Yokogawa Multi Channel Oxygen Analyzer System ZR22/AV550G - Manual (Page 223)

IM 11M12D01-01E 12-13
12. Troubleshooting
(3) If there is no failure in the wiring, the electrical circuits inside the converter may
possibly fail. Contact the service personnel at Yokogawa Electric Corporation.
CAUTION
• The operating temperature range of the Model ZO21D Detector is -10
Њ C to 80Њ C
(except for the high-temperature detector ZO21D-H). Since a cold junction tempera-
ture alarm for this analyzer is not generated until the temperature exceeds 155
Њ C, if
the Model ZO21D Detector is used, be careful in controlling the ambient temperature
of the terminal block.
6) Alarm 6: Process gas alarm
When process gas alarm is assigned to a contact input, the power to the detector heater
is turned off for safety during continuous input of the contact signal. The power to the
heater will be turned on again after the contact input is removed, and then warm-up will
start. After the warm-up the averaging converter will go in measurement mode automati-
cally.
7) Alarm 7: Calibration gas pressure low alarm
When calibration gas pressure low is assigned to a contact input, calibration and
indication check are not performed during the input of the contact signal. If the averag-
ing converter receives this contact input during the calibration or indication check
process, it will abort the ongoing calibration or indication check, After the contact input
is removed, subsequent calibrations and indication checks will be enabled.
8) Alarm 8: Asymmetry alarm
CAUTION
This function, alone, is not sufficient to ensure the accuracy and reliability of this
instrument. Read the following thoroughly, and use it as just one of several trouble-
shooting tools. Note that shipping-time default is for this function to be disabled.
(1) Cause
In general, sensor aging causes a change in the slope of the compensation line. If the
detector tip is clogged, however, this can cause a shift in both zero and span calibration
results. Such an offset can be compensated for by zero shift alone. This alarm occurs if,
when the last two calibration results are compared, the shift indicates such a tip-clogging
pressure-related effect.