Yokogawa Single Channel Oxygen Analyzer System ZR22/ZR402 - Manual (Page 188)

IM 11M12A01-03E 12-4
(5) Even if items (2) to (4) are normal, the heater overcurrent protection fuse may have
blown. Check for wiring problems such as the following:
1) Heater terminals shorted.
2) Heater terminal(s) shorted to ground.
3) Heater terminals shorted to power supply.
If the internal fuse blows, this cannot be replaced by the user. Contact your Yokogawa
service representative.
CAUTION
• Measure the thermocouple resistance value after the difference between the detector
tip temperature and the ambient temperature decreases to 508C or less. If the
thermocouple voltage is large, accurate measurement cannot be achieved.
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 electrical
circuits inside the converter.
• Writing-to memory Failure
It is suspected that a failure has occurred in an operation writing to the memory
(EEPROM) mounted in the electrical circuits inside the converter.
<Locating 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 electrical circuits 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 electrical circuits is suspected.
Consult the service personnel at Yokogawa Electric Corporation.