Endress+Hauser Fieldbus Levelflex M FMP45 Operating Instructions Manual page 93

Levelflex M FMP45 with FOUNDATION Fieldbus
Installing FMP45 with
Gasphase Compensation
(Coax only)
!
Endress + Hauser
Application
For level measurement in steam applications at high pressures and temperatures.
At high pressures and temperatures, the speed at which microwave signals are propagated in steam
(polar media) is reduced above the liquid being measured. Automatic gas phase compensation
allows this physical effect to be corrected from a measurement technology point of view.
The accuracy of measurement is the higher the larger the reference Lref and the smaller the
measuring range is:
If there are fast changes in pressure, there may be an additional error, since the measured reference
distance is filtered with twice the time constant of the level measurement.
In addition, condition of imbalance (e.g. due to heating) may cause density and pressure gradients
within the medium and condensation of steam at the probe. As a result, the level readings at
different locations inside the tank may very slightly.
Caused by this application influences the measuring error may be increased by a factor up to 2 to3.
Note!
Coax probes with reference reflection can be installed in any tank (free in the tank or into a bypass).
Coax probes are completely mounted and adjusted ex work. After mounting they are ready for use,
additional settings are not necessary.
45
reference distance Lref:
40
35
30
25
20
15
10
5
0 500 1000 1500 2000 2500
distance media / flange [mm]
300
550
3000 3500 4000
Technical data
L00-FMP4xxxx-05-00-00-yy-003
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