User's Manual

69
9 Diagnosis, asset management and service
VEGAPULS 69 • 4 … 20 mA/HART - two-wire
47247-EN-170315
Error Reason Removal
4 … 20 mA signal not sta-
ble
•
Fluctuations of the
measured variable
•
Set damping appropriate to the instrument via the
display and adjustment module or PACTware/DTM
4 … 20 mA signal missing
•
Electrical connection
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 voltage too
low or load resistance
too high
•
Check, adapt if necessary
Current signal greater than
22 mA or less than 3.6 mA
•
Electronics module in the
sensor defective
•
Exchange the instrument or send it in for repair
The below tables show typical examples of application-related
measurement errors with bulk solids. A distinction is made between
measurement errors during:
•
Constant level
•
Filling
•
Emptying
The images in column "Errorpattern" show the real level as a broken
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
Notes:
•
Whenever the sensor displays a constant value, the reason could
also be that the fault setting of the current output is set to "Hold
value"
•
If the level indication is too low, the reason could be a line resist-
ance that is too high
Measurement error with constant level
Fault description Error pattern Cause Rectication
1. Measured value
shows a too low or too
high level
Level
time
0
•
Min./max. adjustment not
correct
•
Adapt min./max. adjustment
•
Incorrectlinearizationcurve
•
Adaptlinearizationcurve
Treatment of measure-
ment errors with bulk
solids