Opti-Sciences Fluorescence Probe

Printable PDF: 64000-14 Opti-Sciences Fluorescence Probe Adapter installation instructions

Instructions for installing the 6400-14 Opti-Sciences Probe Adapter onto the LI-6400/XT Portable Photosynthesis System.

The 6400-14 Opti-Sciences Fluorescence Probe Adapter is used to connect the probe from an Opti-Sciences Chlorophyll Fluorometer (Opti-Sciences, Tyngsboro, MA, USA) to the LI-6400 sensor head. This adapter chamber allows you to make simultaneous measurements of photosynthesis (with the LI-6400) and chlorophyll fluorescence. The 6400-14 replaces the upper leaf chamber cuvette on the LI-6400 sensor head, as described below.


  1. Unhook the PAR sensor connector from the port on the side of the sensor head by gently pulling straight out. You will need to remove the tripod mounting bracket, if attached, to access the connector.
  2. Remove the upper half of the leaf chamber cuvette (or the 6400-02 LED Light Source) using the 3/32” hex key provided in the spare parts kit. The upper half of the leaf chamber is secured by two long screws that can be seen in front of the cuvette.
  3. Figure 1‑1. Remove the two screws from the upper leaf chamber cuvette.
  4. Before installing the 6400-14 assembly, transfer (or install new) air passage O-rings from the upper leaf chamber cuvette to the adapter chamber.
  5. Install the 6400-14 assembly with the two long screws from Step 2. Attach the PAR sensor connector as shown in Figure 2. Make sure the PAR sensor is attached to the connector near the rear of the analyzer housing, not to the log switch connector.
  6. Use the Installation Menu (in the Config Menu) to generate a configuration file. If there is no entry for the 6400-14 in the Installation Menu, then use either the 6400-06 or 6400-10.

Making Measurements

  1. Insert the probe into the adapter chamber.
  2. Figure 1‑2. Attach the 6400-14 with the two long screws.
  3. Tighten the set screw to hold the probe in place.
  4. Figure 1‑3. Insert the probe into the 6400-14 chamber and tighten the set screw.
  5. Orient the sensor head and 6400-14 chamber so that the leaf and PAR sensor are exposed to full sun as much as possible; some shading may occur regardless of the orientation, however.