The CPEC200 is a closed-path eddy-covariance system that measures surface-atmosphere exchange of carbon dioxide, water vapor, heat, and momentum. The system includes Campbell Scientific's EC155 closed-path gas analyzer, our CSAT3A sonic anemometer, and our CR3000 datalogger, along with the other hardware and software needed for a turn-key eddy-covariance system.
Benefits and Features
- Fully integrated system with all the plumbing
- Low power operation
- Excellent frequency response
- Optional automatic zero and span
Technical Description
The gas analyzer’s small sample cell volume (5.9 ml) minimizes the sample residence time (50 ms at the system’s nominal flow rate, 7 LPM). This gives excellent frequency response (5.8 Hz half-power bandwidth) with low total system power (12 W).
Eddy-Covariance Measurements
CO2 and H2O are measured with an EC155 Closed-Path Gas Analyzer. Three-dimensional wind speed and sonic air temperature are measured with a CSAT3A sonic anemometer head.
CPEC200 System Enclosure
A 16 in. by 18 in. fiberglass enclosure houses the datalogger, optional data storage peripheral, optional valve module, and the electronics that interface with the CPEC200 pump module. The CPEC200 system enclosure can be mounted to a tripod mast, CM106 tripod leg base, tower legs, or a large diameter pole.
CPEC200 Pump Module
The pump module, a standard component of the CPEC200 system, consists of a small dual-head diaphragm pump with a brushless DC motor mounted inside a fiberglass enclosure. An integral cable connects the pump module to the CPEC200 system enclosure, which provides power, temperature measurement and control, pressure measurement, and pumping speed measurement and control.
Valve Module (Optional)
Campbell Scientific offers two valve module versions. The basic three-valve module (pn 27559) enables the CPEC200 system to automatically perform zero, CO2 span, and H2O span measurements. The six-valve module (pn 26578) includes three additional valves to allow more CO2 span tanks to be measured. The valve module is housed inside the CPEC200 system enclosure. The outlet of the manifold has a proportional valve to automatically control the flow of zero/span gas.
Scrub Module (Optional)
A scrub module (pn 27423) is available for the CPEC200 which provides a zero air reference source for the CPEC200 without the need for an extra cylinder which can be useful in remote applications. The CPEC200 scrub modules pulls ambient air through three bottles of molecular sieve, effectively scrubbing CO2 and water vapor from ambient air to produce the reference zero. The scrub module and its small diaphragm pump are housed within a weather-tight fiberglass enclosure which is compatible with a variety of mounting options.
CPEC200 Specifications
- Operating Temperature Range: -30° to +50°C
- Input Voltage RAnge: 10.5 to 16.0 Vdc
- Power: 12 W (typical), 35 W (max, at cold startup)
System Enclosure
- Dimensions:
52.1 x 44.5 x 29.7 cm
(20.5 x 17.5 x 11.7 in.)
- Weight
- Basic System: 11.6 kg (25.5 lb)
- CR3000: 1.6 kg (3.7 lb)
- CFM100/NL115: 0.2 kg (0.4 lb)
- Three-Valve Module: 1.5 kg (3.3 lb)
- Six-Valve Module: 1.9 kg (4.2 lb)
Pump Module
- Cable Length: 3.0 m (10 ft)
- Inlet Connection: 3/8-in. Swagelok®
- Pumping Speed: 3 to 9 LPM (automatically controlled at the setpoint, typically 7 LPM)
- Pressure Sensor Range: 15 to 115 kPa
- Dimensions:
35.6 x 29.2 x 13.5 cm
(14.0 x 11.5 x 5.3 in.)
- Weight without mounting bracket: 5.4 kg (11.8 lb)
Valve Module
- Inlets for Three-Valve Module: Zero, CO2span, and H2O span
- Inlets for Six-Valve Module: Zero, CO2 span 1 to CO2 span 4, and H2O span
- Outlets: Analyzer and H2O Bypass
- Connections: 1/4-in. Swagelok®
- Dimensions:
14.0 x 12.7 x 14.0 cm
(5.5 x 5.0 x 5.5 in.)
- Weight of Three-Valve Module: 1.5 kg (3.3 lb)
- Weight of Six-Valve Module: 1.9 kg (4.2 lb)
Scrub Module
- Enclosure Dimensions:
39.4 x 34.3 x 20.3 cm
(15.5 x 13.5x 8.0 in.)
- Power:
0 W quiescent,
2 W with pump running,
8 W with heater running
- Weight: 9.6 kg (21.1 lb)
- Cylinder volume: 480 cm3 each
- Molecular sieve size: 1.6 – 2.5 mm beads
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