State detection device for detecting operation state of high-frequency heating apparatus

Abstract

An operating state detection technique is provided which makes it possible to accurately detect an abnormality of a high-frequency heating apparatus. An anode current detected by the anode current detection resistorof a magnetron is inputted into the A/D converter terminal of a microcomputeron a control panel circuit board side. The current is subjected to an analog-to-digital conversion to thereby obtain an anode voltage IaDC value. The microcomputerdetermines an operating state based on a plurality of the anode voltage IaDC values thus read. Further, the microcomputerobtains a summed value of the IaDC values corresponding to one period of the revolution of rotary antennasto thereby determines the operating state of the high-frequency heating apparatusbased on the summed value. According to the aforesaid IaDC value reading method, it makes it possible to accurately detect an abnormality without an erroneous operation also in correspondence to the change of the feeding distribution. Further, the microcomputerchanges, in accordance with the set output of the high-frequency heating apparatus, a threshold value used for determining the abnormality and a changing value (increasing amount) from the start of the operation with respect to the change of the output of the apparatus and the operating state of a heated subject etc., whereby it makes it possible to accurately detect an abnormality without an erroneous operation.