KCO-NO2 User’s Manual
90-0201-01
Kele • 3300 Brother Blvd. • Memphis, TN 38133
Page: 13
WWW.KELE.COM
The procedure below MUST be done twice for each sensor: first it is done as a zero calibration
using the zero gas and only after a SUCCESSFUL zero calibration has been completed, the same
procedure below is done again as a span calibration using the required span gas.
5.2 Calibration Procedure
The progress and status of the calibration process is indicated by the color and flash-state of the
front cover status LED of the sensor being calibrated.
For each calibration proceed as follows:
1.
Flow the appropriate calibration gas to the sensor being calibrated using a calibration cap,
following the instructions for the calibration kit being used.
2.
Start the desired calibration by pressing either the ‘ZERO’ or ’SPAN’ button of the sensor being
calibrated (see Figure 9) for 3 seconds until the sensor’s status LED starts blinking YELLOW.
Gas sampling starts immediately.
3.
Ensure that the calibration cap 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 gas sampling
was successful or RED if not.
If successful (blinking GREEN):
The sampling completed successfully.
Disconnect the gas and press the same button that started the calibration again for 3 seconds
indicating the cal gas has been removed. The LED then blinks GREEN/YELLOW for 2 minutes
indicating that the calibration was accepted.
If NOT successful (blinking RED):
The sampling can be re-started while the LED is blinking RED by pressing the same button that
started the calibration again for three seconds until the LED again blinks YELLOW, then go to step
3 above.
OR
The sample can be discarded and the previous calibration restored by removing the calibration gas
from the sensor then pressing and quickly releasing the same button that started the calibration. The
LED switches to blinking RED/YELLOW for two minutes to indicate that the calibration was NOT
applied.
In either case, the calibration is complete when the LED again 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 KCO-NO2 goes into Sensor Expired mode
with the front cover LED slowly blinking RED, the analog output at a constant 20 mA
and the warning/ventilation relay activated. The sensor is no longer operational and
must be replaced.
