UWT NivoGuide 8100, Instruction Manual

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NivoGuide® 8100 • Two-wire 4 … 20 mA/HART
7 Diagnostics and servicing
58878-EN-190215
Error Cause Rectification
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 for application-relevant
measurement errors. There are two measurement errors:
•
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
Fig. 19: The broken line 1 shows the real level, the continuous line 2 shows the
level displayed by the sensor
Note:
•
Wherever the sensor displays a constant value, the reason could
also be the fault setting of the current output 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 Cause Rectification
1. Measured value shows a
too low or too high level
Level
time
0
•
Min./max. adjustment not correct
•
Adapt min./max. adjustment
•
Incorrect linearisation curve
•
Adapt linearisation curve
•
Running time error (small measure-
ment error close to 100 %/serious
error close to 0 %)
•
Repeat setup
Treatment of measure-
ment errors