| 摘要 |
A method of operating an induction distance sensor employs a sensor having a vane or tongue of magnetic material disposed movably between two inductive coils for changing their inductances in the opposite sense upon movement of the tongue. With respect to sensor signals Us and Ue, the method employs the portion UsL of Us which is in phase with the imaginary part UeL of Ue. Furthermore, the value UsL measured in this way is to be further increased by Ue/UeL in order to compensate for the temperature influences on the ohmic resistances. Furthermore, the errors which can be caused by erroneous controls Ue1 and Ue2 are also corrected. For this purpose, the total voltage is applied at intervals to a reference sensor which consists of a precision resistance divider. In this way, the exact middle point M of the total voltage Ue=Ue1 and Ue2 can be determined by measurement, and the middle-point voltage Um with respect to zero potential determined, which is divided into the real part U MR which is in phase with Ue and the imaginary part UML which lags behind it by 90 degrees. With the phase angle (alpha) between UeR and UeL, the correction value is (Delta)UsL=UMR*sin (alpha)+UML*cos (alpha).
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