VEGA VEGAPULS 41 4 … 20 mA; HART compact sensor - Manual (Page 14)

14 VEGAPULS 41 – 4 … 20 mA
26620-EN-041227
Screwed antenna on1½“ mounting boss
2.2 Measurement of liquids
Most commonly, the mounting of radar sen-
sors is done on short DIN socket pieces. The
lower side of the instrument flange is the
reference plane for the measuring range. The
socket piece should be as short as possible,
max. 70 mm.
When mounting on dished vessel tops, the
antenna length should at least correspond to
the length of the socket.
On dished vessel tops, please do not mount
the instrument in the centre or close to the
vessel wall.
Dished tank tops can act as paraboloidal
reflectors. If the radar sensor is placed in the
focal point of the parabolic tank top, the radar
sensor receives amplified false echoes. The
radar sensor should be mounted outside the
focal point. Parabolically amplified echoes are
thereby avoided.
Horn antenna directly on the vessel top
If the stability of the vessel will allow it (sensor
weight), flat mounting directly on the vessel
top is a good and economical solution. The
top side of the vessel is the reference plane.
The screwed antenna is used mainly on very
small vessels. The antenna fits into even the
smallest vessel connection openings (1
1 /
2
“
socket). The socket must not be longer than
70 mm.
Mounting and installation
Reference
plane
< 70 mm
Filled vessel
In a completely filled vessel, you see addi-
tional multiple echoes at two, three or four
times the distance of the product surface
echo.