Yokogawa Integral Oxygen Analyzer ZR202 - Manual (Page 142)

<12. Troubleshooting>
12-3
IM 11M12A01-04E
(3) Next, check the resistance of the thermocouple from the probe. Use a multimeter to measure the
thermocouple resistance between terminal 3 (red cable connected) and terminal 4 (white cable
connected) as indicated in Figure 12.3.
The thermocouple is normal if the resistance is 5Ω or less. If the value is higher than 5Ω, the
thermocouple wire may be broken or about to break. In this case, replace the heater assembly (refer
to Section 11.1.3, “Replacement of the Heater Assembly”).
CAUTION
Measure the thermocouple resistance value after the difference between the probe tip temperature
and the ambient temperature decreases to 50°C or less. If the thermocouple voltage is large,
accurate measurement cannot be achieved.
F12.3E.ai
1
2
3
4
YEL
GRN
RED
WHT
Thermocouple Multimeter
(Ω)
Figure 12.3
(4) If the inspection indicates that the thermocouple is normal, the electronics may be defective.
Consult your local Yokogawa service or sales representative.
12.1.2.3 Error-3: A/D Converter Failure/Error-4: Writing-to-memory Failure
• A/D Converter Failure
It is suspected that a failure has occurred in the A/D converter mounted in the converter
electronics.
• Writing-to-memory Failure
It is suspected that a failure has occurred in an operation writing to the memory (EEPROM)
mounted in the converter electronics.
<Locating the failure and take measures>
Turn off the power to the converter once and then restart the converter. If the converter operates
normally after restarting, an error might have occurred due to a temporary drop in the voltage (falling
below 85 V, the least amount of voltage required to operate the converter) or a malfunction of the
electronics affected by noise. Check whether or not there is a failure in the power supply system or
whether the converter and detector are securely grounded.
If the error occurs again after restarting, a failure in the electronics is suspected. Consult the service
personnel at Yokogawa Electric Corporation.