Calibration Method
Before you begin ensure the unit is turned on and allowed to stabilise at its working temperature
before performing any of the calibration options, this will typically be 15-20 minutes.
To achieve the processes set out in this section, press ‘Key 3 – Calibration’ from the ‘Main’ menu. The
first screen displayed provides the option to select the gas that requires calibration.
Screen 19 - Calibration menu
The exact calibration method can vary depending on the gases used.
Zero Calibration
For maximum accuracy it is recommended that the
measurement channel is zeroed using bottled gas
(certified 100% N
2
). Due to the CO2 cross-gas effect on N2O, if nitrogen
gas is not available the
optional soda lime CO
2
filter kit can be fitted to the gas inlet. This allows the user to perform a zero
using normal air as the soda lime CO
2
filter will absorb virtually all CO
2
from the sample air. For both
these options select 'Key 1-Zero with N
2
' from the user calibration menu.
Note: In normal use, it is recommended that the soda lime CO
2
filter kit is always used. This is kit is
not required for normal use of the G210, as it measures CO
2
as standard. For further information
about cross-gas effects, refer to section Cross-Gas Effects of this manual.
Note: For all three of the aforementioned methods of zeroing and Air calibrating the instrument, it
is preferred that the instrument is left in its ‘on state’ to reach thermal equilibrium before
completing this process (approximately 40 minutes). However, the instrument can be zeroed or Air
calibrated immediately after turning it on and then subsequently used to measure but this process
must be repeated after the 40 minute thermal equilibrium time.
From the calibration menu, Select ‘Key 1 - Zero with N
2
’ (recommended) and either attach the
100% N
2
or soda lime CO
2
filter kit.
Press the ‘Start’ key. The instrument will now wait (a minimum of 60 seconds) for the gas
reading to stabilise at the correct level. If zeroing with the soda lime kit in fresh air press the
‘Pump’ key to draw in fresh air. This operation will time out after one hour if readings cannot be
stabilised.
The instrument will then indicate a successful zero has been completed. Press the soft-key
‘Accept’ to confirm the calibration and store the new user offset. Alternatively, soft-key ‘Reject’
to exit without change.
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