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Unformatted text preview: following formula
π ⋅µr ⋅ µ 0 ⋅ κ ⋅f Whereby µ0
f = 1.257 ⋅ 10-6 Vs/Am = Magnetic field constant
= Relative permeability
= Frequency It can be seen that the greater the permeability and the conductivity of the material,
the smaller the penetration depth. If the material thickness of the object being
detected by an inductive proximity sensor is less than the penetration depth of the
field, then a part of the field is outside the plate, thus resulting in greater switching
distances. Materials Penetration depth [mm] Copper 0.073 Aluminium 0.094 Brass 0.16 Table 11.1.3: Field penetration depths at a frequency of f = 800 kHz © Festo Didactic GmbH & Co. KG • FP 1110 163 11. Physical fundamentals 11.1.2 Capacitive proximity sensors
The active element of a capacitive proximity sensor consists of a capacitor, which is
made up of a disc-shaped metallic electrode and a beaker-shaped half-open metallic
shield. If a non-conductive or conductive material is introduced into the active zone
in front of the sensor, capacity C of the ca...
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This note was uploaded on 11/01/2012 for the course CHEMICAL 102 taught by Professor Jamesrodriguez during the Spring '12 term at Universidad Politécnica de Cartagena.
- Spring '12