KROHNE BM 702 EN - Manual (Page 16)

16 Installation and operating instructions BM 702 (06/04)
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Sump non
measurable
zone
tank height
(Fct. 3.1.1)
Fct. 3.1.4
upper reference point
(top edge of tank connecting flange)
block distance (Fct. 3.1.2)
response
current output
20
mA
max
(Fct. 3.3.4)
4
min
(Fct. 3.3.3)
lower reference point
(tank bottom / datum point)
Fct. 3.1.5
threshold
measuring
mA
[e.g.: 5.30 m]
[e.g.: 0]
[e.g.: 0]
[e.g.: 0.6 m]
[e.g.: 0.4 m]
[e.g.: 4.0 m]
range
Empty-tank spectrum
To enable the BM 702 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, 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 702 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.