Growth Chambers and Greenhouses
Analyzers can be configured to monitor CO2/H2O and trigger fans or injection of CO2 and/or H2O, keeping levels within a desired range. User-supplied relays can also trigger devices such as pumps, valves, dialers, or audible alarms.
Analyzers have the stability and durability to continuously monitor atmospheric CO2 and H2O. The included software facilitates configuration, control, data collection, and graphical data display.
Other common applications include:
- Measuring pCO2 and DIC
- Indoor air quality monitoring
- Building system efficiency (ventilation systems)
- Process control
- Atmospheric profiling
- Leakage monitoring
- TOC analysis systems
Careful design of thermostatically controlled IR detection system gives you excellent stability.
Integrated thermistors and a pressure transducer provide high accuracy for the concentration calculation over the entire measurement range.
A pressure transducer within the gas flow path compensates, and corrects for, changes in barometric pressure.
A foam enclosure surrounding the optical path maintains a controlled thermal environment and protects the bench from mechanical shock and vibration.
- Measurement range: 0-20,000 ppm
- LI-850 Within 1.5% of reading
- LI-830 Within 3% of reading
- Calibration Drift:
- Zero Drift1: <0.15 ppm/°C
- Span Drift2: <0.03%/°C
- Total Drift at 370 ppm3: <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: 0-60 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 Drift1 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 with 1 sec signal filtering: <0.01 mmol mol-1
- Sensitivity to CO2: <0.0001 mmol mol-1 H2O/ppm CO2
- 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
- Dimensions: 6.7 cm corner-to-corner
- Resolution: 400 x 200 px; monochrome
- Power consumption: <200 µW
- Displayed variables: CO2 reading, H2O reading (LI-850 only), optical bench temperature, and pressure.
- Output rate: Up to 2 measurements per sec
- Response time (T90):
- CO2: <3.5 seconds from 0-375 ppm
- H2O: <3.5 seconds from 0-21 ppm mmol mol-1
- Measurement principle: Non-Dispersive Infrared
- CO2: Traceable gases to WMO standards from 0-3,000 ppm; traceable gases to EPA protocol gases from 3,000-20,000 ppm
- H2O (LI-850 only): NIST traceable LI-610 Portable Dew Point Generator
- Pressure compensation range: 50-110 kPa
- Maximum gas flow rate: 1 liter min-1
- Output signals: Two analog voltage (0-2.5 V or 0-5 V) and two current (4-20 mA)
- Digital outputs: TTL (0-5V) 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°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”)
- 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
- Zero drift is the change with temperature at 0 concentration.
- Span drift is the residual error after re-zeroing following a temperature change.
- Total drift is the change with temperature without re-zeroing or re-spanning.