Unformatted text preview: 10 4. Inductive proximity sensors A standardised calibrating plate is used to determine the switching distance of
inductive proximity sensors. Only in this way can useful comparisons of switching
distances of different inductive proximity sensors be made. The standard measuring
plate is made of steel S 235 JR and is 1 mm thick. It is square and the length of a side
is equal to
• the diameter of the active surface of the sensor,
• three times the nominal switching distance.
The higher of the two values is to be used as the lateral length of the standard
calibrating plate. Using plates with larger areas does not lead to any significant
changes in the switching distance measured. However, if smaller plates are used
this leads to a reduction of the switching distance derived.
Also, the use of different materials leads to a reduction of the effective switching
distance. The reduction factors for different materials are listed in the table below. Material Reduction factor Steel S 235 JR (old: St37) 1.0 Chrome nickel 0.70 – 0.90 Brass 0.35 – 0.50 Aluminium 0.35 – 0.50 Copper 0.25 –...
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- Spring '12
- pH, proximity sensors, Festo Didactic GmbH, Festo Didactic GmbH & Co