Geotech GEM5000 - Page 126

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Page 126 of 127
Operating Manual
OMGEM5KN – Iss. 5.1
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Copyright – Geotechnical Instruments (UK) Ltd
GEM5000
transferred using the GAM download software.
NO
2
Nitrogen dioxide
Operating language
The operator can choose the default operating
language for the analyser. Choices are English,
German, Spanish, French and Italian.
PPM
Parts per million
Pump
Used to draw the gas sample from the sample point to
the analyser.
Select the pump key on the analyser to activate.
ID
The user definable identification tag allocated to a
sample point.
Relative pressure
The pressure at the sample point ‘relative’ to
atmospheric (barometric) pressure.
Relative pressure transducer
The internal component used to measure the relative
pressure.
Residual N
2
The calculation for the residual N
2
used on the latest
version of the GEM5000 platform is as follows:
Residual N
2
= Balance – (O
2
% x 3.76)
Where, Balance = 100% - (CH
4
% + CO
2
% + O
2
%) and
3.76 is the ratio of O
2
to N
2
in ambient air (79/21)
Sample tube
The tube used to obtain a sample of gas from the
sample point to the analyser.
Span
The point at which the gas analyser is calibrated when
a known quantity of the target gas is present.
Span multi gas
Term by which the span calibration of the three main
gas channels is known. This option must only be used
when the calibration gas being used is a combination of
CH
4
CO
2
O
2
.