Yokogawa Integral Oxygen Analyzer ZR202 - Manual (Page 178)

<12. Troubleshooting>
12-8
IM 11M12A01-02E
<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.
12.2.2.4 Alarm 8: EMF Stabilization Time-up Alarm
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.
<Locating cause of failure, and countermeasures>
(1) Carry out calibration by passing the calibration gas at the specified flow (600 ± 60 ml/min)
after checking that there is no leakage in the tubing.
(2) If calibration is carried out normally, perform a steady operation without changing the
conditions. If the error occurs again, check whether or not the reason is applicable to the
following and then replace the sensor assembly.
• A lot of dust and the like may be sticking to the tip of the detector probe. If dust is found,clean
the probe (see Section 11.1.1).
In addition, if an error occurs in calibration even after the sensor assembly is replaced, the
influence of sample gas flow may be suspected. Do not let the sample gas flow toward the
tip of the detector probe, for example, by changing the mounting position of the detector.
12.2.2.5 Alarm 10: Cold Junction Temperature Alarm
This alarm is generated when the temperature of the cold junction located at the terminal block of
the detector falls below -25 °C or exceeds 155 °C. Check the following:
Display “C.J.temperature” in the Detailed-data display. If “C.J.temperature” is indicated as 200 °C
or -50 °C, the following can be considered.
(1) Breakage of the cold junction signal wires between the converter and the detector, or the
cable is not securely connected to the connecting terminals.
(2) The positive and negative poles of the cold junction signal wiring are shorted out in the
wiring extension or at the connection terminals.
8th Edition : Jan.13,2012-00