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FC-21 Flow Computer
13.2 Diagnosis Flow Chart and Troubleshooting
Is there an input power
supply voltage across
Terminals 23 and 24?
No
Yes
Check the connections
according to the circuit
diagrams.
Check junction box fuses.
Is the Display Backlight
Visible?
No
Yes
Check/Replace internal
fuse. If fuse is OK,
Factory Service Required.
Is there a black bar
across the display?
Yes
No
Does the display
alternate between blank
and sign on message?
Yes
No
Does the display show
an error message?
Yes
No
See section 12.3 for
cause and remedy.
No system or process
errors present.
Are the Display
Characters Visible?
No
Yes
The display may not be
visible with ambient
temperatures below -10 °C
Allow the instrument to
warm up.
Contact factory if
necessary
Check line voltage.
If voltage is OK,
Factory Service Required.
Check line voltage.
If voltage is OK,
Factory Service Required.
All instruments undergo various stages of quality control during pro-
duction. The last of these stages is a complete calibration carried out
on state-of-the-art calibration rigs.
A summary of possible causes is given below to help you identify
faults.
