KROHNE BM 702 A EN - Manual (Page 42)

6
OPERATION
42
BM 702 A
www.krohne.com 09/2009 - 4000643301 - MA BM 702 A R01 en
6.5.4 Empty-tank spectrum
To enable the device 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.
Empty-tank spectrum recording via display
After selecting menu item Fct. 3.5.2 Fct. 3.5.2 Fct. 3.5.2 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 and can be switched on again at a later date.
• "Record": the existing empty-tank spectrum is to be deleted and a new one recorded.
After selecting "Record": if other parameters had previously been changed, the query "Store
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).
• "Average": (values are averaged; this setting can be used for most applications).
After selecting with the ↑ key, press the ^ key to select "Total" or the ↑ key to select "Partial".
• When "Total" 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 distance, 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...30 cm / 7.9...11.8" from the actual product distance.
Subsequently press key ^ to start recording the empty-tank spectrum. The display starts with
"200" and counts down to "0". The sign "Wait ..." is shown in the display. "Ready" appears after
approx. 1...3 minutes. Then press key ^ five times to store the recorded empty-tank spectrum,
which is taken into account for measurements.
.book Page 42 Thursday, September 3, 2009 2:53 PM