KROHNE BM 70 A Installation And Operating Instructions Manual page 43

8.5.2 Volume measurement (example)
• In order to be able to measure volume with
the BM 70 A/P, a conversion table (volume
table) needs to be compiled with the PC-
CAT program (see Sect. 8.12).
•
By means of the volume table, various
levels are allocated to specific volumes
previously calculated or measured out.
Volume table
Tank height (Fct. 3.1.1):
Antenna extension (Fct. 3.1.6):
Block distance (Fct. 3.1.2):
Response threshold, maximum measurable level = 5.30 m, equivalent to a volume of 16.80 m ³
(calculated from lower reference point)
Current output I
Switching output
Display
Installation and operating instructions BM 70 A/P
•
•
Unit volume (Fct. 3.2.3): m
Set table (PC-CAT):
6.00 m
0.20 m
0,70 m
= tank height - block distance
(Fct. 3.1.1) (Fct. 3.1.2)
= 6,00 m - 0,70 m
Function I (Fct 3.3.1):
Range I (Fct. 3.3.2):
Scaling 4 mA (Fct. 3.3.3):
Scaling 20 mA (Fct. 3.3.4):
Function S (Fct. 3.6.1):
Type S (Fct. 3.6.2):
Threshold(Fct. 3.6.3):
Hysteresis (Fct. 3.6.4)
Function, display (Fct. 3.2.1):
Unit, conversion (Fct. 3.2.2):
In the case of non-sy mmetrical tanks, e.g.
tanks with dished bottom, the accuracy of
volume measurement will depend on the
number of set "level/volume pairs". The
maximum number of pairs (points) that can
be set is 50; the volume is linearly
determined (interpolated) between 2 points.
In the following example, 4 data pairs have
been progra mmed.
3
Point Level
0.00 m
0.25 m
0.50 m
5.30 m
CONVERSION
4 - 20 mA
3
0.00 m , corresponds to 4 mA
3
16.80 m , corresponds to 20 mA
LEVEL
LOW
(=if level drops below threshold
5.00 m
0.10 m
CONVERSION
3
m (cubic meter)
Page: 43
Volume
0.25 m³
0.70 m³
1.40 m³
16.80 m³
)
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