Berthold LB 442, Operating Manual

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7.2 Tare Measurement
70
The external tare measurement can also be interrupted or contin-
ued again by pressing the < run > button.
Current Output during Tare Measurement
During tare measurement the current output (26a/26c) does not
supply any current (0 mA).
Manual Input of the Tare Count Rate
You may also enter the tare count rate manually. Confirm you en-
try with < enter >.
Verification and Correction of the Tare Measurement
Check whether the tare value is correct by running the belt without
load for several minutes. During measurement, watch how the
value in the tonnage memory changes. If this change is too big,
you have to repeat tare measurement.
7.2.2 Tare Compensation
All changes occurring in the course of time have to be compen-
sated for by a tare measurement. This includes changes of the
conveyor belt, for example replacement of belts or chains links.
Tare must also be determined again when the belt has been re-
placed. Recalibration is not necessary.
The same applies if the source is replaced after several years.
If a tare measurement is performed after calibration, all count
rates of the calibration points are converted in accordance with the
new calculated tare count rate. As a result, the calibration curve
remains unchanged, even if it is calculated again with these val-
ues.
Therefore, a tare measurement can be carried out any time and
used for correction of the calibration.
Furthermore, one or several calibration points can be added any
time. When adding calibration points, the calibration curve has to
be calculated new (see next section).