Programmed preheating oven control esp. for dental laboratory - involves individual heater operation with shared provision for emergency working with substd. power stage or controller

A number of ovens (V1,V2,etc.) are equipped with modulr power output stages (E) and electric heater windings (H) providing all-round heating of the walls when workpeices are introduced through frontal flaps (1) with safety interlock contacts (2). The output stages (E1,E2,etc.) are connected by separate data lines (a,b,c,etc.) to a single control unit (S) with conventional microprocessor-controlled circuits for heater operation timing and temp. regulation. The control program is input via a keyboard (T). Ovens may share a common standby output stage or control unit. ADVANTAGE - Safety in presence of disturbances is enhanced with less complex cabling.