Pc to Pc Communication

8/7/2019 Pc to Pc Communication

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CHAPTER ONE

INTRODUCTION

1.1 Overview

Today computers are available in many offices and homes and therefore there is a

need to share data and programs among various computers with the advancement

of data communication facilities. The communication between computers has

increased and thus has extended the power of computer beyond the computer

room. Now a user sitting at one place can communicate with computers at any

remote sites through communication channel. Thus data transmission is the

movement of information using some standard methods. These methods include

electric signals carried along a conductor, optical signals along optical fibers and

electromagnetic signals through space. If PCs are connected through

communication channel, the data and information, computer files and any other

program can be transmitted to other computer systems within seconds. Power line

communication is a system for carrying data on a conductor which isalso used for

electric power transmission. Broadband over Power Lines (BPL) uses PLC by

sending and receiving information bearing signals over power lines to provide

access to the Internet. Electrical power is transmitted over high voltage

transmission lines, distributed over medium voltage, and used inside buildings at

lower voltages. Power line communications can be applied at each stage. Most

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PLC technologies limit themselves to one set of wires (for example, premises

wiring), but some can cross between two levels (for example, both the distribution

network and premises wiring). All power line communications systems operate by

impressing a modulated carrier signal on the wiring system. Different types of

power line communications use different frequency bands, depending on the signal

transmission characteristics of the power wiring used. Since the power wiring

system was originally intended for transmission of AC power, in conventional use,

the power wire circuits have only a limited ability to carry higher frequencies. The

propagation problem is a limiting factor for each type of power line

communications. A new discovery called E-Line that allows a single power

conductor on an overhead power line to operate as a waveguide to provide low

attenuation propagation of RF through microwave energy lines while providing

information rate of multiple Gbps is an exception to this limitation. Data rates over

a power line communication system vary widely. Low-frequency (about 100-

200 kHz) carriers impressed on high-voltage transmission lines may carry one or

two analog voice circuits, or telemetry and control circuits with an equivalent data

rate of a few hundred bits per second; however, these circuits may be many miles

long. Higher data rates generally imply shorter ranges; a local area network

operating at millions of bits per second may only cover one floor of an office

building, but eliminates installation of dedicated network cabling.





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1.2 Literature Review

PC to PC is one of the most common forms of communication that could be found

in various offices, homes, industries and companies all over the world. Several

forms of PC to PC communication exist and one form [1] is by the Ethernet where

the PCs are connected to a common Bus system and share information together,

the connection arrangement between the computers could be Star, Mesh and Tree.

Two computers can also share information through the internet [2] which is the

widest form of communication between computers all over the world through the

help of routers, switches and gateways. It is important to also know that

communication between computers could be done through wireless

communication such as the infrared, however, infrared has high frequency thus its

signals cannot penetrate through obstacles and also cannot travel for a longer

distance. Bluetooth technology could also be use as a communication medium for

computers, although it has lower frequency as compare to infrared it signals cannot

travel for longer distances [3, 4]. Wireless fidelity (Wi-Fi) is another form of

communication medium for PCs and is one of the Wireless Personal Area

Networks (WPAN). Virtual Local Area Networks (VLAN) are another form of

communication medium for computers and is known to be the efficient and

inexpensive form of communication medium for computers [5]. Communication




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through PCs could be achieved through the use of ZIGBEE (IEEE 802.15.4) which

uses low power transmitter and receivers and inexpensive hardware architecture

[6]. It could be seen that several methods are been employed as form of

communication between computers, however, there is room for exploring

inexpensive way of communication. Power line communication is known to be the

most inexpensive method of communication because the distribution or

transmission line is available in almost every part of the country [7].

1.3 Project Organization

This project, present an effective communication between the two PCs through a

communication line with the help of an embedded processor where embedded

processor is connected with a temperature sensor with the sensor output is an

analog data which is digitized with a help of an A/D converter and with help of

application software temperature data is logged into one PC and it is transmitted to

other PC through the communication line. The project is organized as follows:

chapter two deals with hardware description, chapter three deals with

microcontroller interfacing, chapter four deals with PC to PC communication using

PLC, chapter five deals with the description of the development system and finally,

chapter six deals conclusion and future works.





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CHAPTER TWO

HARDWARE DESCRIPTION

2.1 Introduction

This chapter will focus on the features microcontroller (AT89C52) such as

memory unit, serial to parallel communication unit, timer unit and further look at

microcontroller interfacing including speed sensing mechanism and H-bridge to

change the direction of rotation of the motor

2.2 Features of AT89C51 Microcontroller (Target Processor)

AT89C52 is a slightly [9] more powerful microcontroller which provides

highly flexible and cost effective solutions to many embedded control applications.

Following are the features. It has 256 bytes of internal RAM compared to 128 in

the standard 8051.It is low power; high performance CMOS 8-bit microcomputers

with 8K bytes of flash programmable and erasable read only memory

(PEROM).Fully static operation: 0 Hz to 24 MHz. It has 32 programmable I/Olines. A third 16-bit Timer/counter is present inside this microcontroller to

strengthen its operation, compared to only 2 timers in standard 8051.It has eight

interrupt sources. One more additional feature of AT89C52 is that it has 26 special

function registers, 5 more than the standard 8051.The device is manufactured using

ATMEL s high-density non volatile memory technology and is compatible with

the industry-standard 80C51 and 80C52 instruction set and pin out. The AT89C52

[9] is a low-power, high-performance CMOS 8-bit microcomputer with 8K bytes

of Flash programmable and erasable read only memory (PEROM). The on-chip

Flash allows the program memory to be reprogrammed in-system or by a

conventional nonvolatile memory programmer.





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2.3 Description to Embedded Controllers

Microcontroller, as the name suggests, are small controllers. These are like

single chip computers that are often embedded into systems to function as processing

/controllers unit. For example, a remote control may probably have microcontrollers

inside that do decoding and other controlling functions. They are also used in

automobiles, washing machines, microwave ovens, toys etc, where automation is

needed. The key feature of microcontrollers includes:

High integration of Functionality- Microcontrollers sometimes are called single chip

computers because they have on-chip memory and I/O circuitry and other circuitries

that enable them to function as small standalone computers without other supporting

circuitry.

Field Programmability, Flexibility- Microcontrollers often uses EEPROM or EPROM

as their storage device to allow field programmability so they are flexible to use. Once

the program is tested to be correct then large quantities of microcontrollers can be

programmed to be used in embedded systems.

Easy to Use - Assembly language is often used in microcontroller and since they

usually follow RISC architecture, the instruction set is small. The development package

of microcontrollers often includes an assembler ,a simulator ,a programmer to burn





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the chip and a demonstration board .Some packages include a high level language

compiler such as a C compiler and more sophisticated libraries.

2.3.1 Memory Unit

Memory is part of [10] the microcontrollers whose function is to store data. The

easiest way to explain it is to describe it as one big closet with lots of drawers. Suppose

that the drawers are marked in such a way that they cannot be confused, then their

contents will be easily accessible. It is enough to know the that all





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Fig 2.1 Memory Unit of Microcontroller

memory components are exactly like that. For a certain input, the contents of the

addressed memory location can be accessed. Two new concepts are brought to us:

addressing and memory location. Memory consists of all memory locations, and

addressing is nothing but selecting one of them. This means that when a desired




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memory location is selected, there is the need to wait for the contents of that location.

Besides reading from a memory location, memory must also provide for writing onto it.

This is done by supplying [11] an additional line called control line. This line is

designated R/W (read/write). Control line are used in the following way: if r/w=1,

reading is done, and if opposite is true then writing is done on the memory location.

Memory is the first element, and a few other operations are needed for the running of

the microcontroller.

2.3.2 Central Processing Unit

Let s add three memory locations to a specific block that will have a built in capability

to multiply, divide, subtract, and move its contents from one memory location onto

another. This is called Central Processing Unit (CPU). Its memory locations are

called registers.





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Fig 2.2 Central Processing Unit of Microcontroller

Registers are therefore memory locations whose role is to help with performing various

mathematical operations or any other operations with data wherever data can be found.

Look at the current situation. There are two independent entities (memory and CPU)

which are interconnected that enhance the exchange of data and functionality. An

example is adding the contents of two memory locations and returning the result again k

to memory will need a connection between memory and CPU. Simply stated, there

must be some way through which data moves from one block to another.

2.3.3 Input-Output Unit




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The locations just added are called ports . There are several types of ports: Input,

output or bidirectional ports. When working with ports, first of all it is necessary to

choose which port is to be worked with, and then to send data to, or take it from the

port.

Fig 2.3 Input-Output Unit of Microcontroller

When working with it the port acts like a memory location. Something is simply being

written into or read from it, and it could be noticed on the pins of the microcontroller.





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2.3.4 Serial Communication

Beside stated [9] above we ve added to the already existing unit the possibility of

communication with an outside world. However, this way of communicating has

drawbacks. One of the basic drawbacks is the number of lines which need to be used in

order to transfer data. What if it is being transferred to a distance of several kilometers?

The number of lines time s numbers of kilometers doesn t promise the economy of the

project. This means that the number of lines must be reduced in a manner that will

not lessen its functionality. Suppose we are working with three lines only, and that one

line is used for sending data ,other for receiving, and the third one is used as a reference

line for both the input and output side. In order for this to work, there is the need to set

the rules for the exchange of data. These rules are called protocol. Protocol is, therefor,

defined in advance so that there wouldn t be any misunderstanding between the sides

that are communicating with each other. The logical unit 1 is set up on the

transmitting line until transfer begins. Once the transfer starts, the transmission line is

lowered to logical 0 for a period of time, designated T, so the receiving side will

know that it is receiving data, and so it[10] will activate its mechanism for reception.

Returning to the transmission side and start putting logic zeros and ones in the

transmitter line in the order of a bit of the lowest value to a bit of the highest value. Let

each bit stay on line for a time period T, and in the end, or after the 8th

bit bring the








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logical unit 1 back on the line which will mark the end of the transmission of one

data. This protocol just described is called, in professional literature, NRZ (Non-Return

to Zero).

Fig 2.4 Serial Communication

As there are separate lines for receiving and sending, it is possible to receive and send

data at the same time. The so called full-duplex mode blocks which enables this way of





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communication is called a serial communication block. Unlike the parallel transmission,

data moves here bit by bit, or in a series of bits from which the term serial

communication is derived. After the reception of data, the need to read it from the

receiving location and [11] store it in memory as opposed to sending where the process

is reversed. Data goes from memory through the buys to the sending location, and then

to the receiving unit according to the protocol

2.3.5 Timer Unit

After the explanation of serial communication explained, it is clear that data can be

received, sent and processed data serially.

Fig 2.5 Timer

However, in order to utilize it in industry a few additionally blocks are needed. One of

these is the timer block which is significant to us because it gives information about

time, duration, protocol etc. The basic unit of the timer is a free-run counter which is in

fact a register whose numeric value increments by one in even intervals, so that by





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taking its value during periods T1 and T2 and on the basis of their difference the time

lapsed can be determined . This is a very important part of the microcontroller whose

understanding requires timing





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CHAPTER THREE

MICROCONTROLLER INTERFACING

3.1 Introduction

This Chapter will focus on the microcontroller interfacing devices such as

Analogue to Digital Convertor (ADC)

3.2 Description of ADC0804

The ability to convert analog signals to digital and vice-versa is very important in

signal processing. The objective of an A/D converter is to determine the output

digital word corresponding to an analog input signal. The Datasheet for

ADC0804LCN shows the pin out and a typical application schematic. The A/D

converter operates on the successive approximation principle. Analog switches

are closed sequentially by successive-approximation logic until the analog

differential input voltage [Vin(+) - Vin(-)] matches a voltage derived from a tapped

resistor string across the reference voltage. The normal operation proceeds as

follows. On the high-to-low transition of the WR input, the internal SAR latches

and the shift-register stages are reset, and the INTR output will be set high. As long

as the CS input and WR input remain low, the A/D will remain in a reset state.

Conversion will start from 1 to 8 clock periods after at least one of these inputs

makes a low-to-high transition. After the requisite number of clock pulses to





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complete the conversion, the INTR pin will make a high-to-low transition. Easy

interface to all microprocessors, or operates "stand alone". It has the following

features: Differential analog voltage inputs, Logic inputs and outputs meet both

MOS and TTL voltage level specifications, Works with 2.5V (LM336) voltage

reference, On-chip clock generator, 0V to 5V analog input voltage range with

single 5V supply, No zero adjust required, 0.3[Prime] standard width 20-pin DIP

package

Figure.3.1.ADC Interfacing

As shown in the typical circuit, ADC0804 can be interfaced with any

microcontroller. A minimum of 11 pins are needed to interface ADC0804, eight

for data pins and 3 for control pins. As shown in the typical circuit the chip select

pin can be made low if the microcontroller port is not being used for any

other peripheral (multiplexing).





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The ADC0804 IC is an 8-bit parallel ADC in the family of the ADC0800 series

from National Semiconductor. It work with +5 volts and has a resolution of 8 bits.

In the ADC0804, the conversion time varies depending on the clocking signals

applied to the CLK IN pin, but make sure it cannot be faster than 110us.

CS = Chip select is an active low input used to ACTIVATE the ADC0804 chip. To

access the ADC0804, this pin must be LOW

RD = The ADC converts the analog input to its binary equivalent and holds it in an

internal register. RD is used to get the converted data out of the ADC0804 chip.

When CS = 0, if H-to-L pulse is applied to the RD pin, the 8-bit digital output

shows up at the D0-D7 data pins. RD also known as output enables (OE)

WR = this is an active low input used to inform the ADC0804 to start the

conversion process. If CS = 0 when WR makes a low-to-high transition, the

ADC0804 start converting the analog input value of Vin to an 8-bit digital number.

When the data conversion is completed, the INTR pin is forced low by the

ADC0804

INTR = this is an output pin and is active low. It is a normally high pin and when

the conversion is finished, it goes low to signal the CPU that the converted data is

ready to be picked up. After INTR goes low, we make CS = 0 and send a high-to-

low pulse to the RD pin to get data out of the ADC0804 chip. CLK IN and CLK

R : CLK IN is an input pin connected to an external clock source when an external

clock is used for timing. However, the ADC chip has an internal clock generator.

To use the internal clock generator or known as self clocking of ADC chip, the

CLK IN and CLK R pins are connected to a capacitor and a resistor. In that case







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the clock frequency is determined by the equation: f = 1/1.1 RC. Typical value are

R = 1 0 kohm and C = 150 pF. Substituting in the equation we will get the value of

f = 606 kHz. Vin(+) and Vin(-): These are the differential analog inputs where Vin

= Vin(+) - Vin(-). Often the pin Vin(-) is connected to ground and the Vin(+) pin is

used as the analog input to be converted to digital. Vcc = this is the +5 volt power

supply. It is used as a reference voltage when the Vref/2 input is not connected.

3.3 General Description of LM35 Temperature Sensor

The LM35 series are precision integrated-circuit temperature sensors, whose

output voltage is linearly proportional to the Celsius (Centigrade) temperature. The

LM35 thus has an advantage over linear temperature sensors calibrated in ° Kelvin,

as the user is not required to subtract a large constant voltage from its output to

obtain convenient Centigrade scaling. The LM35 does not require any external

calibration or trimming to provide typical accuracies of ±1 4°C at room

temperature and ±3 4°C over a full 55 to +150°C temperature range. Low cost is

assured by trimming and calibration at the wafer level. The LM35 s low output

impedance, linear output, and precise inherent calibration make interfacing to

readout or control circuitry especially easy. It can be used with single power

supplies, or with plus and minus supplies. As it draws only 60 A from its supply,

it has very low self-heating, less than 0.1°C in still air. The LM35 is rated to

operate over a 55° to +150°C temperature range, while the LM35C is rated for a





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40° to +110°C range ( 10° with improved accuracy). The LM35 series is

available packaged in hermetic TO-46 transistor packages, while the LM35C,

LM35CA, and LM35D are also available in the plastic TO-92 transistor package.

The LM35D is also available in an 8-lead surface mount small outline package and

a plastic TO-220 package . It is calibrated directly in ° Celsius (Centigrade) ,

Linear + 10.0 mV/°C scale factor, 0.5°C accuracy guaranteeable (at +25°C), Rated

for full 55° to +150°C range, Suitable for remote applications, Low cost due to

wafer-level trimming, Operates from 4 to 30 volts, Less than 60 A current drain





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Fig: 3.2 Temperature Sensor




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Fig: 3.3 Temperature to Digital Converter

3.4 NETWORK INTERFACE CARD:

A network card, network adapter or NIC (network interface card) is a piece of

computer hardware designed to allow computers to communicate over a computer

network. It is both an OSI layer 1 (physical layer) and layer 2 (data link layer)

device, as it provides physical access to a networking medium and provides a low-

level addressing system through the use of MAC addresses. It allows users to

connect to each other either by using cables or wirelessly. Although other network

technologies exist, Ethernet has achieved near-ubiquity since the mid-1990s. Every

Ethernet network card has a unique 48-bit serial number called a MAC address,

which is stored in ROM carried on the card. Every computer on an Ethernet




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network must have a card with a unique MAC address. No two cards ever

manufactured share the same address. This is accomplished by the Institute of

Electrical and Electronics Engineers (IEEE), which is responsible for assigning

unique MAC addresses to the vendors of network interface controllers.

Whereas network cards used to be expansion cards that plug into a computer bus,

the low cost and ubiquity of the Ethernet standard means that most newer

computers have a network interface built into the motherboard. These

motherboards either have Ethernet capabilities integrated into the motherboard

chipset, or implemented via a low cost dedicated Ethernet chip, connected through

the PCI (or the newer PCI express bus). A separate network card is not required

unless multiple interfaces are needed or some other type of network is used. Newer

motherboards may even have dual network (Ethernet) interfaces built-in.

The card implements the electronic circuitry required to communicate using a

specific physical layer and data link layer standard such as Ethernet or token ring.

This provides a base for a full network protocol stack, allowing communication

among small groups of computers on the same LAN and large-scale network

communications through routable protocols, such as IP. There are four techniques

used to transfer data, the NIC may use one or more of these techniques.





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· Polling is where the microprocessor examines the status of the peripheral

under program control.

· Programmed I/O is where the microprocessor alerts the designated

peripheral by applying its address to the system's address bus.

· Interrupt-driven I/O is where the peripheral alerts the microprocessor that it's

ready to transfer data.

· DMA is where the intelligent peripheral assumes control of the system bus

to access memory directly. This removes load from the CPU but requires a

separate processor on the card.

A network card typically has a twisted pair, BNC, or AUI socket where the

network cable is connected, and a few LEDs to inform the user of whether the

network is active, and whether or not there is data being transmitted on it. The

Network Cards are typically available in 10/100/1000 Mbit/s(Mbit/s). This means

they can support a transfer rate of 10 or 100 or 1000 Megabits per second.

A network interface card is used to connect a computer to an Ethernet network.

The card (shown in the figure below) provides an interface to the media. This may

be either using an external transceiver (as shown) or through an internal integrated

transceiver mounted on the network interface card PCB. The card usually also

contains the protocol control firmware and Ethernet Controller needed to support

the Medium Access Control (MAC) data link protocol used by Ethernet.







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Fig: 3.4 Network Interface Card

Network Interface Card for connection of a computer to an Ethernet Network

3.5 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. Also on a

number of Telebit modem models the secondary channel is present. It can be used

to query the modem status while the modem is on-line and busy communicating.




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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.

Fig.3.5 RS232 DB9 pinout

The pinout 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





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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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CHAPTER FOUR

PC TO PC COMMUNICATION USING PLC

4.1 Introduction

This Chapter will concentrate on the Architecture and Operation PC to PC

communication using PLC with the application of software.

4.2 General Architecture and Operation

Fig.4.1 General Architecture of PC to PC Communication using PLC







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PLC

Fig.4.3 Flow Chart Operation PC to PC Communication using PLC

END

MICROCONTROLLER

RECIEVES DIGITAL O/P FROM

ADC

INITIALISE THE SENSOR TO

RAD TEMPERATURE

ADC CONVERTS ANALOGE O/P

TO DITAL

PC 1 RECIEVES DATA FROM

MOCROCONTROLLER

PC 2 RECIEVES DATA FROM

PC 1




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4.3 Operation of PC to PC Communication using PLC

Here the embedded processor is connected to a temperature sensor. The sensor

output is an analog data which is digitized with a help of an A/D converter. The

temperature data is logged into one PC and it is transmitted to other PC through the

communication line. Application software has been developed to enable the

process easy using high level graphical programming language Visual Basic. All

power line communication systems operate by impressing a modulated carrier

signal on the wiring system. Different types of power line communications use

different frequency bands, depending on the signal transmission characteristics of

the power wiring used. Since the power wiring system was originally intended for

transmission of AC power, in conventional use, the power wire circuits have only a

limited ability to carry higher frequencies. The propagation problem is a limiting

factor for each type of power line communications. A new discovery called E-Line

that allows a single power conductor on an overhead power line to operate as a

waveguide to provide low attenuation propagation of RF through microwave

energy lines while providing information rate of multiple Gbps is an exception to

this limitation.

Data rates over a power line communication system vary widely. Low-frequency

(about 100-200 kHz) carriers impressed on high-voltage transmission lines may





32

carry one or two analog voice circuits, or telemetry and control circuits with an

equivalent data rate of a few hundred bits per second; however, these circuits

may be many miles long. Higher data rates generally imply shorter ranges; a local

area network operating at millions of bits per second may only cover one floor of

an office building, but eliminates installation of dedicated network cabling







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converted code cannot be written directly on to the microcontroller. This means

there is the need to use a special technique to load the program into the

microcontroller. One of the methods is to use a microcontroller with a flash

memory. Flash memory is similar to erasable programmable read only memory. So

once program is written and debugged using cross compiler, we need to flash the

program on to the flash memory of the memory. Once program is flashed the

microcontroller is loaded with the hex code and it will be ready for execution

5.1.1 INTRODUCTION TO KEIL:

Keil software provides the premier 8051 development tools to industry .The keil

software comprises of different tool kits. A tool kit consist of several application

programs which can be used to create the 8051 application .When using keil

software for a project the development cycle is some what similar to a software

development project .It consist of creating source file in C or assembly language

compiling or assembling the source files, debugging error in the source file,

linking file from complier and assembler and finally building a project linking all

the files and testing the linked application.

5.1.2 FUNCTIONING OF KEIL

All files created through the micro vision integrated development environment

are passed to the C51 compiler or A51 assembler. The compiler and assembler

process the source files and create relocatable object files. Object files created by

the compiler or assembler may be used by the library manager to create a library.

A library is a specially formatted, ordered program collection of object modules

that a linker can process. When the linker processes a library, only the object

modules in the library necessary for program creation are used. Object files created





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by the compiler and assembler and library files created by the library manager are

processed by the linker to create an absolute object module. An absolute object file

or module is an object file with no reloadable code. All the code in an absolute

object file resides at fixed locations.

The absolute object file created by the linker may be used to program EPROM or

other memory devices. The absolute object module may also be used with the

dScope-51 debugger / simulator or with an in-circuit emulator. The dScope-51

source level debugger/simulator is ideally suited for fast, reliable high-level-

language program debugging. The debugger contains a high-speed simulator and a

target debugger that let can be used to simulate an entire 8051 system including

on-chip peripherals. By loading specific I/O drivers, the attributes and peripherals

of a variety of 8051 family can be stimulated. The RTX-51 real time operating

system is a multitasking kernel for the 8051 family. The RTX-51 real time kernel

simplifies the system design, programming, and debugging of complex

applications where fast reaction to time critical events are essential. The kernel is

fully integrated into the C51compiler and is easy to use. Task description tablesand operating system consistency are automatically controlled by the BL51 code

banking linker/locater.

5.1.3 DEVELOPMENT TOOLS IN KEIL

The Fig 4.1 shows the full extent of the Keil Software 8051 development tools.

The tools listed in this diagram comprise the professional developer s kit. In

addition to the professional kit, Keil Software provides a number of other tool kits

for the 8051 developer. The most capable kit is the professional developer s kit is

described as follows:





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The professional developer s k it includes everything the professional 8051

developer needs to create sophisticated embedded applications. This tool kit

includes the following components:

· C51 Optimizing C compiler,

· A51 Macro Assembler,

· BL51 Code Banking Linker/Locator,

· OC51 Banked Object file converter,

· OH51 Object-Hex converter,

· LIB51 Library Manager,

· dScope-1 Simulator/debugger,

· tScope-51 Target Debugger,

· Monitor-51 ROM Monitor and Terminal Program,

· Integrated Development Environment,

· RTX-51 Tiny Real-Time Operating System.

In addition, the professional developer s kit includes the following tools for

Windows users:

· dScope-51 Simulator/Debugger for windows,

· Micro Vision/51 Integrated Development Environment for windows.

The professional developer s kit can be configured for all 8051 derivatives. The

tools included in this kit can run any compatible computer.

5.1.4 C51 OPTIMIZING CROSS COMPILER

The C programming language is a general-purpose programming language that

provides code efficiency, elements of structured programming, and a rich set of

operators. Its generality, combined with its absence of restrictions, make C a





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convenient and effective programming solution for a wide variety of software

tasks. Many applications can be solved more easily and effectively with C than

with other more specialized languages. The Keil software C51 optimizing cross

compiler for the MS-DOS operating system is a complete implementation of the

ANSI (American National Standards Institute) standard for the C language. The

C51 compiler generates code for the 8051 microprocessor but is not a universal C

compiler adapted for the 8051 target. It is a ground-up implementation dedicated to

generating extremely fast and compact code for the 8051 microprocessor. For most

8051 applications, the C51 compiler gives software developers the flexibility of

programming in /c while matching the code efficiency and speed of assembly

language. Using a high-level language like C has many advantages over assembly

language programming. For example:

§ Knowledge of the processor instruction set is not required. A rudimentary

knowledge of the 8051 s memory architecture is desirable but not necessary.

§ Register allocation and addressing mode details are managed by the

compiler.§ The ability to combine variable selection with specific operations improves

program readability.

§ Keywords and operational functions that more nearly resemble the human

thought process can be used.

§ Program development and debugging times are dramatically reduced when

compared to assembly language programming.

§ The library files that are supplied provide many standard routines (such as

formatted output, data conversions, and floating-point arithmetic) that may

be incorporated into our application.





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§ Existing routine can be reused in new programs by utilizing modular

programming techniques available with C.

§ The C language is very portable and very popular. C compilers are available

for almost all target systems. Existing software investments can be quickly

and easily converted from or adapted to other processors or environments.

5.1.5 A51 MACRO ASSEMBLER

The A51 assembler is a macro assembler for the 8051 microcontroller family. It

translates symbolic assembly language mnemonics into relocatable object code

where the utmost speed, small code size, and hardware control are critical. The

macro facility speeds development and conserves maintenance time since common

sequences need only be developed once. The A51 assembler supports symbolic

access to all features of the 8051 architecture and is configurable for the numerous

8051 derivatives. The A51 assembler translates an assembler source file into a

relocatable object module. If the DEBUG control is used, the object file contains

full symbolic information for debugging with dScope or an in-circuit emulator. Inaddition to the object file, the A51 assembler generates a list file which may

optionally include symbol table and cross reference information. The A51

assembler is fully compatible with Intel ASM-51 source modules. The A51

assembler supports all members of the 8051 family. The special function register

(SFR) set of the 8051 is predefined. However, the NOMOD51 control lets you

override these definitions with processor-specific include files. The A51 assembler

is shipped with include files for the 8051, 8051fx, 8051GB, 8052, 80152, 80451,

80452, 80515, 80C517, 80C517A, 8x552, 8xC592, 8xCL782, 8xCL410 and

80C320 microcontrollers. You can easily create include files for other 8051 family

members.







39

5.1.6 BL51 CODE BANKING LINKER/LOCATOR

The 51 code banking linker/locator combines one or more object modules into a

single executable 8051 program. The linker also resolves external and public

references, and assigns absolute addresses to relocatable programs segments. The

BL51 code banking linker/locator processes object modules created by the keil

C51 compiler and A51 assembler and the Intel PL/M-51 compiler and ASM-51

assembler. The linker automatically selects the appropriate run-time library and

links only the library modules that are required. Normally, the BL51 code banking

linker/locator is invoked from the command line specifying the names of the object

modules to combine. The default controls for the BL51 code banking linker/locator

have been carefully chosen to accommodate most applications without the need to

specify additional directives. However, it is easy to specify custom settings for

applications.

5.1.7 OC51 BANKED OBJECT FILE CONVERTER

The OC51 banked object file converter creates absolute object modules for each

code bank in a banked object module. Banked object modules are created by the

BL51 code banking linker/locator when a bank switching application is created.

Symbolic debugging information is copied to the absolute object files and can be

used by dScope or an in-circuit emulator. The OC51 banked object file converter

may be used to create absolute object modules for the command area and for each

code bank in your banked object module. The Intel HEX files may then be

generated for each of the absolute object modules using the OH51 object-hex

converter.





40

5.1.8 OH51 OBJECT-HEX CONVETER

The OH51 object-hex converter creates Intel hex files from absolute objectmodules. Absolute object modules can be created by the BL51 code baking linker

or by the OC51 banked object file converter. Intel hex files are ASCII files that

contain a hexadecimal representation of an application. They can be easily loaded

into a device programmer for writing on Erasable programmable read only

memory.

LIB51 LIBRARY MANAGER

The LIB51 library manager allows for the creation and maintenance of library

files. A library file is a formatted collection of one or more object files. Library

files provide a convenient method of combining and referencing a large number of

object files. Libraries can be effectively used by the BL51 code banking

linker/locator. The LIB51 library manager allows for the creation of a library file,

addition or removal of object modules to or from a library file, and may be

controlled interactively or from the command line.

DSCOPE-51 FOR WINDOWS

DScope-51 is a source level debugger and simulator for programs created with the

keil C51 compiler and A51 assembler and the Intel PL/M-51 compiler and ASM-

51 assembler. Dscope-51 is a software-only product that allows for the simulation

of the features of an 8051 without actually having target hardware. Scope-51 may

be used to test and debug an embedded applications before actual 8051 hardware is

ready. Dscope-51 simulates a wide variety of 8051 peripherals including the

internal serial port, external I/O, and timers.




41

5.1.9 µVISION/51 FOR WINDOWS

Microvision/51 is an integrated software development platform that includes a full

function editor, project manager, make facility, and environment control for the

keil 8051 tools. When using a µVision/51 speeds the embedded applications

development may be enhance by providing the following:

§ Standard Windows user interface,

§ Dialog boxes for all environment and development tool settings,

§ Multiple file editing capability,

§ Full function editor with user-definable key sequences,

§ Application manager for adding external programs into the pull-down

menu,

§ Project manager for creating and maintaining projects,

§ Integrated make facility for building target programs from your

projects,

§ On-line help system.

5.2 TARGET PROCESSOR

In this project microcontroller AT89C52 (Target processor) is used to governs all

the essential process which has to be executed during acquisition.

Microcontroller, as the name suggests, are small controllers. These are like single chip

computers that are often embedded into systems to function as processing /controllers

unit. For example, a remote control may probably have microcontrollers inside that do

decoding and other controlling functions. They are also used in automobiles, washing

machines, microwave ovens, toys etc, where automation is needed. The key features

of microcontrollers include:





42

High integration of Functionality

Microcontrollers sometimes are called single chip computers because they have

on-chip memory and I/O circuitry and other circuitries that enable them to

function as small standalone computers without other supporting circuitry.

Field Programmability, Flexibility

Microcontrollers often use EEPROM or EPROM as their storage device to allow

field programmability so they are flexible to use. Once the program is tested to

be correct then large quantities of microcontrollers can be programmed to be used

in embedded systems.

Easy to Use

Assembly language is often used in microcontroller and since they usually follow

RISC architecture, the instruction set is small. The development package of

microcontrollers often includes an assembler ,a simulator ,a programmer to

burn the chip and a demonstration board .Some packages include a high level

language compiler such as a C compiler and more sophisticated libraries.

5.3 APPLICATION SOFTWARE DESCRIPTION

Application software is a computer program that functions and is operated by

means of a computer, with the purpose of supporting or improving the software

user s work. In other words, it is the subclass of computer software that employs

the capabilities of a computer directly and thoroughly to a task that the user wishes

to perform. This should be contrasted with system software (infrastructure) or

middleware (computer services/ processes integrators), which is involved in

integrating a computer s various capabilities, but typically does not directly apply





43

them in the performance of task s that benefit the user. In this context the term

application refers to both the application software and its implementation. In some

types of embedded systems, the application software and the operating system

software may be indistinguishable to the user, as in the case of software used to

control a VCR, DVD player or microwave oven.

The application software for this project has been developed from a high level

graphical programming language (visual basic).This method of implementation

gives the user a more flexibility to have hands on the system. The application

software is a virtual representation of the actual instrument and provides all

facilities for the user to control the working of the system. This technique of

operating the system (the actual instrument) is highly advantageous, as it does not

permit the actual instrument to be misused, for example, here, the minimum and

maximum ranges of the system is defined and hence prevents the user from

exceeding the limits. Thus the application software provides high security to the

actual instrument. Moreover certain graphical representation of the real time values

with high resolution can also be implemented.





44

SCREEN SHOTS





45




46

CHAPTER SIX

CONCLUSION AND FUTURE WORK

In this project PC to PC communication using PLC has been designed and

implemented successfully. Though various modes of communication are present in

this time power line communication is a more secure method of data transfer. In

real time several thousands of PC can be connected, making communication

simpler. Custom built hardware along with application software is provided to

have a real time control over the programmable hardware. It be must be noted that

the information from the microcontroller to PC 1 could be transmitted using

wireless and could be considered as future work




47

REFERENCES

[1] B. L kakrati and A. K fsator, PLC, 24th

Edition, Scand and Company,

New Delhi, 2000.

[2] J. B Gupta, Electrical Technology, 12th

Edition, S. K Kataria and Sons,

Delhi, 2003.

[3] D. G. Fink and H. W. Beaty, Standard Handbook for Electrical Engineers,

13th

Edition, McGraw Hill, Singapore, 1993.

[4] E. Frounza, Data Communcation, 7th

Edition, Addison Weseley Longman

Limited, Edinburgh Gate, England, 1995.

[5] J. O. Bird and P. J Chivers, Engineering and Physical Science Pocket Book,

Newnew 1995.

[6] H. Uppal , Electrical Power System, 3rd

Edition, New Delhi, India, 1995.

[7] R. J. Surakumar, N. P. Subramaniam, and S. Ganesan, DC Motor Control

Through Remote Embedded Linux, IEEE Transactions, vol 12-35, page 34,

Nov 2005

[8] K. S. Ravash, RF-600DC Wireless Variable Speed DC Motor Controller,

IEEE Trans.Page 65, Dec 2007.




[9] http://meseec.ce.rit.edu/eecc250-winter99/250-2-9-2000.pdf

11/10/2009

[10] http://www.mikroe.com/en/books/picbook/1_chapter.htm

13/10/2009

[11] http://www.allheadlinenews.com/articles/7012111732#ixzz0TMaQxsK

15/10/2009

[12] http://www.c++.com/en/books/picbook/1_chapter.htm

15/10/2009

[13] http://microp.ce.rit.edu/eecc250-winter99/250-2-9-2000.pdf

17/10/2009

[14] http://spsen.ce.rit.edu/eecc250-winter99/250-2-9-2000.pdf

17/10/2009

[15] http://Hbridge.ce.rit.edu/eecc250-winter99/250-2-9-2000.pdf

19/10/2009

[16] http://dcmotor.ce.rit.edu/eecc250-winter99/250-2-9-2000.pdf

19/10/2009



Pc to Pc Communication

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