Endress+Hauser Levelflex M FMP40 - Page 70

Commissioning Levelflex M FMP40 FOUNDATION Fieldbus
70 Endress+Hauser
6.7.5 Mapping (empty curve) and difference curve
To suppress interference signals, the envelope curve is not directly evaluated in the Levelflex.
The mapping (empty curve) is first subtracted from the envelope curve.
The system looks for level echoes in the resulting difference curve.
Difference curve = envelope curve - mapping (empty curve)
The mapping (empty curve) should be a good representation of the probe and the empty tank or
silo. Ideally, only the signals from the medium being measured remain in the difference curve.
6.7.6 Mapping
• Factory mapping
Mapping (empty curve) is already available in the device when the device is delivered.
•Customer mapping
In a partially filled state, the distance up to 10 cm before the actual total level can be mapped
(range of mapping = actual distance from total level - 10 cm), or values > LN can be mapped in
the case of empty tanks.
• Dynamic mapping
It is not static like factory and customer-specific interference echo suppression. Instead, it follows
directly from static mapping and constantly adapts to the changing features of the probe
environment during ongoing operation. Thus, dynamic mapping does not have to be recorded
explicitly.
6.7.7 Echo threshold
Maximum points in the difference curve are only accepted as reflection signals if they are above a
specified threshold. This threshold depends on the location and is automatically calculated from the
ideal echo curve of the probe used. The calculation of the threshold in question depends on the
"Installation" customer parameter in the extended calibration function.
6.7.8 Navigation in the envelope curve display
Using navigation, the envelope curve can be scaled horizontally and vertically and shifted to the left
or the right. The active navigation mode is indicated by a symbol in the top left hand corner of the
display.
L00-FMPxxxxx-07-00-00-en-004
…
Move mode:
- m
-
oved to the left
moved to the right
Horizontal Zoom mode:
- h
-
orizontal zoom in
horizontal zoom out
Vertical Zoom mode:
- vertical zoom (4 steps)