LI-840A Specifications*

CO2

  • Measurement Range: 0-20,000 ppm
  • Accuracy: < 1.5% of reading
  • Calibration Drift
    • Zero Drift1: <0.15 ppm/°C
    • Span Drift2: <0.03%/°C
    • Total Drift3 at 370 ppm: <0.4 ppm/°C
  • RMS Noise @ 370 ppm with 1 second signal filtering: <1ppm
  • Sensitivity to water vapor: <0.1 ppm CO2/mmol/mol H2O

H2O

  • Measurement Range: 0-60 mmol/mol
  • Accuracy: < 1.5% of reading
  • H2O Calibration Drift
    • Zero Drift1 at 0 mmol/mol: <0.003 mmol/mol°C
    • Span Drift2 at 10 mmol/mol: <0.03%/°C
    • Total Drift3 at 10 mmol/mol: <0.009 mmol/mol/°C
  • RMS Noise at 10 mmol/mol with 1 sec signal filtering: <0.01 mmol/mol
  • Sensitivity to CO2: <0.0001 mmol/mol H2O/ppm CO2
  • Instrument Update Rate: Up to 2 Hz
  • Measurement Principle: Non-Dispersive Infrared (NDIR)
  • Traceability: Traceable to gases to WMO standards for CO2. NIST traceable LI-610 Portable Dew Point Generator for H2O
  • Pressure Compensation Range: 15 kPa-115 kPa (2.2-16.7 psi)
  • Maximum Gas Flow Rate: 1 liter/min (0.035 ft3/min)
  • Output Signals: Two analog voltage (0-2.5 V or 0-5 V) and two current (4-20mA)
  • Digital: TTL (0-5V) or Open Collector
  • DAC Resolution: 14-bit across user-specified range
  • Source Life: ˜18,000 Hours (2+ years)
  • Power Requirements: Input Voltage 12-30 VDC
    • 1.2 A @ 12V (14W) maximum during warm-up with heaters on
    • 0.3A @ 12V (3.6W) average after warm-up with heaters on
  • Operating Temperature Range: -20°C to +45°C
  • Relative Humidity Range: 0 to 95% RH, Non-condensing
  • Dimensions: 22.23 x 15.25 x 7.62 cm (8.75” x 6” x 3”)
  • Weight: 1 kg (2.2 lbs)
  • Optical Cell Volume: 14.5 mL

1 Zero drift is the change with temperature at 0 concentration
2 Span drift is the residual error after re-zeroing following a temperature change
3 Total drift is the change with temperature without re-zeroing or re-spanning

*Specifications subject to change without notice


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