The PID has been optimized to produce a firm response to the temperature changes of the set profile (shown in the lower pane). As seen here, the real measured thermal mass temperature in absolute terms is shown; it follows the set temperature quite closely. The heater current (middle pane) is strongly commanded by the PID and forces the measured temperature to follow the set temperature. The difference between the real temperature and the desired temperature is shown in the upper pane. The graph clearly illustrates that it remains under the expected ±0.6°C accuracy threshold. The different curves represent one case each of a worst-case scenario where the passive elements (resistor and thermistor) are exhibiting the minimum or maximum values according to specification. Such simulations will be very helpful when the time comes to build the printed circuit board for complete test and evaluation, and finally, to qualify the design for production and application end-use.