Function And System Design; Measuring Principle - Endress+Hauser Levelflex FMP56 Technical Information

Levelflex FMP56, FMP57

Measuring principle

Endress+Hauser

Function and system design

General principles
The Levelflex is a "downward-looking" measuring system that functions according to the time-of-
flight method (ToF). The distance from the reference point to the product surface is measured. High-
frequency pulses are injected to a probe and led along the probe. The pulses are reflected by the
product surface, received by the electronic evaluation unit and converted into level information. This
method is also known as TDR (time domain reflectometry).
R
LN
 1 Parameters for level measurement with guided wave radar
LN Probe length
D Distance
L Level
R Reference point of measurement
E Empty calibration (= zero)
F Full calibration (= span)
If the ε value is less than 7 in the case of rope probes, measurement is not possible in the area
r
of the tensioning weight (0 to 250 mm (0 to 9.84 in) from the probe end), (lower blocking
distance).
The reference point R of the measurement is located at the process connection.
D
E
L
20 mA
100%
F
4 mA
0%
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