Dear Sir,

I have stored setpoint value in EEPROM memory in by keypad and I want to compare setpoint value with process value. Process value is stored in one array, say data[5]. I read the setpoint value from EEPROM and again stored in another array, say presetvalue[5]. I am using below logic to compare the both value but it is not working properly. I have used RC0 pin, which is connected to LED. When PV is higher than SV then RC0 pin will be high so LED should be glow.


for(i=0;i<5;i++) // To read the setvalue from EEPROM
{
value=eeprom_read(i);
presetvalue=value; // Stored setvalue in presetvalue[5] array
}

for(i=0;i<5;i++) // Comparison logic for setvalue and process value

{
if(data > presetvalue) // When PV>SV, RC0 pin high
{
RC0=1;
i=5;
}


else if(data==presetvalue) // If equal then compare next bit (From MSB
to LSB)
{ RC0=1; }


else if(data < presetvalue) // When PV<SV, RC0 pin low
{
RC0=0;
i=5;
}
}

Plz suggest me where may be problem.

If there is another good logic, then plz suggest me.

Thanks in advance,

 

How are these values loaded? You may be having a big/little endian issue.

In what way is it not working?

 

The way you set up the Comparison loop has it only check the zero element.

If it is > or < then i=5 and you drop out. Only when they are equal do you go onto the next element.

Is that OK or do you want to check all 5 elements?

In the future please use the code tag button ( the # symbol) so your code looks more like this:

for(i=0;i<5;i++) // To read the setvalue from EEPROM
{
 value=eeprom_read(i);
 presetvalue=value; // Stored setvalue in presetvalue[5] array
} 
for(i=0;i<5;i++) // Comparison logic for setvalue and process value
{ 
 if(data > presetvalue) // When PV>SV, RC0 pin high
 { 
  RC0=1;
  i=5;
 }
 else if(data==presetvalue) // If equal then compare next bit (From MSB to LSB)
 { RC0=1; }
 
 else if(data < presetvalue) // When PV<SV, RC0 pin low
 {
  RC0=0;
  i=5;
 }
}