Sensor Monitoring of a Position Measurement Apparatus by Means of Thermal Noise

A position measurement apparatus includes a material measure and a scanning apparatus, which can move with respect to the material measure, with the scanning apparatus having at least one receiver turn arrangement, by means of which measurement markings on the material measure can be scanned. The scanning apparatus further includes an evaluation apparatus which can measure the electrical receiver voltage which is pressed on the receiver turn arrangement, in order to produce a position signal therefrom. The evaluation apparatus is designed to determine a noise measure from the receiver voltage, with comparison means furthermore being provided, which can compare the noise measure with a predeterminable tolerance band. The evaluation apparatus further includes an indication means which can indicate that the noise measure is outside the tolerance band.