The present invention concerns a device (1) for the determination and/or monitoring of at least one process size (P) of a medium (M) comprising a sensor unit (2) with a mechanically oscillable unit (4) in the form of a vibrating fork with a first (9a) and a second oscillator element (9b),and with at least one first piezoelectric element (11a),which first piezoelectric element (11a) is located at least partially in the first oscillating element (9a). Furthermore, the present invention concerns a procedure for the symmetry of vibration elements (11a, 11b). An electronics (6) of the device is designed to stimulate the mechanically oscillable unit (4) by means of an inducement signal (A) to mechanical vibrations, to receive the mechanical vibrations of the oscillable unit (4) and to convert them into a first reception signal (EA), to generate the call signal (A) from the first reception signal (EA) in such a way,that there is a predetermined phase shift between the inducement signal (A) and the first receiving signal (EA) and to determine the process size (P) from the first receiving signal (EA). According to the invention, the electronics (6) has at least one adjustable impedance element (13a) which is switched to the first piezoelectric element (11a) in series.
展开▼
