VEGA VEGAPULS 56 Profibus PA - Manual (Page 29)

VEGAPULS 56 Profibus PA 29
Pipe antenna: The surge pipe open to the bottom
must have a vent or equalisation hole on top.
Correct Wrong
Mounting and installation
In products with a small relative dielectric
constant, a > 45° deflector plate installed
under the end of the standpipe will prevent
the vessel bottom from being detected as
level instead of the product surface.
Vent hole
Pipe antenna systems must be provided with
a vent hole at the upper end of the surge
pipe. A missing hole will cause inaccurate
measurements.