Measurement error during filling – VEGA VEGAPULS 62 (≥ 2.0.0 - ≥ 4.0.0) 4 … 20 mA_HART - two-wire, approval according to LPR radio standard User Manual

Page 61

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background image

Fault description

Error pattern

Cause

Rectification

3. Measured value
jumps towards 100 %

Level

time

0

l Due to the process, the amp-

litude of the product echo sinks

l A false signal suppression was

not carried out

l Carry out false signal suppres-

sion

l Amplitude or position of a false

echo has changed (e.g. con-
densation, buildup); false sig-
nal suppression no longer
matches

l Determine the reason for the

changed false echoes, carry
out false signal suppression, e.
g. with condensation

Measurement error during filling

Fault description

Error pattern

Cause

Rectification

4. Measured value re-
mains unchanged du-
ring filling

Level

time

0

l False echoes in the close

range too big or product echo
too small

l Strong foam or spout genera-

tion

l Max. adjustment not correct

l Remove false echoes in the

close range

l Check measurement situation:

Antenna must protrude out of
the socket, installations

l Remove pollution on the an-

tenna

l Minimize interfering installa-

tions in the close range by
changing the polarization di-
rection

l Create a new false signal sup-

pression

l Adapt max. adjustment

5. Measured value re-
mains in the bottom
section during filling

Level

time

0

l The tank floor echo is larger

than the product echo, e.g.
with products with ε

r

<

2.5 oil-

based, solvents

l Application parameter "Me-

dium", check Vessel height and
Floor form, adapt if necessary

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

VEGAPULS

62 • 4 … 20 mA/HART - two-wire, approval according to LPR radio standard

61

9 Diagnosis, Asset Management and service

41718

-EN

-120301

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