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 Architecture

1.4.2 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

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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 Relays

2.2.2.1 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

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3 PROGRAMABLE LOGIC CONTROLLER (PLC)

3.1 Hardware Overview

3.2 PLC‘s 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

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CHAPTER 1 INTRODUCTION

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

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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

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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

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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 sensor’s

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

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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

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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 sent

to managers and engineers, while emergency safety alarms should

be broadcast to all field operators.

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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 server’s

polling.

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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 mission

critical industrial processes where reliability and performance

are paramount. In addition, specific development is performed

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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 each

market segment. Cyber security for SCADA Systems is suitable

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

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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 user’s 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

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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

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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 company’s

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.

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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 user’s 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.

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CHAPTER 2

SYSTEM DEVOLPMENT

2.1 BLOCK DIAGRAM

The block diagram of the SCADA based power control system is shown:

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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)

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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.

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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)

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

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

capacitor.

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

can’t 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 the

small 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

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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

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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

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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.

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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 are

implemented. 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

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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

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Figure 2.2.3 (a) RS232 Serial Connector Pin

Assignment.

The picture of the serial interface used is shown below:

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RS 232Serial Interface (Female Part)

RS 232 Serial Interface (Male Part)

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

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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-Bradley

distributor for more information concerning the MicroView

Operator Interface and accessories

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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:

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Figure 3.1 Physical Structure Of PLC (Micrologix 1000)

3.2 PLC‘s 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.

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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 the

controller 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.

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The hardware feature of the controller are:

Figure 3.2 Hardware Structure Of PLC

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3.3 Horizontal View Of PLC

Figure 3.3 Horizontal View Of PLC

3.4 Vertical View Of PLC

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Figure 3.4 Vertical View of PLC

3.5 Wiring Diagram Of PLC

The connection with wires as shown in the wiring of PLC

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Figure 3.5 Wiring Diagram Of PLC

3.6 Connection of Computer With PLC

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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

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3.7 DH-485 Network

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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).

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With the logic program entered into the controller, placing

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

controller’s 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 PLCBuilt-in EEPROM memory. Retains your program and all of

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

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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

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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 for

the 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.

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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

instruction’s 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

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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.

Add these actions to the functional specifications.

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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:

Program documentation. Allows you to add comments to

rungs, instructions,

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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.

3.13 System Requirements for Micrologix 1000

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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 VERSAE Series Notebook

GATEWAY 2000models 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.

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

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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

SCADA system. For power control SCADAs mostly used as

designing, integrating, installing, and maintaining automated

power systems as follows :

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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

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OTHER APPLICATIONS

1. WATER/CO2 INJECTION WELL SCADA MONITORING

SYSTEM

2. PUMPJACK/SCREWPUMP SCADA & TELEMETRY.

3. WATER DISPOSAL HIGH TANK LEVEL SHUTDOWN

SYSTEM

4. 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

9. WATER RESERVOIR PUMP CONTROL

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