| 摘要 |
PROBLEM TO BE SOLVED: To detect a rotational frequency accurately without being influenced thereby even if a deformation such as swelling is generated in a rotator by high speed rotation, when detecting the rotational frequency by converting a periodical change of the magnetic field intensity generated following rotation of the rotator, into an electric signal by a detection element. SOLUTION: When the rotational frequency of a rotator such as a press rotor is shifted from low speed rotation to high speed rotation and the frequency of a signal from the detection element exceeds a prescribed value, gain adjustment is prohibited, and when the frequency of the signal is below the prescribed value, gain adjustment is permitted. By this processing, in a process from the low speed rotation to the high speed rotation and then to the low speed rotation, when shifting from the high speed rotation to the low speed rotation, the signal from the detection element does not become small, and the level of the signal from the detection element does not become below a threshold, and resultantly the rotational frequency can be detected accurately. COPYRIGHT: (C)2007,JPO&INPIT
|
