A note about temperature sensors and calibration

A project log for RV Rooftop A/C MPU Replacement

This project chronicles the successes, and frustrations to defeating the securities put in place by RV appliance manufacturers.

Daniel RosemanDaniel Roseman 08/26/2014 at 12:260 Comments

So, just to address the niceties of the temperature inputs. I honestly did not have to do much except realize that the numbers were related. This is to say, the numbers for three of the four inputs (Room Air, Outdoor Coil, Outdoor Air) are input/10 = Celsius. The last (Indoor Coil) is input/10 = Fahrenheit. This is how the factory designed it. This helped rapid prototyping quite a bit as I didn't have to do any calibration. The reason for Indoor Coil being different from all of the others is because it runs below 0 Celsius. The Celsius temp probes would not be able to sense anything below (or close to) 0. So, they calibrated the Indoor Coil for Fahrenheit.