ANALOX O2 PORTABLE OXYGEN ANALYSER
Operators Manual MO2-807-02 January 2009
Page 5
3.0
Air Calibration
3.1
Air calibration is essential before every use and is performed as
follows.
3.2
Ensure that any flow adaptors are removed and the reading on the
display has stabilised.
3.3
Expose the analyser to clean air for two minutes and adjust the
calibration knob until the display reads the correct value using the
humidity chart ( you can find the humidity chart on the inside of the
back cover ). If this is not possible refer to paragraph 3.4 or to
section 8.0 Maintenance.
3.4
It is possible that at very high altitude normal calibration is not
achievable. In this event you must ascertain the actual pressure in
BAR and multiply the atmospheric oxygen percent (20.9%) by this
pressure and set the reading during calibration to the calculated
level (this is the surface equivalent oxygen percentage). When
you measure the level of oxygen in the sample you must divide
the reading by the same atmospheric pressure value to obtain the
true percentage of Oxygen in your sample.
For Example: At an atmospheric pressure of 0.8 BAR the surface
equivalent oxygen percentage is 20.9% x 0.8 = 16.7%O2 Surface
Equivalent. If the reading you then obtain from your sample is
32.0% you must divide this by 0.8 to obtain the true Oxygen
percentage, 32.0/0.8 = 40.0%O2 True Percentage.
3.5
The analyser is now ready for oxygen measurement.
WARNING
The analyser is sensitive to Oxygen partial pressure.
Calibration must always be carried out at the same
atmospheric pressure as Oxygen measurement.
