Caution – Yokogawa Integral Oxygen Analyzer ZR202 User Manual

Page 166

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IM 11M12A01-05E

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 5V or less. If the value is higher
than 5V, 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 508 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
(V)

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 cause the failure, and countermeasures>

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.

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