Dear Sir/Madam please give any idea/concept for AC Phase detecting either Present/Absent (Logic 1/0)without converting DC volt to detect TTL PIC16F676 microcontroller someone already implemented this products but know i am also implementing this concept on same circuits but I have dont know the logic/ C code for this know I am tried as follows but still i cant able to detecting phase


three phase (RY & B) AC analog inputs directly connected microcontroller pin without converting DC volts / reduced the voltage by using resistor divider circuit series with of 2.2Mohm 0.5watt+5Mohm 0.25watt connected to microcontroller(PIC16F676 pins RA0,RA1 & RA2). and internal oscillator like


#define _XTAl_FREQ 4000000

__CONFIG(0x3FF4)

#define R_phase RA0

#define Y_phase RA1

#define B_phase RA2


#define Three_phase_LED RC0

#define Two_phase_LED RC1

#define Single_phase_LED RC2

#define NO_phase_LED RC3


char phaseRflag = 0; // flag variables for each phase

char phaseYflag = 0;

char phaseBflag = 0;


char single_phase_flag = 0; // used for single phase detection test


unsigned int sample = 0; // used to set "for loop" duration


void main()

{

CMCON=0x07;

ANSEL=0x00;

TRISA =0b001111;

PORTA=0b001111;

TRISC=0b000000;

PORTC=0b00000;


while(1) // while loop to test phases continously

{

phaseRflag = 0; // phase flags are set to zero

phaseYflag = 0;

phaseBflag = 0;



// a "for loop" tests the inputs for 20 milliseconds, setting a flag if a logic 1 is read


for(sample = 16000; sample > 0; sample--) // test all phases for at least 20 milliseconds

{

if(R_phase) // if a 1 is detected on a phase set a flag to 1;

phaseRflag = 1;

if(Y_phase)

phaseYflag = 1;

if(B_phase)

phaseBflag = 1;

} // end of the for loop


// phase tests running as before, except now looking at the flag settings

// test for all phases on ------------------------------------------------------


if(phaseRflag && phaseYflag && phaseBflag)

Three_phase_LED = 1; // RC0 pin connected(Three_phase) LED will Glow ON

else

Three_phase_LED = 0;


// test for phase R and B on ------------------------------------------------


if(phaseRflag && phaseBflag && !phaseYflag)

Two_phase_LED = 1; // RC1 pin connected(Two_phase) LED will Glow ON

else

Two_phase_LED = 0;


// test for a single phase on -------------------------------------------------


single_phase_flag = 0; // set if only a single phase was detected


if(phaseRflag || !phaseYflag || !phaseBflag) // only R_phase is on

single_phase_flag = 1;



if(!phaseRflag || phaseYflag || !phaseBflag) // only Y_phase is on

single_phase_flag = 1;



if(!phaseRflag || !phaseYflag || phaseBflag) // only B_phase is on

single_phase_flag = 1;



if(single_phase_flag == 1) // if a single phase was detected

Single_phase_LED = 1; // RC2 pin connected(Single_phase) LED will Glow ON

else

Single_phase_LED = 0; // single phase LED off



// test for no phases on ------------------------------------------------------



if(!phaseRflag && !phaseYflag && !phaseBflag)

NO_phase_LED = 1; // RC3 pin connected(No_phase) LED will Glow On

else

NO_phase_LED = 0;

} // end of while loop

} // end of main



In this program only

NO_phase_LED = 1; LED is On always....

 

No matter how large the resistors are, you cannot connect three-phase AC power directly to a microcontroller. Also, this topic is not allowed on this forum because it can kill you.

ak