MICRO-EPSILON combiSENSOR 64x0 Instruction Manual page 12

Functional Principle, Technical Data
Fig. 2 Sensor arrangement for thickness measurement
The thickness of the insulator is calculated from the following factors: max. working distance, capacitive dis-
placement signal A and the dielectric constant of the insulator:
T = S (eddy) - A (capa) *
combiSENSOR 64x0
A
T
T<A
Insulator (
Ground electrode

r

1

r
Sensor
)
Target
r
T
S
WD
A
* + Offset
100 %
WD
Offset
Target thickness [µm]
Signal eddy sensor [%]
Signal capacitive sensor [%]
Dielectric constant (insulator)
r
Working distance [µm]
Constant [µm], standard value = 0
Page 12