The document describes a digital wattmeter project. A digital wattmeter measures electric power or supply rate of electrical energy in watts for a given circuit. It also measures current in amps and voltage. The summary describes the key components of a digital wattmeter including a digital voltmeter, digital ammeter, and a program to measure and display current, voltage, and power on an LCD screen. When current exceeds a set limit, the program triggers an alarm and turns connected devices off.

1. A Major project
on
DIGITAL WATTMETER
-S.SRAVANKUMARREDDY (11B91A04A5)
-R.ARJUNBABU (11B91A04A0)
-S.VAMSHIKRISHNAREDDY (11B91A04A1)

2. WHAT IS digital WATTMETER ?
The wattmeter is an instrument for measuring the electric power or the supply rate
of electrical energy in watts of any given circuit. Electromagnetic wattmeter s are used
for measurement of utility frequency and audio frequency power; other types are
required for radio frequency measurements.

3. What is digital voltmeter?
Digital Voltmeters (DVMs) are a special case of A/Ds.
DVMs are voltmeters - i.e. they measure voltage - and are general
purpose instruments commonly used to measure voltages in labs
and in the field. DVMs display the measured voltage using LCDs
or LEDs to display the result in a floating point format.

4. What is digital ammeter ?
Ammeter, instrument for measuring either direct or alternating electric
current, in amperes. An ammeter can measure a wide range of current values
because at high values only a small portion of the current is directed through
the meter mechanism; a shunt in parallel with the meter carries the major
portion.

5. PROGRAM of digital wattmeter
sbit LCD_RS at RB0_bit;
sbit LCD_EN at RB1_bit;
sbit LCD_D4 at RB2_bit;
sbit LCD_D5 at RB3_bit;
sbit LCD_D6 at RB4_bit;
sbit LCD_D7 at RB5_bit
sbit LCD_RS at RB0_bit;
sbit LCD_EN at RB1_bit;
sbit LCD_D4 at RB2_bit;

6. sbit LCD_D5 at RB3_bit;
sbit LCD_D6 at RB4_bit;
sbit LCD_D7 at RB5_bit
sbit button1 at RD0_bit;
sbit button2 at RD1_bit;
sbit button3 at RD2_bit;
sbit device1 at RC0_bit;
sbit device2 at RC1_bit;
sbit device3 at RC2_bit;
unsigned char byte[]="0123456789";
unsignedint temp,temp1,i1,i2;
unsignedint w1;
char a;

7. sbit buzzer at RD4_bit;
void main()
{
TRISD0_bit=TRISD1_bit=TRISD2_bit=1;
TRISD5_bit=TRISD6_bit=TRISD7_bit=0;
TRISC0_bit=0;
device1=device2=device3=1;
delay_ms(300);
device1=device2=device3=0;
buzzer=0;

8. button1=button2=button3=1;
LCD_init();
ADC_init();
LCD_cmd(_LCD_clear);
LCD_cmd(_lcd_cursor_off);
lcd_out(1,9,"Imax=90");
lcd_out(2,10,"Wm=1090");
delay_ms(100);

9. while(1)
{
lcd_out(1,9,"Imax=90");
lcd_out(2,10,"Wm=1090");
if(button1==0)
{
while(button1==0);
device1=~device1;
}
if(button2==0)
{
while(button2==0);
device2=~device2;
}

10. if(button3==0)
{
while(button3==0);
device3=~device3;
}
i1=ADC_read(1);
i1=i1/1.80;
i1=i1*10;
if(i1<90)
{

11. lcd_chr(1,1,'I');
lcd_chr(1,2,'=');
lcd_chr(1,3,byte[i1/100%10]);
lcd_chr(1,4,byte[i1/10%10]);
lcd_chr(1,5,byte[i1%10]);
lcd_chr(1,6,'m');
lcd_chr(1,7,'A');
w1=12.1*i1;
w1=w1*10;
lcd_chr(2,1,'W');
lcd_chr(2,2,'=');

12. lcd_chr(2,3,byte[w1/10000%10]);
lcd_chr(2,4,byte[w1/1000%10]);
lcd_chr(2,5,byte[w1/100%10]);
lcd_chr(2,6,byte[w1/10%10]);
lcd_chr(2,7,'m');
lcd_chr(2,8,'W');
delay_ms(100);
}
if(i1>95)
{
w1=i1*12.1;
lcd_chr(1,3,byte[i1/100%10]);
lcd_chr(1,4,byte[i1/10%10]);
lcd_chr(1,5,byte[i1%10]);

13. lcd_chr(2,3,byte[w1/1000%10]);
lcd_chr(2,4,byte[w1/100%10]);
lcd_chr(2,5,byte[w1/10%10]);
lcd_chr(2,6,byte[w1%10]);
delay_ms(1000);
LCD_cmd(_lcd_clear);
LCD_out(1,1,"Overload Occurs ");
LCD_out(2,1,"Devices Turn OFF");
for(a=0;a<12;a++)
{
buzzer=1;
delay_ms(100);
buzzer=0;

14. delay_ms(100);
device1=device2=device3=0;
}
LCD_cmd(_lcd_clear);
}
}}

15. Circuit diagram of digital wattmeter