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LI-7500DS Open Path CO2/H2O Analyzer

Fast open-path CO2/H2O measurements in ambient air

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Built for eddy covariance, the LI-7500DS Open Path CO2/H2O Analyzer delivers high-speed CO2 and water vapor measurements in ambient air with low power needs and minimal upkeep in real-world conditions.

  • Take ambient air measurements even in the most demanding or remote environments.
  • Use ~4 W during normal operation, the lowest power demands of any EC gas analyzer.
  • Reduce complexity with open-path, in-air measurements—no pumps or tubes required.
  • Get long-term stability and minimal drift through improved optics and temperature controls.

KEY FEATURES

Stable Measurements

Get stable data across wide temperature fluctuations, thanks to the temperature-controlled source and detector.

The Complete Picture

Add a 3D sonic anemometer for wind measurements and collect meteorological, radiation, and soil data with LI-COR Biomet System sensors.

Built for Rough Sites

Rely on field-ready optics that resist dust and wear with scratch-resistant windows that maintain data quality in tough conditions.

Effortless Integration

LI-7500DS-based eddy covariance systems gain access to LI-COR Cloud® and its next-generation data processing and analysis tools.

Proven Performance:

The Global Standard in Eddy Covariance

See how the LI-7500DS performs over time. These figures (below) illustrate optical filters and drift resistance in real-world conditions—delivering long-term, accurate, and dependable data.

Figure 1: CO2 measurements from three LI-7500RS analyzers (which use the same optics as the LI-7500DS) and three LI-7500A analyzers (average and spread). The y-axis shows the deviation from a control reference. CO2 measurements from the LI-7500RS analyzers drifted considerably less and had smaller instrument-to-instrument variability than those from the original LI-7500A models. Data show the typical improvement expected from the LI-7500RS analyzer.
Figure 2: Water vapor measurements from three LI-7500RS analyzers (which use the same optics as the LI-7500DS) and three LI-7500A analyzers (average and spread). The y-axis shows the deviation from a control reference. Measurements from the LI-7500RS analyzers drifted several times less, and had smaller instrument-to-instrument variability when compared with original LI-7500A models.

Next-Gen Data Analysis

Bring your system online. Each LI-COR eddy covariance system is equipped with SmartFlux® Core, the on-site hardware that sends data to LI-COR Cloud.

Explore

Remote access

View, share, and download CO2 and H2O data from your lab or collaborating sites anywhere in the world.

Shareable data

Allow other researchers to conveniently access your data—even if they do not own a LI-COR device themselves.

Tailored data analytics

Access detailed analytics built from your LI-7500DS's data streams within LI-COR Cloud.

Easy configuration

Follow a straightforward, guided configuration that anyone on your team can do—no technical expertise required.

Design Your Own System

Outfit your eddy covariance site with pre-configured sensors packages made to fit your research needs. Choose a package when you create your own EC system today.

Design Your System

Specifications

CO2 Measurements

  • Calibration Range: 0 to 3000 µmol mol-1
  • Accuracy: Within 1% of reading
  • Zero Drift(per °C):
    • ±0.1 ppm typical
    • ±0.3 ppm maximum
  • RMS Noise (typical @ 370 ppm CO2):
    • @5 Hz: 0.08 ppm
    • @10 Hz: 0.11 ppm
    • @20 Hz: 0.16 ppm
  • Gain Drift (% of reading per °C @ 370 ppm):
    • ±0.02% typical
    • ±0.1% maximum
  • Direct Sensitivity to H2O (mol CO2 mol-1 H2O):
    • ±2.00E-05 typical
    • ±4.00E-05 maximum

    • H2O Measurements

    • Calibration Range: 0 to 60 mmol mol-1
    • Accuracy: Within 1% of reading
    • Zero Drift (per °C):
      • ±0.03 mmol mol-1 typical
      • ±0.05 mmol mol-1 maximum
    • RMS Noise (typical @ 10 mmol mol-1 H2O):
      • @5 Hz: 0.0034 mmol mol-1
      • @10 Hz: 0.0047 mmol mol-1
      • @20 Hz: 0.0067 mmol mol-1
    • Gain Drift (% of reading per °C @ 20 mmol mol-1):
      • ±0.15% typical
      • ±0.30% maximum
    • Direct Sensitivity to CO2 (mol H2O/mol CO2):
      • ±0.02 typical
      • ±0.05 maximum

General

  • Fundamental Gas Sampling Rate: 150 Hz
    • Bandwidth: 5, 10, or 20 Hz; software selectable
    • Type: Absolute, open-path, non-dispersive spectroscopy
  • Detector: Thermoelectrically cooled lead selenide
    • Path Length: 12.5 cm (4.92″)
  • Air Temperature Thermistor: 10K ohm @ 25 °C
    • Measurement Range: -40 to 70 °C
    • Sensor Accuracy: ±0.25 °C from -20 to 70 °C
    • Resolution: 0.003 °C @ 25 °C
  • Pressure Sensor:
    • Measurement Range: 20 to 110 kPa
    • Sensor Accuracy: ±0.4 kPa from 50 to 110 kPa
    • Resolution: 0.006 kPa
  • Outputs: Ethernet
  • Operating Temperature Range: -25 to 50 °C (-40 to 50 °C verification on request)
  • Relative Humidity Range: 0-95% (non-condensing)
  • Weatherproof Rating: Tested to IEC IP65 standard
  • User Interface: Windows® PC software
  • Power Requirements: 9 to 33 VDC, reverse voltage protected
  • Steady-State Power Consumption: 4 W typical at 25 °C
    8 W max over operating range of -25 to 50 °C
  • Head:
    • Size: Diameter 6.5 cm, Length 30 cm
    • Weight: 0.67 kg; 1.3 kg with mounting post
    • Head Cable Length: 200 cm
  • DSI Box:
    • Size: 13.24 x 14.64 x 6.24 cm (H x W x D)
    • Weight: 0.93 kg

Specifications subject to change without notice.

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