Fixed Target Suppression; Application - Trouble Shooting - Pepperl+Fuchs LUC4T-G5S-IU-V15 Handbuch

4.2 Fixed target suppression

If you want to use the fixed target suppression you have to do at least the „empty" calibration outside the vessel.
You can decide if you want to do the „full" calibration in or outside the vessel. We recommend you to do the following:
a) „Empty" calibration outside the vessel
b) Fixed target suppression in mounted position
c) „Full" calibration in mounted position
You can suppress echoes of fixed targets within a certain range. See the following sketch. You find a brace built
into the vessel that produces an undesired echo. Without the fixed target suppression the measurement would be
incorrect under certain circumstances. The fixed target suppression fixes this problem but reduces the signal
strength. In extreme cases you have to evaluate this reduction more precise to find out whether or not this might
cause measuring problems.
brace
medium
5. Possible measuring problems
• Braces, insertions or sticking media
⇒ fixed target suppression
• incoming liquids
⇒ correct mounting
• Sticking media in the vessel
⇒ correct mounting or fixed target suppression
• strong surface motion
⇒ correct mounting, bypass if necessary
• foam on liquid
⇒ echo analysis, please ask our application engineers for advice
• changing temperatures
⇒ temperature compensation with external temperature sensor, please ask our application engineers for advice
• discontinuous measurement values
⇒ false pre-set of fixed target suppresion, reset (delete) fixed taget suppresion (see short reference set-up see 7.7)
zero / spann adjustment programed without waiting for measurement integration delay (15 sec) (see 7.4)
Display of general failures
If a failure occurs the red failure LED is blinking with a frequency of 2 Hz, the output will be 21 mA / 10.5 V.
Display with missing echo.
If the echo is missing the red failure LED is blinking with a frequency of 2 Hz, the output will be 21 mA / 10.5 V.
Subject to reasonable modifications due to technical advances.
Pepperl+Fuchs Group · Tel.: Germany (6 21) 7 76-22 22 · USA (3 30) 4 25 35 55 · Singapore 7 79 90 91 · Internet http://www.pepperl-fuchs.com
Parameterization / Possible Measuring Problems
echo signal
Evaluation threshold without fixed target suppresion
Evaluation threshold after fixed target suppresion
attenuationtime of transducer
dead band
parasitic echo
level
S
Copyright Pepperl+Fuchs, Printed in Germany
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