Circuitry for and a method of compensating drift in resistance in eddy current probes

A method of configuring an eddy current non-destructive inspection device, wherein the inspection device including an eddy current probe having a probe circuit including coil components wherein the passage of a probe current through the probe circuit is effective to induce eddy currents in a test object when the probe and the test object are coupled, and the probe is effective to sense the eddy currents, wherein the probe circuit has a dynamically changing probe resistance,

• wherein the method comprising the steps of,
• generating an at least one inspection frequency signal and a low frequency AC signal, wherein the inspection frequency signal processes the sensed eddy currents to sensed signal, wherein the at least one inspection frequency signal affects the eddy currents and the sensed signal;
• receiving and processing the sensed signal and producing resulting signals by using a processing circuit, the resulting signal including a signal drift caused by change in coil conditions including temperature change, wherein the processing circuit further comprising at least one compensator,
• conducting coil monitoring by detecting the low frequency AC signal, applying a low pass filter and calculating a compensated value of the probe resistance with the signal drift annihilates and by which further deriving at least one compensation operation,
• correcting the resulting signals and producing corrected resulting signals based on at least one predetermined compensating operation that includes the compensated value of the dynamic probe resistance.