What’s the difference between the LI-830 and LI-850?

The LI-830 measures CO₂ in air. The LI-850 measures both CO₂ and water vapor in air. The H₂O measurement allows the LI-850 to account for band-broadening due to water vapor, and therefore the LI-850 reports CO₂ concentrations with precision of 1.5% of the reading, in contrast to the 3% precision provided by the LI-830.

Versatility that is just right

Whether you are monitoring ambient CO₂ concentrations, controlling a process, or measuring CO₂ for an experiment, the LI-830 and LI-850 can provide the data you need for many applications.

The CO₂ measurement range of 0 to 20,000 ppm, H₂O measurement range of 0 to 60 mmol/mol (LI-850 only), and output rate of 2 measurements per second (2 Hz) are ideal for atmospheric air measurements and many general-purpose applications. Featuring USB, serial, and analog outputs, data can be logged to a personal computer, data logger, or your own data recording device, such as an Arduino^®.

Low power requirements and light weight make it ideal for remote, mobile, and battery-powered deployments, including UAVs (drones) or on weather stations. The wide operating temperature range and onboard temperature measurements ensure consistent performance – even if ambient temperature changes rapidly.

The LI-830 and LI-850 are available with an optional pump for an out-of-the box flow solution and an optional display to view measurements in real time without a computer or datalogger. All LI-830 and LI-850 gas analyzers feature configurable alarms to trigger a switch when a CO₂ or H₂O threshold is crossed.

Dependability that is just right

The LI-830 and LI-850 are dependable and robust, providing low cost of operation. User-serviceable components minimize downtime. If maintenance is needed, you can do it yourself, typically, and the instruments do not require factory recalibration after service.

Measurements that are just right

With the LI-830 and LI-850, you don’t need to wonder about the quality of the measurements. You can trust the data while you turn your attention to more pressing concerns. Each LI-830 and LI-850 is calibrated at the factory with gas standards that are traceable to the WMO, EPA protocol gases, and NIST. Temperature controlled, insulated optics provide precision, stability, and accuracy over the full measurement range.

How do they work?

The LI-830 and LI-850 use non-dispersive infrared (NDIR) gas analysis to measure gases in air. A broad-band optical source delivers infrared radiation through the sample onto optically filtered detectors. Optical detectors measure the sample and reference bands to compute absorption by CO₂ and H₂O (LI-850 only). The CO₂ concentration is computed by fitting absorption to a double-rectangular hyperbola (a ratio of polynomials). The H₂O concentration in the LI-850 is computed with a third-order polynomial. Coefficients for the polynomials are determined by a thorough factory calibration procedure for each instrument, and the factory calibration is then verified across the measurement range.

Simplicity that is just right

Simple hardware and intuitive software mean that you can start taking measurements right away. You can view data, configure the analyzers, and set up data logging to your Windows^® or macOS^® personal computer. Each analyzer includes a USB cable and a universal power adapter that is compatible with mains power worldwide (100 to 240 VAC, 50 or 60 Hz input; 12 VDC output).

Just right for your application

With high-quality measurements, these small, light gas analyzers bring great performance at a great price for uses ranging from permanent installations to aerial platforms. The LI-830 and LI-850 are just right for many applications, including: