The DS18B20 datasheet shows an expected error of +-.5 degrees C. Does this mean that one unit could take 2 readings back to back and they could differ by 1 degree C or is it saying that 2 different units taking simultaneous readings could differ by 1 degree C? I am researching this for an application that requires a stable temperature more than it requires an accurate temperature so it doesn't matter if the unit is off by +.4 degrees C for example, but it would matter if it is off by +.4 degrees C on this reading and then on the next reading it is off by -.3 degrees C.