| 摘要 |
PROBLEM TO BE SOLVED: To accurately correct the temperature of a detecting coil by detecting a value of temperature resistance of the coil and obtaining temperature data. SOLUTION: Switches 22, 24 which are arranged in parallel connection to capacitors C1, C2 making up an electromagnetic circuit, are controlled so as to be turned on for a constant period by a timer 35, and thereby the capacitors C1, C2 short-circuit. A signal of the DC component flows through a resistor and the detecting coil, and then a DC voltage component is detected from a potential dividing ratio of the coils 14, 15 to resistors R1, R2. A value of coil temperature corresponding to the DC voltage component is searched from a temperature memory table, the amount of phase shift of detected pulse signals is corrected by the correction data based of the value of coil temperature, and therefore the temperature of the detecting coil is accurately corrected. COPYRIGHT: (C)2003,JPO |
