OS-2 Oxygen Sensor
1/27/2021
Kele, Inc. • 3300 Brother Blvd. • Memphis, TN 38133
Page 8 of 14
5.2 Z
ERO
C
ALIBRATION
P
ROCEDURE
The Zero calibration procedure below 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).
Apply the nitrogen (zero) 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 ’ZERO’ button (see
Figure 9) for 3 seconds until the front cover LED starts blinking YELLOW, indicating that gas sampling is in progress.
1.
Ensure that the calibration adapter remains correctly seated and calibration gas continues to flow for the
2 minute sampling period.
2.
At the end of the sampling period, the sensor’s status LED blinks GREEN if the calibration was successful
or RED if not.
3A. If successful (blinking GREEN):
The gas sampling completed successfully. Turn off the calibration gas flow, remove the calibration adapter
then
press and hold
the ‘ZERO’ calibration button until the LED blinks GREEN/YELLOW indicating that the
calibration gas has been removed, the 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 cause of zero calibration sampling failure is insufficient gas flow or leaks around the
calibration adapter failing to completely immerse the sensor in nitrogen. Verify that calibration gas is still
flowing at the required rate (typically about 0.2 liters per minute) and the calibration adapter is properly
positioned.
The calibration sampling can be re-started
while the LED is blinking RED by again
pressing and holding
the ‘ZERO’ button until the LED blinks YELLOW, then return to step 1 above.
To exit the zero calibration routine preserving the original calibration:
turn off the calibration gas flow
and remove the calibration adapter, then
press and quickly release
the ‘ZERO’ button. The status LED will
blink RED/YELLOW indicating that the calibration gas has been removed, the original calibration has been
restored and the unit is in standby for two minutes while the sensor re-equilibrates to the ambient
atmosphere before normal operation resumes. The original calibration is completely restored when the
status LED returns to steady GREEN.
