9
3 Product description
VEGAFLEX 83 • 4 … 20 mA/HART - two-wire
41834-EN-120726
TS
d1
h1
h2
d2
1
L2
L1
Fig. 2: Interface measurement
1 Sensor reference plane (seal surface of the process fitting)
d1 Distance to the interface (HART value 1)
d2 Distance to the level (HART value 3)
TS Thickness of the upper medium (d1 - d2)
h1 Height - Interface
h2 Height - Level
L1 Lower medium
L2 Upper medium
Upper medium (L2)
•
The upper medium must not be conductive
•
The dielectric constant of the upper medium must be known (input
required). Min. dielectric constant: rod version 1.6. You can find a
list with the dielectric constants on our home page: www.vega.com
•
The composition of the upper medium must be stable, no varying
products or mixtures
•
The upper medium must be homogeneous, no stratifications
within the medium
•
Min. thickness of the upper medium 50 mm (1.97 in)
•
Clear separation from the lower medium, no emulsion phase, no
mull layer
•
If possible, no foam on the surface
Lower medium (L1)
•
The dielectric figure must be 10 higher than the dielectric constant
of the upper medium, preferably electrically conductive. Example:
upper medium dielectric constant 2, lower medium at least dielec-
tric constant 12.
The instrument is always preset to the application "
Level measure-
ment
".
For the interface measurement, you can select the requested output
signal with the setup.
Prerequisites for inter-
face measurement
Output signal
