34 • Measuring Mode, Normal Operation
GX-2012 Operator’s Manual
%LEL Sensor Relative Responses
Although the standard factory setup and calibration for the combustible gas channel is to
methane (CH
4
), the combustible sensors will respond to other combustible gases as well.
The table below lists the conversion factors for several hydrocarbon gases
for the % LEL
combustible sensor if it is calibrated to methane
. Conversion factors are not available
for the % volume TC sensor. To use this table, multiply the display reading on the
combustible gas channel by the factor in the appropriate row to obtain the actual gas
concentration. For example, if you are detecting pentane and the display reads 10% LEL
on the combustible gas channel, you actually have 10% LEL x 1.56 = 15.6% LEL pentane
present.
Snap Log Mode
The snap logging function in Snap Log Mode allows the user to record data at a specific
time and have it saved to the data logger. The data is assigned a snap log ID and is saved
with the station ID that was in use when the data was taken.
To enter Snap Log Mode and record snap log data:
1. Press and hold the (SHIFT)
button, then press and hold the AIR
button and hold
both until you hear a beep. The unit will cycle through the following screens.
Table 3: LEL Hydrocarbon Conversions
Gas
LEL Conversion
Factor (Methane
Calibration)
Gas
LEL Conversion
Factor (Methane
Calibration)
Acetone
1.79
Iso Butane
1.47
Acetylene
1.92
MEK
2.27
Benzene
2.00
Methane
1.00
Ethane
1.09
Methanol
1.92
Ethanol
2.50
Pentane
1.56
Ethylene
1.06
Propane
1.35
Heptane
2.50
Propylene
1.32
Hexane
2.08
Toluene
3.13
Hydrogen
1.25
Xylene
4.27
IPA
2.78
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