Endress+Hauser Fieldbus Levelflex M FMP41C Operating Instructions Manual page 71

Levelflex M FMP41C with FOUNDATION Fieldbus
!
Endress + Hauser
6.8.2 Envelope curve with the ToF Tool
After the basic setup, an evaluation of the measurement using the envelope curve is
recommended (see Page 71).
Note!
For the optimization of the measurement the installation of the Levelflex in another place can be
executed when enterference echoes.
An evaluation of the measurement with the aid of the envelope curve
Typical curve shape:
The following examples display typical curve shapes for a rope or rod probe in an empty tank. For
all probe types, a negative probe end signal is shown. For rope probes, the end weight causes an
additional preliminary positive echo (see rope probe diagram).
[mV]
400.00
300.00
200.00
100.00
0.00
-100.00
-200.00
-300.00
Launch pulse
-400.00
F
-500.00
0.00 0.20 0.40 0.60
Rod probe
Level echoes are detected as positive signals in the envelope curve. Interference echoes can be both
positive (e.g. reflections from internals) and negative (e.g. nozzles). The envelope curve, the map
and the differential curve are used for the evaluation.Level echoes are searched for in the differential
curve.
[mV]
400.00
300.00
200.00
100.00
0.00
-100.00
(1.00 m, -143.00 mV)
-200.00
Probe end signal
-300.00
Launch pulse
-400.00
E LN
-500.00
0.80 1.00 [m] 0.00
Commissioning
L00-FMP4xxxx-20-00-00-en-007
(1.08 m, -115.00 mV)
Probe end signal
F E LN
0.20 0.40 0.60 0.80 1.00
Rope probe
L00-FMP40xxx-05-00-00-en-024
1.20 1.40 [m]
71