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BM 70 A Kurzanleitung
Seite: 13
4. Entwurf 03/97
Empty-tank spectrum
To enable the BM70 A to identify and blank out interference signals, e.g. caused by
fixed and moving tank internals, the tank profile (empty-tank spectrum) needs to be
recorded once only prior to (initial) start-up. For recording, the tank should be
completely empty and all moving parts (e.g. agitators) switched on. If major
interference through internals is not expected, recording of the empty-tank spectrum
can also be dispensed with, since the factory has already carried out and stored a
partial empty spectrum of the flange system.
After selecting menu item Fct. 3.5.2, press key
. The display then shows whether
the empty spectrum is currently ON or OFF. Then press the
key if no change is to
be made, or use the
key to choose between the following options:
•
ON: the empty-tank spectrum is (again) switched on and taken into account for
measurements.
•
OFF: the empty-tank spectrum is not taken into account for measurements, but
remains stored in the BM 70 A and can be switched on again at a later date.
•
RECORDING: the existing empty-tank spectrum is to be deleted and a new one
recorded.
After selecting "RECORDING": if other parameters had previously been changed,
the query "ACCEPT YES" is first made as to whether they are to be stored. In this
case, confirm by pressing
. To record, use the
key to select one of the following
options:
•
MAX. VALUES: (only maximum values are taken into account when the empty-
tank spectrum is recorded; useful e.g. with “difficult“ agitators).
•
AVERAGING: (values are averaged; this setting can be used for most
applications).
After selecting with the
key, press the
key to select COMPLETE or the
key to
select PARTIAL.
•
When COMPLETE is selected, the empty-tank spectrum is recorded over the
entire range (tank height).
•
If the tank has not been fully drained, the empty-tank spectrum can also be
recorded up to a certain range, in which case the menu item PARTIAL should
be selected. When this has been selected, a query takes place by way of the
key concerning the distance value up to which the empty-tank spectrum is to
be recorded. The tank area below the current filling level is then excluded from
the empty-tank recording. It is recommended to maintain a safety distance of
20 to 30 cm from the actual distance.
Subsequently press key
to start recording the empty-tank spectrum. The display
starts with “1000“ and counts down to “0“. The sign WAIT flashes in the display.
FINISHED appears after approx. 1.5 minutes. Then press key
five times to store
the recorded empty-tank spectrum, which is taken into account for measurements.
Conversion table/Volume table
A table consisting of a maximum of 50 points can be stored in the BM 70 A for non-
linear or linear conversion of the level, e.g. into a volumetric value. This table,
however, can only be programmed with the PC-CAT program.
