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LI-820 CO2 Gas Analyzer Brochure
LI-7000
High Speed, High Precision
Differential Analyzer
CO2 /H2O Analyzer
The LI-7000 is a high performance, dual cell, differential gas analyzer. It uses a dichroic beam
splitter and two separate detectors to measure infrared absorption by CO2 and H2O in the
same gas stream. At the heart of the LI-7000 is an innovative optical bench that can be dis-
mantled and cleaned by the user without the need for factory recalibration.
The LI-7000 CO2 /H2O Analyzer
• Large diameter air inlet and outlet
ports that virtually eliminate back pres-
sure, even at flow rates of 10 l/min
• Direct connection of air fittings to the
optical bench eliminates diffusive leaks
• Durable sapphire optical bench win-
dows which are extremely hard and
scratch resistant
• Built-in pressure sensor with 0.1%
accuracy, for automatic compensation
for pressure changes in the sample cell
• Built-in auxiliary pump can be used
for either sample or reference cell
• Intelligent diagnostic indicators warn
of potential problems before data are
compromised
• Real-time charting
The LI-7000 is ideal for a variety
of high speed, high precision
differential projects.
LI-7000 CO2/H2O Analyzer - Advantages .................................................................. Page 1
The LI-7000 also features:
The LI-7000 is ideally suited for applications that demand high speed, high precision measure-
ments in absolute and/or differential modes, including plant gas exchange using chamber-based
methods, atmospheric-surface flux eddy covariance and Bowen ratio techniques, vertical profil-
ing, and general atmospheric monitoring. The cleanable optics and software functions such as
integration and peak detection operations are important features for applications such as the
measurement of dissolved CO2 (pCO2), and Total Organic Carbon (TOC) in aqueous samples.
The LI-7000’s inherent stability and wide operating temperature range make it well suited for
the rigorous demands of cross-sectional measurements of plumes from point sources such as
volcanoes, geothermal degassing locations, or industrial sites.
• Atmospheric Monitoring
• Animal Respiration
• Industrial Monitoring
• Greenhouse Applications
• Insect Respiration
• Soil CO2 Flux Measurements
• Growth Chamber Applications
• Photosynthesis and Transpiration Studies
• Plant Physiology
• Oceanographic Studies (pCO2 and TOC)
LI-7000 CO2/H2O Analyzer - Applications .................................................................. Page 2
For Eddy Covariance Analyzers, visit www.licor.com/ec-analyzers
Flexibility
Applications
• A spinning chopper shutter disk allows for
radiation to alternately pass through each
gas sampling cell. The rotation of the disk
is precisely controlled at a high chopping
frequency, which reduces sensitivity of
the detector to low frequency vibrations.
This results in lower analyzer noise, fast
response, and increased sensitivity.
• Modular components in user accessible
areas of the analyzer provide a simple
method of cleaning the gas sampling cells
and changing internal chemicals to mini-
mize the need for factory service.
• Two auxiliary input channels (10 Hz band
width) which can be used to input an
analog signal from an external sensor. CO2
and H2O references may be input through
these channels.
• Four fully configurable digital-to-analog
converters (DACs) which are updated at
600 Hz provide output signals that are
directly proportional to gas concentration
or other meaningful units. Both USB and
RS-232 interfaces are provided for data
output at rates of up to 50 Hz.
Design features that contribute to the LI-7000
performance are:
• A long life (>5 years), vacuum sealed tungsten
filament source. This source has low power
consumption, and is highly stable.
• Nickel-plated optical cells to
minimize water sorption. The
optical cells can be removed
and cleaned with compressed
air or water, and reassembled
without requiring factory reca-
libration.
• CO2 and H2O detectors
simultaneously measure CO2
and H2O vapor in the same air
stream.
• Digital Signal Processing immediately digitizes
the signal from the detectors. All further signal
processing is in the digital domain to avoid
analog component drifts.
User accessible module allows for
cleaning of gas measurement cells
Long life, tungsten filament source
Chopping shutter disk for increased sensitivity
Internal chemicals are easily replaced
Built-in pressure sensor
Detectors measure CO2 and H2O vapor in the same air stream
Nickel-plated optical cells
LI-7000 CO2/H2O Analyzer - Technology ................................................................... Page 3
Technology
Chopper Motor
Housing
Source
CO2 Detector
H
2O
D
et
ec
to
r
Aperture
Lens
Lens
Window
Window
Chopping
Shutter
Cell A or B
Dichroic Beam
Splitter
Mirror
CO2 FilterH2O Filter
Soda Lime/Desiccant
Bottles
Operational Overview
The LI-7000 is a differential analyzer, in which a
gas of known concentration (which can be zero)
is put in the reference cell (A), and an unknown
gas is put in the sample cell (B). The instrument
software provides continuous output of the ab-
solute concentration in the sample cell as well
as the differential concentration.
The infrared source provides radiation through
both optical paths, which is directed to CO2
and H2O detectors. Internal chemicals keep
the detector and chopper housings free of
CO2 and H2O vapor.
LI-7000 CO2/H2O Analyzer - Technology ................................................................... Page 4
Built-in air pump
for scrubbng the
reference cell
AC or DC Power
Serial data output at
rates up to 50 Hz
Large diameter inlet ports allow high
flow rates and eliminate diffusive leaks
USB data output rate up to 50 Hz
Auxiliary input and analog output channels
connect to detachable terminal strips
Windows Interface
Simple PC-compatible software for Win-
dows® provides easy access to all instrument
functions, including calibration, data output
options, and the display of output variables.
The main window allows for viewing real-time
data in text or graphical form.
Any software communications program capa-
ble of sending command strings and receiving
ASCII data can be used to communicate with
the LI-7000. All instrument functions can also
be accessed at the LI-7000 front panel. Cus-
tom displays with up to 8 variables, updated
in real time, are available on the LCD.
The LI-7000 has a 40 character x 8 line backlit LCD that displays real-time measured values. The
variables to be displayed are chosen from a list, and as many as 8 can be viewed on a single
display screen. Different screens can be programmed and accessed quickly by pressing a single
numeric key on the keypad. More than 50 different measured and diagnostic variables, including
CO2 and H2O measurements as mole fraction, partial pressure, dew point (H2O), or raw absorp-
tance values are available for display.
Measured variables can be automatically integrated using built-in integration functions.
Output variables are presented in real-time text or
graphical forms with a simple Windows® interface.
The display can be quickly toggled between text and
graphics modes, where measured or computed vari-
ables can be viewed in real time. Up to 3 sets of plots
can be defined and stored, with as many as 3 plots
per graph set.
The LCD display has adjustable backlighting and
contrast settings.
LI-7000 CO2/H2O Analyzer - Software ..................................................................... Page 5
Screen Display
Software
Eddy Covariance Analyzers
LI-COR offers additional high speed, high precision analyzers which are ideal for measuring ecosystem gas exchange.
For more information on these analyzers, visit: www.licor.com/ec-analyzers
LI-7500A Open Path CO2/H20 Analyzer
The LI-7500A is an open path, high speed, high precision, non-dispersive infrared gas analyzer that accurately mea-
sures densities of carbon dioxide and water vapor in situ. With the eddy covariance technique, these data are used in
conjunction with sonic anemometer wind speed to determine the fluxes of CO2 and H2O into and out of ecosystems.
The LI-7500A and LI-7200 (below) accept analog data from a sonic anemometer and log complete data
sets to a removable USB storage device.
LI-7200 Enclosed CO2/H2O Analyzer
The LI-7200 is a compact, enclosed CO2/H2O analyzer that combines the benefits of
open and closed path gas analyzers. It is an integrated system designed to provide
continuous measurements in harsh weather conditions and environments, with very low
power consumption.
LI-7700 Open Path CH4 Analyzer:
The open path design of the LI-7700 provides solutions to many of the challenges of
measuring atmospheric CH4 flux over various ecosystems, while providing excellent co-
spectra. No external pumps or tubing are required, and low power requirements for the
entire system enable the LI-7700 to be powered with solar panels in remote locations
(~ 8W during normal operation). Self-cleaning optics provide low maintenance require-
ments and more robust data.
LI-7000 CO2/H2O Analyzer - Ordering Information ........................................................ Page 6
LI-7000 CO2/H2O Gas Analyzer
Includes external battery leads, scrubber
tube, AC power cord, RS-232 serial cable,
USB cable, Windows® Interface Software
and factory calibration.
LI-7000DP
Special pricing package, includes the LI-7000
CO2/H2O Gas Analyzer and the LI-610 Dew
Point Generator, which can be used to cali-
brate the water channel of the LI-7000.
LI-610 Portable Dew Point Generator
Includes 610-01 AC Module and 610-04 BNC to mV Recorder Leads.
Ordering Information
Type: Differential, non-dispersive infrared gas analyzer.
Detectors: Two solid state detectors; one each for CO2 and H2O,
filtered with center wavelengths at 4.255 and 2.595 microns,
respectively.
Chopping Frequency: 600 Hz.
Source: Single source, lifetime > 5 years.
Optical Bench: One optical bench. Sample cell size: 9.53 mm
Dia. × 152.4 mm L (3/8" × 6"). Volume: 10.86 cm3.
Warm-up Time: Approximately 2 minutes to operation.
Gas Pressure: Maximum allowable pressure is 115 kPa (17 psi)
with pressure sensor connected. 200 kPa (29 psi) max. w/o pres-
sure sensor connected.
Maximum Flow through Analyzer: >50 liters/min.
Internal Pump Max Flow Rate: Approximately 1 liter/minute.
Display: 40 character × 8 line backlit LCD.
Back Panel Connections:
Analog: 4 user-scalable DAC's, 600 Hz update frequency
(±5V maximum, 14-bit).
RS-232: 9600 to 115,200 baud.
USB: Data output rate up to 50 Hz. USB 2.0 compliant.
Auxiliary Input Channels: 2, -2.5 to +2.5V. Common mode input
voltage range ±2.5V.
Power Requirements: 100-240 VAC, 50-60 Hz, or 10.5-16 VDC,
4 amp max.
Power Consumption: 15-40 Watts DC (dependent on
temperature and pump usage).
Temperature Range: 0-50 °C ambient, 0-55 °C bench.
Size: 5" H × 9.875" D × 14.5" L (12.7 × 25 × 36.8 cm).
Weight: 19.4 lbs. (8.8 kg).
CO2 Analyzer Specifications
Range: 0-3000 µmol/mol.
Accuracy: 1% nominal.
Zero Drift (with temperature): <0.1 µmol/mol/°C.
Span Drift: <0.2% of reading/°C.
Water Sensitivity: <0.1 µmol/mol CO2/mmol/mol H2O (Soft-
ware algorithm corrects for band broadening effects).
Calibration: Factory linearization over 0-3000 µmol/mol range
using NIST-traceable standard gases.
Pressure Range: 0 to 115 kPa absolute.
Display Resolution: .01 µmol/mol.
Signal Noise: See table below.
H2O Analyzer Specifications
Range: 0-60 mmol/mol. Optical bench and interconnecting
hoses must be maintained above the dewpoint temperature by
the user.
Accuracy: 1%.
Zero Drift: <0.1 mmol/mol/°C.
Span Drift: <0.4% of reading/°C.
Signal Noise: See table below.
Calibration: LI-610 Dew Point Generator
LI-7000 Specifications
CO2 (370 µmol/mol) H2O (10 mmol/mol)
Average Time (s) Bandwidth (Hz) RMS Noise (ppb) Peak-to-Peak (ppb) RMS Noise (ppm) Peak-to-Peak (ppm)
20 0.025 6 39 0.4 3
1 0.5 25 173 2 12
0.5 1 35 245 2 17
0 20 157 1096 11 75
Noise Specifications (Typical)
LI-COR Biosciences
4647 Superior Street • P.O. Box 4425 • Lincoln, Nebraska 68504
North America: 800-447-3576 • International: 402-467-3576 • FAX: 402-467-2819
envsales@licor.com • envsupport@licor.com • www.licor.com
In Germany – LI-COR GmbH:
+49 (0) 6172 17 17 771 • envsales-gmbh@licor.com • envsupport-gmbh@licor.com
In UK, Ireland, and Scandinavia – LI-COR Biosciences UK Ltd.:
+44 (0) 1223 422102 • envsales-UK@licor.com • envsupport-UK@licor.com
6/2011 980-07980
The LI-COR board of directors would like to take this opportunity to
return thanks to God for His merciful providence in allowing LI-COR
to develop and commercialize products, through the collective
effort of dedicated employees, that enable the examination of the
wonders of His works.
“Trust in the LORD with all your heart and do not lean on your own
understanding. In all your ways acknowledge Him, and He will
make your paths straight.”
—Proverbs 3:5,6
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