General Description

What's What

This procedure should be followed if you have just taken delivery of your LI-820. Check the packing list to verify that you have received everything that was ordered and that you have also received the following items:

  • RS-232 Cable - (part number 392-04993), used to connect the LI-820 to your computer. This cable is a null modem (cross-over) type cable; a straight through type cable will not work with the LI-820. Appendix B shows the pin assignments for the DB-9 connector on the LI-820 front panel.
  • 820-500 Data Communications Software - This Windows-compatible software is used to communicate with your computer. The software is provided on CD. A complete description of this software can be found in Section 3, Operation.
  • Standard Spare Parts Kit (part number 9980-012) - This kit contains replacement parts for your LI-820. As you become familiar with the analyzer you will learn which items to keep close at hand and which items can be stored away. Some of the items in the spare parts kit include:
Description Qty. LI-COR Part No.
Spares Kit, includes:    
Polyurethane Mounting Feet 4 234-02268
Mounting Screws 4 149-02610
Terminal Block 1 331-05273
Bev-a-line Tubing 12' 222-01824
Balston Air Filter 2 300-01961
Quick Connect Unions 2 300-03123
Rapid Tube Fitting Nut 2 9861-036
2A Fuse 2 439-03952
Cleaning Kit, includes: 1 9980-013
5" Cleaning Swabs 5 610-05315
O-Rings 4 192-00226
Pre-formed Optical Bench Tubing 4 6580-010


The LI-820 is an economical high performance, non-dispersive infrared gas analyzer designed to be used for a wide variety of applications. Some of the LI-820's important features include:

  • The 14 cm (5.5") optical bench is used to measure CO2 concentrations over a range of 0 - 20000 ppm.
  • The optical bench is fully serviceable by the user; cleaning the optical bench is a simple process, and does not affect the instrument calibration.
  •  Simple Windows® software provides for easy user calibration and data output.


  • Avoid storing the LI-820 in very humid conditions for more than several days. Doing so can cause the optical sensor to become saturated with humidity, which will temporarily affect measurements when the instrument is removed from storage. See for more details.
  • The optical bench is maintained at a constant 50 °C. Avoid direct exposure to sunlight or extremely high temperatures that may elevate the temperature inside the LI-820 case.
  • The optical source is sensitive to vibration, and can be damaged by strong vibrations or jarring. Do not drop the LI-820, or expose it to severe mechanical shock.
  • Do not use abrasive cleansers when cleaning the optical bench, as damage to the gold plating may result. Instructions for cleaning the optical bench can be found in Section 5.