Specifications

CO₂ measurements

Measurement range: 0 to 20,000 ppm

Accuracy

LI-850: Within 1.5% of reading

LI-830: Within 3% of reading

Calibration drift

Zero drift1 Zero drift is the change with temperature at 0 concentration.: <0.15 ppm / °C

Span drift2 Span drift is the residual error after re-zeroing following a temperature change.: <0.03% / °C

Total drift at 370 ppm3 Total drift is the change with temperature without re-zeroing or re-spanning.: <0.4 ppm / °C

RMS noise at 370 ppm with 1 sec signal filtering: <1 ppm

Sensitivity to water vapor (LI-850 only): <0.1 ppm CO₂ / mmol mol^-1 H₂O

Lower limit of detection: 1.5 ppm

H₂O measurements (LI-850 only)

Measurement range: 0 to 60 mmol mol^-1

Accuracy: Better than 1.5% of reading

Calibration drift

Drift at 0 mmol mol^-1: <0.005 mmol mol^-1 / °C

Span drift at 10 mmol mol^-1: <0.006 mmol mol^-1 / °C

Total drift at 10 mmol mol^-1: <0.016 mmol mol^-1 / °C

RMS noise at 10 mmol mol^-1 with 1 sec signal filtering: <0.01 mmol mol^-1

Sensitivity to CO₂: <0.0001 mmol mol^-1 H₂O / ppm CO₂

Lower limit of detection: 0.015 mmol mol^-1

General

Output rate: Up to 2 measurements per second

Response time (T90)

CO₂: <3.5 seconds from 0 to 375 ppm

H₂O (LI-850 only): <3.5 seconds from 0 to 21 mmol mol^-1

Measurement principle: Non-Dispersive Infrared

Traceability

CO₂: Traceable gases to WMO standards from 0 to 3,000 ppm; traceable gases to EPA protocol gases from 3,000 to 20,000 ppm

H₂O (LI-850 only): NIST traceable LI-610 Portable Dew Point Generator

Pressure compensation range: 50 to 110 kPa

Maximum gas flow rate: 1 liter min^-1

Output signals: Two analog voltage (0 to 2.5 V or 0 to 5 V) and two current (4 to 20 mA)

Digital outputs: TTL (0 to 5 V) or Open Collector

DAC resolution: 16 bits across user-specified range

Power requirements

Input voltage: 12-30 VDC

After warmup (without pump): 0.33A @ 12 VDC (4.0 W) average

After warmup (with pump): 0.42A @ 12 VDC (5.0 W) average

During warmup: 1.2 A @ 12 VDC (14 W) maximum

Operating temperature range: -20 to 45 °C

Relative humidity range: 0 to 95% RH, Non-condensing

Dimensions: 22.23 cm W × 15.25 cm D × 7.62 cm H

Weight

No pump, no display: 1.0 kg

No pump, with display: 1.02 kg

With pump, no display: 1.3 kg

With pump, with display: 1.32 kg

Internal optical cell volume: 14.5 mL

Pump specifications (optional)

Operating temperature range: 5 to 45 °C

Storage temperature range: -20 to 60 °C

Operating humidity range: 0 to 80% RH

Nominal flow rate: 0.75 liters minute^-1

Power consumption: 1 W (nominally)

Expected life span: 8,000 hrs in standard conditions with a normal load

Display specifications (optional)

Dimensions: 6.7 cm corner-to-corner

Resolution: 400 × 200 px; monochrome

Power consumption: <200 µW

Displayed variables: CO₂ reading, H₂O reading (LI-850 only), optical bench temperature, and pressure.

Dimensional drawings

Serial cable pin assignments

The image below shows the pin assignments for the 9-pin RS-232 serial connector.

Serial communication parameters

The LI-830 and LI-850 can communicate through a RS-232 serial port on the front of the instrument. You may need to set the communication parameters on your computer or your terminal emulator program. The RS-232 port is configured as Data Terminal Equipment (DTE) with no hardware handshaking. It is bi-directional, meaning information can be transferred both into and out of the instrument. The port is configured as follows:

• Baud Rate: 9600 bps
• Data Bits: 8
• Parity: None
• Stop Bits: 1
• Flow Control: None

Specifications subject to change without notice.