ABB PFEA 113, Руководство пользователя

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Tension Electronics PFEA113, User Manual
Appendix A Technical Data for Tension Electronics PFEA113
A-4 3BSE029382R0101 Rev C
A.3 Segmented Roll Scale Factor (SRSF)
Segmented Roll Scale Factor (SRSF) is used to compensate the total measured tension and
present an estimate of total tension when not all rolls are supported by load cells at both ends in
a segmented roll application.
The total force in the load cells measuring direction is F
RTension
= Tension/Wrapgain. If the
number of installed load cells is less than the number of roll supports, the total measured force,
F
Rmeasured
will be less than F
RTension
. To present an estimate of the total web tension, T
estimate
,
in those segmented roll applications, a segmented roll scale factor (SRSF) can be set.
T
estimate
= F
Rmeasured
x WrapGain x SRSF
Note: individual signals (Tension A, Tension B and so on) and difference signals (A-B, A-C,
D-AI2 and so on) are not multiplied with SRSF.
The following section describes how to calculate the SRSF.
In the examples are segmented rolls with four rolls used, but with the description below can
SRSF easily be calculated in other segmented roll applications.
If a segmented roll have more than one electronic i.e. more than four load cells, the SRSF must
be calculated separately for each electronic unit.
If N/m, kN/m, kg/m or pli is selected as presentation unit, the individual signals (Tension A,
Tension B and so on) and difference signals (A-B, A-C, D-AI2 and so on) are divided with the
set web width.
Figure A-2. Segmented roll
A.3.1 Simplified calculation of SRSF
If all rolls have the same length and we neglect that the width of the web is less than the distance
between the end support points, the calculation can be done in the following way.
Figure A-3. Load cells at the end and in the middle of the segmented roll.
Distance between the end support points
Width of the web
Z1
Z2 Z3