Calibration
4-1
Section IV.
Calibrating LI-COR Instruments
General Information
The LI-610 can be used to calibrate water vapor gas analyzers such as the
LI-COR LI-6262, LI-7000, LI-7500, and LI-840 CO
2
/ H
2
O Gas
Analyzers, the gas analyzer in the LI-6400 Portable Photosynthesis
System, and instruments that use relative humidity sensors, including the
LI-COR LI-1600 Steady State Porometer, and the LI-6000 and LI-6200
Portable Photosynthesis Systems, among others. The LI-610 can also be
used to verify the calibration of dew point hygrometers.
☞
An article written by LI-COR Applications Scientist Dayle McDermitt
(HortScience, Dec. 1990) discusses a variety of topics concerning
stomatal control of leaf conductance, including the effects of sensor or
calibration errors on the accuracy of conductance measurements, the
relationship between molar conductance units presently used and
velocity units used in older literature, as well as other considerations.
Reprints of this article are available on request from LI-COR.
Calibrating the LI-6400 H
2
O Analyzer
Setting the H
2
O Span
To check the span of the H
2
O analyzer, you’ll need a known
concentration of H
2
O, provided by the LI-610. The H
2
O IRGA gain
adjustment is a process by which the user can manually (using the arrow
keys
↑↓
) adjust the values of G
wr
and G
ws
(see Equations (14-5) and (14-
6) on page 14-5 of LI-6400 Book 3).
