Yokogawa Integral Oxygen Analyzer ZR202 - Manual (Page 165)

IM 11M12A01-05E 12-2
12.1.2 Measures to Take When an Error Occurs
12.1.2.1 Error-1: Cell Voltage Failure
Error-1 occurs when the cell (sensor) voltage input to the converter falls below -50 mV
(corresponding to about 200% O
2
). The following are considered to be the causes for
the cell voltage falling below -50 mV:
(1) Continuity failure between the sensor assembly electrode and the contact
(2) Damage or deterioration of the sensor assembly
(3) Improper connection between the sensor and the electronics.
(4) Wiring failure inside the detector
(5) Abnormality in the converter electronics
<Locating cause the failure, and countermeasures>
1) Turn off the power to the equipment.
2) Remove the sensor assembly from the probe. Check for dirty or corroded sensor
parts, including electrode and contact.
3) If the contact part is normal, the sensor assembly may be damaged or deteriorated.
Replace the sensor assembly. In this case, be sure to replace the metal O-ring and
contact.
4) If Error-1 still occurs, check that the sensor and the electronics are properly con-
nected.
5) Remove the probe to gain access to the two connectors (four connectors for the
optional automatic calibration unit), as indicated in Figure 12.2. Check these
connectors are properly connected.
6) If Error-1 still occurs, the electronics may be defective. Contact your local Yokogawa
service or sales representative.
12.1.2.2 Error-2: Heater Temperature Failure
This error occurs if the detector heater temperature does not rise during warm-up, or if
the temperature falls below 7308 C or exceeds 7808 C after warm-up is completed.
Causes considered for cases where Error-2 occurs independently are shown below.
(1) Faulty heater in the probe (heater wire breakage)
(2) Faulty thermocouple in the probe
(3) Failure in the converter electronics
<Locating cause of failure, and countermeasures>
(1) Turn off the power to the analyzer.
(2) Remove the probe from the analyzer. Also remove all the connectors between the
converter and probe. Measure the resistance of the heater wire (yellow wire) from the
probe as indicated in Figure 12.2. The heater unit is normal if the resistance is lower
than about 90V. If the resistance is higher than that value, the heater unit may be
defective. In this case, replace the heater unit (refer to Section 11.1.3, “Replacement
of the Heater Unit”).
F12.2E.EPS
Multimeter
(V)
Heater wire
Figure 12.2