VEGA VEGASON 51P…53P Profibus PA - Manual (Page 34)

34 VEGASON 51P … 53P
Mounting and installation
Correct and wrong length of socket piece
Wrong
Correct
Reference plane
³ 60 mm
Wrong
Mounting on a vessel with parabolic tank top
Correct
~ 1 /
2
vessel
radius
Wrong
³ 60 mm
Parabolic effects of rounded or arched
vessel tops
Round or parabolic tank tops act like a para-
bolic mirror on the signals. If the sensor is
placed at the focal point of such a parabolic
tank top, the sensor receives amplified false
echoes. The optimum location is generally in
the area of half the vessel radius from the
centre.
Socket piece too long
If the sensor is mounted in a socket exten-
sion that is too long, strong false echoes are
caused, and measurement is hindered. Make
sure that the transducer protrudes at least
30 mm out of the socket piece.