Siemens SITRANS LR250 Operating Instructions Manual page 179

Symptom
Reading erratic
Reading response
slow
Reads correctly but
occasionally reads
high when vessel is
not full
Level reading lower
than actual material
level
SITRANS LR250 (PROFIBUS PA)
Operating Instructions, 08/2014, A5E32221386-AC
Cause
echo confidence weak
liquid surface vortexed
material filling
Fill Rate (2.3.8.2.) setting
incorrect
detecting close range echo
•
build up near top of vessel or
•
nozzle
nozzle problem
•
material is within Near Range
•
zone
multiple echoes processed
•
vessel near empty and low
•
dK material
Action
refer to Confidence (2.5.9.1.)
•
use Auto False Echo Suppression (2.5.10.1.) and Auto
•
False Echo Suppression Range (2.5.10.2.)
use foam deflector or stillpipe
•
decrease Fill Rate (2.3.8.2..)
•
relocate device to side pipe
•
increase confidence threshold in Echo Threshold (2.5.7.3.)
•
Re-locate SITRANS LR250
•
increase measurement response if possible
•
clean the antenna
•
use Auto False Echo Suppression (2.5.10.1.) and Auto
•
False Echo Suppression Range (2.5.10.2.)
decrease Near Range (2.5.1.) (minimum value depends on
•
antenna type)
raise SITRANS LR250
•
ensure Algorithm (2.5.7.1.) is set to tF (First echo)
•
ensure Material (1.2.) selection is LIQUID LOW DK
•
set Position Detect (2.5.7.2.) to Hybrid
•
check the setting for CLEF Range (2.5.7.4.): see the table
•
below Propogation Factor (2.5.3.) for recommended
settings
Diagnosing and troubleshooting
10.4 Operation troubleshooting
177