LI-COR LI-7815, Instruction Manual

Page: 65 / 98

Setting the span
Select a quality span gas with a CO
2
concentration near or slightly above the con-
centrations you expect to measure.
Caution: Do not use nitrogen-balanced gas. Use air-balanced gas for both the zero
and span.
1
Power on the instrument and let it warm up.
2 Plumb a gas to the air inlet as shown in Figure 6-1 on page 6-1.
Set the pressure between ambient and 35 kPa (5 PSI) above ambient.
Observe the measurements on the home screen until they have stabilized. The slope
will be near zero.
3
Span the analyzer.
Under
Options > Calibration > CO
2
Span
, enter the concentration of the gas and
click
Span CO
2
.
Recovering from a bad calibration
In the event that an attempt to zero or span fails to work as intended, you can
restore previous zero and span settings by selecting the file and clicking
Restore
.
Factory Reset
reloads the factory original zero and span calibration parameters.
Section 6. Maintenance
6-3 Setting the span