<12. Troubleshooting>
12-3
IM 11M12A01-04E 11th Edition : Jul. 19, 2017-00
(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.
n 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.
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