<12. Troubleshooting>
12-4
IM 11M12G01-02EN 1sh Edition : Mar. 25, 2021-00
(6) TC+ ,TC- thermocouple terminals wired to detector with reverse (wrong) polarity.
Overcurrent protection is triggered if there are problems in the heater wiring. When the protective
circuit is triggered, the internal fuse blows and the heater is disconnected, resulting in Alarm 017
(temperature failure).
<Locating cause of failure, and countermeasures>
(2) Remove the cable from terminals 7 and 8 of the detector and measure the resistance value
between these terminals. The heater unit is normal if the resistance is lower than about
replace the heater unit (refer to Section
“11.1.4 Replacement of the Heater Unit”). In
less.
(3) Ensure that TC+ terminal (terminal 3 in detector) is connected to converter TC+ terminal,
and TC- terminal (terminal 4) is connected to converter TC- terminal.
(4) Remove the wiring from terminals 3 and 4 of the detector and measure the resistance value
between these terminals. The thermocouple is considered normal if the resistance value is
broken or is about to break. In this case, replace the heater unit (refer to Section
“11.1.4
Replacement of the Heater Unit”). Also, check that the wiring resistance between the
(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:
(a) Heater terminals shorted.
(b) Heater terminal(s) shorted to ground.
(c) Heater terminals shorted to power supply.
If the internal fuse blows, this cannot be replaced by the user. Contact your Yokogawa service
representative.
NOTE
detector tip and the ambient atmosphere has decreased to 50°C or less. If the thermocouple
voltage is large, accurate measurement cannot be achieved.
(3) Alarm 018: A/D Converter Failure/Alarm 019: Sensor EEPROM Failure
l 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.
l Sensor EEPROM 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>
operates normally after restarting, an alarm might have occurred due to a temporary drop in the
the power supply system or whether the converter and detector are securely grounded.
If the alarm occurs again after restarting, a failure in the electrical circuits is suspected.
Consult the service personnel at Yokogawa.
(4) Miscellaneous Failure (Alarm 001 to 004, 020)
An internal failure has occurred. Contact your Yokogawa service representative.
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