Method for determining or monitoring a predetermined fill level, a phase boundary or a density of a medium

摘要

A method and an apparatus for determining or monitoring a predetermined fill level, a phase boundary or a density of a medium in a container with an oscillatable unit. The oscillatable unit is placed at the height of the predetermined fill level and is excited to oscillate successively with discrete exciter frequencies following one another in a frequency scanning operation (sweep) within a predeterminable frequency band in the working range of the oscillatable unit. The corresponding oscillations of the oscillatable unit are received in the form of received signals; wherein that exciter frequency is ascertained in the frequency scanning operation, at which the oscillatable unit oscillates with an oscillation frequency, which has a predetermined phase shift between the transmission signal and the received signal; and wherein the transmitting/receiving unit excites the oscillatable unit to oscillate with the ascertained oscillation frequency.

主权项

1. A method for determining or monitoring a predetermined fill level, a phase boundary or a density of a medium in a container with an oscillatable unit, comprising the steps of:
placing the oscillatable unit at the height of the predetermined fill level; exciting the oscillatable unit to oscillate by means of a frequency scanning operation within a predeterminable frequency band in the working range of the oscillatable unit successively with discrete exciter frequencies following one another; receiving the corresponding oscillations of the oscillatable unit in the form of received signals; ascertaining the exciter frequency in the frequency scanning operation, at which the oscillatable unit oscillates with an oscillation frequency, which has a predetermined phase shift between the transmission signal and the received signal; and the transmitting/receiving unit excites the oscillatable unit to oscillate with the oscillation frequency ascertained or wherein a subsequent frequency scanning operation is started, wherein: the oscillation frequency at the predetermined phase shift between the transmission signal and the received signal is ascertained by evaluating amplitudes of the received signals received by the transmitting/receiving unit or by evaluating phase shift between the transmission signal and the received signal.