046-07-GA_Oxi_B-a_eng 9
5.3.
Errors during calibration and measurement
?
Measurement fluctuates by more than 1 Vol. % O
2
?
The sensor should be in thermal equilibrium with the environment
?
Note sensor response time (see socket label)
?
The sensor opening should be clean and dry
?
Gases mixed with ambient air during calibration
?
Internal electrical fault in device
?
inform your dealer!
? ?
The device does not display the expected measurement
?
Calculation of the gas mixture is faulty
?
Manometer is faulty
?
Device is not calibrated
?
Sensor not in thermal equilibrium with the environment
?
Sampled gas mixed with ambient gas
?
Device shows "
ERR
" for approx. 6 seconds after being switched on
?
Device must be returned to dealer to be checked!
? ?
Display goes out soon after switching the device on or does not come on at all
?
Battery is discharged
?
Replace battery!
The oxygen sensor wears out during its service life even when the device
is switched off. The sensor must be replaced if it is not possible to achieve
either 20.9% O
2
or 100% O
2
during calibration
or if the measurement is not
plausible after checking the possible causes of error described above.
5.4.
Influencing factors
Influence of gas pressure and measured gas humidity
The oxygen sensor measures the partial pressure of oxygen in the gas being
measured, but the device displays the concentration of oxygen and must
therefore be calibrated.
The calibration process equates the partial pressure of oxygen in dry ambient air
to a volume concentration of 20.9%O
2
. Depending on the absolute humidity of
the gas being measured, the proportion of oxygen (partial oxygen pressure) in
the gas fluctuates slightly. The effect of humidity can be ignored as the difference
between absolutely dry and saturated gas is less than 1% O
2
over the entire
working temperature range.
