Stability and Linearity of PI Capacitive Position Sensors
The Latest Information on Capacitive Nanometrology Position Sensors is Available Here
PI capacitive position sensor electronics incorporate a proprietary design providing superior linearity, low sensitivity to cable capacitance, low background noise and low drift.The Integrated Linearization System (ILS) compensates for influences caused by errors, such as non parallelism between the plates. A comparison between a conventional capacitive position sensor system and the results obtained with the PI ILS is given in Fig. 5.4/1.
Nonlinearity of conventional capacitive position sensor
system vs. PI ILS system.
Fig. 5.4/2, shows the linearity of a P-752.1C PZT Flexure NanoPositioning Stage with integrated Capacitive Position Sensor operated in closed loop mode. All errors contributed by the mechanics, PZT drive, sensors and electronics are included in the resulting linearity of better than 0.02%.
Linearity of a P-752.1C, 15 µm PZT NanoPositioning Stage
operated with E-500/E-509.C1 control electronics. The travel range is 15 µm,
the gain 1.5 µm / V. Linearity is better than 0.02 %.
The exceptional long term stability of the PI capacitive position sensor/electronics design is shown in Fig. 5.4/3.
Measurement stability of a E-509.C1 Capacitive Position Sensor Control Board with 10 pF
reference capacitor over 3 ½ hours.
