Yokogawa Integral Oxygen Analyzer ZR202 - Manual (Page 157)

IM 11M13A01-04E 12-3
12. Troubleshooting
(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 5
⍀ or less. If the value is higher than
5
⍀, the thermocouple wire may be broken or about to break. In this case, replace the
heater unit (refer to Section 11.1.3, “Replacement of the Heater Unit”).
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 thermo-
couple voltage is large, accurate measurement cannot be achieved.
F12.3E.EPS
1
2
3
4 YEL
GRN
RED
WHT
Thermocouple Multimeter
(
⍀ )
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 taking measure>
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.