Apparatus for determining and/or monitoring the viscosity of a medium in a container

An apparatus for determining and/or monitoring the level of a medium in a container and for determining and/or monitoring the viscosity of a medium in a container, having:

• a unit which can oscillate;
• an exciter/reception unit;
• and a control/evaluation unit, said unit is arranged at a defined measurement position within the container and/or in which case said unit is fitted such that it is immersed as far as a defined immersion depth in the medium in the container, and in which case, said exciter/reception unit excites said unit to oscillate and/or in which case said exciter/reception unit receives the oscillations from said unit, wherein:
• said control/evaluation unit drives said unit as a limit switch in a first operating mode and as a viscosity sensor in a second operating mode;
• said control/evaluation unit uses frequency (fr) changes to determine the level of the medium;
• said control/evaluation unit uses the frequency/phase curve (φ=g(f)) of said unit to determine the viscosity (η) of the medium;
• and
• said control/evaluation unit has an associated memory unit in which data are stored which model the functional relationship between the frequency (f) and the phase (φ) of the oscillations of said unit which can oscillate, for different damping factors (ξ) and/or for different viscosities (η).