3. Control of electric resistance ovens

Resistance ovens provide a high degree of temperature accuracy, which depends on the control chain. In practice, however, a distinction must be made between :

• temperature indication, information derived from a measurement enabling appropriate action to be taken (by an operator or by a control system). It must be specified which temperature is to be taken into account: load temperature (generally difficult to measure), furnace chamber temperature, resistance temperature. The accuracy of temperature measurements determines the accuracy of the control system;

• actual temperature control, achieved by an automatic system that controls the temperature as a function of its deviation from a setpoint. Modeling provides invaluable assistance in optimizing the control system, thanks to knowledge of the "thermal model"...