Function "Envelope Curve Display" (0E3) - Endress+Hauser Levelflex M FMP41C Operating Instructions Manual

Commissioning
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6.7

Function "envelope curve display" (0E3)

You can obtain the following information from the envelope curve display in this function:
envelope curve
minimum distance
mapping
substracted signal
6.7.1 Envelope curve
The Levelflex emits individual pulses in quick succession and scans their reflection with a slightly
variable delay. The energy values received are ordered by their time-of-flight. The graphic
representation of this sequence is known as an "envelope curve".
6.7.2 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.
quality of
full calibr. evaluated echo
distance of
of the plot evaluated echo
full calibr.
empty calibr.
Levelflex M FMP41C PROFIBUS PA
evaluated echo
empty calibr. is marked
maximum distance
probe length of the plot
level echo
empty calibr.
level echo
probe length
Endress+Hauser
L00-FMPxxxxx-07-00-00-en-003