provide this current and a transistor is usually used to amplify thesmall IC current to the larger value required for the relay coil.

    Relays are usually SPDT or DPDT but they can have many

    more sets of switch contacts, for example relays with 4 sets of

    20

  • 7/30/2019 Scada Based Plc

    21/51

    changeover contacts are readily available. For further information

    about switch contacts and the terms used to describe them. We are

    using three relays in our project . The picture of the relay used is

    shown below:

    Figure 2.2.2 Physical Structure Of Power Relay

    The need to consider several features when choosing a relay:

    2.2.2.1 Physical Size And Pin Arrangement

    21

    http://zettlernb.en.alibaba.com/product/0/52313152/Others/Power_relay/showimg.html
  • 7/30/2019 Scada Based Plc

    22/51

    If you are choosing a relay for an existing PCB you will

    need to ensure that its dimensions and pin arrangement are suitable.

    You should find this information in the supplier's catalogue.

    2.2.2.2 Coil Voltage

    The relay's coil voltage rating and resistance must suit the

    circuit powering the relay coil. Many relays have a coil rated for a

    12V supply but 5V and 24V relays are also readily available. Some

    relays operate perfectly well with a supply voltage which is a little

    lower than their rated value.

    2.2.2.3 Coil Resistance

    The circuit must be able to supply the current required by the

    relay coil. You can use Ohm's law to calculate the current:

    Voltage/Resistance

    22

  • 7/30/2019 Scada Based Plc

    23/51

    2.2.2.4 Switch Ratings (Voltage and Current)

    The relay's switch contacts must be suitable for the circuit

    they are to control. You will need to check the voltage and current

    ratings. Note that the voltage rating is usually higher for AC, for

    example: "5A at 24V DC or 125V AC".

    2.2.2.5 Switch Contact Arrangement (SPDT, DPDT etc)

    Most relays are SPDT or DPDT which are often described as

    "single pole changeover" (SPCO) or "double pole changeover"

    (DPCO).

    Advantages to use of Relays:

    Relays can switch AC and DC, transistors can only switch

    DC.

    Relays can switch high voltages, transistors cannot.

    Relays are a better choice for switching large currents (> 5A).

    Relays can switch many contacts at once.

    23

  • 7/30/2019 Scada Based Plc

    24/51

    2.2.3 SERIAL INTERFACE (RS232)

    2.2.3.1 RS232 Serial Cable Layout

    Almost nothing in computer interfacing is more confusing

    than selecting the right RS232 serial cable. These pages are

    intended to provide information about the most common serial

    RS232 cables in normal computer use, or in more common

    language "How do I connect devices and computers using RS232".

    2.2.3.2 RS232 Serial Connector Pin Assignment.

    The RS232 connector was originally developed to use 25

    pins. In this DB25 connector pin out provisions were made for a

    secondary serial RS232 communication channel.

    In practice, only one serial communication channel with

    accompanying handshaking is present. Only very few computers

    have been manufactured where both serial RS232 channels areimplemented. Examples of this are the Sun Sparc Station 10 and 20

    models and the Dec Alpha Multia. Also on a number of Telebit

    modem models the secondary channel is present. It can be used to

    24

  • 7/30/2019 Scada Based Plc

    25/51

    query the modem status while the modem is on-line and busy

    communicating. On personal computers, the smaller DB9 version

    is more commonly used today. The diagrams show the signals

    common to both connector types in black. The defined pins only

    present on the larger connector are shown in red. Note, that the

    protective ground is assigned to a pin at the large connector where

    the connector outside is used for that purpose with the DB9

    connector version.

    The pin out is also shown for the DEC modified modular

    jack. This type of connector has been used on systems built by

    Digital Equipment Corporation; in the early days one of the leaders

    in the mainframe world. Although this serial interface is

    differential (the receive and transmit have their own floating

    ground level which is not the case with regular RS232) it is

    possible to connect RS232 compatible devices with this interface

    because the voltage levels of the bit streams are in the same range

    25

  • 7/30/2019 Scada Based Plc

    26/51

    Figure 2.2.3 (a) RS232 Serial Connector Pin

    Assignment.

    The picture of the serial interface used is shown below:

    26

    RS 232Serial Interface (Female Part)

    RS 232Serial Interface (Male Part)

  • 7/30/2019 Scada Based Plc

    27/51

    Figure 2.2.3(b) Physical Structure Of Serial Interface RS 232

    (Female and Male Part)

    Figure 2.2.3(c) Connection Diagram Of Serial Interface RS

    232(Female and Male Part)

    CHAPTER 3

    PROGRAMABLE LOGIC CONTROLLER (PLC)

    3. MICROLOGIX 1000 PROGRAMMABLE

    CONTROLLERS

    The MicroLogix 1000 Programmable Controllers are

    designed to electronically control your application. The controllers

    27

  • 7/30/2019 Scada Based Plc

    28/51

    are available in either 16 I/O points (10 inputs and 6 outputs) or 32

    I/O points (20 inputs and 12 outputs) in 5 electrical configurations.

    The I/O options and electrical configurations make them ideal for

    almost any application.

    The controllers are programmed in familiar ladder logic. This

    symbolic programming language is based on relay ladder wiring

    diagrams that simplify the creation and troubleshooting of your

    control program. The comprehensive instruction set includes

    simple bit, timer, and counter instructions as well as powerful

    application instructions such as sequencers, high-speed counter,

    and shift registers.

    To get your application running smoothly, you need a quick

    and simple way to program your controller. The MicroLogix 1000

    Programmable Controller family offers you two software packages

    and one diagnostic hand-held programmer to help you accomplish

    this task.

    The MicroView Operator Interface enables you to monitor

    and control your application with a combination of large memory

    capacity, flexible file addressing, user-defined function keys, and

    an easy-to-read display. Contact your local Allen-Bradleydistributor for more information concerning the MicroView

    Operator Interface and accessories

    28

  • 7/30/2019 Scada Based Plc

    29/51

    3.1 Hardware Overview

    The MicroLogix 1000 programmable controller is a packaged

    controller containing a power supply, input circuits, output circuits,

    and a processor. The controller is available in 10 I/O, 16 I/O and

    32 I/O configurations, as well as an analog version with 20 discrete

    I/O and 5 analog I/O. We are using 10 I/O Configuration:

    In such PLC, Inputs are six and outputs are four. The picture

    of the PLC used is shown below:

    29

  • 7/30/2019 Scada Based Plc

    30/51

    Figure 3.1 Physical Structure Of PLC (Micrologix 1000)

    3.2 PLCs Input And Outputs Terminals

    Two I/O point sizes (i.e., 16 and 32 I/O). Covers a breadth of

    applications.

    Five electrical configurations. Offers you a controller that meets

    your electrical requirements:

    1. 24V dc inputs and relay outputs with a 120/240V ac power

    supply.

    2. 120V ac inputs and relay outputs with a 120/240V ac power

    supply.

    3. 24V dc inputs and relay outputs with a 24V dc power supply.

    4. 24V dc inputs and 24V dc FET and relay outputs with a 24V

    dc power Supply.

    5. 120V ac inputs and triac and relay outputs with a 120/240V ac

    power supply.

    30

  • 7/30/2019 Scada Based Plc

    31/51

    Five output commons on relay output units and three on

    MOSFET units (at least two isolated relays per controller). Allows

    outputs on the same unit to switch different control voltages.

    Multiple input commons. Allows the controller with DC

    inputs to accept sink and source type sensors.

    Compact size. Enables the MicroLogix 1000 Programmable

    Controller to fit in tight spaces.

    Adjustable DC input filters. Allows you to customize your

    input response time to various applications. For a listing of

    the adjustable DC input filter settings.

    Built-in sensor DC power supply on AC powered units.

    Eliminates the need for an external DC power supply in

    many applications.

    RS-232 communication channel. Allows you to connect thecontroller directly to your personal computer or telephone

    modem.

    Auto-ranging AC power supply. Allows you to install the

    MicroLogix 1000 Programmable Controller in virtually any

    application worldwide.

    OEM protection. Allows you to protect proprietary

    algorithms, prevent program alterations, and stop

    unauthorized access to the controller.

    31

  • 7/30/2019 Scada Based Plc

    32/51

    32

  • 7/30/2019 Scada Based Plc

    33/51

    The hardware feature of the controller are:

    Figure 3.2 Hardware Structure Of PLC

    33

  • 7/30/2019 Scada Based Plc

    34/51

    3.3 Horizontal View Of PLC

    Figure 3.3 Horizontal View Of PLC

    3.4 Vertical View Of PLC

    34

  • 7/30/2019 Scada Based Plc

    35/51

    Figure 3.4 Vertical View of PLC

    3.5 Wiring Diagram Of PLC

    The connection with wires as shown in the wiring of PLC

    35

  • 7/30/2019 Scada Based Plc

    36/51

    Figure 3.5 Wiring Diagram Of PLC

    3.6 Connection of Computer With PLC

    36

  • 7/30/2019 Scada Based Plc

    37/51

    The connection of Micrologix 1000 PLC with PC as point to

    point connection is shown below:

    Figure 3.6 Point to Point Connection Of PC To PLC

    37

  • 7/30/2019 Scada Based Plc

    38/51

    3.7 DH-485 Network

    38

  • 7/30/2019 Scada Based Plc

    39/51

    3.8 Principles Of Machine Control

    The controller consists of a built-in power supply, central

    processing unit (CPU),inputs, which you wire to input devices

    (such as pushbuttons, proximity sensors, limit switches), and

    outputs, which you wire to output devices (such as motor starters,

    solid-state relays, and indicator lights).

    39

  • 7/30/2019 Scada Based Plc

    40/51

    With the logic program entered into the controller, placing

    the controller in the Run mode initiates an operating cycle. The

    controllers operating cycle consists of a series of operations

    performed sequentially and repeatedly, unless altered by your

    program logic.

    3.9 Memory Features Of Micrologix 1000 PLC

    Built-in EEPROM memory. Retains your program and all of

    your data if your controller loses power, eliminating the need for

    40

  • 7/30/2019 Scada Based Plc

    41/51

    battery or capacitor backup. Optimized 1K user memory capacity.

    Provides ample memory to meet your application needs including:

    over 735 word application program.

    more than 250 data words comprised of 512 bits, 40 timers,

    32 counters, 16 controls, 105 integers, and 33 diagnostic

    registers comprehensive instruction set.

    Allows you to develop a program using over 65 programming

    instructions from the following categories:

    bit

    timer/counter

    comparison

    math

    data handling

    program flow

    application specific (e.g., sequencer, shift register, and

    FIFO/LIFO)

    high-speed counter

    Efficient instructions. Condenses multiple rungs into a single

    instruction.

    3.9 Processing Features of Micrologix 1000 PLC

    41

  • 7/30/2019 Scada Based Plc

    42/51

    Superior high-speed counter. Offers immediate control of

    program outputs since the high-speed counter operates independent

    of the program scan. In addition, the high-speed counter provides:

    high count frequency of 6.6 kHz

    eight operating modes including up count, bi-directional, and

    quadrate

    interrupt latency of less than 1ms.

    Fast throughput. Allows for typical throughput time of 1.5 ms

    for a 500 instruction program._ Throughput is the time it takes forthe controller to sense an input to the time of controlling a

    corresponding output. To calculate your program execution time.

    The On/Off status in the output image table is sent to the outputs to

    turn physical devices On and Off.

    The status of contacts in the program is determined from the

    I/O tables.

    Instructions are executed.

    New status of output coils and registers are written to the

    output image table.

    42

  • 7/30/2019 Scada Based Plc

    43/51

    The On/Off status of the input devices are read from the

    inputs and written into the input image table. Communication with

    development tools; internal housekeeping, such as updating the

    time base and status file, and performing rescan

    3.10 Operating Cycle Of PLC

    Input scan the time required for the controller to scan and

    read all input data typically accomplished within seconds.

    Program scan the time required for the processor to

    execute the instructions in the program. The program scan

    time varies depending on the instructions used and each

    instructions status during the scan time.

    Output scan the time required for the controller to scan

    and write all output data typically accomplished with in

    seconds.

    Service communications the part of the operating cycle in

    which communication takes place with other devices, such as

    an HHP or personal computer.

    Housekeeping and overhead time spent on memory

    management and updating timers and internal registers. You

    enter a logic program into the controller using a

    43

  • 7/30/2019 Scada Based Plc

    44/51

    programming device. The logic program is based on your

    electrical relay.

    Figure 3.8 Operating Cycle Of PLC

    Program Development Process For PLC as follows :

    How you want your automated process to operate ?

    Identify the hardware requirements.

    Match inputs and outputs with actions of the process.

    44

  • 7/30/2019 Scada Based Plc

    45/51

    Add these actions to the functional specifications.

    Do you need:

    Special interrupt routines?

    High-speed counting features?

    Sequencing Operations?

    FIFO or LIFO stack operations?

    Make sure I/O addresses match correct input and output

    devices.

    Enter program using the programming device.

    Review your functional specification and detailed analysis

    for missing or incomplete information.

    Monitor and, if necessary, troubleshoot the program that you

    entered.

    Resulting programs should match functional specifications.

    3.12 Software Features of Micrologix 1000

    Both the MicroLogix 1000 Programming Software (v1.0 or

    later) and APS software (v5.1 or later) offer:

    45

  • 7/30/2019 Scada Based Plc

    46/51

    Program documentation. Allows you to add comments to

    rungs, instructions,

    and addresses.

    Online context sensitive help. Makes programming and

    troubleshooting easier to perform.

    Cut, copy, and paste editor. Allows you to efficiently

    modify your ladder logic program.

    Search and replace. Allows quick modification of ladder

    logic to accommodate program changes.

    RS-232 DF1 full duplex protocol. Supports remote

    programming through a telephone modem.

    Program reports. Allows you to create processor

    configuration, cross reference, program listing, and data

    table reports.

    Global language support. Provides separate programming

    packages In English, French, German, Italian, and

    Spanish.

    Command line entry of instructions and parameters. Saves

    time by reducing keystrokes.

    46

  • 7/30/2019 Scada Based Plc

    47/51

    3.13 System Requirements for Micrologix 1000

    Both the MicroLogix 1000 Programming Software (v1.0 or

    later) and APS ( v5.1 or later) can be used with:

    Allen-Bradley T47 or T70 terminal

    386/SX

    NEC VERSA E Series Notebook

    GATEWAY 2000 models 386DX/25, 386DX33,

    486DX/33, 486DX2/50, and 486DX2/66 personal computers

    The computer must have:

    640 Kbytes of RAM (At least 2 meg. of extended memory is

    required.)

    10 M byte fixed-disk drive (APS requires 3.5 Mbytes of free

    disk space.)

    DOS version 3.3 or higher

    3.14 Power Distribution

    There are some points about power distribution that you

    should know:

    The master control relay must be able to inhibit all machine

    motion by removing power to the machine I/O devices when

    the relay is de-energized.

    47

  • 7/30/2019 Scada Based Plc

    48/51

    If you are using a dc power supply, interrupt the load side

    rather than the ac line power. This avoids the additional delay

    of power supply turn-off. The dc power supply should be

    powered directly from the fused secondary of the

    transformer. Power to the dc input and output circuits is

    connected through a set of master control relay contacts.

    3.15 Preventing Excessive Heat

    For most applications, normal convective cooling keeps the

    controller within. The specified operating range. Ensure that the

    specified operating range is maintained. Proper spacing of

    components within an enclosure is usually sufficient for heat

    dissipation.

    CHAPTER 5

    Conclusion

    The trend in automated power systems is to use SCADA

    systems based on PLCs, advanced communication systems, and

    PC-based software. This project presents the basic knowledge

    needed to choose technology, design a system, and select a

    48

  • 7/30/2019 Scada Based Plc

    49/51

    SCADA system. For power control SCADAs mostly used as

    designing, integrating, installing, and maintaining automated

    power systems as follows :

    Control system architecture, design, and specification

    generation

    CAD-based layout and design of control enclosures and

    RTUs

    Fabrication of control panels in a UL-certified shops.

    SCADA software programming from leading vendors like

    ROCKWELL.

    Integration of industrially-hardened PLC-based control

    systems.

    Field start-up, calibration, and training services.

    Support and maintenance services for existing systems

    49

  • 7/30/2019 Scada Based Plc

    50/51

    OTHER APPLICATIONS

    1. WATER/CO2 INJECTION WELL SCADA MONITORING

    SYSTEM

    2. PUMPJACK/SCREWPUMP SCADA & TELEMETRY.

    3. WATER DISPOSAL HIGH TANK LEVEL SHUTDOWN

    SYSTEM4. VARIABLE FREQUENCY DRIVE (VFD) SCADA

    COMMUNICATION

    5. SEWAGE TREATMENT PLANT INFLOW TELEMETRY

    6. MUNICIPAL WATER SYSTEM - TAIL END DATA

    EXTENSION & WIDE

    AREA SCADA.

    7. REMOTE VALVE CONTROL

    8. CELLULAR TELEMETRY

    50

  • 7/30/2019 Scada Based Plc

    51/51

    9. WATER RESERVOIR PUMP CONTROL