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<12. Troubleshooting>
12-7
IM 11M12A01-02E 16th Edition : Mar. 19, 2020-00
(6) If the sensor assembly has deteriorated gradually, check the condition of the sensor
assembly following the procedure below.
a. Use the [Page Scroll] key to check Cell Resistance. It should be 200 V or less if the cell
(sensor) is new. On the other hand, if the cell (sensor) is approaching the end of its service
life, it will be 3 to 10 kV.
b. Use the [Page Scroll] key to check Cell Robustness. It should say “Life > 1 year” if the cell
(sensor) is in good condition.
Span gas ratio: - 2 . 9 %
Zero gas ratio: 7 0 . 3 %
Response time: 0 s
Cell robustness: life< 1 month
Cell temperature: 1 0 6 7 °C
C.J.temperature: 4 7 °C
Tag:
Hold
F12.7E.ai
Figure 12.7
n
Alarm 7: Span-point Calibration Coefficient Alarm
In automatic or semi-automatic calibration, this alarm is generated when the span correction ratio
is out of the range of 0 ± 18% (refer to Section 9.1.4, 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
in Calibration setup.
(2) The flow of the span gas is out of the specified flow value (600 ± 60 ml/min).
(3) The sensor assembly is damaged and the cell voltage is abnormal.
<Locating cause of failure, 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 point 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 <Search for cause of failure and taking measure> in
Section 12.2.2.2, Alarm 6: Zero-point Calibration Coefficient Alarm.