Det-Tronics MOS H2S Gas Sensor User Manual
Page 24
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1.4
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fault Message Display
Blank Display
“COMPUTER”
“FAILURE”
“WDT”
“FAILURE”
“EEPROM”
“FAILURE”
“EXT RSET”
“PROBLEM”
“24V P.S.”
“FAILURE”
“5V P.S”
“FAILURE”
“SENSOR”
“PROBLEM”
“REPLACE”
“SENSOR”
“CAL”
“ABORTED”
“SENSOR”
“E.O.L.”
“ZERO”
“DRIFT”
Explanation and Corrective action
EEPROM sumcheck failure. Cycle power to clear fault. If fault persists, return the unit to the factory
for repair.
RAM or processor failure. Cycle power to clear fault. If fault persists, return the unit to the factory
for repair.
Watchdog timer failure. Cycle power to clear fault. If fault persists, return the unit to the factory for
repair.
Activate the Cal/Reset switch using the Cal Magnet, then perform Setup and Calibration procedures.
If fault persists, return the unit to the factory for repair.
External reset button has been activated for 15 seconds or longer. Self-clearing when button is
released.
External 24 volt power supply is not in the 15 to 32 volt range. Check and correct input voltage.
During normal operating mode, this fault is self clearing when the fault is corrected. If fault occurs
during warmup or calibration modes, activate the Cal/Reset switch using the Cal Magnet.
Internal 5 volt analog power supply is not in the 4.75 to 5.35 volt range. During normal operating
mode, this fault is self clearing when the fault is corrected. If fault occurs during warmup or calibration
modes, activate the Cal/Reset switch using the Cal Magnet. If fault persists, return the unit to the
factory for repair.
Sensor input fault. In normal operating mode, the unit automatically goes through Warmup when this
fault clears. If this fault occurs at the end of the warmup period or calibration procedure, recalibrate
the sensor. If fault persists, check sensor condition and wiring.
(In calibration mode) sensor is defective. Replace sensor and perform calibration procedure.
(Cal Message) Time ran out while waiting for the gas reading to stabilize. Activate the Cal/Reset
switch using the Cal Magnet.
(Cal Message) Sensor reaching End Of Life. Consider replacement of the sensor in the next 1 or 2
calibrations.
Negative zero drift. Sensor input is –9% full scale or lower. Perform sensor calibration.
Table 8—Fault Messages, Explanations And Corrective Action