The LI-820 CO2 Gas Analyzer has undergone some important and exciting changes this summer and these are available to you as a free firmware update. With the new firmware, the LI-820 provides a continuous measurement range (0-20,000 ppm CO2) with a single optical path (14 cm)! To take advantage of this upgrade, download and install the firmware on your instrument, install the 14 cm optical bench, set the instrument zero, and perform a two-point span. All new LI-820s are shipped with the new firmware, factory calibration, and the two-point span. LI-820s with serial numbers below CGA-1269 can be updated by installing the new instrument firmware, setting the zero, and setting the two-point span.
The importance of the user-calibration:
The two-point span sets the span slope value using two non-zero gases. It requires the use of two span tanks – one fairly low (e.g. 300 to 600 ppm CO2), and the other near the high end of the desired operating range (e.g. 20,000 ppm CO2). This ensures the accuracy of measurements across the measurement range. See the LI-820 CO2 Manual (Section 3) for more detailed instructions on this calibration procedure.
LI-820 software downloads can be found here:
LI-820 Software Downloads page