Equipped with safety door to relieve an explosion pressure (explosion preventive vent door) and an interlock door knob to reliably secure main unit and door. The product is integrated with the following interlock functions: ①Through the door lock mechanism, device runs while door is locked. ②Through the explosion detector (set on top), operation stops when activated. Standard functions include program operation and other high precision functions. Improved safety functions include self diagnostic, automatic overheat prevention and key lock.