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Function, Construction and Purpose
The object detector S-SW-8 is a capacity sensor system with a differential signal evaluation to detect
the presence of metallic and other conductive objects
contactlessly
with the help of connected
sensor electrodes.
The object detector S-SW-8 is mainly used in conveyor technology to control roller conveyors. This
sensor system offers particular advantages in heavily polluted environments, like rolling mills, blast-
ing systems, paint booths, etc. The reason is the insignificant effect on the functions from contami-
nation of slag, metal dust or blasting media on its detection area.
On the first use, the unit must run the calibration process.
The detector area must be free of
mobile objects and people during the calibration process. The bias point state is recorded and saved
as a reference.
After that, objects can enter the detection area. If the sensitivity is set appropriately, the presence of
the new objects is detected. A potential-free contact relay turns ON/OFF according to the IN/OUT
movement of objects over the sensing area (the switching position vary according to the type of
objects and configured sensitivity).
The sensor system consists of two parts:
1.
Evaluation unit
:
Correct connection of the reference potential for the evaluation unit is
essential for proper functionality (connection of the earth potential)
(X1/3).
The evaluation unit uses sensor electrodes for detection. They are mounted
in a poly-carbonate case (IP65) and placed near the electrodes.
2.
Sensor electrode
:
The sensor electrodes are not included in the delivery package.
Their
design depends on the specific user application and must be carried out in
compliance with certain rules (see below) in accordance with the technical
requirements. The shape of the electrodes determines the detection area:
– Narrow electrodes cause
small switching hysteresis,
– wide electrodes cause
large switching hysteresis.
The electrodes are connected to the evaluation unit.
