GasTech Cannonball3, Reference Manual

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Note: Remember to continue to flow calibration gas into
the calibration balloon throughout the span calibration
procedure.
9. When finished, use the navigation arrows to highlight EXIT
and press the MODE button to exit and save the new
calibration settings.
SAVE CHANGES
YES NO Cancel
10. Press the MODE button with yes highlighted to save
changes. Remove all fittings before turning the instrument
back on and returning to normal operation.
Note: The calibration reminder is only reset when all toxic
and LEL sensors have been successfully span calibrated.
4.6.3 O
2
zero calibration
The Cannonball3 includes a “real” zero calibration adjustment
for the oxygen sensor. The O
2
zero calibration should not be
confused with the fresh air calibration adjustment. The O
2
zero
calibration adjustment is used to calibrate the oxygen sensor in
an atmosphere containing no oxygen, while the fresh air zero
calibration adjustment is used to calibrate the oxygen sensor in
an atmosphere containing 20.9% oxygen.
Note: The O
2
zero calibration adjustment for the
Cannonball3 must be performed using calibration gas
containing 99.9% N
2
(nitrogen) or better.
To complete the O
2
zero calibration:
1. Turn the instrument on and wait at least three minutes to
allow sensor readings to stabilize fully before initiating any
calibration procedures.
2. Enter the Main Menu as described above in section 3.1.
MAIN MENU
SCREEN CALIBRATION
VIEW ALARMS
DATALOGGER OPTIONS
ID INFO
EXIT
3. Use the navigation arrows to select CALIBRATION and
press the MODE button.
CALIBRATION MENU
GAS VALUES SPAN CAL
HISTORY O
2
ZERO CAL
FRESH AIR
REMINDER
EXIT
4. Use the navigation arrows to highlight O
2
ZERO CAL and
press the MODE button.
Do O
2
Zero Calibration
YES NO
5. Press the MODE button with YES highlighted to begin the
O
2
zero calibration.
Apply a gas mixture
Containing no oxygen
As discussed above, the Cannonball3 includes a built-in
continuous sample draw pump that draws the gas sample into
the sensor compartment. As such, there are two viable
methods for delivering the gas to the sensor chamber for span
calibration: a standard 1 liter/minute regulator with the
calibration balloon that is included with every Cannonball3, or
with a demand flow regulator and a small piece of tubing.
6.a If using a calibration balloon, fill the empty balloon with
calibration gas until it is full. Connect the calibration
balloon assembly to the inlet coupling on the Cannonball3.
Continue to flow gas to the balloon throughout the span
calibration procedure.
6.b. If using a demand flow regulator, attach the regulator to
the gas cylinder and then connect it to end of the sample
probe assembly with a short piece of tubing. The
Cannonball3’s continuous sample pump will draw the
appropriate amount of calibration gas throughout the span
calibration procedure.