VEGA VEGAPULS 51K…54K Profibus PA - Manual (Page 26)

26 VEGAPULS 51P … 54P
24890-EN-041227
Mounting and installation
3.5 Common installation mistakes
Socket piece too long
If the sensor is mounted in a socket exten-
sion that is too long, false reflections are
caused, and measurement is hindered. Make
sure that the horn antenna protrudes at least
10 mm out of the socket piece. If you use a
rod antenna, the socket piece can have a
length of max. 100 or 60 mm (with a rod
length of 545 mm, the socket piece can have
a length of max. 250 mm).
Horn antenna: correct and incorrect socket length
Rod antenna: correct and incorrect socket length
Incorrect
Correct Incorrect
Incorrect
Mounting on a vessel with parabolic tank top
Correct
~ 1 /
2
vessel
radius
Incorrect
- 100 mm
(250 mm)
Correct
< 100 mm
(250 mm)
Parabolic effects on dished or arched
vessel tops
Round or parabolic tank tops act on the ra-
dar signals like a parabolic mirror. If the radar
sensor is placed at the focal point of such a
parabolic tank top, the sensor receives am-
plified false echoes. The optimum mounting
location is generally in the range of half the
vessel radius from the centre.
≥ 10 mm
Wrong orientation to the product
Weak measuring signals are generated if the
sensor is not directly pointed at the product
surface. Orient the sensor axis perpendicu-
larly to the product surface to achieve opti-
mum measuring results.
Reference
plane