transformer monitor protection

8/4/2019 Transformer Monitor Protection

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Transformer Protection From Over Load

And Monitoring of Load current in PC

ABSTRACT

The aim of the project work is to protect the distribution transformer or any other power

transformer, burning due to the overload. Normally most of the transformers are burning

because of over load; hence by incorporating monitoring and control circuits, life of the

transformer can be.

In this project we designed a system in such a way that it will monitor the load of the

transformer continuously and that information is transferred to the control room. In the mainstation these parameters are displayed on the PC monitor. In the display unit we can view the

continuous information of transformer i.e. due to what reason the transformer has been failed,

when the power is resumed etc.,. With the help of this kind of system, the maintenance staff

of the department can have a continuous vigilance over the transformer.

In this project work, for the demonstration purpose a small step-down transformer of 12V, 1

amps rating at secondary is considered and small bulbs are connected as a load. In thisproject we are using CT transformer for measuring load current. All these parameters are

converted into digital value by using ADC. If the parameters of the transformer (Current)

regain the limited range values then Transformer will automatically shutdown.

Microcontroller near the transformer section will continuously transmit all the parameters of

the transformer to PC of control room.

HARDWARE COMPONENTS:

Microcontroller

Power supply

Relay

www.final-yearprojects.co.cc | www.troubleshoot4free.com/fyp/


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Loads

ADC 0804

Current Transformer

PC

SOFTWARE TOOLS:

Keil micro vision

Embedded C

Express PCB

Applications:

This project is used for protecting Transformers in sub stations, generating

stations etc.

Used for Industrial protection

BLOCK DIAGRAM:

Microcontroller

Power supply

Transformer

CT

A

D

C

RELAY

PC

LOAD



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INDEX

CONTENTS

Abbreviations

1. Figure Locations2. Introduction to the project3. Block Diagram4. Block Diagram Description5. Schematic

6. Schematic Description7. Hardware Components

Micro controllers ADC 0804

Relay

Power Supply8. Circuit Description9. Software components

a. About Keil

b.Embedded C

10. Conclusion (or) Synopsis

11.Future Aspects

Bibliography



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Abbreviations:

ACC - Accumulator

B - B Register

PSW - Program Status Word

SP - Stack Pointer

DPTR - Data pointer

DPL - Low byte

DPH - High byte

P0 - Port 0

P1 - Port 1

P2 - Port 2

P3 - Port 3

IE - Interrupt Enable control

IP - Interrupt Priority control

TMOD - Timer/Counter Mode control

TCON - Timer/Counter control

T2CON - Timer/counter 2 control

T2MOD - Timer/counter mode2 control

TH0 - Timer/counter 0high byte

TL0 - Timer/counter 0 low byte

TH1 - Timer/counter 1 high byte


TH2 - Timer/counter 2 high byte


RCAP2H - T/C 2 capture register high byte

RCAP2L - T/C 2 capture register low byte



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SCON - Serial control

SBUF - Serial data buffer

PCON - Power control

PCB - Printed circuit Board

AGC - Automatic Gain Control

RF - Radio Frequency

HT - Holteks Company

LCD - Liquid Crystal Display

IR - Infrared Radio Frequency

INTRODUCTION:



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Examples of Embedded Systems:

Avionics, such as inertial guidance systems, flight control hardware/software and other

integrated systems in aircraft and missiles

Cellular telephones and telephone switches

Engine controllers and antilock brake controllers for automobiles

Home automation products, such as thermostats, air conditioners, sprinklers, and security

monitoring systems

Handheld calculators

Handheld computers

Household appliances, including microwave ovens, washing machines, television sets,

DVD players and recorders

Medical equipment

Personal digital assistant

Videogame consoles

Computer peripherals such as routers and printers.

Industrial controllers for remote machine operation.



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BLOCK DIAGRAM:

EXPLANATION:

Power supply:

In this system we are using 5V power supply for microcontroller of Transmitter section

as well as receiver section. We use rectifiers for converting the A.C. into D.C and a step down

transformer to step down the voltage. The full description of the Power supply section is given in this

documentation in the following sections i.e. hardware components.

Microcontroller:

In this project the microcontroller plays a major role, here micro controller scan the output ofcurrent transformer through adc and send respective signals to PC and PC displays the status of the

transformer under test in monitor..

Microcontroller

Power supply

Transformer

CT

A

D

C

RELAY

PC

LOAD



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ADC0804:

The output of the current transformer connected to adc0804. Actually current transformer is ananalog devise, so the output will be in analog form but the microcontroller not understanding the analogvalues. So, we need to convert the analog output into digital form. ADC0804 performs the conversion to

digital from analog. ADC0804 is a 8 bit converter.Relay:

It is used as electro mechanical switch.

Current transformer:

It is used to measure the load on transformer. And the output of this transformer is connected toADC. Because it is analog device and the output is in the form of analog variable. So, we need to convert

it to digital.

SCHEMATIC:



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EXPLANATION:

Aim of our project is continuously monitor of the transformer and if any load on that transformerincreases we protect that transformer. In this project we make use of PC, Micro controller, Transformerunder test and relay.

In this project current transformer acts as input. We are connecting the output of currenttransformer to 6th pin of ADC0804. The 6th pin of ADC0804 acts as analog input.

In this project PC acts as output. And PC is connected to microcontroller through RS232. We useMAX232 IC to interface RS232 to uc. The RX and TX pin means 2nd and 3rd pins of RS232 is connectedto 14 and 13th pins of MAX232. 11th and 12th pins of MAX232 is connected to 10th and 11th pins ofcontroller. 10th and 11th pins of controller are P3.0 and P3.1. This entire section acts as output and



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controller sends the signal through RS232 to PC and it will displayed on PC. We are using serialcommunication.

We use one relay to provide 230 volts for load. Relay is a electro mechanical switch.

Power supply is connected to 40th pin of the uc. 20th pin is grounded. Crystal oscillator is

connected to 18th and 19th pin of uc. Resets switch is connected to 9th pin of uc.

MICROCONTROLLER (AT89S51)

Features:

Compatible with MCS-51 Products

4K Bytes of In-System Programmable (ISP) Flash Memory

Endurance: 1000 Write/Erase Cycles

4.0V to 5.5V Operating Range

Fully Static Operation: 0 Hz to 33 MHz



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Three-level Program Memory Lock

128 x 8-bit Internal RAM

32 Programmable I/O Lines

Two 16-bit Timer/Counters

Six Interrupt Sources

Full Duplex UART Serial Channel

Low-power Idle and Power-down Modes

Interrupt Recovery from Power-down Mode

Watchdog Timer

Dual Data Pointer

Power-off Flag

Fast Programming Time

Flexible ISP Programming (Byte and Page Mode)

Description:

The AT89S51 is a low-power, high-performance CMOS 8-bit microcontroller with 4K

bytes of in-system programmable Flash memory. The device is manufactured using

Atmels high-density nonvolatile memory technology and is compatible with the

industry- standard 80C51 instruction set and pinout. The on-chip Flash allows the

program memory to be reprogrammed in-system or by a conventional nonvolatile

memory programmer. By combining a versatile 8-bit CPU with in-system

programmable Flash on a monolithic chip, the Atmel AT89S51 is a powerful

microcontroller which provides a highly-flexible and cost-effective solution to many

embedded control applications.



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The AT89S51 provides the following standard features:

4K bytes of Flash, 128 bytes of RAM, 32 I/O lines, Watchdog timer, two data

pointers, two 16-bit timer/counters, a five vector two-level interrupt architecture, a

full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the

AT89S51 is designed with static logic for operation down to zero frequency and

supports two software selectable power saving modes. The Idle Mode stops the CPU

while allowing the RAM, timer/counters, serial port, and interrupt system to continue

functioning. The Power-down mode saves the RAM contents but freezes the

oscillator, disabling all other chip functions until the next external interrupt or

hardware reset.



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Pin Description:

VCC - Supply voltage.

GND - Ground.

Port 0: Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each

pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be

used as high-impedance inputs. Port 0 can also be configured to be the multiplexed

low-order address/data bus during accesses to external program and data memory.In this mode, P0 has internal pull-ups. Port 0 also receives the code bytes during

Flash programming and outputs the code bytes during program verification.

External pull-ups are required during program verification.



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Port 1 Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1

output buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins,

they are pulled high by the internal pull-ups and can be used as inputs. As inputs,

Port 1 pins that are externally being pulled low will source current (IIL) because of

the internal pull-ups. Port 1 also receives the low-order address bytes during Flash

programming and verification.

Port 2 Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 2 output

buffers cansink/source four TTL inputs. When 1s are written to Port 2 pins, they arepulled high by the internal pull-ups and can be used as inputs. As inputs, Port 2 pins

that are externally being pulled low will source current (IIL) because of the internal

pull-ups. Port 2 emits the high-order address byte during fetches from external

program memory and during accesses to external data memory that use 16-bit

addresses (MOVX @ DPTR). In this application, Port 2 uses strong internal pull-ups

when emitting 1s. During accesses to external data memory that use 8-bit

addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special

Function Register. Port 2 also receives the high-order address bits and some control

signals during Flash programming and verification.

Port 3 Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output

buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins, they are

pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 3 pins

that are externally being pulled low will source current (IIL) because of the pull-ups.

Port 3 receives some control signals for Flash programming and verification. Port 3

also serves the functions of various special features of the AT89S51, as shown in

the following table.



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RST Reset input. A high on this pin for two machine cycles while the oscillator is

running resets the device. This pin drives High for 98 oscillator periods after the

Watchdog times out. The DISRTO bit in SFR AUXR (address 8EH) can be used todisable this feature. In the default state of bit DISRTO, the RESET HIGH out feature

is enabled.

ALE/PROG Address Latch Enable (ALE) is an output pulse for latching the low byte of

the address during accesses to external memory. This pin is also the program pulse

input (PROG) during Flash programming. In normal operation, ALE is emitted at a

constant rate of 1/6 the oscillator frequency and may be used for external timing or

clocking purposes. Note, however, that one ALE pulse is skipped during each access

to external data memory. If desired, ALE operation can be disabled by setting bit 0

of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC

instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has

no effect if the microcontroller is in external execution mode.

PSEN Program Store Enable (PSEN) is the read strobe to external program memory.

When the AT89S51 is executing code from external program memory, PSEN is

activated twice each machine cycle, except that two PSEN activations are skipped

during each access to external data memory.

EA/VPP External Access Enable. EA must be strapped to GND in order to enable the

device to fetch code from external program memory locations starting at 0000H up

to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally

latched on reset. EA should be strapped to VCC for internal program executions.



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This pin also receives the 12-volt programming enable voltage (VPP) during Flash

programming.

XTAL1 Input to the inverting oscillator amplifier and input to the internal clock

operating circuit.

XTAL2 Output from the inverting oscillator amplifier

Special Function Registers

A map of the on-chip memory area called the Special Function Register (SFR) space

is shown in Table 1.

Note that not all of the addresses are occupied, and unoccupied addresses may not

be implemented on the chip. Read accesses to these addresses will in general

return random data, and write accesses will have an indeterminate effect.



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User software should not write 1s to these unlisted locations, since they may be

used in future products to invoke new features. In that case, the reset or inactivevalues of the new bits will always be 0.

Interrupt Registers: The individual interrupt enable bits are in the IE register. Two

priorities can be set for each of the five interrupt sources in the IP register.



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Dual Data Pointer Registers: To facilitate accessing both internal and external data

memory, two banks of 16-bit Data Pointer Registers are provided: DP0 at SFR

address locations 82H- 83H and DP1 at 84H-85H. Bit DPS = 0 in SFR AUXR1 selects

DP0 and DPS = 1 selects DP1. The user should always initialize the DPS bit to the

appropriate value before accessing the respective Data Pointer Register.

Power Off Flag: The Power Off Flag (POF) is located at bit 4 (PCON.4) in the PCON

SFR. POF is set to 1 during power up. It can be set and rest under software control

and is not affected by reset.



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Memory Organization

MCS-51 devices have a separate address space for Program and Data Memory. Up

to 64K bytes each of external Program and Data Memory can be addressed.

Program Memory If the EA pin is connected to GND, all program fetches are directed

to external memory. On the AT89S51, if EA is connected to VCC, program fetches to

addresses 0000H through

FFFH are directed to internal memory and fetches to addresses 1000H throughFFFFH are directed to external memory.

Data Memory the AT89S51 implements 128 bytes of on-chip RAM. The 128 bytes

are accessible via direct and indirect addressing modes. Stack operations are

examples of indirect addressing, so the 128 bytes of data RAM are available as

stack space.

Watchdog Timer (One-time Enabled with Reset-out)

The WDT is intended as a recovery method in situations where the CPU may be

subjected to software upsets. The WDT consists of a 14-bit counter and the

Watchdog Timer Reset (WDTRST) SFR. The WDT is defaulted to disable from exiting

reset. To enable the WDT, a user must write 01EH and 0E1H in sequence to the

WDTRST register (SFR location 0A6H). When the WDT is enabled, it will increment



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every machine cycle while the oscillator is running. The WDT timeout period is

dependent on the external clock frequency. There is no way to disable the WDT

except through reset (either hardware reset or WDT overflow reset). When WDT

overflows, it will drive an output RESET HIGH pulse at the RST pin.

Using the WDT To enable the WDT, a user must write 01EH and 0E1H in sequence

to the DTRST register (SFR location 0A6H). When the WDT is enabled, the user

needs to service it by writing 01EH

and 0E1H to WDTRST to avoid a WDT overflow. The 14-bit counter overflows when it

reaches 16383 (3FFFH), and this will reset the device. When the WDT is enabled, it

will increment every machine cycle while the oscillator is running. This means the

user must reset the WDT at least every 16383 machine cycles. To reset the WDT

the user must write 01EH and 0E1H to WDTRST. WDTRST is a write-only register.

The WDT counter cannot be read or written. When WDT overflows, it will generate

an output RESET pulse at the RST pin. The RESET pulse duration is 98xTOSC, where

TOSC=1/FOSC. To make the best use of the WDT, it should be serviced in those

sections of code that will periodically be executed within the time required to

prevent a WDT reset.

WDT During Power-down and Idle

In Power-down mode the oscillator stops, which means the WDT also stops. While in

Powerdown

mode, the user does not need to service the WDT. There are two methods of exiting

Power-down mode: by a hardware reset or via a level-activated external interrupt,

which is enabled prior to entering Power-down mode. When Power-down is exited

with hardware reset, servicing the WDT should occur as it normally does whenever

the AT89S51 is reset. Exiting Power-down with an interrupt is significantly different.

The interrupt is held low long enough for the oscillator to stabilize. When theinterrupt is brought high, the interrupt is serviced. To prevent the WDT from

resetting the device while the interrupt pin is held low, the WDT is not started until

the interrupt is pulled high. It is suggested that the WDT be reset during the

interrupt service for the interrupt used to exit Power-down mode. To ensure that the

WDT does not overflow within a few states of exiting Power-down, it is best to reset



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the WDT just before entering Power-down mode. Before going into the IDLE mode,

the WDIDLE bit in SFR AUXR is used to determine whether the WDT continues to

count if enabled. The WDT keeps counting during IDLE (WDIDLE bit =

0) as the default state. To prevent the WDT from resetting the AT89S51 while in

IDLE mode, the user should always set up a timer that will periodically exit IDLE,

service the WDT, and reenter IDLE mode.

With WDIDLE bit enabled, the WDT will stop to count in IDLE mode and resumes the

count upon exit from IDLE.

UART The UART in the AT89S51 operates the same way as the UART in the

AT89C51.

Timer 0 and 1 Timer 0 and Timer 1 in the AT89S51 operate the same way as Timer

0 and Timer 1 in the AT89C51.

Interrupts The AT89S51 has a total of five interrupt vectors: two external interrupts

(INT0 and INT1), two timer interrupts (Timers 0 and 1), and the serial port interrupt.

These interrupts are all shown in

Figure 1. Each of these interrupt sources can be individually enabled or disabled by

setting or clearing a

bit in Special Function Register IE. IE also contains a global disable bit, EA, which

disables all interrupts at once. Note that Table 4 shows that bit position IE.6 is

unimplemented. In the AT89S51, bit position IE.5 is also unimplemented. User

software should not write 1s to these bit positions, since they may be used in future

AT89 products. The Timer 0 and Timer 1 flags, TF0 and TF1, are set at S5P2 of the

cycle in which the timers overflow. The values are then polled by the circuitry in the

next cycle.



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Oscillator Characteristics

XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier

that can be configured for use as an on-chip oscillator, as shown in Figure 2. Either

a quartz crystal or ceramic resonator may be used. To drive the device from an

external clock source, XTAL2 should be left unconnected while XTAL1 is driven, as

shown in Figure 3. There are no requirements on the duty cycle of the external



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clock signal, since the input to the internal clocking circuitry is through a divide-by-

two flip-flop, but minimum and maximum voltage high and low time specifications

must be observed.

Idle Mode In idle mode, the CPU puts itself to sleep while all the on-chip peripheralsremain active. The mode is invoked by software. The content of the on-chip RAM

and all the special function registers remain unchanged during this mode. The idle

mode can be terminated by any enabled interrupt or by a hardware reset. Note that

when idle mode is terminated by a hardware reset, the device normally resumes

program execution from where it left off, up to two machine cycles before the

internal reset algorithm takes control. On-chip hardware inhibits access to internal

RAM in this event, but access to the port pins is not inhibited. To eliminate the

possibility of an unexpected write to a port pin when idle mode is terminated by areset, the instruction following the one that invokes idle mode should not write to a

port pin or to external memory.

Power-down Mode



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In the Power-down mode, the oscillator is stopped, and the instruction that invokes

Powerdown is the last instruction executed. The on-chip RAM and Special Function

Registers retain their values until the Power-down mode is terminated. Exit from

Power-down mode can be initiated either by a hardware reset or by activation of an

enabled external interrupt into INT0 or INT1. Reset redefines the SFRs but does not

change the on-chip RAM. The reset should not be activated before VCC is restored

to its normal operating level and must be held active long enough to allow the

oscillator to restart and stabilize.

Program Memory Lock Bits

The AT89S51 has three lock bits that can be left unprogrammed (U) or can be

programmed (P) to obtain the additional features listed in the following table.

When lock bit 1 is programmed, the logic level at the EA pin is sampled and latched

during reset. If the device is powered up without a reset, the latch initializes to a

random value and holds that value until reset is activated. The latched value of EA

must agree with the current logic level at that pin in order for the device to function

properly.

Programming the Flash Parallel Mode



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The AT89S51 is shipped with the on-chip Flash memory array ready to be

programmed. The programming interface needs a high-voltage (12-volt) program

enable signal and is compatible with conventional third-party Flash or EPROM

programmers. The AT89S51 code memory array is programmed byte-by-byte.

Programming Algorithm: Before programming the AT89S51, the address, data, and

control signals should be set up according to the Flash programming mode table

and Figures 13 and 14. To program the AT89S51, take the following steps:

1. Input the desired memory location on the address lines.

2. Input the appropriate data byte on the data lines.

3. Activate the correct combination of control signals.

4. Raise EA/VPP to 12V.

5. Pulse ALE/PROG once to program a byte in the Flash array or the lock bits. The

bytewrite cycle is self-timed and typically takes no more than 50 s. Repeat steps 1

through 5, changing the address and data for the entire array or until the end of the

object file is reached.

Data Polling: The AT89S51 features Data Polling to indicate the end of a byte write

cycle. During a write cycle, an attempted read of the last byte written will result inthe complement of the written data on P0.7. Once the write cycle has been

completed, true data is valid on all outputs, and the next cycle may begin. Data

Polling may begin any time after a write cycle has been initiated.

Ready/Busy: The progress of byte programming can also be monitored by the

RDY/BSY output signal. P3.0 is pulled low after ALE goes high during programming

to indicate BUSY. P3.0 is pulled high again when programming is done to indicate

READY.

Program Verify: If lock bits LB1 and LB2 have not been programmed, the

programmed code data can be read back via the address and data lines for

verification. The status of the individual lock bits can be verified directly by reading

them back.



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Reading the Signature Bytes: The signature bytes are read by the same procedure

as a normal verification of locations 000H, 100H, and 200H, except that P3.6 and

P3.7 must be pulled to a logic low. The values returned are as follows.

(000H) = 1EH indicates manufactured by Atmel

(100H) = 51H indicates 89S51

(200H) = 06H

Chip Erase: In the parallel programming mode, a chip erase operation is initiated by

using the proper combination of control signals and by pulsing ALE/PROG low for a

duration of 200 ns - 500 ns. In the serial programming mode, a chip erase operation

is initiated by issuing the Chip Erase instruction. In this mode, chip erase is self-

timed and takes about 500 ms. During chip erase, a serial read from any address

location will return 00H at the data output.

Programming the Flash Serial Mode

The Code memory array can be programmed using the serial ISP interface while

RST is pulled to VCC. The serial interface consists of pins SCK, MOSI (input) and

MISO (output). After RST is set high, the Programming Enable instruction needs to

be executed first before other operations can be executed. Before a reprogramming

sequence can occur, a Chip Erase operation is required.

The Chip Erase operation turns the content of every memory location in the Code

array into FFH. Either an external system clock can be supplied at pin XTAL1 or a

crystal needs to be connected across pins XTAL1 and XTAL2. The maximum serial

clock (SCK) frequency should be less than 1/16 of the crystal frequency. With a 33

MHz oscillator clock, the maximum SCK frequency is 2 MHz.

Serial Programming Algorithm

To program and verify the AT89S51 in the serial programming mode, the following

sequence is recommended:

1. Power-up sequence:

Apply power between VCC and GND pins.



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Set RST pin to H.

If a crystal is not connected across pins XTAL1 and XTAL2, apply a 3 MHz to 33 MHz

clock to XTAL1 pin and wait for at least 10 milliseconds.

2. Enable serial programming by sending the Programming Enable serial instruction

to pin MOSI/P1.5. The frequency of the shift clock supplied at pin SCK/P1.7 needs to

be less than the CPU clock at XTAL1 Divided by 16.

3. The Code array is programmed one byte at a time in either the Byte or Page

mode. The write cycle is self-timed and typically takes less than 0.5 ms at 5V.

4. Any memory location can be verified by using the Read instruction that returns

the content at the selected address at serial output MISO/P1.6.

5. At the end of a programming session, RST can be set low to commence normal

device operation.

Power-off sequence (if needed):

Set XTAL1 to L (if a crystal is not used).

Set RST to L.

Turn VCC power off.

Data Polling: The Data Polling feature is also available in the serial mode. In this

mode, during a write cycle an attempted read of the last byte written will result in

the complement of the MSB of the serial output byte on MISO.

Serial Programming Instruction Set

The Instruction Set for Serial Programming follows a 4-byte protocol and is shown inTable 8 on page 18.

Programming Interface Parallel Mode



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Every code byte in the Flash array can be programmed by using the appropriate

combination of control signals. The write operation cycle is self-timed and once

initiated, will automatically time itself to Completion.

All major programming vendors offer worldwide support for the Atmel

microcontroller series.

Please contact your local programming vendor for the appropriate software revision.



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After Reset signal is high, SCK should be low for at least 64 system clocks before it

goes high to clock in the enable data bytes. No pulsing of Reset signal is necessary.

SCK should be no faster than 1/16 of the system clock at XTAL1.

For Page Read/Write, the data always starts from byte 0 to 255. After the command

byte and upper address byte are

latched, each byte thereafter is treated as data until all 256 bytes are shifted in/out.

Then the next instruction will be ready to be decoded.



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*NOTICE: Stresses beyond those listed under Absolute Maximum Ratings may

cause permanent damage to the device. This is a stress rating only and functional

operation of the device at these or any other conditions beyond those indicated in

the operational sections of this specification is not implied. Exposure to absolute

maximum rating

conditions for extended periods may affect device reliability.

Serial Communication:

Computers can transfer data in two ways: parallel and serial. In parallel data

transfers, often 8 or more lines (wire conductors) are used to transfer data to a

device that is only a few feet away. Examples of parallel data transfer are printers

and hard disks; each uses cables with many wire strips. Although in such cases a

lot of data can be transferred in a short amount of time by using many wires in



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parallel, the distance cannot be great. To transfer to a device located many meters

away, the serial method is used. In serial communication, the data is sent one bit at

a time, in contrast to parallel communication, in which the data is sent a byte or

more at a time. Serial communication of the 8051 is the topic of this chapter. The

8051 has serial communication capability built into it, there by making possible fast

data transfer using only a few wires.

If data is to be transferred on the telephone line, it must be converted from

0s and 1s to audio tones, which are sinusoidal-shaped signals. A peripheral device

called a modem, which stands for modulator/demodulator, performs this

conversion.

Serial data communication uses two methods, asynchronous and

synchronous. The synchronous method transfers a block of data at a time, while

the asynchronous method transfers a single byte at a time.

In data transmission if the data can be transmitted and received, it is a

duplex transmission. This is in contrast to simplex transmissions such as with

printers, in which the computer only sends data. Duplex transmissions can be half

or full duplex, depending on whether or not the data transfer can be simultaneous.

If data is transmitted one way at a time, it is referred to as half duplex. If the data

can go both ways at the same time, it is full duplex. Of course, full duplex requirestwo wire conductors for the data lines, one for transmission and one for reception,

in order to transfer and receive data simultaneously.

Asynchronous serial communication and data framing

The data coming in at the receiving end of the data line in a serial data

transfer is all 0s and 1s; it is difficult to make sense of the data unless the sender

and receiver agree on a set of rules, a protocol, on how the data is packed, how

many bits constitute a character, and when the data begins and ends.

Start and stop bits

Asynchronous serial data communication is widely used for character-

oriented transmissions, while block-oriented data transfers use the synchronous

method. In the asynchronous method, each character is placed between start and



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stop bits. This is called framing. In the data framing for asynchronous

communications, the data, such as ASCII characters, are packed between a start bit

and a stop bit. The start bit is always one bit, but the stop bit can be one or two bits.

The start bit is always a 0 (low) and the stop bit (s) is 1 (high).

Data transfer rate

The rate of data transfer in serial data communication is stated in bps (bits

per second). Another widely used terminology for bps is baud rate. However, the

baud and bps rates are not necessarily equal. This is due to the fact that baud rate

is the modem terminology and is defined as the number of signal changes per

second. In modems a single change of signal, sometimes transfers several bits of

data. As far as the conductor wire is concerned, the baud rate and bps are the

same, and for this reason we use the bps and baud interchangeably.

The data transfer rate of given computer system depends on

communication ports incorporated into that system. For example, the early

IBMPC/XT could transfer data at the rate of 100 to 9600 bps. In recent years,

however, Pentium based PCS transfer data at rates as high as 56K bps. It must be

noted that in asynchronous serial data communication, the baud rate is generally

limited to 100,000bps.

Computers can transfer data in two ways: parallel and serial. In

parallel data transfers, often 8 or more lines (wire conductors) are used to transfer

data to a device that is only a few feet away. Examples of parallel transfers are

printers and hard disks; each uses cables with many wire strips. Although in such

cases a lot of data can be transferred in a short amount of time by using many

wires in parallel, the distance cannot be great. To transfer to a device located many

meters away, the serial method is used. In serial communication, the data is sentone bit at a time, in contrast to parallel communication, in which the data is sent a

byte or more at a time. The 8051 has serial communication capability built into it,

there by making possible fast data transfer using only a few wires. The PC uses RS

232 as a Serial Communication Standard.



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RS232 Standards

To allow compatibility among data communication equipment made by

various manufacturers, an interfacing standard called RS232 was set by the

Electronics Industries Association (EIA) in 1960. In 1963 it was modified and called

RS232A. RS232B AND RS232C were issued in 1965 and 1969, respectively. Today,

RS232 is the most widely used serial I/O interfacing standard. This standard is used

in PCs and numerous types of equipment. However, since the standard was set

long before the advert of the TTL logic family, its input and output voltage levels are

not TTL compatible. In RS232, a 1 is represented by -3 to -25V, while a 0 bit is +3to +25V, making -3 to +3 undefined. For this reason, to connect any RS232 to a

microcontroller system we must use voltage converters such as MAX232 to convert

the TTL logic levels to the RS232 voltage levels, and vice versa. MAX232 IC chips

are commonly referred to as line drivers.

RS232 pins

RS232 cable connector commonly referred to as the DB-25 connector. In labeling, DB-

25P refers to the plug connector (male) and DB-25S is for the socket connector (female). Sincenot all the pins are used in PC cables, IBM introduced the DB-9 Version of the serial I/O

standard, which uses 9 pins only, as shown in table.

DB-9 pin connector

1 2 3 4 5

6 7 8 9

(Out of computer and exposed end of cable)

Pin Functions:

Pin Description



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1 Data carrier detect (DCD)2 Received data (RXD)3 Transmitted data (TXD)4 Data terminal ready(DTR)5 Signal ground (GND)

6 Data set ready (DSR)7 Request to send (RTS)8 Clear to send (CTS)9 Ring indicator (RI)Note: DCD, DSR, RTS and CTS are active low pins.

The method used by RS-232 for communication allows for a simple connection of three lines

namely Tx, Rx, and Ground.

TXD: carries data from DTE to the DCE.

RXD: carries data from DCE to the DTE

SG: signal ground

8051 connection to RS232



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The RS232 standard is not TTL compatible; therefore, it requires a Line

Driver such as the MAX232 chip to convert RS232 voltage levels to TTL levels, and

vice versa.

The 8051 has two pins that are used specifically for transferring and

receiving data serially. These two pins are TXD and RXD and are a part of the port 3

(P3.0 and P3.1). Pin 11 of the 8051 is designated as TXD and pin 10 as RXD. These

pins are TTL compatible; therefore, they require a line driver to make them RS232

compatible. One such line driver is the MAX232 chip.

MAX232 converts from RS232 voltage levels to TTL voltage levels, and vice

versa. One advantage of the MAX232 chip is that it uses a +5V power source

which, is the same as the source voltage for the 8051. In the other words, with a

single +5V power supply we can power both the 8051 and MAX232, with no need

for the power supplies. The MAX232 has two sets of line drivers for transferring and

receiving data. The line drivers used for TXD are called T1 and T2, while the line

drivers for RXD are designated as R1 and R2. In many applications only one of each

is used.

MAX 232 Serial Line Drivers:

The pin-out diagram of MAX 232 is shown below.



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MAX 232E Dual Driver/Receiver

MAX 232 Operating Circuit:



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Pin 10, 11 form the dual inputs with TTL logic whereas 14, 7 form the outputs for RS

232 logic. And the 12, 9, 13, 8 form the vice versa inputs and outputs as shown in

fig.

The inputs and outputs of the drivers and receivers are shown in fig above.



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Power supply

The power supplies are designed to convert high voltage AC mains

electricity to a suitable low voltage supply for electronics circuits and other devices. A power

supply can by broken down into a series of blocks, each of which performs a particular function.

A d.c power supply which maintains the output voltage constant irrespective of a.c mains

fluctuations or load variations is known as Regulated D.C Power Supply

For example a 5V regulated power supply system as shown below:

Transformer:

A transformer is an electrical device which is used to convert electrical power from

one

Electrical circuit to another without change in frequency.



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Transformers convert AC electricity from one voltage to another with little loss of power.

Transformers work only with AC and this is one of the reasons why mains electricity is AC.

Step-up transformers increase in output voltage, step-down transformers decrease in output

voltage. Most power supplies use a step-down transformer to reduce the dangerously high mains

voltage to a safer low voltage. The input coil is called the primary and the output coil is called

the secondary. There is no electrical connection between the two coils; instead they are linked by

an alternating magnetic field created in the soft-iron core of the transformer. The two lines in the

middle of the circuit symbol represent the core. Transformers waste very little power so the

power out is (almost) equal to the power in. Note that as voltage is stepped down current is

stepped up. The ratio of the number of turns on each coil, called the turns ratio, determines the

ratio of the voltages. A step-down transformer has a large number of turns on its primary (input)

coil which is connected to the high voltage mains supply, and a small number of turns on itssecondary (output) coil to give a low output voltage.

An Electrical Transformer

Turns ratio = Vp/ VS = Np/NS

Power Out= Power In

VS X IS=VP X IP

Vp = primary (input) voltage

Np = number of turns on primary coil

Ip = primary (input) current



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RECTIFIER:

A circuit which is used to convert a.c to dc is known as RECTIFIER. The

process of conversion a.c to d.c is called rectification

TYPES OF RECTIFIERS:

Half wave Rectifier

Full wave rectifier

1. Centre tap full wave rectifier.

2. Bridge type full bridge rectifier.

Comparison of rectifier circuits:

Parameter

Type of Rectifier

Half wave Full wave

Bridge

Number of diodes

1

2

4

PIV of diodes

Vm

2Vm Vm

D.C output voltage

Vm/

2Vm/

2Vm/



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Vdc,at

no-load

0.318Vm

0.636Vm 0.636Vm

Ripple factor

1.21

0.482

0.482

Ripple

frequency

f 2f

2f

Rectification

efficiency

0.406

0.812

0.812

Transformer

Utilization

Factor(TUF)

0.287 0.693 0.812

RMS voltage Vrms Vm/2 Vm/2 Vm/2

Full-wave Rectifier:

From the above comparison we came to know that full wave bridge rectifier as moreadvantages than the other two rectifiers. So, in our project we are using full wave

bridge rectifier circuit.

Bridge Rectifier: A bridge rectifier makes use of four diodes in a bridge arrangement to achieve

full-wave rectification. This is a widely used configuration, both with individual diodes

wired as shown and with single component bridges where the diode bridge is wired

internally.

A bridge rectifier makes use of four diodes in a bridge arrangement as shown

in fig(a) to achieve full-wave rectification. This is a widely used configuration, both

with individual diodes wired as shown and with single component bridges where the

diode bridge is wired internally.



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Fig(A)

Operation:

During positive half cycle of secondary, the diodes D2 and D3 are in forward biased

while D1 and D4 are in reverse biased as shown in the fig(b). The current flow

direction is shown in the fig (b) with dotted arrows.

Fig(B)

During negative half cycle of secondary voltage, the diodes D1 and D4 are in

forward biased while D2 and D3 are in reverse biased as shown in the fig(c). The

current flow direction is shown in the fig (c) with dotted arrows.



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Fig(C)

Filter:

A Filter is a device which removes the a.c component of rectifier

output but allows the d.c component to reach the load

Capacitor Filter:

We have seen that the ripple content in the rectified output of half waverectifier is 121% or that of full-wave or bridge rectifier or bridge rectifier is 48%

such high percentages of ripples is not acceptable for most of the applications.

Ripples can be removed by one of the following methods of filtering.

(a) A capacitor, in parallel to the load, provides an easier by pass for the ripples

voltage though it due to low impedance. At ripple frequency and leave the d.c.to

appears the load.

(b) An inductor, in series with the load, prevents the passage of the ripple current

(due to high impedance at ripple frequency) while allowing the d.c (due to low

resistance to d.c)



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(c) Various combinations of capacitor and inductor, such as L-section filter

section filter, multiple section filter etc. which make use of both the properties

mentioned in (a) and (b) above. Two cases of capacitor filter, one applied on half

wave rectifier and another with full wave rectifier.

Filtering is performed by a large value electrolytic capacitor connected across the DC

supply to act as a reservoir, supplying current to the output when the varying DC voltage from

the rectifier is falling. The capacitor charges quickly near the peak of the varying DC, and then

discharges as it supplies current to the output. Filtering significantly increases the average DCvoltage to almost the peak value (1.4 RMS value).

To calculate the value of capacitor(C),

C = *3*f*r*Rl

Where,

f = supply frequency,

r = ripple factor,

Rl = load resistance

Note: In our circuit we are using 1000F. Hence large value of capacitor is placed to

reduce ripples and to improve the DC component.

Regulator:

Voltage regulator ICs is available with fixed (typically 5, 12 and 15V) or variable

output voltages. The maximum current they can pass also rates them. Negative

voltage regulators are available, mainly for use in dual supplies. Most regulators

include some automatic protection from excessive current ('overload protection')

and overheating ('thermal protection'). Many of the fixed voltage regulator ICs have

3 leads and look like power transistors, such as the 7805 +5V 1A regulator shown

on the right. The LM7805 is simple to use. You simply connect the positive lead of

your unregulated DC power supply (anything from 9VDC to 24VDC) to the Input pin,



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connect the negative lead to the Common pin and then when you turn on the

power, you get a 5 volt supply from the output pin.

Fig 6.1.6 A Three Terminal Voltage Regulator

78XX:

The Bay Linear LM78XX is integrated linear positive regulator with three

terminals. The LM78XX offer several fixed output voltages making them useful in

wide range of applications. When used as a zener diode/resistor combination

replacement, the LM78XX usually results in an effective output impedance

improvement of two orders of magnitude, lower quiescent current. The LM78XX is

available in the TO-252, TO-220 & TO-263packages,

Features:

Output Current of 1.5A

Output Voltage Tolerance of 5%

Internal thermal overload protection

Internal Short-Circuit Limited

No External Component

Output Voltage 5.0V, 6V, 8V, 9V, 10V,12V, 15V, 18V, 24V



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Offer in plastic TO-252, TO-220 & TO-263

Direct Replacement for LM78XX

ANALOG TO DIGITAL CONVERTER

8-Bit, Microprocessor-Compatible, A/D Converters

The ADC080X family is CMOS 8-Bit, successive approximation A/D converters

which use a modified potentiometer ladder and are designed to operate with the

8080A control bus via three-state outputs. These converters appear to the

processor as memory locations or I/O ports, and hence no interfacing logic is

required. The differential analog voltage input has good common mode-rejection

and permits offsetting the analog zero-input voltage value. In addition, the voltage

reference input can be adjusted to allow encoding any smaller analog voltage span

to the full 8 bits of resolution.

Features

80C48 and 80C80/85 Bus Compatible - No Interfacing

Logic Required

Conversion Time . . . . . . . . . . . . . . . . . . . . . . . . . .


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Analog Voltage Input Range

(Single + 5V Supply) . . . . . . . . . . . . . . . . . . . . . . 0V to 5V

No Zero-Adjust Required

80C48 and 80C80/85 Bus Compatible - No Interfacing

Logic Required



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As the peripheral signals usually are substantially different from the ones that micro-

controller can understand (zero and one), they have to be converted into a pattern which can be

comprehended by a micro-controller. This task is performed by a block for analog to digital

conversion or by an ADC. This block is responsible for converting an information about some

analog value to a binary number and for follow it through to a CPU block so that CPU block can

further process it.

fig- 4.1

This analog to digital converter (ADC) converts a continuous analog input signal,

into an n-bit binary number, which is easily acceptable to a computer.

As the input increases from zero to full scale, the output code stair steps. The

width of an ideal step represents the size of the least significant Bit (LSB) of the

converter and corresponds to an input voltage of VES/2n for an n-bit converter.

Obviously for an input voltage range of one LSB, the output code is constant. For a

given output code, the input voltage can be any where within a one LSB

quantization interval.

An actual converter has integral linearity and differential linearity errors.

Differential linearity error is the difference between the actual code-step width and

one LSB. Integral linearity error is a measure of the deviation of the code transitionpoints from the fitted line.



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The errors of the converter are determined by the fitting of a line through the

code transition points, using least square fit, the terminal point method, or the zero

base technique to provide the reference line.

A good converter will have less than 0.5 LSB linearity error and no missing

codes over its full temperature range. In the basic conversion scheme of ADC, the

un-known input voltage VX is connected to one input of an analog signal

comparator, and a time dependant reference voltage VR is connected to the other

input of the comparator.

In this project work ADC 080X (8 Bit A/D converter) is used to convert analog

voltage variations (according to the condition of the parameters) into digital pulses.

This IC is having built in multi-plexer so that channel selection can be done

automatically.

FUNCTIONAL DESCRIPTION:

The ADC 0804 shown in figure can be functionally divided into

2 basic sub circuits. These two sub circuits are an analog

multiplexer and an A/D Converter. The multiplexer uses 8 standard

CMOS analog switches to provide to up to 4 analog inputs. The

switches are selectively turned on, depending on the data latched in

to 3-bit multiplexer address register.

The second functional block, the successive approximation A/D converter, transforms the

analog output of the multiplexer to an 8-bit digital word. The output of the multiplexer goes to



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one of two comparator inputs. The other input is derived from a 256R resistor ladder, which is

tapped by a MOSFET transistor switch tree. The converter control logic controls the switch tree,

funneling a particular tap voltage to comparator. Based on the result of this comparison, the

control logic and the successive approximation register (SAR) will decide whether the next tap to

be selected should be higher or lower than the present tap on the resistor ladder. This algorithm is

executed 8 times per conversion, once every 8-clock period, yielding a total conversion time of

clock periods.

When the conversion cycle is complete the resulting data is loaded into the

TRI-STATE output latch. The data in the output latch can be then be read by the

host system any time before the end of the next conversion. The TRI-STATE

capability of the latch allows easy interfaces to bus oriented systems.

The operation on these converters by a microprocessor or some control logic is very

simple. The controlling device first selects the desired input channel. To do this, a 3-bit channel

address is placed on the A, B, C in and out pins; and the ALE input is pulsed positively, clocking

the address into the multiplexer address register. To begin the conversion, the START pin is

pulsed. On the rising edge of this pulse the internal registers are cleared and on the falling edge

the start conversion is initiated.

As mentioned earlier, there are 8 clock periods per approximation. Even

though there is no conversion in progress the ADC0804 is still internally cycling

through these 8 clock periods. A start pulse can occur any time during this cycle but

the conversion will not actually begin until the converter internally cycles to the

beginning of the next 8 clock period sequence. As long as the start pin is held high

no conversion begins, but when the start pin is taken low the conversion will start

within 8 clock periods. The EOC output is triggered on the rising edge of the start

pulse. It, too, is controlled by the 8 clock period cycle, so it will go low within 8 clock

periods of the rising edge of the start pulse. One can see that it is entirely possible

for EOC to go low before the conversion starts internally, but this is not important,

since the positive transition of EOC, which occurs at the end of a conversion, is what

the control logic is looking for.



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Once EOC does go high this signals the interface logic that the data resulting from the

conversion is ready to be read. The output enable(OE) is then raised high. This enables the TRI-

STATE outputs, allowing the data to be read. Figure shows the timing diagram.

MUX

Addres

4 x 1

Analog

MUX

CONTROL LOGIC

SAR

TRI-

STATE

Output



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RELAYS

Relay is an electrically operated switch. Current flowing through the coil of the

relay creates a magnetic field which attracts a lever and changes the switch

contacts. The coil current can be on or off so relays have two switch positions and

they are double throw (changeover) switches.

Relays allow one circuit to switch a second circuit which can be completely

separate from the first. For example a low voltage battery circuit can use a relay to

switch a 230V AC mains circuit. There is no electrical connection inside the relay

between the two circuits; the link is magnetic and mechanical.

The coil of a relay passes a relatively large current, typically 30mA for a 12V

relay, but it can be as much as 100mA for relays designed to operate from lower



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voltages. Most ICs (chips) cannot provide this current and a transistor is usually

used to amplify the small IC current to the larger value required for the relay coil.

The maximum output current for the popular 555 timer IC is 200mA so these

devices can supply relay coils directly without amplification.

Relays are usually SPDT or DPDT but they can have many more sets of switch

contacts, for example relays with 4 sets of changeover contacts are readily

available. For further information about switch contacts and the terms used to

describe them please see the page on switches.

Most relays are designed for PCB mounting but you can solder wires directly

to the pins providing you take care to avoid melting the plastic case of the relay.

The supplier's catalogue should show you the relay's connections. The coil will be

obvious and it may be connected either way round. Relay coils produce brief high

voltage 'spikes' when they are switched off and this can destroy transistors and ICs

in the circuit. To prevent damage you must connect a protection diode across the

relay coil.

The animated picture shows a working relay with its coil and switch contacts.

You can see a lever on the left being attracted by magnetism when the coil is

switched on. This lever moves the switch contacts. There is one set of contacts

(SPDT) in the foreground and another behind them, making the relay DPDT.

The relay's switch connections are usually labeled as COM, NC and NO:

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COM = Common, always connect to this, it is the moving part of the switch.

NC = Normally Closed, COM is connected to this when the relay coil is off.

NO = Normally Open, COM is connected to this when the relay coil is on.

Connect to COM and NO if you want the switched circuit to be on when the

relay coil is on.

Connect to COM and NC if you want the switched circuit to be on when the

relay coil is off.

Choosing a relay

You need to consider several features when choosing a relay:

1. Physical size and pin arrangement If you are choosing a relay for an existing

PCB you will need to ensure that its dimensions and pin arrangement are

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

2. Coil voltage the relay's coil voltage rating and resistance must suit the circuit

powering the relay coil. Many relays have a coil rated for a 12V supply but 5V

and 24V relays are also readily available. Some relays operate perfectly well

with a supply voltage which is a little lower than their rated value.

3. Coil resistance the circuit must be able to supply the current required by the

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

Relay coil

current =

supply

voltage

coil

resistance

4. For example: A 12V supply relay with a coil resistance of 400 passes a

current of 30mA. This is OK for a 555 timer IC (maximum output current

200mA), but it is too much for most ICs and they will require a transistor to

amplify the current.

5. Switch ratings (voltage and current) the relay's switch contacts must be

suitable for the circuit they are to control. You will need to check the voltage

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

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

6. Switch contact arrangement (SPDT, DPDT etc).

Most relays are SPDT or DPDT which are often described as "single pole

changeover" (SPCO) or "double pole changeover" (DPCO). For further

information please see the page on switches

Protection diodes for relays

Transistors and ICs (chips) must be protected from the brief high voltage 'spike'

produced when the relay coil is switched off. The diagram shows how a signal diode

(eg 1N4148) is connected across the relay coil to provide this protection. Note that

the diode is connected 'backwards' so that it will normally not conduct. Conduction

only occurs when the relay coil is switched off, at this moment current tries to

continue flowing through the coil and it is harmlessly diverted through the diode.

Without the diode no current could flow and the coil would produce a damaging

high voltage 'spike' in its attempt to keep the current flowing.

Relays and transistors compared

Like relays, transistors can be used as an electrically operated switch. For

switching small DC currents (< 1A) at low voltage they are usually a better choice

than a relay. However transistors cannot switch AC or high voltages (such as mains

electricity) and they are not usually a good choice for switching large currents

(> 5A). In these cases a relay will be needed, but note that a low power transistor

may still be needed to switch the current for the relay's coil! The main advantagesand disadvantages of relays are listed below:

Advantages of relays:

Relays can switch AC and DC, transistors can only switch DC.

Relays can switch high voltages, transistors cannot.

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

Relays can switch many contacts at once.

Disadvantages of relays:

Relays are bulkier than transistors for switching small currents.

Relays cannot switch rapidly (except reed relays), transistors can switch

many times per second.

Relays use more power due to the current flowing through their coil.

Relays require more current than many chips can provide, so a low

power transistor may be needed to switch the current for the relay's coil.

Details:

These SPDT relays covers switching capacity of 10A in spite of miniature size for

PCB Mount.

Contact Rating

12A at 120VAC

10A at 120VAC

10A at 24VDC

Coil Resistance

400ohm 12VDC

Life expectancy

Mechanical 10,000,000 operations at no load

Electrical 100,000 at rated resistive load

Applications:

Domestic Appliances

Office Machines

Audio Equipment

Coffee-Pots



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Control units

CIRCUIT DESCRIPTION:

In this project we designed a system in such a way that it will monitor the load of the transformer

continuously and that information is transferred to the control room. In the main station these

parameters are displayed on the PC monitor. In the display unit we can view the continuous

information of transformer i.e. due to what reason the transformer has been failed, when the power is

resumed etc.,. With the help of this kind of system, the maintenance staff of the department can have

a continuous vigilance over the transformer.

In this project work, for the demonstration purpose a small step-down transformer of 12V, 1 amps

rating at secondary is considered and small bulbs are connected as a load. In this project we are

using CT transformer for measuring load current. All these parameters are converted into digital

value by using ADC. If the parameters of the transformer (Current) regain the limited range values



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then Transformer will automatically shutdown. Microcontroller near the transformer section will

continuously transmit all the parameters of the transformer to PC of control room.

Software Components:

ABOUT SOFTWARE

Softwares used are:

*Keil software for c programming

*Express PCB for lay out design

*Express SCH for schematic design

What's New in Vision3?

Vision3 adds many new features to the Editor like Text Templates, Quick Function

Navigation, and Syntax Coloring with brace high lighting Configuration Wizard for

dialog based startup and debugger setup. Vision3 is fully compatible to Vision2and can be used in parallel with Vision2.

What is Vision3?

Vision3 is an IDE (Integrated Development Environment) that helps you write,

compile, and debug embedded programs. It encapsulates the following

components:

A project manager.

A make facility.

Tool configuration.

Editor.

A powerful debugger.



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To help you get started, several example programs (located in the \C51\Examples,

\C251\Examples, \C166\Examples, and \ARM\...\Examples) are provided.

HELLO is a simple program that prints the string "Hello World" using the

Serial Interface. MEASURE is a data acquisition system for analog and digital systems.

TRAFFIC is a traffic light controller with the RTX Tiny operating system.

SIEVE is the SIEVE Benchmark.

DHRYis the Dhrystone Benchmark.

WHETS is the Single-Precision Whetstone Benchmark.

Additional example programs not listed here are provided for each device

architecture.

Building an Application in Vision2

To build (compile, assemble, and link) an application in Vision2, you must:

1. Select Project -(forexample,166\EXAMPLES\HELLO\HELLO.UV2 ).

2. Select Project - Rebuild all target files or Build target.

Vision2 compiles, assembles, and links the files in your project.

Creating Your Own Application in Vision2

To create a new project in Vision2, you must:

1. Select Project - New Project.

2. Select a directory and enter the name of the project file.

3. Select Project - Select Device and select an 8051, 251, or C16x/ST10 device

from the Device Database.

4. Create source files to add to the project.

5. Select Project - Targets, Groups, Files. Add/Files, select Source Group1, and

add the source files to the project.

6. Select Project - Options and set the tool options. Note when you select the

target device from the Device Database all special options are set

automatically. You typically only need to configure the memory map of your



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Typical, the tool settings under Options Target are all you need to start a new

application. You may translate all source files and line the application with a click on

the Build Target toolbar icon. When you build an application with syntax errors,

Vision2 will display errors and warning messages in the Output Window Build

page. A double click on a message line opens the source file on the correct location

in a Vision2 editor window. Once you have successfully generated your application

you can start debugging.

After you have tested your application, it is required to create an Intel HEX

file to download the software into an EPROM programmer or simulator. Vision2

creates HEX files with each build process when Create HEX files under Options for

Target Output is enabled. You may start your PROM programming utility after the

make process when you specify the program under the option Run User Program

#1.

CPU Simulation

Vision2 simulates up to 16 Mbytes of memory from which areas can be mapped for

read, write, or code execution access. The Vision2 simulator traps and reports

illegal memory accesses.

In addition to memory mapping, the simulator also provides support for the

integrated peripherals of the various 8051 derivatives. The on-chip peripherals of

the CPU you have selected are configured from the Device.

Database selection

you have made when you create your project target. Refer to page 58 for more

Information about selecting a device. You may select and display the on-chip

peripheral components using the Debug menu. You can also change the aspects of

each peripheral using the controls in the dialog boxes.

Start Debugging



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You start the debug mode of Vision2 with the Debug Start/Stop Debug Session

command. Depending on the Options for Target Debug Configuration, Vision2 will

load the application program and run the startup code Vision2 saves the editor

screen layout and restores the screen layout of the last debug session. If the

program execution stops, Vision2 opens an editor window with the source text or

shows CPU instructions in the disassembly window. The next executable statement

is marked with a yellow arrow. During debugging, most editor features are still

available.

For example, you can use the find command or correct program errors. Program

source text of your application is shown in the same windows. The Vision2 debug

mode differs from the edit mode in the following aspects:

_ The Debug Menu and Debug Commands described on page 28 are Available.

The additional debug windows are discussed in the following.

_ The project structure or tool parameters cannot be modified. All build Commands

are disabled.

Disassembly Window

The Disassembly window shows your target program as mixed source and assembly

program or just assembly code. A trace history of previously executed instructions

may be displayed with Debug View Trace Records. To enable the trace history, set

Debug Enable/Disable Trace Recording.

If you select the Disassembly Window as the active window all program step

commands work on CPU instruction level rather than program source lines. You can

select a text line and set or modify code breakpoints using toolbar buttons or the

context menu commands.

You may use the dialog Debug Inline Assembly to modify the CPU

instructions. That allows you to correct mistakes or to make temporary changes to

the target program you are debugging.



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Steps for executing the Keil programs:

1. Click on the Keil uVision Icon on Desktop

2. The following fig will appear

3. Click on the Project menu from the title bar

4. Then Click on New Project



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5. Save the Project by typing suitable project name with no extension in u rown folder sited in either C:\ or D:\

6. Then Click on Save button above.



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7. Select the component for u r project. i.e. Atmel

8. Click on the + Symbol beside of Atmel

9. Select AT89C51 as shown below



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10. Then Click on OK

11. The Following fig will appear

12. Then Click either YES or NOmostly NO

13. Now your project is ready to USE

14. Now double click on the Target1, you would get another option Source

group 1 as shown in next page.



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15. Click on the file option from menu bar and select new



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16. The next screen will be as shown in next page, and just maximize it by

double clicking on its blue boarder.

17. Now start writing program in either in C or ASM

18. For a program written in Assembly, then save it with extension . asm

and for C based program save it with extension .C



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19. Now right click on Source group 1 and click on Add files to Group Source

20.Now you will get another window, on which by default C files will appear.



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21. Now select as per your file extension given while saving the file

22. Click only one time on option ADD

23. Now Press function key F7 to compile. Any error will appear if so happen.

24. If the file contains no error, then press Control+F5 simultaneously.

25. The new window is as follows



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26. Then Click OK

27. Now Click on the Peripherals from menu bar, and check your required port as shown

in fig below

28. Drag the port a side and click in the program file.

29. Now keep Pressing function key F11 slowly and observe.

30. You are running your program successfully



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Conclusion

The project PC BASED TRANSFORMER MONITOR AND

PROTECTION has been successfully designed and tested.

Integrating features of all the hardware components used have developed it. Presence ofevery module has been reasoned out and placed carefully thus contributing to the best working of

the unit.

Secondly, using highly advanced ICs and with the help of growing technology the

project has been successfully implemented.



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Future Enhancement

In this project, we can use the RF technology for transmitting the signals from transformer to the

PC at the substation. The RF module covers the minimum range. Whereas in the place of RFmodule if we use the latest technology called Zig-bee that covers the maximum range than RF.

If there is any extension of the bus station the Zig-bee will able to transmit the address to the

receiver station.



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BIBLIOGRAPHY

The 8051 Micro controller and Embedded Systems

-Muhammad Ali Mazidi

Janice Gillispie Mazidi

The 8051 Micro controller Architecture, Programming & Applications

-Kenneth J. Ayala

Fundamentals Of Micro processors and Micro computers

-B. Ram

Micro processor Architecture, Programming & Applications

- Ramesh S. Gaonkar

Electronic Components

-D.V. Prasad

References on the Web:

www.national.com

www.atmel.com

www.microsoftsearch.com

http://www.national.com/http://www.atmel.com/http://www.microsoftsearch.com/http://www.national.com/http://www.atmel.com/http://www.microsoftsearch.com/

transformer monitor protection

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