What's what

If you have just taken delivery of the LI-6800 check the packing list and verify that you have received everything that you ordered. The following pages present the components available for the LI-6800. Chambers and light sources are introduced in Chambers and light sources.


Part Number LI‑6860

The console provides the operating system, interface, air conditioning, and data logging. The right side of the console has the power button, head and fluorometer cable connectors, air supply to head connector, and the power cable connector. A 25-pin D-sub (DB25) connector provides customizable digital and analog inputs and outputs (see Using auxiliary channels). The accessory connector is to control a second light source.

Cable connectors for the head, fluorometer, accessories, and power supply.
Figure 1‑4. Console cable connections and air outlet.

The back (Figure 1‑5) of the console has an Ethernet port (LAN) to connect to a network with the Ethernet cable. It has two USB Type A host ports and one USB Type B port. You can insert a USB storage device into the host port and transfer files to and from the LI-6800. The USB Type B port is not supported currently.

Components that condition the air.
Figure 1‑5. Air intakes, conditioning components and Ethernet connection.

The CO2 scrub column, humidifier column, desiccant column, and CO2 cartridge holder are on the back of the console. The columns hold materials that condition the air stream—to establish the CO2 and water vapor concentrations that you specify. The air inlet cover provides access to the intake air filter. The Auxiliary Air Inlet is to inject a custom gas mix, if you want to start with a gas other than ambient air, such as a tank of low O2 for measurements under non-photorespiratory conditions.

Sensor head

Part Number LI‑6850

The sensor head includes the sample and reference gas analyzers, flow meters, a spring-loaded latching mechanism, a Peltier thermoelectric cooler, and a system of valves. A leaf chamber and optional light source connect to the head. The chambers feature independently-articulated hinges to help form a good seal around unevenly-shaped leaves. Chambers also have three positions:

  • Open: The lower chamber is all the way open, ready to accept a leaf.
  • Parked: The first stop on the way to closed. Squeeze the handle until it clicks, then release. This is to adjust the position of a leaf before clamping down on it. Store and ship the head with the chamber in this position.
  • Closed: This is the position for making measurements. Squeeze the handle firmly and then release it. The chamber will close, compressing the gaskets.

Two stabilizing posts (part number 9868-518) are included with some chambers. The posts should be used for laboratory measurements and removed for field measurements to protect them from damage.

Figure 1‑6. The head features the handle and latch mechanism, interchangeable leaf chambers, a display, LI-190R quantum sensor, the log button, and scroll buttons.
Figure 1‑7. The connectors on the front of the head.

Head cable assembly

Part Number 9968-092

The cable assembly consists of a cable for communication and power, and one Bev-a-line tube for conditioned air. To install the cable, orient the red dot on the cable toward the top of the head or console and press the cable in place.


The following components are available for the LI-6800.

External quantum sensor

Part Number 190R-6800

An LI-190R quantum sensor mounts on the sensor head. The entire assembly, including the sensor, mounting bracket, and cable is part number 190R-6800. If reordering, LI-190R is the sensor by itself.

Rechargeable batteries

Part Number 442-11807

The instrument includes three batteries. Batteries are shipped in a partially charged state. They should be fully charged prior to the first use. Leaving them discharged can result in damage to the batteries. One battery will provide approximately six hours of use, but this will vary depending on how you use the system.

Gas conditioning components

Three compounds—a CO2 scrubber (soda lime), a desiccant (Sorbead®), and humidifier substrate (Stuttgarter Masse) are included with the instrument, as well as several boxes of CO2 cartridges. In the table below, quantity indicates the number included with the instrument.

Description Quantity Part Number
Soda Lime 2 jars 9964-090
Sorbead® Orange CHAMELEON® silica gel beads 0.45 kg bag 622-16951
8-gram CO2 cartridges (Box of 25) 3 boxes 9968-227

AC power supply and cord

Part Number 9968-232

The power supply delivers power to the instrument and charges batteries in the console any time the device is plugged into an AC power supply. It is compatible with 110 VAC 60 Hz and 240 VAC 50 Hz power. The power supply can accept a C13 coupler (called an IEC cord). The instrument will include one of the following:

Description Part Number
For USA, Canada, Mexico, and Japan; NEMA 5-15; Type B 390-00787
For Europe, South America, and Asia; CEE 7/7; Type C 390-01486
For United Kingdom; Type G 390-03089
For Israel; SI32; Type H 390-03059
For Australia; Type I 390-03095

Warning: Use the safety-approved power cord supplied with the instrument. The power supply is equipped with a 3-wire grounding plug. This plug will only fit into a grounded outlet. Do not defeat the purpose of the grounding-type plug. Do not place the power cord where it will be walked on or exposed to water or chemical spills.

Power supply adapter

Part Number 9968-242

This optional component allows you to power the LI-6800 from an external power supply, such as a deep cycle battery.

Ethernet cable

Part Number 616-06116

Standard category 5e (Cat5e) network cable to connect the LI-6800 to a computer or network. Length of 2.1 meters (7 feet). The network port sis labeled LAN on the back of the console.

Caution: Do not use network cables other than the one provided. Other network cables may result in improper electrical performance.

Instrument case

Part Number 9968-222

The hard-shell, foam padded case can hold the console, head, and a variety of accessories. Store the instrument in the case when it is not in use. Always use the case to protect the instrument during shipping (see Preparation for shipping).

Accessory case

Part Number 9968-223

An accessory case is included with some configurations. The accessory case has two levels. If you are unable to find something, be sure to lift off the upper foam pad to access the second level.


Part Number 609-15790

Optional stand for the console or head.


Part Number 609-19238

Optional stand for the head.


Part Number 609-15791

Optional attachment for the head. Securely holds the head to a tripod or monopod while allowing adjustment to a full range of positions.

Carrying harness

Part Number 9968-221

Optional harness to position the console in front of carrier's torso for easy access to controls. Includes shoulder straps, waist strap, D-rings (part number 193-15728), and screws (part number 150-15736; M5, 10 mm length) to attach the D-rings.

Single-bay battery charger

Part Number 590-11830

Dock to charge a single battery. Includes power cord for outlet power and 12 VDC adapter for automobile power supplies.

Subsample kit

Part Number 9968-210

The optional subsample kit makes it possible to sample the air stream before and after the leaf chamber. It has hose barb connectors for the air streams, T-fittings, and needle valves.

Description Quantity Part Number
Hose barbs; Metric; M5×0.8 to 1/8" ID 4 300-15712
Hose barbs; U.S.; 5/16"-24 × 1/4" 2 300-14479
T-fittings 4 300-07385
Needle valves 2 300-10471

CO2 tank adapter kit

Part Number 9968-109

An optional adapter to connect a tank of pure CO2 to the injector. Includes both English and metric hardware.

Zero calibration kit

Part Number 9968-258

The zero calibration kit includes two chemical columns that can be installed (one at a time) on the tube between the console and head to ensure that the air is scrubbed of CO2 and H2O during a zero calibration. See Zeroing with chemicals for details.

Head chemical bottles

Part Number 9968-094

The internal head chemical bottles ensure that the gas analyzers themselves are free of CO2 and H2O vapor. We recommend replacing the head chemicals every three years.

Instrument spare parts kit

Part Number 9968-173

This box contains spare and replacement parts for your LI-6800 console and head. Contact your sales representative for replacement parts. The spare parts kit fits into the top of the accessories case.

Description Quantity Part Number
Chamber Springs; Low Pressure 2 9968-240
Leaf Temperature Thermocouple Assembly 1 9968-245
Thermocouple Hole Plug 1 6568-523
Chamber Feet 2 9968-253
Quick-Connect Coupler 1 300-07125
Hose Barb; Brass; 10-32 to 1/8" 1 300-02547
Filter for Scrub Tube/Head; 10 Micron 12 300-14319
Filter Seal for Scrub Tube 6 6368-225
Bev-a-line Tubing; ¼" diameter; 4.5 Meters 1 222-01824
Console Intake Air Filter with O-rings 1 9968-211
Propafilm™ Kit; includes Double-sided Tape 1 9964-151
Flexible Chamber Air Ducts 2 6368-345
Chamber Duct Cover Gasket 1 6568-346
O-ring; 6×1.5 mm; for Heat Exchanger Tubes 8 192-14314
O-ring; 10×1.5 mm; for Leaf Thermocouple 6 192-14435
O-ring; 55×2 mm; for Chamber Bottom and Heat Exchanger 3 192-14438
O-ring; 44×2 mm; for Chemical Column Cap 6 192-14541
O-ring; 12×1.5 mm; for IRGA Reflectors 4 192-15947
O-ring; AS 005 Urethane; for CO2 Cartridge 6 192-14864
O-ring; .055IDx.032CS; for Leaf Temperature Thermocouple 1 192-19386
Chamber Electronics Gasket 2 6568-327
Leaf Chamber Air Filter Gasket 3 6568-485
Leaf Chamber Air Filter Retention Plate 1 9868-484
Chamber Latch Grommet 2 196-14475
Screw; M2×0.4 10 mm; for IRGA Reflectors 6 151-15742
Screw; M3×0.5 5.2 Shoulder Screws for Chamber Latch 6 146-14474
Screw; M4×0.7; 16 mm; Phillips; for Bulkhead 6 150-14431
Screw; M3×0.5 6 mm; Phillips; for Chamber Bottom and Air Duct 6 150-14477
Screw; M4×0.7 12 mm; Captive Screws for Mounting Chamber 2 144-15344
Screw; M2×0.4 6 mm; for Mixing Fan Shield and Leaf Chamber Air Filter 6 150-15422


The spare parts kit includes several tools that are used for maintenance.

Description Quantity Part Number
Screwdriver; #1 Phillips; 60 mm Blade 1 611-15867
Screwdriver; #2 Phillips; 150 mm Blade 1 611-15837
Hex Key; 1.5 mm 1 611-15953
Foam-Tipped Swabs; Small 8 610-16093
Foam-Tipped Swabs; Large 8 610-05315
Glove; Lint-free Soft Cotton, Small 1 pair 229-10716
Glove; Lint-free Soft Cotton, Large 1 pair 229-10715
Screen Cleaning Cloth 1 229-16069
Anti-static Wrist Strap 1 619-05291