scada systems for power distribution for large machines and lighting loads [part2]

SCADA systems for power distribution

School Of Engineering Page 1

CHAPTER 1

INTRODUCTION



1. INTRODUCTION

1.1 INTRODUCTION

The aim of our project is to design a system to monitor and control the

power for motors and lighting systems using SCADA (Supervisory Control and Data

Acquisition) system. SCADA systems are used to monitor and control a plant or

equipment in industries such as telecommunications, water and waste control,

energy, oil and gas refining and transportation.

The input voltage, input current, frequency, power factor to a particular load

are all directly fed to PIC (Peripheral Interface Controller) microcontroller measured

by suitable step down voltage and current transformers. The PIC is programmed to

calculate the above mentioned parameters. It will be interfaced with a relay to

control the load and a GSM modem . In case of an abnormal trend in any of the

parameters the system will atonce notice the engineer and turns of the load.

The power condition and controlling through the SCADA system is carried

out with the help of LAB VIEW software. LabVIEW (short for Laboratory Virtual

Instrument Engineering Workbench) is a system-design platform and development

environment for a visual programming language from National Instruments. The

labview user interface will have means of monitoring the parameters , setting the

threshold values and control the load. The interface will also be equipped to show a

histogram of the various parameters with time.

1.2 EXISTING SYSTEM

Current, Voltage, Frequency, Power factor were measured by means of

various analog devices and manual database system. Its difficult to analyse the trend

in these parameters as it has to be done manually. Remote controlling and

coordination of the machines is a tedious task.

A particular person should be near to the machine in order to monitor the

Current, Voltage, Frequency , Power factor by using different processing elements

and analog elements. The data have to be manually entered in a log book.



1.3 DRAWBACKS

Gives inaccurate production information.

Increase company downtime.

Minimum safety.

Increase the working time of human.

Careless operation may cause fault

Error margin is high.

Trend analysis is difficult

Remote control and coordination is difficult.

Maintaining database is difficult

1.4 PROPOSED SYSTEM

This project is very useful to monitor the voltage, current, frequency and power

factor of the machines . The parameters are monitored by means of a SCADA

system . The parameters are measured by a embedded system which is designed to

measure and indicate the parameters. The load potential and current are fed to the

system by means of suitable current transformers and potential transformers .

The system will also be equipped with a GSM system to alert the engineer in

an event of malfunction . The system will be interfaced with a computer by means of

a RS232 protocol . In this project we create the SCADA interface with the help of

Lab VIEW. It will also have the provision to display the histograms of various

parameters thus enabling to easily analyse the trend in variation of the parameters

1.5 ADVANTAGES

Improved accuracy in parameter measurement

Time saving

Safety increased considerably as the worker need not be close to machine

Error margin is min.

Trend analysis is an easy task

Remote control and coordination is possible.

Digital database management is simpler



CHAPTER 2

LITERATURE REVIEW



2. LITERATURE REVIEW

Company Overview

2.1 ABOUT BHEL:

BHEL is an integrated power plant equipment manufacturer and one of the

largest engineering and manufacturing companies in India in terms of turnover. It

was established in 1964, ushering in the indigenous Heavy Electrical Equipment

industry in India - a dream that has been more than realized with a well-recognized

track record of performance. The company has been earning profits continuously

since 1971-72 and paying dividends since 1976-77.

BHEL is engaged in the design, engineering, manufacture, construction,

testing, commissioning and servicing of a wide range of products and services for the

core sectors of the economy, viz. Power, Transmission, Industry, Transportation

(Railway), Renewable Energy, Oil & Gas and Defence. BHEL have 16

manufacturing divisions, two repair units, four regional offices, eight service centres

and 15 regional centres and currently operate at more than 150 project sites across

India and abroad. BHEL research and development (R&D) efforts are aimed not

only at improving the performance and efficiency of BHEL existing products, but

also at using state-of-the-art technologies and processes to develop new products.

The high level of quality & reliability of BHEL products is due to adherence

to international standards by acquiring and adapting some of the best technologies

from leading companies in the world including General Electric Company, Alstom

SA, Siemens AG and Mitsubishi Heavy Industries Ltd., together with technologies

developed in BHEL own R&D centres.

Most of BHEL manufacturing units and other entities have been accredited to

Quality Management Systems (ISO 9001:2008), Environmental Management

Systems (ISO 14001:2004) and Occupational Health & Safety Management Systems

(OHSAS 18001:2007).



BHEL have a share of 57% in Indias total installed generating capacity

contributing 69% (approx.) to the total power generated from utility sets (excluding

non-conventional capacity) as of March 31, 2013.

BHEL have been exporting power and industry segment products and

services for over 40 years. BHELs global references are spread across over 75

countries. The cumulative overseas installed capacity of BHEL manufactured power

plants exceeds 9,000 MW across 21 countries including Malaysia, Oman, Iraq, the

UAE, Bhutan, Egypt and New Zealand. BHEL physical exports range from turnkey

projects to after sales services.

2.2 BHEL TRICHY:

BHELs Tiruchirapalli complex is Indias largest manufacturer of boilers

and auxiliaries providing total boiler land solution for Utility, Industrial, Captive

power and Heat Recovery applications.

The plant achieved its full annual capacity to design manufacture and supply

high pressure boiler equipment up to 4000MW in 1984 with boiler unit ratings up to

500MW.

BHEL, trichy has over the years seen formidable growth in capacity,

capability, turnover and profitability. Product diversification has resulted in the

development of new products enabling BHEL to absorb morden technologies. Such

innovations result in continuous updating of manufacturing facilities to serve the

customers in a more comprehensive way and for improving quality and productivity.

THE BHEL TIRUCHIRAPALLI COMPLEX COMPRISES FIVE

UNITS:

High Pressure Boiler plant (HPBP) Trichy

Seamless steel Plant (SSTP) Trichy



Boiler Auxiliaries Plant (BAP) Ranipet

Piping Center (PC) Chennai

Industrial Valves Plant (IVP) Govindwal.

POWER CAPABILITY:

BHEL has supplied boilers and auxiliaries accounting for nearly 70% of

the installed thermal power generation capacity in India. BHEL has successfully

executed boiler projects in Malaysia and the Middle East and continues to secure

repeat orders from overseas customers for servicing and renovation of boilers.

For power generation application, BHEL Designs, Engineers,

Manufactures, Suppliers, Erects and Commissions boilers of any rating upward of 30

MW.

For higher capacities, BHEL also offers customers the option of once

through type steam generators in addition to conventional natural and controlled

circulation types.BHEL utility boilers account for over 65% of the total installed

thermal power generation capacity in India.

BHEL supplies steam generators rating up to 450 ton/hr, for industrial

application to suit the requirements of industries viz. Fertilizers, Petro chemical,

refinery, steel, paper and other process industries.

Boilers of various types are supplied including vertical package (Oil/Gas

Fixed), Vertical units (Oil/Gas/Coal fixed), fluidized bed combustion (Coal and

other solid fuels), Chemicals recovery, Waste of heat recovery , Stoker fixed

chemical recovery boilers of capacity ranging from 100 to 1350 ton/day of dry solids

are manufactured for the paper and pulp industry.



2.3ABOUT BUILDING 50:

TUBULAR PRODUCTION SHOP:

Building 50 is to produce the tubular products. Ti consists of machines like

Bending machine.

Tig and mig welding machine.

Induction pressure machine.

Resistance and flash bed welding machine.

Panel processing machine.

Stud welding machine.

Continuous discharge furnace.

BAY 1- Heat recovery stream generator module & water wall panel.

BAY 2- Water wall panel.

BAY 3- Re-heater coils & super heater coils.

BAY 4- Low temperature super heater coils.

BAY 5- Flat thin welding panels.

BAY 6- Heat temperature shop.

BAY 7- Low temperature super heater coils.

BAY 8- Economizer coils.

BAY 9- Radiant roof panel.

BAY A- tube preparation.

BAY B- Shipping.

TUBULAR PRODUCTION:

In tubular production building tubes are brought as raw materials then, they

are made to prepare. The tubes are first subjected to end cutting process. Here the

tube ends are cut to correct size & then send to end preparation process.

In end preparation the cut end of the tubes are chambered deals with tapering the

tube end form. This chambered ends are bored slightly to make it easy to be welded



with another tube. Other than these three basic process like cleaning for removing

rust & painting tubes for further protection are done to make the tubes ready to build

boiler protection.

MAJOR ACTIVITIES:

Erection & commissioning of all new machines in short period.

In house designing fabrication & erection of tubes & coil handling

system.

System improvement to enhance productivity.

LPG convertion of producer gas furnace.

Indigenous development of machine.



CHAPTER 3

PROJECT DETAILS



3.PROJECT DETAILS

3.1 SYSTEM SPECIFICATION

3.1.1 HARDWARE REQUIREMENTS:

Power supply:

230-12v transformer

bridge rectifier

capacitor

7805 IC

Micro controller(PIC16F877A)

Voltage measurement:

Voltage transformer

Bridge rectifier

Capacitor

Resistor

Current measurement:

Current transformer

Bridge rectifier

Capacitor

Resistor

Power factor measurement:



Voltage transformer

Current transformer

Resistor

LM358

Switch

Relay

Diode

Transistor

16X2 Lcd display

LED

3.1.2 SOFTWARE REQUIREMENTS:

LABVIEW [ National Instruments]

MPLab

Proteus [ISIS]

PIC programmer



3.2 BLOCK DIAGRAM

Fig 1 : Block Diagram

BLOCK DIAGRAM DESCRIPTION

Potential Transformer

Potential transformers are used in usually in industrial and power plant

settings to reduce the AC voltage of a power line to a lower value (typically 120 or

70 volts full scale) for instrumentation purposes. They are low power, have accurate

voltage ratios and good galvanic isolation to isolate the instrumentation (and the

operators) from dangerous voltages and power. In this system the input of the PIC

microcontroller can withstand only upto 5 V. The load voltage is stepped down by



means of a PT and is fed to a precision rectifier and to the ZCD circuits for the

measurement of Voltage and Power Factor and Frequency.

Current Transformer

Current transformers are used to scale a large AC current which can be 10s of

thousands of amps or more to be measured to a lower value, typically 1 or 5

Amperes that does not require heavy wires to carry the full current flow to be

measured into the instrumentation. They are low power, do not disturb the current to

be measured, have accurate current ratios, and like potential transformers, good

galvanic isolation to isolate the instrumentation (and the operators) from dangerous

voltages and power. The current transformer steps down the current to suitable

values to be fed to the PIC. The output of the CT is fed across the Shunt resistor and

is also fed to the ZCD for measuring the load Current and Power factor.

Precision Rectifier

The precision rectifier, also known as a super diode, is a configuration obtained with

an operational amplifier in order to have a circuit behave like an

ideal diode and rectifier. It is useful for high-precision signal processing. Rectifier

circuits are used in the design of power supply circuits. In such applications, the

voltage being rectified are usually much greater than the diode voltage drop,

rendering the exact value of the diode drop unimportant to the proper operation of

the rectifier. The stepped down load output from the Potential Transformer is fed to

the Precision rectifier where its rectified to +6V . This is further fed across a variable

voltage divider circuit from which it is fed to the PIC. Voltage is calculated taking

the ratios of the divider and PT into consideration . The voltage divider circuit is

employed as the maximum input that can be given to a PIC input is +5V .



Shunt Resistor

A shunt resistor is a precision device used to measure current in an electrical circuit.

Also known as a current shunt or an ammeter shunt, it works by measuring the

voltage drop across a known resistance. Ohms law states that V = I x R, or solving

for I, I = V / R, where I is current, V is voltage, and R is resistance. If the resistance

is known and the voltage drop is measured, then the current can be determined.

Shunt resistors are used to measure currents that would potentially damage a

device. This could be a result of the magnitude of the current passing through the

circuit or the possibility of current spikes. They usually have a small, well-defined

resistance so as not to affect the current they are measuring. A shunt resistor

typically looks different from a normal resistor, having two large terminals with one

or more strips of metal connecting them. The resistance of a metal is inversely

proportional to its cross-sectional area, so the more strips a shunt resistor has, the

lower its resistance.

ZCD

A comparator is a circuit that accepts two voltages, V1 and V2 and outputs zero volts

if V1>V2 or outputs a positive voltage level if V2>V1. Comparators can be built

from operational amplifiers. They are basic operational amplifier circuits that

compare two voltages simultaneously and switch the output according to the

comparison. Zero crossing detection circuit is a comparator example. A zero

crossing detector literally detects the transition of a signal waveform from positive

and negative, ideally providing a narrow pulse that coincides exactly with the zero

voltage condition.

Here two ZCD are used one for current and voltage . In order to measure the

power factor the time gap between two positive edges of the comparator o/ps are

measured and the power factor is calculated from it . The frequency is also measured

from any one of the comparator circuit



Logic Circuit

Logic circuit is an electric circuit whose output depends upon the input in a way that

can be expressed as a function in symbolic logic; it has one or more binary inputs

(capable of assuming either of two states, e.g., "on" or "off") and a single binary

output. Logic circuits that perform particular functions are called gates. Basic logic

circuits include the AND gate, the OR gate, and the NOT gate, which perform the

logical functions AND, OR, and NOT. Logic circuits can be built from any binary

electric or electronic devices, including switches, relays, electron tubes, solid-

state diodes, and transistors; the choice depends upon the application and design

requirements. Modern technology has produced integrated logic circuits, modules

that perform complex logical functions. A major use of logic circuits is in electronic

digital computers.

LCD

LCD (Liquid Crystal Display) screen is an electronic display module and find a wide

range of applications. In this project we use a 16*2 LCD display. A 16x2 LCD

display is very basic module and is very commonly used in various devices and

circuits. These modules are preferred over seven segments and other multi

segment LEDs. The reasons being: LCDs are economical; easily programmable;

have no limitation of displaying special & even custom characters (unlike in seven

segments), animations and so on.

A 16x2 LCD means it can display 16 characters per line and there are 2 such

lines. In this LCD each character is displayed in 5x7 pixel matrix. This LCD has two

registers, namely, Command and Data.

The command register stores the command instructions given to the LCD. A

command is an instruction given to LCD to do a predefined task like initializing it,

clearing its screen, setting the cursor position, controlling display etc. The data

register stores the data to be displayed on the LCD.

Here the LCD is used to display the various parameters that is Voltage ,

Current , Power Factor and Frequency.



PIC MICROCONTROLLER

PIC is a family of modified Harvard architecture microcontrollers made

by Microchip Technology, derived from the PIC1650

originally developed

by General Instrument's Microelectronics Division. The name PIC initially referred

to Peripheral Interface Controller The first parts of the family were available in

1976; by 2013 the company had shipped more than twelve billion individual parts,

used in a wide variety of embedded systems.

Early models of PIC had read-only memory (ROM) or field-programmable

EPROM for program storage, some with provision for erasing memory. All current

models use Flash memory for program storage, and newer models allow the PIC to

reprogram itself. Program memory and data memory are separated. Data memory is

8-bit, 16-bit and in latest models, 32-bit wide. Program instructions vary in bit-count

by family of PIC, and may be 12, 14, 16, or 24 bits long. The instruction set also

varies by model, with more powerful chips adding instructions for digital signal

processing functions.

The various inputs for the parameter measurement are fed to the PIC. PIC

calculates the parameters and drives the relay and alarm circuit . The PIC is

interfaced to a computer using RS232 protocol

DRIVER CIRCUIT

In electronics,a driver is an electrical circuit or other electronic component used to

control another circuit or component, such as a high-power transistor, liquid crystal

display (LCD), and numerous others.

They are usually used to regulate current flowing through a circuit or is used

to control the other factors such as other components, some devices in the circuit.

The term is often used, for example, for a specialized integrated circuit that controls

high-power switches in switched-mode power converters. An amplifier can also be

considered a driver for loudspeakers, or a constant voltage circuit that keeps an

attached component operating within a broad range of input voltages.



Transistor triggered driver circuits are used in order to activate the Relay and

Alarm . A high output from the PIC will enable the circuits to activate or drive the

Relay/Alarm system

RS 232

The RS-232 interface is the Electronic Industries Association (EIA) standard for the

interchange of serial binary data between two devices. It was initially developed by

the EIA to standardize the connection of computers with telephone line modems.

The standard allows as many as 20 signals to be defined, but gives complete freedom

to the user. Three wires are sufficient: send data, receive data, and signal ground.

The remaining lines can be hardwired on or off permanently. The signal transmission

is bipolar, requiring two voltages, from 5 to 25 volts, of opposite polarity.

An RS-232 serial port was once a standard feature of a personal computer,

used for connections to modems, printers, data storage, uninterruptible power

supplies, and other peripheral devices. However, RS-232 is hampered by low

transmission speed, large voltage swing, and large standard connectors. In modern

personal computers, USB has displaced RS-232 from most of its peripheral interface

roles.

RELAY

A relay is an electrically operated switch. Many relays use an electromagnet to

mechanically operate a switch, but other operating principles are also used, such

as solid-state relays. Relays are used where it is necessary to control a circuit by a

low-power signal (with complete electrical isolation between control and controlled

circuits), or where several circuits must be controlled by one signal. The first relays

were used in long distance telegraph circuits as amplifiers: they repeated the signal

coming in from one circuit and re-transmitted it on another circuit. Relays were used



extensively in telephone exchanges and early computers to perform logical

operations.

A type of relay that can handle the high power required to directly control an

electric motor or other loads is called a contactor. Solid-state relays control power

circuits with no moving parts, instead using a semiconductor device to perform

switching. Relays with calibrated operating characteristics and sometimes multiple

operating coils are used to protect electrical circuits from overload or faults; in

modern electric power systems these functions are performed by digital instruments

still called "protective relays".

In this system the relay isolates the load from the supply in an event of

abnormal parameter readings or if the maintenance switch is switched.

ALARM

Alarm circuit is used to notify the user of large variations in circuit parameters.

Transistor triggered buzzer circuit is employed. On event of a variation in parameter

an ouput from a pin of pic will trigger the transistor causing the buzzer to activate.



3.3 CIRCUIT DIAGRAM AND EXPLANATION

3.3.1 Complete Circuit

Fig 2 : Complete Circuit Diagram



3.3.2 Voltage Measurement Circuit

Fig 3 : Voltage Measurement Circuit

The circuit is designed to monitor the supply voltage. Supply voltage that has to be

given is stepped down by the potential transformer which is rectified by the precision

rectifier. The precision rectifier is a configuration obtained with an operational

amplifier in order to have a circuit behaving like an ideal diode or rectifier.

The full wave rectifier is the combination of half wave rectifier and a

summing amplifier. When the input voltage is negative, the diode is reverse biased ,

thus it works like an open circuit. There will be no current flow through the load and

hence the output voltage will be zero. When the input is positive , it is amplified ny

the operational amplifier which makes the diode forward biased. Current will flow in

the load and because of the feedback circuit the output voltage is equal to the input.

When the input voltage is greater than zero, the diode D2 is ON and D1 is

OFF, hence the output is zero. When the input voltage is less than zero, D2 is OFF

and D1 is ON, and the output will be similar to the input but with an amplification of

R2/R1. The full wave rectifier working depends on the fact that both the half wave

rectifier and the summing amplifier are precision circuits. It operates by producing

an inverted half wave rectified signal and then adding the signal at double amplitude



to the original signal in the summing amplifier. The result is a reversal of the

selected polarity of the input signal.

Then the output of the rectifier is adjusted to 0-5v with the help of a variable resistor

VR1.

The input is given to the ADC module where it is converted on the basis of

the calculated ratios of transformer and rectifier circuit.

3.3.3 Current Measurement Circuit

Fig 4 : Current Measurement Circuit

This circuit is designed to monitor the supply current. The supply current that

has to be monitored is stepped down by the current transformer. The step down

current is converted to the required value by the help of a shunt resistor. Then the

converted voltage is rectified by the precision rectifier. The precision rectifier is a

configuration obtained with a operational amplifier in order to have a circuit

behaving like an ideal diode or rectifier.

The full wave rectifier combination of half wave precision rectifier and

summing amplifier. When the input voltage is negative, there is a negative voltage

on the diode 2, hence it works as an open circuit. There will be no current through



the load and therefore the output voltage is zero. When the input is positive it is

amplified the operational amplifier and it turns the diode ON. There is current in the

load and because of the feedback circuit , the output voltage will be equal to input

voltage.

In this case , when the input is greater than zero D2 is ON and D1 is OFF,

hence the output will be zero. When the input is less than zero , D2 iss OFF and D1

is ON and output is like the input but with an amplification of R2/R1. The full wave

rectifier working depends on the fact that both the half wave rectifier and the

summing amplifier are precision circuits. It operates by producing an inverted half

wave rectified signal and adding that signal at double amplitude to the original signal

in the summing amplifier. The result is reversal of the selected polarity of the input

signal.

The potential across the Shunt resistor is fed to the PIC which is

measured and current is calculated from the potential.

3.3.4 Power factor and Frequency Measurement Circuit

Fig 5 : Power factor and Frequency Measurement Circuit



This circuit is designed to find the power factor in the power line. The power line

voltage and current is monitored through the potential and current transformers

respectively.

The potential transformer is used to step down the main supply voltage to the low

voltage level. The voltage level is stepped down from 230 voltage ac to 6v ac. A zero

crossing detector is used as analog circuit to achieve the converting process of the

current and voltage signals. the outputs of the current and voltage transformers are

connected to numbered pins 2 and 6 of

LM358, respectively. When AC signal is applied to LM358, the output of LM358 is

1 as logically (5 Volt) while signal is crossing from the zero point. If the AC signal

is different from zero, the output is 0 (0 Volt). The input and output signals of

LM358 are given in Fig.

Fig 6 : LM358 Input/Output waveform

There are two inputs and outputs of LM358. One of them is used for the current

signal. The other one is used for the voltage signal. The current and voltage signals

are taken the same phase for measuring the power factor.The

current and voltage signals taken from the load are adapted into LM358 using

current and voltage transformers The logical voltage and current signals are inserted

pins RA2and RA3 of PIC16F877. TIMER0 of PIC16F877 is worked when the

voltage signal is passing from zero point.TIMER0 is stopped when current signal is

passing from zero point. TIMER0 is a special storage at the 01h address of RAM. It

is possible to start counting from 00h address or any wanted number and to make



zero of its content. The logic and algorithm of the measurement is depicted in the

below figure.

Fig 7 : Powerfactor program flow chart



3.3.5 Frequency Measurement

TIMER0 is stopped when current signal is passing from zero point. TIMER0 is a

special storage at the 01h address of RAM. It is possible to start counting from 00h

address or any wanted number and to make zero of its content. The counter is

verified at the end of 60 seconds and the frequency is identified on the basis of

counter value. An output from one of the LM358 ZCD is fed to RC0 from which the

frequency is measured.

3.3.6 GSM interface Circuit

Fig 8 : GSM interface circuit

SIM300 GSM Modem is able to take any GSM network operator SIM card and

behave

just like a mobile phone with its own unique phone number. The RS232 interface

lets modem to communicate with RS232 port of PC or compatible embedded

system circuitry. Implementation of SMS controlled devices, Auto reply; remote

control is possible via SIM300. The modem can be directly interfaced with

microcontroller. It can be used to send, receive and process SMS/ call.

The MAX232 is an IC, first created in 1987 by Maxim Integrated Products, that

converts signals from an RS-232 serial port to signals suitable for use

in TTL compatible digital logic circuits. The MAX232 is a dual driver/receiver

and typically converts the RX, TX, CTS and RTS signals. The MAX232(A) has



two receivers (converts from RS-232 to TTL voltage levels), and two drivers

(converts from TTL logic to RS-232 voltage levels). This means only two of the

RS-232 signals can be converted in each direction. Typically, a pair of a

driver/receiver of the MAX232 is used for TX and RX signals, and the second

one for CTS and RTS signals.

When any one of the parameter exhibits any abnormal variation the relay will

isolate the load and sends a message One of the parameter has exceeded the

limit to the corresponding engineer thereby helping the engineer know the

situation.

3.3.7 PC interface Circuit

Fig 9 : PC interface circuit

The MAX232 is an IC, first created in 1987 by Maxim Integrated Products, that

converts signals from an RS-232 serial port to signals suitable for use

in TTL compatible digital logic circuits. The MAX232 is a dual driver/receiver

and typically converts the RX, TX, CTS and RTS signals. The MAX232(A) has

two receivers (converts from RS-232 to TTL voltage levels), and two drivers

(converts from TTL logic to RS-232 voltage levels). This means only two of the

RS-232 signals can be converted in each direction. Typically, a pair of a



driver/receiver of the MAX232 is used for TX and RX signals, and the second

one for CTS and RTS signals.

Data is transferred across PC and embedded system via RS232 protocol . The

system is controlled and communicated by the System control user interface

program designed in LABVIEW. Utilising the user interface we can use the

computer to turn on and off the system , monitor the parameters as well present

the engineer with the histograms or variation pattern of various parameters.

3.3.8 Interfacing GSM and PC to the same PIC

Fig 10 : GSM PIC simultaneous interfacing

Since only one USART pins are available in the PIC16f877a its essential that

we employ some mechanism to connect both GSM modem and PC to the same PIC.

A relay mechanism has been employed in this project. The system remains

connected to the computer normally. On event of any abnormal parameter variation

the GSM relay actuates and GSM comes into connection with the USART pin

isolating the system for the moment and notifying the engineer. Thus we can connect

both computer and GSM modem without employing multiple Microcontrollers



.3.9 Alarm Circuit

Fig 11 : Alarm circuit

This circuit is used to control the buzzer/speaker circuit. When any one of the

parameters exceeds normal values alarm is triggered. When a high pulse is given to

the base of the transistor, it starts conducting and completes the speaker circuit

thereby causing the alarm to sound .



3.3.10 Relay Circuit

Fig 12 : Relay circuit

A relay is an electromagnetic switch which is used to switch High Voltage/Current

using Low power circuits. Relay isolates low power circuits from high power

circuits. It is activated by energizing a coil wounded on a soft iron core. A relay

should not be directly connected to a microcontroller, it needs a driving circuit. A

relay can be easily interfaced with microcontroller using a transistor as shown

below. Transistor is wired as a switch which carries the current required for

operation of the relay. When the pin of the PIC microcontroller goes high, the

transistor turns On and current flows through the relay. The diode D1 is used to

protect transistor and the microcontroller from Back EMF generated in the relays

coil. Normally 1N4148 is preferred as it is a fast switching diode having a peak

forward current of 450mA. This diode is also known as freewheeling diode.



The Relay Circuit is used to isolate the load from the supply that is turn of

the load in an event of parameter variation . When a parameter exceeds the limit the

relay is actuated thereby removing the load or turning it off.

3.3.11 Complete Working

This system is used to control the AC load using a PC and monitor its

parameters . The voltage , current , power factor and frequency parameters are

continuously monitored . The parameters are monitored in the LCD display as well

as in the computer . From the computer we are able to control the load and also view

the histogram. The relay circuit is activated when any one of the parameters is

exceeded and also the alarm is also triggered . If the maintenance switch is turned on

the relay keeps the load isolated for maintenance purpose.

3.4 USER INTERFACE

Fig 13 : User Interface



The User Interface application facilitates the communication between the user and

embedded system through Computer. The application is developed by means of

LAB VIEW software by National Instruments .

LabVIEW (short for Laboratory Virtual Instrument Engineering Workbench) is a

system-design platform and development environment for a visual programming

language from National Instruments.

The graphical language is named "G" (not to be confused with G-code).

Originally released for the Apple Macintosh in 1986, LabVIEW is commonly used

for data cquisition, instrument control, and industrial automation on a variety of

platforms including Microsoft Windows, various versions of UNIX, Linux, and Mac

OS X.

LabVIEW ties the creation of user interfaces (called front panels) into the

development cycle. LabVIEW programs/subroutines are called virtual instruments

(VIs). A key feature of LabVIEW is the extensive support for interfacing to devices

such as instruments, cameras, and other devices. Users typically interface to

hardware by either writing direct bus commands (USB, GPIB, Serial...) or using

high-level, device-specific, drivers that provide native LabVIEW function nodes for

controlling the device. National Instruments makes thousands of device drivers

available for download on the Instrument Driver Network (IDNet).

The UI developed here has the means of cotrolling (ON/OFF) the load using

the computer. The threshold values of the various parameters for a particular load

can be set from the Parameter Control section . The Indicator module displays the

real time values of the four parameters. In case of any abnormal variation in

parameters the blinkers at the right end corner will indicate which parameter has

exceeded the limits. The real time parameters are stored in a database and can be

viewed in a graphical manner on clicking the HISTOGRAM button .The UI depicted

here is the one designed for the model that is to control one AC load. It can be

modified to include all the equipments in the Bay.



3.4.1 HISTOGRAM

Histogram provides the graphical representation of the various parameters

against time. The real time parameters will be stored in computer database. On

clicking the Histogram Button in the UI a graph plotting all the parameters against

time will be shown. Histogram is very useful to analyse the trend in variation of the

parameters. Histograms are helpful in comparing the performance of load with

standard values. A typical Histogram used in the system is shown below

Fig 14 : Histogram

The real time values of the various parameters can be stored in a database and

produced later for analysis purpose . A window showing the real time values of the

different parameters of all the equipments in the bay is shown. The real time

parameters of all the equipments in Bay 50 has been depicted in the below figure .



Fig 15 : Real time data

Advantages of using Histograms :

Real time comparison of parameter variation is possible

Can easily identify the trend in parameter variation

Time based load parameter variation can be viewed



CHAPTER 4

PROJECT OUTCOME



4. PROJECT OUTCOME

An embedded system capable of monitoring the parameters of the equipments in a

factory and protecting the equipment has been developed . The system is capable of

being controlled remotely from a computer by means of UI application developed in

LAB VIEW . The connection between the measurement system and computer has

been employed by means of RS232 protocol .GSM system employed will help the

engineer notify any error at the instant . An effective system capable of monitoring

controlling the equipments in factories and notifying the engineer has been

developed

The proposed system has the following advantages

Accurate parameter measurement is possible

As all the measurements are done in real time , its time and cost effective.

The load parameters can be measured remotely , that is the worker need not

be close to the system for measurement , hence safety factor is

considerably increased

As human error probability is completely removed the margin of error in

parameter measurement is reduced

Since histograms are available time based parameter variation analysis of

AC load is possible

As Relay mechanism has been employed it protects the equipment in an

event of abnormal parameter variation.

Since digital database has been employed its management is much simpler

and can be used conveniently for analysis.

Use of GSM technology helps in notifying the engineer any abnormality in

the factory.

Following are the limitations of the project

Wired communication has been employed between remote computer and

system , any mechanical damage to the wire will shut down the system.



In order to facilitate wireless communication all the parameters for all the

equipment have to be transferred after encryption making it difficult and

costly to implement

Reliability of system is moderate due to the failure chances of the

microcontroller



CHAPTER 5

CONCLUSION



5.1 CONCLUSION

The proposed system will help in improving the overall efficiency of the

factory. Though the initial cost in setting up such a system is high the payback

period is quite low and helps in improving the output of factory. Timely maintenance

and protection of system can be ensured by employing this system. We have

proposed a brief or abstract system here.

E a c h a n d e v e r y p r o j e c t i s n e v e r c o m p l e t e a s n e w t h i n g s a r

e l e a r n e d f u r t h e r modifications can be done. The system can be further

developed to accommodate more parameters and add new facilities.

5.2 FUTURE SCOPE

The development of this project surely prompts many new areas of

investigation. This project has wide scope to implement it in any factory bays with

multiple equipments operating simultaneously. This project covers all functionalities

related load parameter analysis and control. Hence it can be implemented any-where

else after minute organization level customization

Moreover some parts of the project have remained uncompleted due to some

reasons. First of all limitations of our project, which has been discussed in previous

topic make place for future enhancements.

The project can be developed to measure more parameters such as harmonics

and so . In the proposed system the data communication between system and

computer is facilitated by RS232 protocol. It can be replaced by wireless

communication such as IR or any other encrypted protocol. In future the system may

be equipped with optoelectronic isolators thereby increasing the factor of safety and

accuracy more.



CHAPTER 6

BIBILOGRAPHY



6. BIBLIOGRAPHY

Books

Process Control Automation , Instrumentation and SCADA

Microcontroller Programming : An Introduction Syed R Rizvi

Papers

Supervisory control and data acquisition : Gaushell, D.J. ; Westin

Engineering, Inc., San Jose, CA, USA ; Darlington, H.T. Published

in: Proceedings of the IEEE (Volume:75 , Issue: 12 )

Websites

www.best-microcontroller-projects.com/pic-projects.html www.engineersgarage.com/embedded/pic-microcontroller-projects

www.embedded-lab.com

www.alldatasheets.com

www.electrofriends.com



CHAPTER 7

APPENDIX



7.1 APPLICATIONS USED

7.1.1 MPLAB

MPLAB IDE is an integrated development environment that provides

development engineers with the flexibility to develop and debug firmware for

various Microchip devices.

MPLAB IDE is a windows-based integrated development for the microchip

technology incorporated PIC microcontroller (MCU) and dsPIC digital signal

controller (DSC) families. In the MPLAB IDE, you can:

Create source code using the built-in editor.

Assemble, compile and link source code using various language tools. An

assembler, linker and librarian come with MPLAB IDE. C compilers are

available from microchip and other third party vendors.

Debug the executable logic by watching program flow with a simulator, such

as MPLAB SIM, or in real time with an emulator, such as MPLAB ICE.

Third party emulators that work with MPLAB IDE are also available.

Make timing measurements.

View variables in watch windows.

Find quick answers to questions from the MPLAB IDE on-line help.

7.1.2 PROTEUS

Proteus 7.0 is a Virtual System Modelling (VSM) that combines circuit simulation,

animated components and microprocessor models to co-simulate the complete

microcontroller based designs. This is the perfect tool for engineers to test their

microcontroller designs before constructing a physical prototype in real time. This

program allows users to interact with the design using on-screen indicators and/or

LED and LCD displays and, if attached to the PC, switches and buttons.

One of the main components of Proteus 7.0 is the Circuit Simulation -- a product that



uses a SPICE3f5 analogue simulator kernel combined with an event-driven digital

simulator that allow users to utilize any SPICE model by any manufacturer.

Proteus VSM comes with extensive debugging features, including breakpoints,

single stepping and variable display for a neat design prior to hardware prototyping.

In summary, Proteus 7.0 is the program to use when you want to simulate the

interaction between software running on a microcontroller and any analog or digital

electronic device connected to it.

7.1.3 LABVIEW

LabVIEW (short for Laboratory Virtual Instrument Engineering Workbench) is a

system-design platform and development environment for a visual programming

language from National Instruments.

The graphical language is named "G" (not to be confused with G-code). Originally

released for the Apple Macintosh in 1986, LabVIEW is commonly used for data

acquisition, instrument control, and industrial automation on a variety of platforms

including Microsoft Windows, various versions of UNIX, Linux, and Mac OS X.

The latest version of LabVIEW is LabVIEW 2014, released in August 2014.

The programming language used in LabVIEW, also referred to as G, is

a dataflow programming language. Execution is determined by the structure of a

graphical block diagram (the LabVIEW-source code) on which the programmer

connects different function-nodes by drawing wires. These wires propagate variables

and any node can execute as soon as all its input data become available. Since this

might be the case for multiple nodes simultaneously, G is inherently capable of

parallel execution. Multi-processing and multi-threading hardware is automatically

exploited by the built-in scheduler, which multiplexes multiple OS threads over the

nodes ready for execution.

LabVIEW ties the creation of user interfaces (called front panels) into the

development cycle. LabVIEW programs/subroutines are called virtual instruments

(VIs). Each VI has three components: a block diagram, a front panel and a connector



panel. The last is used to represent the VI in the block diagrams of other, calling VIs.

The front panel is built using controls and indicators. Controls are inputs they

allow a user to supply information to the VI. Indicators are outputs they indicate,

or display, the results based on the inputs given to the VI. The back panel, which is a

block diagram, contains the graphical source code. All of the objects placed on the

front panel will appear on the back panel as terminals. The back panel also contains

structures and functions which perform operations on controls and supply data to

indicators. The structures and functions are found on the Functions palette and can

be placed on the back panel. Collectively controls, indicators, structures and

functions will be referred to as nodes. Nodes are connected to one another using

wires e.g. two controls and an indicator can be wired to the addition function so

that the indicator displays the sum of the two controls. Thus a virtual instrument can

either be run as a program, with the front panel serving as a user interface, or, when

dropped as a node onto the block diagram, the front panel defines the inputs and

outputs for the given node through the connector pane. This implies each VI can be

easily tested before being embedded as a subroutine into a larger program.

The graphical approach also allows non-programmers to build programs by dragging

and dropping virtual representations of lab equipment with which they are already

familiar. The LabVIEW programming environment, with the included examples and

documentation, makes it simple to create small applications. This is a benefit on one

side, but there is also a certain danger of underestimating the expertise needed for

high-quality G programming. For complex algorithms or large-scale code, it is

important that the programmer possess an extensive knowledge of the special

LabVIEW syntax and the topology of its memory management. The most advanced

LabVIEW development systems offer the possibility of building stand-alone

applications. Furthermore, it is possible to create distributed applications, which

communicate by a client/server scheme, and are therefore easier to implement due to

the inherently parallel nature of G.

Benifits

A key feature of LabVIEW is the extensive support for interfacing to devices such as

instruments, cameras, and other devices. Users typically interface to hardware by



either writing direct bus commands (USB, GPIB, Serial...) or using high-level,

device-specific, drivers that provide native LabVIEW function nodes for controlling

the device. National Instruments makes thousands of device drivers available for

download on the Instrument Driver Network (IDNet).

Code compilation

In terms of performance, LabVIEW includes a compiler that produces native code

for the CPU platform. The graphical code is translated into executable machine code

by interpreting the syntax and by compilation. The LabVIEW syntax is strictly

enforced during the editing process and compiled into the executable machine code

when requested to run or upon saving. In the latter case, the executable and the

source code are merged into a single file. The executable runs with the help of the

LabVIEW run-time engine, which contains some precompiled code to perform

common tasks that are defined by the G language. The run-time engine reduces

compile time and also provides a consistent interface to various operating systems,

graphic systems, hardware components, etc. The run-time environment makes the

code portable across platforms. Generally, LabVIEW code can be slower than

equivalent compiled C code, although the differences often lie more with program

optimization than inherent execution speed.

Large libraries

Many libraries with a large number of functions for data acquisition, signal

generation, mathematics, statistics, signal conditioning, analysis, etc., along with

numerous graphical interface elements are provided in several LabVIEW package

options. The number of advanced mathematic blocks for functions such as

integration, filters, and other specialized capabilities usually associated with data

capture from hardware sensors is immense. In addition, LabVIEW includes a text-

based programming component called MathScript with additional functionality for

signal processing, analysis and mathematics. MathScript can be integrated with

graphical programming using "script nodes" and uses a syntax that is generally

compatible with MATLAB



Code re-use

The fully modular character of LabVIEW code allows code reuse without

modifications: as long as the data types of input and output are consistent, two

subVIs are interchangeable.

The LabVIEW Professional Development System allows creating stand-alone

executables and the resultant executable can be distributed an unlimited number of

times. The run-time engine and its libraries can be provided freely along with the

executable.

A benefit of the LabVIEW environment is the platform independent nature of the G

code, which is (with the exception of a few platform-specific functions) portable

between the different LabVIEW systems for different operating systems (Windows,

Mac OS X and Linux). National Instruments is increasingly focusing on the

capability of deploying LabVIEW code onto an increasing number of targets

including devices like Phar Lap or VxWorks OS based LabVIEW Real-Time

controllers, FPGAs, PocketPCs, PDAs, Wireless sensor network nodes, and

even Lego Mindstorms NXT.

Parallel programming

LabVIEW is an inherently concurrent language, so it is very easy to program

multiple tasks that are performed in parallel by means of multithreading. This is, for

instance, easily done by drawing two or more parallel while loops. This is a great

benefit for test system automation, where it is common practice to run processes like

test sequencing, data recording, and hardware interfacing in parallel.

Ecosystem

Due to the longevity and popularity of the LabVIEW language, and the ability for

users to extend the functionality, a large ecosystem of 3rd party add-ons has

developed through contributions from the community. This ecosystem is available

on the LabVIEW Tools Network, which is a marketplace for both free and paid

LabVIEW add-ons.



User community

There is a low-cost LabVIEW Student Edition aimed at educational institutions for

learning purposes. There is also an active community of LabVIEW users who

communicate through several e-mail groups and Internet forums.

Licensing

Building a stand-alone application with LabVIEW requires the Application Builder

component which is included with the Professional Development System but

requires a separate purchase if using the Base Package or Full Development

System.[1]

There is no LabVIEW 2011 student license for Linux.

Run-time environment

Compiled executables produced by version 6.0 and later of the Application Builder

are not truly standalone in that they also require the LabVIEW run-time engine be

installed on any target computer which runs the application.[2]

The use of standard

controls requires a run-time library for any language. All major operating systems

supply the required libraries for common languages such as C. However, the run-

time required for LabVIEW is not supplied with any operating system and has to be

specifically installed by the administrator or user. This can cause problems if an

application is distributed to a user who may be prepared to run the application but

does not have the inclination or permission to install additional files on the host

system prior to running the executable.

Race conditions and pseudo parallel execution

The G gives the impression of being a parallel language (cf VHDL) that has modules

that run in parallel, however, it is essentially implemented on a non parallel platform

without explicit race condition control. While this simplifies programming it gives a

false impression of security.

Performance

LabVIEW makes it difficult to get machine or hardware limited performance and

tends to produce applications that are significantly slower than hand coded native



languages such as C. This is especially obvious in complex applications involving

several pieces of hardware.

Light weight applications

Very small applications still have to start the runtime environment which is a large

and slow task. This makes writing and running small applications or applications that

might run in parallel on the same platform problematic and tends to restrict

LabVIEW to monolithic applications. Examples of this might be tiny programs to

grab a single value from some hardware that can be used in a scripting language - the

overheads of the runtime environment render this approach impractical with

LabVIEW.



7.2 DATA SHEETS

7.2.1 PIC16F877A MICROCONTROLLER

The microcontroller that has been used for this project is from PIC series.

PIC microcontroller is the first RISC based microcontroller fabricated in CMOS

(complementary metal oxide semiconductor) that uses separate bus for instruction

and data allowing simultaneous access of program and data memory. The main

advantage of CMOS and RISC combination is low power consumption resulting in a

very small chip size with a small pin count. The main advantage of cmos is that it

has immunity to noise than other fabrication techniques.

Various microcontrollers offer different kinds of memories. EEPROM, EPROM,

FLASH etc. are some of the memories of which FLASH is the most recently

developed. Technology that is used in PIC16F877A is flash technology, so that data

is retained even when the power is switched off. CORE FEATURES:

High-performance RISC CPU

Only 35 single word instruction to learn

All single instruction except for program branches which are two cycle

Operating speed: DC - 20 MHz clock input

DC 200 ns instruction cycle

Up to 8K x 14 words of flash program memory,

Up to 368 x 8 bytes of data memory (RAM)

Up to 256 x 8 bytes of EEPROM data memory

Pin out compatible to the PIC 16c 73/74/76/77

Interrupt capability (up to 14 internal/external)

Direct, indirect, and relative addressing modes

Watchdog timer (WDT) with its own on-chip RC oscillator for reliable

operation

Programmable code-protection

Power saving SLEEP mode



Selectable oscillator options

Low-power, high-speed CMOS EPROM/EEPROM technology

Only single 5V source needed for programming capability

In-circuit debugging via two pins

Processor read/write access to program memory

Wide operating voltage range: 2.5V to 5.5V

High sink/source current: 25mA

Low-power consumption:

< 2mA typical @ 5V, 4 MHz & 20mA typical @ 3V, 32 kHz

PERIPHERAL FEATURES:

Timer0: 8-bit timer/counter with 8-bit prescaler

Timer1: 16-bit timer/counter with prescaler, can be incremented

during Sleep via external crystal/clock

Timer2: 8-bit timer/counter with 8-bit period register, prescaler and

post scalar

Two Capture, Compare, PWM modules

- Capture is 16-bit, max. Resolution is 12.5 ns

- Compare is 16-bit, max. Resolution is 200 ns

- PWM max. Resolution is 10-bit

Synchronous Serial Port (SSP) with SPI (Master mode) and I2C

(Master/Slave)

Universal Synchronous Asynchronous Receiver Transmitter

(USART/SCI) with 9-bit address detection

Parallel Slave Port (PSP) 8 bits wide with external RD, WR and CS

controls (40/44-pin only)

Brown-out detection circuitry for Brown-out Reset (BOR)

Analog Features:

- 10-bit, up to 8-channel Analog-to-Digital Converter (A/D)

- Brown-out Reset (BOR)

Analog Comparator module with:



- Two analog comparators

- Programmable on-chip voltage reference

ARCHITECTURE OF PIC 16F877A:

The complete architecture of PIC 16f877A is shown in the figure.

Fig 16 : PIC 16f877a architecture



Fig 17 : PIN DIAGRAM OF PIC 16F877A:



PIN NUMBER DESCRIPTION:

Pin Number Description

1 MCLR/VPP

2 RA0/AN0

3 RA1/AN1

4 RA2/AN2/VREF-/CVREF

5 RA3/AN3/VREF+

6 RA4/T0CKI/C1OUT

7 RA5/AN4/SS/C2OUT

8 RE0/RD/AN5

9 RE1/WR/AN6

10 RE2/CS/AN7

11 VDD

12 VSS

13 OSC1/CLKI

14 OSC2/CLKO

15 RC0/T1OSO/T1CKI

16 RC1/T1OSI/CCP2

17 RC2/CCP1

18 RC3/SCK/SCL

19 RD0/PSP0

20 RD1/PSP1



21 RD2/PSP2

22 RD3/PSP3

23 RC4/SDI/SDA

24 RC5/SDO

25 RC6/TX/CK

26 RC7/RX/DT

27 RD4/PSP4

28 RD5/PSP5

29 RD6/PSP6

30 RD7/PSP7

31 VSS

32 VDD

33 RB0/INT

34 RB1

35 RB2

36 RB3/PGM

37 RB4

38 RB5

39 RB6/PGC

40 RB7/PGD



6.2.2 LM358

Utilizing the circuit designs perfected for recently introduced Quad

Operational Amplifiers, these dual operational amplifiers feature 1) low

power drain, 2) a common mode input voltage range extending to

ground/VEE, 3) single supply or split supply operation and 4) pinouts

compatible with the popular MC1558 dual operational amplifier. The LM158

series is equivalent to onehalf of an LM124.

These amplifiers have several distinct advantages over standard

operational amplifier types in single supply applications. They can operate at

supply voltages as low as 3.0 V or as high as 32 V, with quiescent currents

about onefifth of those associated with the MC1741 (on a per amplifier

basis). The common mode input range includes the negative supply, thereby

eliminating the necessity for external biasing components in many

applications. The output voltage range also includes the negative power

supply voltage.

Short Circuit Protected Outputs

True Differential Input Stage

Single Supply Operation: 3.0 V to 32 V

Low Input Bias Currents

Internally Compensated

Common Mode Range Extends to Negative Supply

Single and Split Supply Operation

Similar Performance to the Popular MC1558

ESD Clamps on the Inputs Increase Ruggedness of the Device without

Affecting Operation



Fig 18 : LM358 pin diagram



Fig 19 : LM358 schematic diagram

The LM258 series is made using two internally compensated, twostage operational

amplifiers. The first

stage of each consists of differential input devices Q20 and Q18 with input buffer

transistors Q21 and Q17 and the differential to single ended converter Q3 and Q4.

The first stage performs not only the first stage gain function but also performs the

level shifting and transconductance reduction functions. By reducing the

transconductance, a smaller compensation capacitor (only 5.0 pF) can be employed,

thus saving chip area. The transconductance reduction is accomplished by splitting

the collectors of Q20 and Q18. Another feature of this input stage is that the input

common mode range can include the negative supply or ground, in single supply

operation, without saturating either the input devices or the differential to single

ended converter. The second stage consists of a standard current source load

amplifier stage.

Each amplifier is biased from an internalvoltage regulator which has a low

temperature coefficient thus giving each amplifier good temperature characteristics

as well as excellent power supply rejection.



Fig 20 : LM358 charecteristics



Fig21 : LM 358 package



6.2.3 LCD DISPLAY

2 x 16 LCD DISPLAY:

Liquid crystal displays (LCDs) have materials which combine the properties

of both liquids and crystals. Rather than having a melting point, they have a

temperature range within which the molecules are almost as mobile as they would be

in a liquid, but are grouped together in an ordered form similar to a crystal.

An LCD consists of two glass panels, with the liquid crystal material sand

witched in between them. The inner surface of the glass plates are coated with

transparent electrodes which define the character, symbols or patterns to be

displayed polymeric layers are present in between the electrodes and the liquid

crystal, which makes the liquid crystal molecules to maintain a defined orientation

angle. One each polarizes are pasted outside the two glass panels. These polarizes

would rotate the light rats passing through them to a definite angle, in a particular

direction.

When the LCD is in the off state, light rays are rotated by the two polarizes

and the liquid crystal, such that the light rays come out of the LCD without any

orientation, and hence the LCD appears transparent. When sufficient voltage is

applied to the electrodes, the liquid crystal molecules would be aligned in a specific

direction. The light passing through the LCD would be rotated by the polarizes

which result in activating/highlighting the desired characters.

The LCDs are lightweight with only a few millimeters thickness. Since the

LCDs consume less power, they are compatible with low power electronic circuits

and can be powered for long durations. The LCDs dont generate light and so light

is needed to read the display. By using backlighting, reading is possible in the dark.

The LCDs have long life and a wide operating temperature range.

Changing the display size or the layout size is relatively simple which makes

the LCDs more customer friendly. The LCDs used exclusively in watches,

calculators and measuring instruments are the simple seven-segment displays, having

a limited amount of numeric data. The recent advances in technology have resulted



in better legibility, more information displaying capability and a wider temperature

range. These have resulted in the LCDs being extensively used in

telecommunications and entertainment electronics. The LCDs have even started

replacing the cathode ray tubes (CRTs) used for the display of text and graphics, and

also in small TV applications.

PIN DIAGRAM OF LCD DISPLAY:

Fig 22 : LCD pin diagram

PIN DESCRIPTION FOR LCD DISPLAY

Pin

No Function Name

1 Ground (0V) Ground

2 Supply voltage; 5V (4.7V 5.3V) Vcc

3 Contrast adjustment; through a variable resistor

VEE

4 Selects command register when low; and data register Register



when high Select

5 Low to write to the register; High to read from the register Read/write

6 Sends data to data pins when a high to low pulse is given Enable

7

8-bit data pins

DB0

8 DB1

9 DB2

10 DB3

11 DB4

12 DB5

13 DB6

14 DB7

15 Backlight VCC (5V) Led+

16 Backlight Ground (0V) Led-

LCD DISPLAY WITH PIC:



6.2.4 MAX232

MAX232 is purposed for application in high-performance information processing

systems and control devices of wide application.

Input voltage levels are compatible with standard _MOS levels.

Output voltage levels are compatible with input levels

of K-MOS, N-MOS and TTL integrated circuits.

Supply voltage : 5V

Low input current: 1.0; 0.1at _ = 25 _.

Output current 24 mA.

Latching current not less than 450 mA at _ = 25_

The transmitter outputs and receiver inputs are protected to 15kV Air

ESD.



Fig 23 : Max232 pinout diagram



7.2.4 GSM SIM 300

Product concept

Designed for global market, SIM300 is a Tri-band GSM/GPRS engine that works on

frequencies EGSM 900 MHz, DCS 1800 MHz and PCS1900 MHz. SIM300

provides GPRS multi-slot class 10 capability and support the GPRS coding schemes

CS-1, CS-2, CS-3 and CS-4.

With a tiny configuration of 40mm x 33mm x 2.85 mm , SIM300 can fit almost all

the space requirement in your application, such as Smart phone, PDA phone and

other mobile device.

The physical interface to the mobile application is made through a 60 pins board-to-

board connector, which provides all hardware interfaces between the module and

customers boards except the RF antenna interface.

The keypad and SPI LCD interface will give you the flexibility to develop

customized applications.

Two serial ports can help you easily develop your applications.

Two audio channels include two microphones inputs and two speaker

outputs. This can be easily configured by AT command.

SIM300 provide RF antenna interface with two alternatives: antenna connector and

antenna pad. The antenna connector is MURATA MM9329-2700. And customers

antenna can be soldered to the antenna pad.

The SIM300 is designed with power saving technique, the current consumption to as

low as 2.5mA in SLEEP mode.

The SIM300 is integrated with the TCP/IP protocolExtended TCP/IP AT

commands are developed for customers to use the TCP/IP protocol easily, which is

very useful for those data transfer applications.



7.3 PROGRAM CODE

#include

#include

#include

#include"pic_lcd4_msb.h"

#include"pic_adc.h"

#include"usart.h"

#define _XTAL_FREQ 4000000

int powerfactor()

{

int a=0,b=0,t=0,x=0;

float tm,pf;

TMR1L=0;

TMR1H=0;

do

{

if(RB0==1)

{

TMR1ON=1;

}

else if((RB0==0)&&(TMR1ON==1))

{

TMR1ON=0;

break;

}

}while(1);

a=((TMR1H*256)+TMR1L)*2;

TMR1L=0;

TMR1H=0;

do



{

if(RB0==1)

{

TMR1ON=1;

if(RB1==1)

{

TMR1ON=0;

break;

}

}

}while(1);

b=(TMR1H*256)+TMR1L;

tm=b/a;

pf=cos(tm*2*3.14);

x=abs(ceil(pf*100));

return(x);

}

void string(char *c)

{

while(1)

{

TXREG=*c;

while(TXIF==0);

__delay_ms(20);

c++;

if(*c=='\0')

break;

}

}

void enter()

{

TXREG=0X0D;



while(TXIF==0);

TXREG=0X0A;

while(TXIF==0);

}

void main()

{

int x=0,y=0,q=0,r=0,a=0,b=0,c=0,m=0;

TRISA=0xFF;

TRISB=0x03;

PORTB=0x00;

TRISC=0X83;

PORTC=0X00;

T1CON=0x0F;

ADCON1=0x80;

Lcd4_Init();

TMR1H=0;

TMR1L=0;

while(1)

{

RC5=0;

RC3=0;

x=Adc10_Cha(0);

y=x/2.67;

Lcd4_Command(0x01);

Lcd4_Display(0x80," voltage ",9);

Lcd4_Decimal3(0xc0,y);

Lcd4_Display(0xc3," v ",3);

__delay_ms(50);

TXREG='v';



while(TXIF==0);

TXREG=y;

while(TXIF==0);

TXREG='w';

while(TXIF==0);

a=Adc10_Cha(1);

b=a*10;

Lcd4_Command(0x01);

Lcd4_Display(0x80," current ",9);

Lcd4_Decimal2(0xc0,b);

Lcd4_Display(0xc2," A ",3);

__delay_ms(50);

TXREG='i';

while(TXIF==0);

TXREG=b;

while(TXIF==0);

TXREG='j';

while(TXIF==0);

TMR1H=0;

TMR1L=0;

__delay_ms(1000);

q=TMR1H*256;

r=q+TMR1L;

Lcd4_Command(0x01);

Lcd4_Display(0x80," frequency ",11);

Lcd4_Decimal2(0xc0,r);

Lcd4_Display(0xc2," hz ",4);

__delay_ms(50);

TXREG='f';



while(TXIF==0);

TXREG=r;

while(TXIF==0);

TXREG='g';

while(TXIF==0);

c=powerfactor();

Lcd4_Command(0x01);

Lcd4_Display(0x80," power factor ",14);

Lcd4_Decimal3(0xc0,c);

Lcd4_Display(0xc3," % ",3);

__delay_ms(50);

TXREG='p';

while(TXIF==0);

TXREG=c;

while(TXIF==0);

TXREG='q';

while(TXIF==0);

if((y>=229)||(b>=5)||(r>=50)||(RC4==1))

{

while(RC4==1);

RC5=1;

RC3=1;

string("AT");

enter();

__delay_ms(500);

string("AT+CMGF=1");

enter();

__delay_ms(500);

string("AT+CMGS=\"9809779967\"");



enter();

__delay_ms(500);

string("some parameters have exceeded the

limits\maintanence mode ");

enter();

__delay_ms(500);

TXREG=0X0D;

while(TXIF==0);

TXREG=0X1A;

while(TXIF==0);

__delay_ms(5000);

while(m==0)

{

if(RC2==1)

{

while(RC2==1);

m=1;

}

}

}

}

}



LAB VIEW Block Diagram

scada systems for power distribution for large machines and lighting loads [part2]

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