K-O2 Oxygen Sensor
5/20/2022
Kele, Inc. • 3300 Brother Blvd. • Memphis, TN 38133
Page 11
www.kele.com
5.4 S
PAN
C
ALIBRATION
P
ROCEDURE
For best accuracy the Zero calibration procedure in section 5.2 should be done before the Span calibration.
Ignore steps in light blue highlight if doing a no-gas span calibration.
The progress and status of the calibration process is indicated by the color and flash-state of the front cover status
LED (see 10).
1.
[Start the calibration gas flowing,] press and hold the ’SPAN’ button (see Figure 8) for 3 seconds until the
status LED starts blinking YELLOW, indicating that gas sampling is in progress.
2.
[Ensure that the calibration adapter covers the sensor completely for the 2 minute sampling period].
At the end of the sampling period, the sensor’s status LED blinks GREEN if the sampling was successful or
RED if not.
3A. If successful (blinking GREEN):
The sampling completed successfully. [Turn off the calibration gas flow, remove the calibration adapter
then]
press and hold
the ‘SPAN’ calibration button until the LED blinks GREEN/YELLOW indicating that
[the calibration gas has been removed,] the new calibration has been applied and the unit is in standby
for two minutes while the sensor re-equilibrates to the ambient atmosphere before normal operation
resumes. The calibration is complete when the status LED returns to steady GREEN.
OR
3B. If NOT successful (blinking RED):
The most likely causes of span gas sampling failure are:
[Insufficient gas flow or leaks around the calibration adapter not completely immersing the
sensor in the calibration gas. Verify that calibration gas cylinder has not run-out and the
calibration adapter is properly positioned.]
The oxygen concentration at the sensor is NOT between 20.8 and 21.0 percent (by volume).
The calibration sampling can be re-started
while the LED is blinking RED by again
pressing and holding
the ‘SPAN’ button until the LED blinks YELLOW, then go to step 1 above.
To exit the span calibration preserving the original calibration
,
press and quickly release
the ‘SPAN’
calibration button. The status LED will blink RED/YELLOW indicating that the calibration gas has been
removed, the original calibration will be preserved and the unit is in standby for two minutes while the
sensor re-equilibrates to the ambient atmosphere before normal operation resumes. The calibration is
complete when the status LED returns to steady GREEN.
At the conclusion of a successful Span calibration the sensitivity of the sensor is compared to its
sensitivity during initial factory calibration. If its sensitivity has fallen below manufacturer’s end-of-life
specification, the K-O2 goes into Sensor Expired mode with the front cover LED slowly blinking RED, the
analog output at a constant 4 mA and the warning/ventilation relay activated. The oxygen sensor is no
longer operational and must be replaced (See section 6).