Siemens SITRANS LR 300, Instruction Manual, Page: 95 / 140

7ML19985CL02 SITRANS LR 300 – INSTRUCTION MANUAL Page 93
m
mmmm
Troub
leshoot
in
g
Maintenance
The SITRANS LR 300 requires no maintenance or cleaning under normal operating
conditions.
Reading erratic echo confidence weak
• refer to P805
• use P837
• use foam deflector or stilling
well
liquid surface vortexed
• decrease measurement
response P003
• relocate unit to side pipe
• increase confidence threshold
P804
material filling
• re-locate SITRANS LR 300
Reading
response slow P003 setting
• increase response if possible
Reads correctly
but occasionally
reads high
when vessel is
not full
• detecting close range echo
• build up near top of tank or
nozzle
• water or other high
ε
r
material in antenna threads
• wrong antenna choice for
application
• nozzle problem
• clean
• rod extensions may be
required
• See Application Example:
Stillpipe or By-pass Pipe on
page 53
• use P837/P838
• upgrade to shielded rod
antenna
Level reading
lower than
material level
• material is within near
blanking zone
• tank near empty and low
ε
r
material
• multiple echoes processed
• decrease blanking P800 (min.
0.4 m)
• raise SITRANS LR 300
• decrease range extension
• set P820 to 12 (First echo)
• nozzle too narrow for length • See Rod Extension
Requirements on page 28
• Upgrade to Shielded Rod
Antenna
• Internal seam in nozzle • Inspect and remove seam
• Use P837
• upgrade to shielded rod
antenna
Symptom Cause Action
Note:
Under severe operating conditions, the antenna may require periodic cleaning.
SITRANS LR 300.book Page 93 Monday, June 10, 2002 7:18 PM