Instruction manual

SM425 INSTRUCTION MANUAL 12.0 TROUBLESHOOTING
188 42500001 REV A
Table 12-1 Types of Errors and Causes
Error Type of error Cause
Error-1 Cell voltage failure The cell (sensor) voltage signal input to the
converter falls below -50 mV
Error-2 Heater temperature
failure
The heater temperature does not rise during
warm-up, or it falls below 730 °C or exceeds
780 °C after warm-up is completed.
Also occurs if the TC+ TC- thermocouple
terminals are wired to converter with reverse
(wrong) polarity.
Error-3 A/D converter
failure
The A/D circuit in the converter has failed
Error-4 Memory failure Data not correctly written to converter
memory
12.1.2 Error Troubleshooting and Corrective Actions
12.1.2.1 Error-1: Cell Voltage Failure
Error-1 occurs when the cell (sensor) voltage input to the converter falls below -50 mV (corresponding to
about 200% O
2
). The following are possible causes for the cell voltage falling below -50 mV:
1. Poor contact in terminal connections between the converter and detector
2. Damaged wiring in the converter to detector cable
3. Damage or failure of the sensor assembly
4. No continuity between the sensor assembly electrode and the contact
5. Faulty detector wiring
6. Converter electronics failure