Fault Analysis - Pepperl+Fuchs LUC-T Series Manual

15.2

Fault analysis

" Bar display flashes
Response of the current output
depends on the setting in V0H7
V0H7=0 -10 % 2.4 mA or 3.8 mA
V0H7=1 110 % 22 mA
V0H7=2 HOLD last value is held
# Measured value in
V0H0 too small
D m/ft (V0H8)
$ Measured value in
V0H0 too large
D m/ft (V0H8)
Analogue output
Error code in V9H0
E641 in V9H0
Echo too weak or foam
on the surface
Distance D in V0H8
too large?
20 mA
expected
Incorrect linearisation?
actual
4 mA t Incorrect current
output?
Distance D in V0H8
too small?
20 mA
actual
Continued on page 30
expected
4 mA t
Possible cause
yes
yes
yes
no
yes
no
yes
yes
no
Removal
• Which error code? see page 28
• Further action depends on the
error code
• Check sensor position
see chapter 6 and page 25
• Multiple echo? see &
• Gas layering? Contact
Pepperl+Fuchs service line
• Check sensor position
see chapter 6 and page 25
Re-enter linearisation curve
see page 22 and page 23
Check values in V0H5 and V0H6
and re-enter if necessary
see page 24
Interference from internals in
measuring range?
Instrument mounted in nozzle?
• Check dimensions of nozzle
see page 9
• Check sensor position
see chapter 6 and page 25
• Select application parameter
0 or 2 in V0H3 see page 21
• Carry out interference echo
suppression see page 25
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