Page 391 - Sensors and Control Systems in Manufacturing

4
5
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D-015
+10 D-015 D-050 D-100 D-050
6
D-100
Analog output (V) –5
+5
0

50 100 150 200 250 300 350 400 450 μm
Standard measuring range
Extended measuring range
FIGURE 7.22 Measuring ranges of different capacitive position sensors,
standard ranges are 1- D-015, 3- D-050, and 4- D-100, while the extended
ranges are 2- D016, 5- D050, and 6- D-100.

in the electronics. The nominal range itself can be increased or
decreased by selecting a different reference capacitor in the electronics
(Fig. 7.22).

7.11 Parallelism of Measuring Surfaces
For optimum results, target and probe plates must remain parallel to
each other during measurement (Figs. 7.23a and 7.23b). Positioning
systems with multilink flexure guidance reduce tip and tilt to negli-
gible levels (Fig. 7.24) and achieve outstanding accuracy.
This effect is negligible in nano-positioning systems with micro-
radian-range guiding accuracy (Fig. 7.24).
Flexure-guided nano-positioning systems offer sub-micro-radian
guiding accuracy and are optimally suited for capacitive sensors
(Fig. 7.24).

7.12 Electronics Support
Standard nano-capacitive position sensor electronics are supported
by all digital controllers. Inputs are developed on I/O controller cards
and on several OEM controllers for high-speed parallel port control-
lers (Fig. 7.25). In addition, nano-capacitive sensors may be devel-
oped to accommodate up to seven channels to meet specific needs.
Various sensor probes are available at 100 µm, 50 µm, and 20 µm
and are developed for nominal measurement range (Fig. 7.26).