LI-COR LI-8100A - Setting the Span: H 2 O

User Calibration
5-5
iv. Click Yes to perform the calibration.
C. Click Close to exit the calibration screen.
Software for Apple iOS
A. Select Calibration from the Utilities menu.
B. Tap the Span button.
i. Enable CO
2
.
ii. Verify that the CO
2
concentration is stable.
iii. Enter concentration of the span gas (μmol/mol).
iv. Tap Send Command.
Setting the Span: H
2
O
Note: Always set the zero before setting the span. To set the H
2
O span, use an air
stream containing a known, stable H
2
O concentration. This is best achieved by
using an instrument such as the LI-610 Dew Point Generator. If the proper
equipment is not available, we strongly recommend that you do not adjust the span
of the H
2
O channel.
1. Verify that the LI-8100A pump is turned on.
2. Plumb the LI-8100A.
A. Connect the output of the LI-610 to the air inlet on the LI-8100A, using a
"Y" fitting.
B. Connect a short piece of tubing (a few inches) to the other end of the "Y"
and allow it to vent to the atmosphere.
C. Set up the LI-610 to provide your air stream with a known dew point and
set the LI-610 flow rate as high as possible (usually between 1.5 and 2.0
L/min.). This will provide extra calibration air that will vent out the "Y"
connector, thus providing adequate air flow to the LI-8100A while
eliminating pressure changes within the optical bench.
3. Calibrate
Windows Software
A. Monitor the H
2
O concentration in the main window of the LI-8100A
Windows interface software. When the concentration is stable proceed to
the calibration window.
B. Select Calibration from the Utilities menu.
C. Click on the Span tab.
i. Enter the span gas dew point (°C).