VEGA VEGAPULS 51K…54K Profibus PA - Manual (Page 27)

VEGAPULS 51P … 54P 27
24890-EN-041227
Direct sensor vertically to the product surface
Correct Incorrect
Ladder
Ladder
Mounting and installation
Sensor too close to the vessel wall
Strong false echoes can also result if the
radar sensor is installed too close to the
vessel wall. Buildup, rivets, screws or weld
joints superimpose their echoes onto the
product i.e. useful echo. Please ensure a
sufficient distance from the sensor to the
vessel wall.
Standpipe installation mistakes
Pipe antenna without ventilation hole
Pipe antenna systems must be provided with
a ventilation hole on the upper end of the
surge pipe. If this hole is absent, incorrect
measurements will result.
If there are good reflection conditions (liquid
medium, no vessel installations), we recom-
mend locating the sensor where there is no
vessel wall within the inner emission cone. For
products in less favourable reflection envi-
ronments, it is a good idea to also keep the
outer emission cone free of interfering instal-
lations. Note chapter "4.1 General installation
instructions“.
Foam generation
Thick, dense and creamy foam on the prod-
uct can cause faulty measurements. Provide
preventative measures against foam or
measure in a bypass tube. Check, if neces-
sary, the possibility of using a different meas-
urement technology, e.g. capacitive
electrodes or hydrostatic pressure transmit-
ters.
Wrong polarisation direction
When measuring in a surge pipe, especially if
there are holes or slots for mixing in the tube,
it is important that the radar sensor is aligned
with the rows of holes.
The two rows of holes (displaced by 180°) of
the measuring tube must be in one plane with
the polarisation direction of the radar signals.
The type label always points in the polarisa-
tion direction.
Pipe antenna: The surge pipe open to the bottom
must have a ventilation or equalisation hole at the
upper end
Correct Incorrect
VEGAPULS 54 on the surge pipe: The sensor type
plate must be aligned with the rows of holes
Type label
Correct Incorrect