YOKOGAWA Vigilant Plant EXA TB Series, Руководство пользователя

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<8. TROUBLESHOOTING>
8-5
IM 12E04A02-02E
(11) FAIL Lamp Is Lit and Other Lamps and Displays Are All Off
This shows a CPU failure occurrence. For con fi rmation, turn off the power one time and then
turn it on again. If the CPU fails, the FAIL lamp immediately lights up. After con fi rmation, request
checking and/or repair of the CPU board.
8.2 Events in Which FAIL Lamp Is Not Lit
If an indication failure occurs that the self-diagnostic function cannot detect, check it by referring
to Table 8.2.
Table 8.2 Phenomena for Failures and their Causes and Countermeasures
Phenomenon for
failure
Possible cause Check and corrective action
a. Turbidity reading
does not
change.
1. Failure of the measuring
lightreceiving element in the
detector
2. Clogging in the piping between
the detector and the header tank
3. If the turbidity reading is fi xed
to 0.00 mg/l and thus does not
change, it is assumed that 0.00
mg/l was entered in reference
sensitivity calibration.
Con fi rm the reading using the calibration plate.
If there is no change, a failure of the measuring
preampli fi er in the detector is assumed. Request
checking and/or repair.
Open the detector and, if measuring water does
not fl ow through the measuring cell, check the
piping and clean it if there is clogging.
Carry out reference sensitivity calibration using
the calibration plate.
b. Fluctuation of
turbidity reading
is large.
1. Unsuitable measuring water
fl owrate
2. Shift of level adjustment for the
measuring cell water surface
3. Turbidimeter not securely fi xed
4. Large vibrations in surroundings
5. The reading may fl uctuate due
to suspended substances in the
sample water.
Open the detector and if the water surface is not
like a mirror fi nish, adjust the fl owrate.
Check the level adjustment
Con fi rm the tightness of the anchor bolts or the
like.
Change the signal averaging coef fi cient greatly. If
the vibrations are violent, change the installation
location.
Greatly change the signal averaging coef fi cient.
c. Abrupt change in
turbidity reading
1. Poor contact in wiring between
the converter and detector
2. In fl uence from air bubbles
Re-tighten the connection terminal screws of the
converter and detector.
Increase the signal averaging coef fi cient.
d. No change in
turbidity reading
1. Check the range setting and
range operation mode.
Auto-range setting (on/off)
Remote range setting (on/off)
Local range setting (1/2/3)
Upper and lower range limit setpoints
e. Turbidity value
drift
1. Contamination of the measuring
cell
2. For the model with automatic
calibration, a dirty zero fi lter
3. Dim light-receiving lens
Clean the measuring cell. For the model with
automatic cleaning, shorten the cleaning interval.
Clean the fi lter element or for use over a
prolonged period, replace it with a new one.
Adjust the temperature so that the difference
between the measuring-water temperature
and the ambient temperature is within the
predetermined valve (30 °C).
If the lens is dirty, clean it.
f. No converter
display
1. Blown converter fuse Replace it with the attached fuse required.
g. The “MEAS”
lamp fl ashes.
1. A high or low alarm is detected. Select FUNCTION “8” and/or FUNCTION
“9” in the <PROGRAM1> mode and change
the setpoint(s), or select FUNTION “9.” in the
<PROGRAM2> mode and reset the function.
The lamp stops fl ashing.
3rd Edition : May. 31, 2010-00