DEVICE FOR DETERMINING AND/OR MONITORING AT LEAST ONE PROCESS VARIABLE FOR A MEDIUM

摘要

The invention relates to a device for determining and/or monitoring at least one first process variable for a medium (3) and to a method for operating the device comprising at least one electronics unit (4) and a sensor unit (2), said electronics unit (6) being designed to impinge upon the sensor unit (2) with an excitement signal (7) which is composed of an excitement carrier signal (8) having an excitement carrier frequency (fT) and an excitement modulation signal (9) having an excitement modulation frequency (fM) and a receiving signal (10) which is to be received by the sensor unit (2), which is composed of a receiving carrier signal (11) and a receiving modulation signal (12). The electronics unit (6) is thereby designed to determine at least the first process variable from the phase shift between the excitement modulation signal (9) and the receiving modulation signal (12).