Intended Use; General Hints For Process Reliability - Roland R1000 Series Manual

Safety advice
1.3

Intended use

Flexible Manufacturing Systems in the sheet processing industry require reliable Double Sheet
Control systems in order to protect presses and other sheet processing machines against damage
caused by feeding multiple sheets.
The Double Sheet Detector R1000 L20 was specifically developed for this technical environment.
The reliable function of the Double Sheet Detector depends therefore most importantly on the
selection of the correct sensors and the mounting of the sensors.
1.4

General hints for process reliability

The process security of the system is influenced by the following factors:
• Stability of the measuring values
• Setting of under-gauge threshold and over-gauge threshold
• Evaluation of the status signals
Stable measuring conditions will result in stable measuring results. Varying measuring results are
undesirable, because in such cases the user is inclined to decrease the under-gauge threshold
LOW and to increase the over-gauge threshold UP. 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:
• Optical characteristics of the material
• Tolerance in material thickness
• Contamination of the material
• Geometric conditions at the place of measurement (Stability of the sensor gaps)
• Contamination of the sensors (dirt, oil ...)
From this some simple rules can be derived, which enable a high process security when abided by:
• Every different sheet (Thickness, material and contour) is measured with separate
measuring program.
• Adjust the switching thresholds as tight as possible!
• Keep the sensor gap constant!
• Make use of the air connection to keep the sensors clean!
Furthermore it is necessary that the machine control:
• checks all status signals of the L20,
• checks the 0-sheet signal.
While measuring, only the 1-sheet signal may occur. If 0-sheet or 2-sheet occurs, the measured
sheet may not be transported on. In such cases, the sheet will usually be removed.
• The machine controls needs to evaluate all status signals !
Checking-up through the 0-sheet signal is to assure that a sheet really is between the sensors
during measuring. If 0-sheet occurs while measuring, the measurement is not correct. For example,
a defective sensor holder might change the sensor gap. Monitoring the sheet thickness would then
only be seemingly performed.
In case of double sheet severe consequences could then result.
8
ROLAND ELECTRONIC GmbH · Otto-Maurer-Str. 17 · DE 75210 Keltern · Phone +49 (0)7236-9392-0 · Fax +49 (0)7236-9392-33
Double Sheet Control System R1000 series L20
with integrated fieldbus interface
Manual
B0063191 / 1.3