Endress+Hauser Profi Bus Levelflex M FMP40 Operating Instructions Manual page 83

Levelflex M FMP40 PROFIBUS PA
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).
[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 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.
[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
(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]
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