Surface measuring apparatus

A method for operating a surface measuring apparatus for measuring a surface of a workpiece, the method comprising:

• a) providing the surface measuring apparatus, the surface measuring apparatus including:
• i) a probe for contacting the surface of the workpiece;
• ii) a feed apparatus for sampling the surface of the workpiece for moving the probe relative to the surface of the workpiece along a feed axis, the probe outputting a probe output signal during the sampling of the workpiece;
• and
• iii) an evaluation apparatus that is in data transmission connection with the probe and is designed and programmed to reconstruct the surface of the workpiece based on the probe output signal;
• b) the evaluation apparatus determining an apparatus frequency signature that represents characteristic natural frequencies of the surface measuring apparatus;
• and
• c) the analysis means detecting and analyzing a temporal course of the apparatus frequency signature in such a way that the functional state of the surface measuring apparatus is assessed based on the temporal course of the apparatus frequency signature.