Manual
Double Sheet Detector R1000 series E20
with integrated fieldbus interface
B0046191 / Rev. 1.12
System description
ROLAND ELECTRONIC GmbH · Otto-Maurer-Str. 17 · DE 75210 Keltern · Phone +49 (0)7236-9392-0 · Fax +49 (0)7236-9392-33
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3 System
description
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Flexible production systems in the sheet processing industry require automated, reliable double
sheet detection in order to protect presses and other processing machinery from damage by
multiple sheets. The E20 was specifically developed for this technical environment.
The E20 is based on the product platform R1000 and consists in the standard version of three
components:
• Control
unit
•
One sensor for ferrous materials
• Sensor
cable
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3.1 Measurement
principle
The double sheet detector is based on the electromagnetic principle. It monitors ferromagnetic
sheets with single sided sensors and exerts forces during the monitoring process only. A change of
the sheet thickness results in a change of induction. The system calculates the sheet thickness
from this change. Corresponding to the pre-set limits 0-sheet, 1-sheet or 2-sheets signals are
generated.
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3.2
General hints for process security
The process security of the system is influenced by the following factors:
•
the stability of the measuring values
•
the setting of under-gauge threshold and over-gauge threshold
•
the evaluation of the status signals
Stable measuring conditions will result in stable measuring results. For measuring procedures with
single-sided contacting sensors the
air gap
between sensor and material surface is a decisive
criterion.
Air gaps varying from measurement to measurement will cause varying mesuring results. Basically,
such situations are bad, since in such cases the user is inclined to decrease the under-gauge
threshold and to increase the over-gauge threshold. On doing so, the user puts up with the
drastically increasing risk of not detecting a double sheet.
The following external factors decisively influence the stability of measuring results and need to be
considered for operation of a double sheet detector:
•
the air gap between sensor and material surface
•
the magnetical characteristics of the material
•
the tolerance in material thickness
From this some simple rules derive, which enable a large degree of process security when abided
by:
•
Always care for good contact of the sensor with the material!
•
Use separate programs to measure different sheet thickness (and alloy)!
•
Adjust the switching thresholds as tight as possible!
