38
9 Diagnosis, Asset Management and service
VEGAPULS WL 61 • 4 … 20 mA/HART - two-wire
38061-EN-121011
Error
Cause
Rectification
4 … 20 mA signal
not stable
– Level fluctua-
tions
– Set damping according to the
instrument via the indicating 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 of application-related meas-
urement errors with liquids. The measurement errors are differentiated
according to the following:
•
Constant level
•
Filling
•
Emptying
The images in column "
Error pattern
" show the real level with a bro-
ken line and the level displayed by the sensor as a continuous line.
1
2
Level
time
0
1 Real level
2 Level displayed by the sensor
Instructions:
•
Wherever the sensor displays a constant value, the reason could
also be the fault setting of the current output to "
Hold value
"
•
In case of a too low level indication, the reason could be a line
resistance that is too high
Treatment of measure-
ment errors with liquids
