Vega VEGAPULS 63 Operating Instructions Manual page 54

9 Diagnosis, Asset Management and service
Treatment of measure-
ment errors with liquids
54
Error Cause
4 ... 20 mA signal – Level fluctua-
not stable tions
4 ... 20 mA signal – Electrical con-
missing nection faulty
– Voltage supply
missing
– Operating volt-
age too low or
load resistance
too high
Current sig- – Electronics
nal greater than module in the
22 mA or less sensor defec-
than 3.6 mA tive
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 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
Rectification
– Set damping according to the
instrument via the display and
adjustment module or PACTware/
DTM
– Check connection according to
chapter "Connection steps" and
if necessary, correct according to
chapter "Wiring plan"
– Check cables for breaks; repair if
necessary
– Check, adapt if necessary
– Exchange the instrument or send it
in for repair
0
VEGAPULS 63 • 4 ... 20 mA/HART two-wire
1
2
time