AirLink 6940XP Operator’s Manual
Sensor Settings and Calibration
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5. If the sensor is in clean air, press
ADD
to select “Yes” and continue to Step 7.
If the sensor is a CO
2
sensor, the sensor is not in clean air, or you do not wish to zero the
sensor, press
SUB
to select “No” and return to the Sensor Settings menu. Pressing
MENU
or
BACK
will also return the instrument to the Sensor Settings menu.
6. For CO
2
sensors or if the sensor is not in clear air, perform the following:
a. Unscrew and remove the rain guard from the assembly.
b. Install the calibration cup to the AirLink 6940XP’s sensor housing.
c. Screw the regulator into the zero air calibration cylinder (100% N
2
cylinder if zeroing a
CO
2
sensor).
d. Use the sample tubing to connect the regulator to the calibration cup.
e. Turn the regulator knob counterclockwise to open the regulator.
f. Allow the gas to flow for 1 minute.
g. Press
MENU
to select the Zero menu item.
h. Press
ADD
to select “Yes”.
7. The unit will automatically begin the 12-second zero process. The display will show a
countdown of the time remaining until the process is complete.
NOTE:
The zero process cannot be stopped without disconnecting the power from the unit.
8. When the zero process is complete, press
MENU
or
BACK
to return to the Sensor Settings
menu.
9. If a zero air calibration cylinder (or 100% N
2
cylinder for CO
2
sensors) was used, turn the
regulator knob clockwise to close the regulator.
Remove the regulator from the zero air cylinder.