VEGA VEGAPULS 56 Profibus PA - Manual (Page 35)

VEGAPULS 56 Profibus PA 35
Mounting and installation
The polarisation direction is in one plane with the
marking hole (the sensor must be directed with the
marking hole to the rows of holes).
Standpipe (pipe antenna) without venti-
lation hole
Pipe antenna systems must be provided with
a ventilation hole on the upper end of the
pipe. If this hole is missing, incorrect meas-
urements will result.
Sensor too close to the vessel wall
If the radar sensor is mounted too close to
the vessel wall, strong false echoes can be
caused. Buildup, rivets, screws or weld joints
superimpose their echoes onto the product
or useful echo. Please ensure sufficient dis-
tance from the sensor to the vessel wall.
In case of good reflection conditions (liquids,
no vessel installations), we recommend se-
lecting the sensor distance such that there is
no vessel wall within the inner emission cone.
For products with less favourable reflective
properties, 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 can cause
incorrect measurements. Provide a means to
prevent foam or measure in a bypass tube.
Check, if necessary, the possibility of using a
different measuring technology, e.g. capaci-
tive electrodes or hydrostatic pressure trans-
mitters.
Pipe antenna: The surge pipe open to the bottom
must have a ventilation hole on top
Correct Wrong
Wrong polarisation direction on the
standpipe
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 polarisation direction is always in the
same plane as the marking hole. Precise
directing is achieved by means of the mark-
ing holes in the intermediate flange.
Marking hole