Method for checking a vibronic measuring system

A method for checking a vibronic measuring system for ascertaining at least one measured variable of a flowable measured substance, comprising:

• said vibronic measuring system including:
• a measuring transducer including:
• a vibration element;
• an electromechanical oscillation exciter for converting electrical power into mechanical power serving for exciting and maintaining forced mechanical oscillations of the vibration element;
• and
• an electrodynamic first oscillation sensor for registering mechanical oscillations of the vibration element at a first oscillation measuring point and for providing at least one electrical, oscillation signal at least partially representing oscillatory movements of the vibration element;
• and
• a transducer-protective housing for the measuring transducer, wherein the at least one oscillation exciter as well as also the first oscillation sensor as well as the vibration element are arranged within the transducer-protective housing;
• the method including steps of:
• positioning a first test magnet at a first test position outside of the measuring transducer for producing a first test magnetic field partially passing through the measuring transducer;
• causing the vibration element to vibrate to generate a first test signal ultimately provided by the first oscillation sensor in the case of the first test magnet positioned at the first test position, and in the case of the first test magnetic field passing through the measuring transducer;
• using the first test signal for ascertaining at least a first characterizing number value, which quantifies a first oscillation characterizing number characterizing oscillations of the vibration element;
• comparing the first characterizing number value with one or more characterizing number threshold values for the first oscillation characterizing number;
• and
• detecting a disturbance of the measuring system if the first characterizing number value exceeds a first characterizing number threshold value, or when the first characterizing number value has left a first value range bounded on one end by the first characterizing number threshold value.