Insensitivity to Cable Influences
The Latest Information on Capacitive Nanometrology Position Sensors is Available Here
When measuring distance by detection of capacitance changes, fluctuations in the cable capacitance can have a negative effect on the accuracy. This is why most capacitive measurement systems only provide satisfactory results with cable lengths to 1 m. With PI capacitive position sensors and electronics cable influence can be neglected for cable lengths up to 3 m.Material Match
The best measuring results can be obtained when the sensor and the part where it is mounted are thermally matched. The greater the mismatch the worse the result. A Super Invar sensor mounted on an aluminum stage will yield the same poor results as an aluminum sensor on a Super Invar stage. When the temperature changes, the sensor will bend and buckle thus significantly reducing overall accuracy.Electrode Geometry, Sensor Surface Flatness and Finish
The target and probe plates are configured in a way that the sensor capacitance in air is 10 pF for all models at nominal measuring distance. This means that one sensor electronic module can operate all sensor ranges without modification.During sensor production, great care is taken to maintain critical mechanical tolerances. Measuring surfaces are diamond-tool machined using sophisticated process control. This creates the smooth, ultra-flat mirrored surfaces required to obtain the highest resolution commercially available.
