OS-2 Oxygen Sensor
1/27/2021
Kele, Inc. • 3300 Brother Blvd. • Memphis, TN 38133
Page 9 of 14
5.3
S
PAN
C
ALIBRATION
P
ROCEDURE
The Zero calibration procedure in section 5.2 MUST be done before the 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 Table 8).
1.
Apply the SPAN calibration gas to the sensor using a calibration adapter, following the instructions for the
calibration kit being used. Ensure that gas is flowing to the sensor, then press and hold the ’SPAN’ button
(see Figure 9) 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 in the calibration gas 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 unchanged
,
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 sensor is no longer operational and must be
replaced (
See Table 7)
