Thermo Scientific G100 Series, Operating Manual

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Calibration
Calibration Method
Thermo Scientific G100 Range CO
2
Analyser
7-3
Calibration Method
Before you begin ensure the unit is stabilised at its working temperature before performing any of the
calibration operations.
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.
The exact calibration method can vary depending on the gases used.
Zero CO
2
Channel:
For maximum accuracy it is recommended that the CO
2
Channel is zeroed using bottled gas (certified
100% N2). However, if nitrogen gas is not available the optional soda lime filter kit can be fitted to the
gas inlet. This allows the user to perform a zero using normal air as the soda lime filter will absorb
virtually all CO
2
from the sample air. For both these options select 'Key 1-Zero with N2' from the user
calibration menu.
If neither of the recommended methods is available the user can select the option to perform an air
calibration. This option assumes that the user has access to fresh air at around 390ppm. Generally, this
can be found outside or in a well ventilated corridor (typically, an office or lab would have a higher
CO
2
concentration).
1. From the ‘Calibration’ Menu, press ‘Key 2 - CO
2
channel’.
2. Press either ‘Key 1 - Zero with N2’ (recommended) or ‘Key 2 - Zero with Air’ fromthe menu.
Then, either attach the 100% N2 or sample pipe to allow access to freshair.
3. Press the ‘Start’ key. The instrument will now wait (approximately 60 seconds) for the gas reading
to stabilise at the correct level. If zeroing with air press the ‘Pump’ key to draw in fresh air.
Calibration
User Calibration