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<12. Troubleshooting>
12-6
IM 11M13A01-04E
(6) If the cell assembly has been gradually deteriorating, check the cell assembly status in the
following procedure:
a. Display “Cell resistance” by specifying the parameter code A21. A new cell will show a cell
resistance value of 200 Ω or less. On the other hand, a cell (sensor) that is approaching the
end of its service life will show a resistance value of 3 to 10 kΩ.
b. Display “Cell robustness” by specifying the parameter code A22. A good cell (sensor) will show
“5,” “life > 1 year” (refer to Subsection 9.1.10).
AL-07: Span Calibration Coefficient (Correction Ratio) Alarm
In calibration, this alarm is generated when the span gas correction ratio is out of the range of 0±18%
(refer to Subsection 9.1.3, “Compensation”).
The following are suspected as the cause:
(1) The oxygen concentration of the span gas does not agree with the value of the span gas set
“Calibration setup.”
(2) The flow of the span gas is out of the specified flow value (600 ± 60 ml/min).
(3) The cell assembly is damaged and the cell voltage is abnormal.
<Locating cause of alarm, and countermeasures>
(1) Confirm the following and carry out calibration again:
If the items are not within their proper states, correct them.
a. If the display “Span gas conc.” is selected in “Calibration setup,” the set value should agree
with the concentration of span gas actually used.
b. The calibration gas tubing should be constructed so that the span gas does not leak.
(2) If no alarm is generated as a result of carrying out re-calibration, it is suspected that improper
calibration conditions were the cause of the alarm in the preceding calibration. In this case, no
specific restoration is necessary.
(3) If an alarm is generated again as a result of carrying out re-calibration, deterioration of or
damage to the cell (sensor) is suspected as the cause of the alarm. Replacement of the cell with
a new one is necessary. However, before replacement, carry out the procedure described in step
(3) and later of <Locating cause of failure, and countermeasure> in Subsection 12.2.2, “AL-06:
Zero Calibration Coefficient Alarm.”
AL-08: EMF Stabilization Time Over
This alarm is generated if the sensor (cell) voltage has not stabilized even after the calibration time is
up for the reason that the calibration gas (zero gas or span gas) has not filled the sensor assembly of
the detector.
<Cause of alarm>
(1) The flow of the calibration gas is less than normal (a specified flow of 600 ± 60 ml/min).
(2) The length or thickness of the calibration gas tubing has been changed (lengthened or
thickened).
(3) The measuring gas flows toward the tip of the probe.
(4) The sensor (cell) response has deteriorated.