VEGA VEGAFLEX 82 Foundation Fieldbus - Manual (Page 60)

60
9 Diagnostics and service
VEGAFLEX 82 • Foundation Fieldbus
44221-EN-130910
Fault description Error pattern Cause Rectification
5. Measured value
jumps sporadically to
100 % during filling
Leve
l
time 0
– Varying condensation or con-
tamination on the antenna
– Carry out a false signal sup-
pression or increase false
signal suppression with con-
densation/contamination in the
close range by editing
– With bulk solids use radar sen-
sor with purging air connection
or flexible antenna cover
Measurement error during emptying
Fault description Error pattern Cause Rectification
6. Measured value re-
mains unchanged in
the close range during
emptying
Level
time 0
– False echo larger than the level
echo
– Level echo too small
– Remove false echoes in the
close range. Check: Antenna
must protrude out of the socket
– Remove contamination on the
antenna
– In case of interferences due to
installations in the close range:
Change polarisation direction
– After removing the false ech-
oes, the false signal suppres-
sion must be deleted. Carry out
a new false signal suppression
7. Measured value
jumps sporadically to-
wards 100 % during
emptying
Level
time 0
– Varying condensation or con-
tamination on the antenna
– Carry out false signal suppres-
sion or increase false signal
suppression in the close range
by editing
– With bulk solids use radar sen-
sor with purging air connection
or flexible antenna cover
8. Measured val-
ue fluctuates around
10 … 20 %
Level
time 0
– Various echoes from an uneven
product surface, e.g. an extrac-
tion funnel
– Check parameter "Type of
medium" and adapt, if neces-
sary
– Optimize installation position
and sensor orientation
– Reflections from the product
surface via the vessel wall
(deflection)
The below tables show typical examples for application-relevant
measurement errors. There are two measurement errors:
•
Constant level
•
Filling
•
Emptying
The images in column "Error pattern" show the real level with a bro-
ken line and the level displayed by the sensor as a continuous line.
Treatment of measure-
ment errors