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Cha p te r

Tubular T w o Inductive Extended Capacitive Extended
Diameter, mm Range, mm Range, mm
18 8 10
30 15 20
34 — 40
Sensing distance for capacitive proximity sensors is a matter of
plate diameter, as coil size is for inductive proximity sensors. Capaci-
tive sensors basically measure a dielectric gap. Accordingly, it is
desirable to be able to compensate for target and application condi-
tions with a sensitivity adjustment for the sensing range. Most capac-
itive proximity switches are equipped with a sensitivity adjustment
potentiometer (Fig. 2.64).

2.7.4 Target Material and Size
The sensing range of capacitive sensors, like that of inductive prox-
imity sensors, is determined by the type of material. Table 1.7 lists the

FIGURE 2.64
Sensitivity
adjustment.

Material Factor
Mild steel 1.0
Cast iron 1.0
Aluminum and copper 1.0
Stainless steel 1.0
Brass 1.0
Water 1.0
Polyvinylchloride (PVC) 0.5
Glass 0.5
Ceramic 0.4
Wood ≥0.2
Lubrication oil 0.1

TABLE 2.7 Target Material Correction