Measurement error during emptying – VEGA VEGAPULS 62 (≥ 2.0.0 - ≥ 4.0.0) 4 … 20 mA_HART four-wire Approval according to LPR radio standard User Manual

Page 59

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background image

Fault description

Error pattern

Cause

Rectification

6. Measured value re-
mains momentarily un-
changed during filling
and then jumps to the
correct level

Level

time

0

l Turbulence on the product

surface, quick filling

l Check application parameters,

change if necessary, e.g. in
dosing vessel, reactor

7. Measured value
jumps towards 0 % du-
ring filling

Level

time

0

l Amplitude of a multiple echo

(vessel top - product surface)
is larger than the level echo

l Check application, especially

Vessel top, Product type, Dis-
hed bottom, High dielectric
value, and adapt if necessary

l The level echo cannot be

distinguished from the false
echo at a false echo position
(jumps to multiple echo)

l Remove/reduce false echo:

minimize interfering installa-
tions by changing the polariza-
tion direction

l Chose a more suitable instal-

lation position

8. Measured value
jumps towards 100 %
during filling

Level

time

0

l Due to strong turbulence and

foam generation during filling,
the amplitude of the product
echo sinks. Measured value
jumps to the false echo

l Carry out false signal suppres-

sion

9. Measured value
jumps sporadically to
100 % during filling

Level

time

0

l Varying condensation or con-

tamination on the antenna

l Carry out a false signal sup-

pression or increase false sig-
nal suppression with
condensation/contamination in
the close range by editing

10. Measured value
jumps to ≥ 100 % or 0 m
distance

Le

ve

l

time

0

l Level echo is no longer de-

tected in the close range due
to foam generation or false
echoes in the close range. The
sensor goes into overfill pro-
tection mode. The max. level
(0 m distance) as well as the
status message "Overfill pro-
tection" are outputted.

l Check measuring site: Antenna

must protrude out of the socket

l Remove pollution on the an-

tenna

l Use a sensor with a more

suitable antenna

Measurement error during emptying

Fault description

Error pattern

Cause

Rectification

VEGAPULS

62 • Approval according to LPR radio standard

59

9 Diagnosis, Asset Management and service

41719

-EN

-120301

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