LI-6400XT Frequently Asked Questions

Q What can I measure using the LI-6400XT?

A You can measure photosynthesis, transpiration, stomatal conductance, sub-stomatal CO2 concentration and others. With the fluorometer, you can measure Fv/Fm, φPSII, ETR (or J), qp and qN. Click here for more information on example measurements.

Q Can the LI-6400XT measure respiration?

A Yes, the LI-6400XT measures leaf dark respiration. To do this, the light source has to be turned off and the reading for respiration appears as a negative photosynthetic rate. The LI-6400XT also measures both insect (part no. 6400-89) and soil respiration (part no. 6400-09).

Q How long will it take me to make a basic snapshot measurement?

A Once turned on, the instrument is ready to go in a couple of minutes, once the analyzers are to temperature. After warm up, a leaf is clamped into the chamber with the appropriate ambient environmental conditions set, and once the chamber air is flushed, a measurement can be logged. A typical measurement takes less than a minute.

Q Am I limited with my chamber options for the LI-6400XT?

A Scientists at LI-COR designed Soil CO₂ Flux Chambers, Conifer Chambers, Narrow Leaf Chambers and more for use with the LI-6400XT. The LI-6400XT allows numerous chambers to be attached to the sensor head, including custom chambers designed by the researcher.

Q Do I need to fill the entire area in the leaf chamber?

A No. Simply enter the actual leaf area into the LI-6400XT software and the calculated values will adjust accordingly. You may also adjust the actual leaf area after logging data in the software. It is important to remember, though, that more leaf area in a chamber results in larger flux and more precision.

Q Can I collect data automatically?

A Yes, various pre-set Autoprograms are loaded in the LI-6400XT software by the factory. You may also write your own Autoprogram using the menu-driven software utility.

Q I'm working in a lab where multiple researchers would be using the same instrument, how can I protect my data and settings?

A The LI-6400XT software allows you to generate personalized configurations that can be saved both on the instrument and your personal computer. This allows the user to define many instrument settings, including data and graphic presentations, which can then be uploaded to the instrument. An individual can customize their software without needing the instrument present.

Q How often do I need to send in my LI-6400XT for factory calibration?

A Factory calibration is suggested every 2 years and includes a number of system tests and maintenance, in addition to calibration of the sensors.

Q What training resources are available to help me learn how to use the LI-6400XT?

A A free training DVD and manuals (both hard-copy and digital format) are included with the purchase of the LI-6400XT, as well as numerous online resources such as webinars and application notes, which are continuously updated. LI-COR also offers hands-on training courses at our headquarters in Lincoln, Nebraska, USA. This course covers the fundamentals of making gas exchange measurements, including survey and response curves, as well as proper maintenance, calibration, and more. See here for a complete description of the course and dates for upcoming training sessions.

Q If I need to change my leaf area, for example, how can I calculate my data?

A The OPEN Version 6.x software creates Microsoft® Excel compatible files. The parameters have embedded equations that allow you to recalculate the data. Users can adjust the scenario and see results without needing to export the data to another program.

Q Can the LI-6400XT integrate into a classroom?

A The LI-6400XT provides students and educators with hands-on experience in learning the principles of photosynthesis, transpiration, and respiration. Software included with each LI-6400XT allows you to control the instrument from a PC, and project real-time data for a class. An Educational Resource Package (part no. 6400-520) contains 10 educational modules in the form of PowerPoint and videos for use in the classroom.

Q Can I upgrade my LI-6400 to the LI-6400XT?

A Yes! The user-installable XT Upgrade Kit (part no. 6400-926) converts your LI-6400 to the LI-6400XT. It includes a new digital board with 400 MHz processor, compact flash/Ethernet card slot, new console shell, Ethernet card adapter and cable, and the OPEN 6.2.x software. It can be factory- or user-installed.


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