METHOD AND DEVICE FOR INDUCTIVE MEASUREMENT OF PHYSICAL PARAMETERS OF AN OBJECT OF METALLIC MATERIAL TOGETHER WITH USE OF THE METHOD AND THE DEVICE

摘要

A method and a device for inductive measurement of physical parameters of an object (1) of metallic material. In a measurement range, there is generated a time-varying magnetic field from a primary coil (4). The magnetic field induces eddy currents in the object which influence the time-varying magnetic field. The field is detected by a measuring coil (4), from which a signal is obtained which carries information about the desired parameters. A field-measuring coil (5) is introduced outside the measurement range but surrounded by an electric circuit generated at the measurement range. The field-measuring coil senses a current (6) which is induced in the electric circuit by the time-varying magnetic field. The interfering magnetic field generated by the current, and which influences the time-varying magnetic field, adds an error to the measurement. The output signal of the field-measuring coil is thereby used to compensate the output signal of the measuring coil such that the error caused by the current in the electric circuit is eliminated.