Detcon IR-542 - Manual (Page 15)

Calibration Fault
If during calibration the sensor circuitry is unable to attain the proper adjustment for zero or span, the sensor will
enter into the calibration fault mode and cause the display to alternate between the sensor’s current status reading and
the calibration fault screen which appears as: “CAL FAULT.2”.
The following conditions will cause a calibration fault:
1 - Zero calibration cannot converge.
2 - Auto span cannot converge (too noisy or too unstable).
3 - Span gas is not applied before 1 minute elapses.
Fail-Safe/Fault Supervision
Model IR-540/IR-541/IR-542 MicroSafe™ sensors are programmed for fail-safe operation. All of the fault conditions
listed below will activate the fault relay, illuminate the fault LED, cause the mA output to drop to zero (0) mA, and
cause the display to read its corresponding fault condition.
Memory Error
If the processor can’t save values to memory, the display will indicate: “MEMORY ERROR”.
Zero Fault
If the sensor should drift below –0.02%, the display will indicate: “ZERO FAULT”.
Lamp Fault
If the lamp signal is lost, the display will indicate: “LAMP FAULT.2”.
Reference Peak High Fault
If the reference peak signal is too high (>3600), the display will indicate: “SIGNAL FAULT.31”.
Active Peak High Fault
If the active peak signal is too high (>3600), the display will indicate: “SIGNAL FAULT.32”.
Reference Peak Low Fault
If the reference peak signal is too low (<500), the display will indicate: “SIGNAL FAULT.41”.
Active Peak Low Fault
If the active peak signal is too low (<500), the display will indicate: “SIGNAL FAULT.42”.
Reference Peak to Peak Low Fault
If the reference peak to peak signal is too low (<200), the display will indicate: “SIGNAL FAULT.51”.
Active Peak to Peak Low Fault
If the active peak to peak signal is too low (<200), the display will indicate: “SIGNAL FAULT.52”.
3.10 D
ISPLAY
C
ONTRAST
A
DJUST
Model IR-540/IR-541/IR-542 MicroSafe™ sensors feature a 16 character backlit liquid crystal display. Like most
LCDs, character contrast can be affected by viewing angle and temperature. Temperature compensation circuitry
included in the MicroSafe™ design will compensate for this characteristic, however temperature extremes may still
cause a shift in the contrast. Display contrast can be adjusted by the user if necessary. However, changing the con-
trast requires that the sensor housing be opened, thus declassif ication of the area is required.
To adjust the display contrast, remove the enclosure cover and use a jewelers screwdriver to turn the contrast
adjust screw located beneath the metallic face plate. The adjustment location is marked “CONTRAST”. See f igure 6
for location.
Detcon Model IR-540/IR-542 Carbon Dioxide Sensor PG.15