Method for operating a magnetic-inductive flow meter with a measuring apparatus for determining measured values which reproduce the field intensity of the electrical field which has been induced by the magnetic field in the flowing medium

摘要

A method for operating a magnetic-inductive flow meter in which the presence of a parasitic magnetic field is detected energizing of electromagnets with at least one first current value and at least one second current value. The measuring apparatus determines first and second measured values from energizing of the electromagnets with the first and second measured values and a first pair of measured values is formed from the first current value and the first measured value and a second pair of measured values is formed from the second current value and the second measured value, the correspondence of the pairs of measured values and of the function of permeability is determined. If correspondence of the pairs of measured values and of the function of permeability is not found that fact is signaled, the lack of correspondence being due to the at least partial presence of a parasitic magnetic field.

主权项

1. A method for operating a magnetic-inductive flow meter having a magnetic field generating apparatus for generating a magnetic field which permeates a flowing medium, a measuring apparatus for determining measured values which reproduce the field intensity of the electrical field which has been induced by the magnetic field in the flowing medium, the magnetic field generating apparatus having at least one electromagnet and a magnetic field conductor which is penetrated at least partially by the magnetic field and the permeability of the magnetic field conductor being a nonlinear function of the magnetic field intensity,
comprising the steps of: energizing the electromagnet with at least one first current value and one second current value, using the measuring apparatus for determining a first measured value when the electromagnet is energized with a first current value and a second measured value when the electromagnet is been energized with a second current value, forming a first pair of measured values from the first current value and the first measured value and a second pair of measured values from the second current value and the second measured value, determining whether or not the pairs of measured values and the function of the permeability correspond, and signalling when the pairs of measured values and the function of permeability lack correspondence due to the presence of a parasitic magnetic field being at least partially in the magnetic field conductor.