inductive sensor unit for detecting a spacing from a metallic object, comprising - a sensor coil, wherein the sensor coil has an inductance and an active resistance, and the sensor coil can be acted on by an excitation signal, - a transistor, - a resistance, - an evaluating unit for determining the spacing, wherein the evaluating unit is arranged for the purpose of providing an evaluation signal in dependence on the determination, - a switching unit for determining an actual value of the inductance of the sensor coil and/or an actual value of the active resistance (R S) of the sensor coil and/or a variable having a functional correlationship with the actual value of the inductance and/or with the actual value of the active resistance (R S) and derived from one or more of the actual values, wherein - the sensor coil is connectible by way of the transistor and the resistance with a voltage source (V+) arranged to provide an excitation signal, wherein a control signal (V Puls) can be fed to the control electrode of the transistor, - the switching unit comprises a computing unit arranged to receive scanning values of a voltage (U 2) of the sensor coil and a voltage (U 1) from the resistance, - the computing unit is configured to determine actual values of the active resistance (R S) and/or the inductance and/or the derived variable from the time plot of the coil voltage at a plurality of time intervals and - the computing unit comprises an interface to provide by means of the interface the actual value of the active resistance and/or the active value of the inductance and/or the derived variable additionally to the evaluation signal. - a sensor coil, wherein the sensor coil has an inductance and an active resistance, and the sensor coil can be acted on by an excitation signal, - a transistor, - a resistance, - an evaluating unit for determining the spacing, wherein the evaluating unit is arranged for the purpose of providing an evaluation signal in dependence on the determination, - a switching unit for determining an actual value of the inductance of the sensor coil and/or an actual value of the active resistance (R S) of the sensor coil and/or a variable having a functional correlationship with the actual value of the inductance and/or with the actual value of the active resistance (R S) and derived from one or more of the actual values, wherein - the sensor coil is connectible by way of the transistor and the resistance with a voltage source (V+) arranged to provide an excitation signal, wherein a control signal (V Puls) can be fed to the control electrode of the transistor, - the switching unit comprises a computing unit arranged to receive scanning values of a voltage (U 2) of the sensor coil and a voltage (U 1) from the resistance, - the computing unit is configured to determine actual values of the active resistance (R S) and/or the inductance and/or the derived variable from the time plot of the coil voltage at a plurality of time intervals and - the computing unit comprises an interface to provide by means of the interface the actual value of the active resistance and/or the active value of the inductance and/or the derived variable additionally to the evaluation signal.