Endress+Hauser Levelflex M FMP40 - Page 76

Commissioning Levelflex M FMP40 FOUNDATION Fieldbus
76 Endress+Hauser
Evaluating the measurement with the aid of the envelope curve
Typical curve shapes:
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).
L00-FMP40xxx-05-00-00-en-024
Level echoes are indicated 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.
400.00
400.00
[mV]
[mV]
300.00
300.00
200.00
200.00
100.00
100.00
0.00
0.00
-100.00
-100.00
-200.00
-200.00
-300.00
-300.00
-400.00
-400.00
-500.00
-500.00
0.00
0.00
0.20
0.20
0.40
0.40
0.60
0.60
0.80
0.80
1.00
1.00 1.20 1.40
[m]
[m]
LN
LN
E
E
F
F
(1.00 m, -143.00 mV)
(1.08 m, -115.00 mV)
Rod probe
Rope probe
Probe end signal
Launch pulse
Probe end signal
Launch pulse