67
PBD-51041066
SITRANS LG270 - Operating Instructions
44295-EN-140321
Code
Text mes-
sage
Cause
Rectification
M505
No echo avail-
able
– Level echo can no longer
be detected
– Clean the antenna
– Use a more suitable
antenna/sensor
– Remove possible false
echoes
–
Optimize sensor position
and orientation
8.4
Rectify faults
The operator of the system is responsible for taking suitable meas-
ures to rectify faults.
The first measures are:
•
Evaluation of fault messages, for example via the display and
adjustment module
•
Checking the output signal
•
Treatment of measurement errors
A PC with the software PACTware and the suitable DTM or the soft-
ware PDM with a suitable DD offer further comprehensive diagnostics
options. In many cases, the reasons can be determined in this way
and faults can be rectified.
Connect a multimeter in the suitable measuring range according to
the wiring plan. The following table describes possible errors in the
current signal and helps to remove them:
Error
Cause
Rectification
4 … 20 mA signal
not stable
– Fluctuations of
the measured
variable
– Set damping according to the
instrument via the display and
adjustment module or PACTware/
DTM
4 … 20 mA signal
missing
– Electrical con-
nection faulty
– Check connection according to
chapter "
Connection steps
" and
if necessary, correct according to
chapter "
Wiring plan
"
– Voltage supply
missing
– Check cables for breaks; repair if
necessary
– Operating volt-
age too low or
load resistance
too high
– Check, adapt if necessary
Current sig-
nal greater than
22 mA or less
than 3.6 mA
– Electronics
module in the
sensor defec-
tive
– Exchange the instrument or send it
in for repair
The below tables show typical examples for application-relevant
measurement errors. There are two measurement errors:
Reaction when malfunc-
tions occur
Procedure for fault recti-
fication
Check the 4
…
20
mA
signal
Treatment of measure-
ment errors
