SHT75 ile Sıcaklık Nem Sensörü Sorunu

[hesap19]

Merhaba.SHT75 sensörünü kullanarak sıcaklık ve nem kontrol devresi yapmaya çalışıyorum.Simülasyon programı olarak proteus pıc programlamak içinde ccsc
dilini kullanıyorum.Proteusta devreyi çalıştırdığımda SHT75 sensörü nemi yüzde 81 gösterirke lcd ye bu değer yüzde 84.2 olarak yansıyor.Aynı şekilde ısıda da
sensör 28 derece gösterirken bu değer lcd ye 27.7 derece olarak yansıyor.Bu sorunu nasıl çözebilirim? cevap yazan herkese şimdiden teşekkür ederim.
CCS C ile yazılmış kaynak kodlar ve proteus şeması bu linkte mevcut: https://www.kontrolkalemi.com/forum/attachments/sht75-rar.33426/

#include <16F877.h>
#device adc=8

#FUSES NOWDT //No Watch Dog Timer
#FUSES XT //Crystal osc <= 4mhz for PCM/PCH , 3mhz to 10 mhz for PCD
#FUSES NOPUT //No Power Up Timer
#FUSES PROTECT //Code protected from reads
#FUSES NOBROWNOUT //No brownout reset
#FUSES NOLVP //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O
#FUSES NOCPD //No EE protection
#FUSES NOWRT //Program memory not write protected
#FUSES NODEBUG //No Debug mode for ICD

#use delay(clock=4000000)
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8)

#include <lcd.c>

#define sht_data_pin PIN_b1//(Data pin veya input)
#define sht_clk_pin PIN_b0

//***** SHT75 Başlatma *****

void comstart (void)
{
output_float(sht_data_pin); //data high
output_bit(sht_clk_pin, 0); //clk low
delay_us(1);
output_bit(sht_clk_pin, 1); //clk high
delay_us(1);
output_bit(sht_data_pin, 0); //data low
delay_us(1);
output_bit(sht_clk_pin, 0); //clk low
delay_us(2);
output_bit(sht_clk_pin, 1); //clk high
delay_us(1);
output_float(sht_data_pin); //data high
delay_us(1);
output_bit(sht_clk_pin, 0); //clk low
}

//***** SHT75 yazma fonksiyonu*****

int1 comwrite (int8 iobyte)
{
int8 i, mask = 0x80;
int1 ack;

//Komut gönderilir
delay_us(4);
for(i=0; i<8; i++)
{
output_bit(sht_clk_pin, 0); //clk low
if((iobyte & mask) > 0) output_float(sht_data_pin); //data high if MSB high
else output_bit(sht_data_pin, 0); //data low if MSB low
delay_us(1);
output_bit(sht_clk_pin, 1); //clk high
delay_us(1);
mask = mask >> 1; //shift to next bit
}

//Shift in ack
output_bit(sht_clk_pin, 0); //clk low
delay_us(1);
ack = input(sht_data_pin); //get ack bit
output_bit(sht_clk_pin, 1); //clk high
delay_us(1);
output_bit(sht_clk_pin, 0); //clk low
return(ack);
}

//***** Function to read data from SHT75 *****

int16 comread (void)
{
int8 i;
int16 iobyte = 0;
const int16 mask0 = 0x0000;
const int16 mask1 = 0x0001;

//shift in MSB data
for(i=0; i<8; i++)
{
iobyte = iobyte << 1;
output_bit(sht_clk_pin, 1); //clk high
delay_us(1);
if (input(sht_data_pin)) iobyte |= mask1; //shift in data bit
else iobyte |= mask0;
output_bit(sht_clk_pin, 0); //clk low
delay_us(1);
}

//send ack 0 bit
output_bit(sht_data_pin, 0); //data low
delay_us(1);
output_bit(sht_clk_pin, 1); //clk high
delay_us(2);
output_bit(sht_clk_pin, 0); //clk low
delay_us(1);
output_float(sht_data_pin); //data high

//shift in LSB data
for(i=0; i<8; i++)
{
iobyte = iobyte << 1;
output_bit(sht_clk_pin, 1); //clk high
delay_us(1);
if (input(sht_data_pin)) iobyte |= mask1; //shift in data bit
else iobyte |= mask0;
output_bit(sht_clk_pin, 0); //clk low
delay_us(1);
}

//send ack 1 bit
output_float(sht_data_pin); //data high
delay_us(1);
output_bit(sht_clk_pin, 1); //clk high
delay_us(2);
output_bit(sht_clk_pin, 0); //clk low

return(iobyte);
}

//***** Function to wait for SHT75 reading *****

void comwait (void)
{
int16 sht_delay;

output_float(sht_data_pin); //data high
output_bit(sht_clk_pin, 0); //clk low
delay_us(1);
for(sht_delay=0; sht_delay<30000; sht_delay++) // wait for max 300ms
{
if (!input(sht_data_pin)) break; //if sht_data_pin low, SHT75 ready
delay_us(10);
}
}

//***** Function to reset SHT75 communication *****

void comreset (void)
{
int8 i;

output_float(sht_data_pin); //data high
output_bit(sht_clk_pin, 0); //clk low
delay_us(2);
for(i=0; i<9; i++)
{
output_bit(sht_clk_pin, 1); //toggle clk 9 times
delay_us(2);
output_bit(sht_clk_pin, 0);
delay_us(2);
}
comstart();
}

//***** Function to soft reset SHT75 *****

void sht_soft_reset (void)
{
comreset(); //SHT75 communication reset
comwrite(0x1e); //send SHT75 reset command
delay_ms(15); //pause 15 ms
}

//***** Function to measure SHT75 temperature *****

int16 measuretemp (void)
{
int1 ack;
int16 iobyte;

comstart(); //alert SHT75
ack = comwrite(0x03); //send measure temp command and read ack status
if(ack == 1) return;
comwait(); //wait for SHT75 measurement to complete
iobyte = comread(); //read SHT75 temp data
return(iobyte);
}

//***** Function to measure SHT75 RH *****

int16 measurehumid (void)
{
int1 ack;
int16 iobyte;

comstart(); //alert SHT75
ack = comwrite(0x05); //send measure RH command and read ack status
if(ack == 1) return;
comwait(); //wait for SHT75 measurement to complete
iobyte = comread(); //read SHT75 temp data
return(iobyte);
}

//***** Function to calculate SHT75 temp & RH *****

void calculate_data (int16 temp, int16 humid, float & tc, float & rhlin, float & rhtrue)
{
float truehumid1, rh;

//calculate temperature reading
tc = ((float) temp * 0.01) - 40.0;

//calculate Real RH reading
rh = (float) humid;

rhlin = (rh * 0.0405) - (rh * rh * 0.0000028) - 4.0;

//calculate True RH reading
rhtrue = ((tc - 25.0) * (0.01 + (0.00008 * rh))) + rhlin;
}

//***** Function to measure & calculate SHT75 temp & RH *****

void sht_rd (float & temp, float & truehumid)
{
int16 restemp, reshumid;
float realhumid;
restemp = 0; truehumid = 0;

restemp = measuretemp(); //measure temp
reshumid = measurehumid(); //measure RH
calculate_data (restemp, reshumid, temp, realhumid, truehumid); //calculate temp & RH
}

//***** Function to initialise SHT75 on power-up *****

void sht_init (void)
{
comreset(); //reset SHT75
delay_ms(20); //delay for power-up
}
void main()
{
float restemp, truehumid;
lcd_init();
sht_init();

while(1)
{
sht_rd (restemp, truehumid);
printf(lcd_putc,"Temp : %3.1f %cC ", restemp, 223);
printf(lcd_putc,"\nRH : %3.1f %% ", truehumid);
delay_ms(500); //delay 500 ms between reading to prevent self heating of sensor
}
}