YOKOGAWA OX400, User Manual

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<7. Inspection and Maintenance>
7-2
IM 11M10B01-01E
7.2.1 Inspection in the Event of an Alarm (ALM)
If an error is detected by the self-diagnosis function of the OX400 during operation, the ERR/ALM
lamp flashes and an alarm (ALM) code is displayed on the sub-display. If an error is detected,
take action according to the Table 7.1.
Table 7.1 Alarm (ALM) Conditions and Actions
Display Content Diagnosis Condition Action
ALM1 Unstable heater
temperature
The heater temperature changed by ±5°C or
more from the standard temperature.
Check to make sure the
sensor gas flow rate or
power supply is not unstable
ALM2 Sensor error The sensor electromotive force during
calibration became greater than ±30% relative
to the standard.
Check the calibration gas
O
2
concentration value
Re-calibrate
Replace the sensor
ALM3 Electromotive force error A sensor electromotive force error of ±15 to
±30% relative to the standard occurred during
calibration.
Check the calibration gas
O
2
concentration value
Re-calibrate
Replace the sensor
ALM4 Asymmetric voltage error The air electromotive force became greater
than ±10 mV during calibration.
Calibration up to ±30 mV is possible.
Calibration beyond ±30 mV is not possible.
Check the air concentration
Re-calibrate
Replace the sensor
ALM5 Calibration error The calibration coefficient became greater than
the specified values (zero: ±50, span: 1 ±0.2).
When zero is ±50 to ±75 and span is 1±0.2 to
1± 0.4, calibration is possible
When zero exceeds ±75 and span exceeds 1
±0.4, calibration is not possible
Check the calibration gas
O
2
concentration
Re-calibrate
Replace the sensor
ALM6 Sensor resistance value
error
The sensor impedance (cell resistance value)
became greater than 1 kΩ during calibration.
Prepare a replacement
sensor
ALM7
Oxygen concentration
high/low limit error
The oxygen concentration became larger than
the high/low limits.
Change the high/low limits
as needed
ALM8 Over range error The oxygen concentration became greater
than 100%FS, or became a negative value.
Change the range
Re-calibrate
7.2.2 Inspection in the Event of an Error (ERR)
If an error is detected during operation, the ERR/ALM lamp turns on and an error (ERR) code is
displayed on the sub-display. If an error is detected, take action according to Table 7.2.
Table 7.2 Error (ERR) Conditions and Actions
Display Factor Diagnosis Condition Action
Err1 Sensor failure Sensor burnout. The sensor
electromotive force became
less than -50 mV.
Replace the sensor
Err2
Heater temperature error The heater temperature
became greater by ±30°C
relative to the standard
temperature.
Replace the heater
Check the temperature adjustment circuit
(Contact our service department)
Err3 Temperature sensor
burnout
The temperature sensor has
burned out.
Replace the heater
(Contact our service department)
Err4 OX400 temperature error The temperature inside the
OX400 became greater
than 70°C.
Check to make sure the ventilation holes,
cooling fan outlet, and line are not blocked,
lines are not blocked, and so on.
Turn the power off and then on.
Err5 CPU failure A CPU failure occurred. Contact our service department.
Err6 Fan stop The cooling fan stopped. Contact our service department.
Note: If an error (ERR) occurs, the heater is turned off. To clear the error, you need to turn the power off and then on. It is
recommended to turn the power off and then on to see whether the error occurs again. Be careful because if the power of the
OX400 is turned off, the contact output “OPEN.”
8th Edition : Jan. 10, 2019-00