Temperature rate change

[yfmoo]

HI cytron ,

LM 35 temperature datasheet show that the temperature rated for full is −55° to +150°C range
I need to calibrate the LM35 to more accuracy( rate for full is 20°C-40°C)
May i know that LM35 temperature sensor can using the PIC 16f877 to fix the temperature range start from 20°C-40°C.

What thing i need to calibrate in PIC or other????

Thanks

[yonghui]

hi there,


i think we cant fix the environment temperature if the temperature want to change. and there is no need to do so right?

the temperature sensor is capable of measuring wide range of temperature, −55° to +150°C which is a good feature that we do not need to limit its capability to only certain 20°C-40°C. we can still use it, even though its capability is higher than we need.

what we can do, is from the programming of the PIC, if u wan to limit it from display temperature out of range of 20°C-40°C, then we ignore the reading which is not in our concern.


yh

[yfmoo]

hi,
so if i need limit the temperature range of 20°C-40°C to display , is it i modify the code at read ADC part?
may u giv me some hint pls....................

thanks

[kl84]

what yonghui meant should be after u read the ADC value, compare it with the range you wish, then set the display at the min if it's lower than min, or set it at max if it's higher than max.

[shiyan]

hi,
so if i need limit the temperature range of 20°C-40°C to display , is it i modify the code at read ADC part?
may u giv me some hint pls....................

Er..... what kind of hint needed? I think, you need to write the program first, display the temperature on LCD and then we talk about how to limit the value , OK?