Help and Documentation

Welcome to the LI-6400 and LI-6400XT Portable Photosynthesis System help and documentation.

Top Resources

Using the LI-6400XT, OPEN software version 6.2.x

(6400_Manual_Using the 6400XT_v6.2.pdf)

Instruction manual for the LI-6400XT Portable Photosynthesis System, software version 6.2.x and above.

Stressed Plants? Integrated Fluorescence and Gas Exchange Measurements Allow You to Discover More


Flyer describing integrated fluorescence and gas exchange measurements made using the 6400-40 Fluorometer and the LI-6400XT Portable Photosynthesis System.

LI-6400 Photosynthesis System Packaging for Shipping Purposes

This Tech Tip/FAQ describes how to package the LI-6400 for shipping.

View all documents...


See all LI-6400/XT videos...

LI-6400/XT Factory Recalibration

Recommended Recalibration Frequency for the LI-6400 and LI-6400XT: Every two years. Note that the analyzers drift very little during this time frame.  The most important reason to return the instrument to the factory is for thorough system testing and maintenance.

What's included with recalibration?

Request Service and Recalibration

To request factory service or recalibration for a LI-COR instrument: Request Factory Service or Recalibration

Service will be performed at our US office in Lincoln, NE USA, European office (LI-COR Biosciences - GmbH), or by a distributor. To locate your country and designated point of contact click here.

Looking for a Calibration Certificate?

Training Courses


Eddy Covariance

Thank you for your registration.

You will receive an email shortly.

If you do not receive it within 24 hours or if you have any questions, please contact LI-COR at 1-402-467-3576.

Thank you for your interest in online eddy covariance training.

This training is full. We will contact you if a spot becomes available or if we add another training date.