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< PART – C Operation and Maintenance >
C-32
IM 39J06B40-01EN 14th Edition: May 30, 2022
C4.5.2. Fault Isolation
If a problem occurs during operation, you can perform fault isolation as described in the
table below. If the DTSX3000 can be booted up and self-diagnosis can be executed,
execute self-diagnosis first and check for any reported hardware problem. If no
hardware problem is detected, check the system as described in the table below. If a
possible hardware problem is identified, or the problem cannot be identified, or the same
problem recurs frequently, contact Yokogawa.
Problem Symptoms Troubleshooting
- No power
(None of the LED
lamps of the
DTSX3000 are lit.)
- The DTSX3000
remains in boot
state.
- Check if the power supply module and the DTSX3000 are installed
properly.
- Check that the SD card is properly inserted. If the SD card is dislodged,
re-insert the SD card.
- Check if the external power source used meets the input specification
requirements of the power supply module.
- If NFPW426 is used, check if the power supply is connected to the
analog field power supply terminal.
- If there is no problem with the installation, the connections and external
power source but the LED lamp of the power supply module is unlit, the
power supply module may be faulty.
- If the LED of the power supply module is lit but the LED lamp of the
DTSX3000 is unlit, either the DTSX3000 or the base module may be
faulty.
The LED of the
DTSX3000 blinks in
red.
- Check message logs for problem description. Re-apply power and see if
the same problem recurs.
- If the same problem recurs frequently even after reapplying power, the
DTSX3000 may be faulty.
Temperature
measurement
completely fails (when
DTSX3000 is used
alone without an optical
switch).
- Check the connection of the optical fiber and if necessary, reconnect
properly.
- Check for any anomaly on the end face of the optical connector.
- Replace the sensor optical fiber with another optical fiber or the Optical
Fiber for DTSX3000 (DTFB10) and check if measurement can be
correctly executed.
- If there is no problem with the optical fiber connection and temperature
measurement completely fails even after replacing the optical fiber, the
DTSX3000 may be faulty.
Noisy temperature
waveform
- Check the ST light and AS light signal levels. It should be about 25 to 27
dB (depending on the temperature) if no optical switch is used. If the
signal levels are normal, there is no hardware failure. Set a longer
measurement time.
- If the ST and AS light signal levels are abnormal, proceed to the previous
row on Temperature measurement completely failed”.
Periodic waveform
observed in
temperature waveform.
- A periodical pattern could be observed in measured temperature
distribution along an optical fiber if part of the optical fiber is wound
around a drum or otherwise bundled together. There is no problem with
the measuring system itself but with the way the optical fiber is installed.
Ensure that no part of the optical fiber is bundled together and repeat
temperature measurement
Temperature
measurement is
incorrect.
- Check if temperature calibration has been done properly.
- If the difference between the calibration temperature and the measured
temperature is large, actual temperature and measured temperature tend
to differ. As far as possible, perform temperature calibration at a
temperature near to measured temperatures.
Temperature waveform
is tilted when
measuring a constant
temperature.
- Check if fiber loss correction has been done.
- Perform loss correction with adequate measurement time and a clean
waveform.
Channel switching by
optical switch fails.
- Check if the HDY, RDY and Ch LED lamps of the optical switch are lit.
- Check if the DTSX3000 and optical switch are installed properly.
- Check for any problem at optic fiber connections.
- Check for any anomaly on fiber connector end faces.
- If the LED lamp of the optical switch is unlit, the optical switch or the base
module may be faulty.