CPEC310 Expandable Closed-Path Eddy-Covariance System with EC155, Pump Module, and Automatic Zero and Span
Fully Expandable Design
Provides additional ports with automatic zero and span
weather applications supported water applications supported energy applications supported gas flux & turbulence applications supported infrastructure applications supported soil applications supported


The CPEC310 is a turn-key, closed-path eddy-covariance (EC) flux system for long-term monitoring of atmospheric-biosphere exchanges of carbon dioxide, water vapor, heat, and momentum. A complete system consists of a closed-path gas analyzer (EC155 closed-path gas analyzer), sonic anemometer (CSAT3A sonic anemometer), datalogger (CR6 datalogger), sample pump, three-valve module that enables automatic zero and COspan measurements (manual H2O span), and accommodations for a CDM-A116 analog input expansion module allowing for additional sensors.

The gas analyzer’s patented vortex intake design (United States Patent No. 9,217,692) and small sample cell volume (5.9 mL) provide a much lower flow rate than other closed-path systems while maintaining excellent frequency response (4.3 Hz cutoff frequency). Additionally, this design makes the system virtually maintenance free while still maintaining an ideal frequency response compared to traditional inline filters. Lower flow allows the CPEC310 to have one of the lowest total system power requirements (12 W) of any closed-path eddy covariance system. Campbell Scientific manufactures all components of the CPEC310, including the datalogger and EasyFlux™ DL software for computing and correcting fluxes, which gives our system the most reliable functionality.

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Benefits and Features

  • Expandable, high-end system with CR6 datalogger processing power and EasyFlux™ DL software to compute and fully correct up to 20 Hz data
  • The 3-valve module makes the CPEC310 the only closed-path eddy covariance system on the market with the ability to perform automatic zero and CO2/H2O span
  • Additional port options for energy balance and atmospheric sensors
  • Ideal system for short or tall towers
  • Simple design provides easy use while maintaining full functionality


Main enclosure for the CPEC310
CPEC310 plumbing

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.

CPEC310 System Enclosure

The CPEC310 has two enclosures: a fiberglass enclosure that houses the CR6 datalogger, pump module, three-valve module, and optional CDM-A116, and the EC100 enclosure for data processing. The CPEC310 can also be equipped with a scrub module for automatic zeroing of the EC155.

CPEC310 Pump Module

The pump module, a standard component of the CPEC310 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 CPEC310 system enclosure, which provides power, temperature measurement and control, pressure measurement, and pumping speed measurement and control.


Operating Temperature Range -30° to +50°C
Input Voltage Range 10.5 to 16.0 Vdc
  • 12 W (typical)
  • 35 W (maximum, at cold startup)

System Enclosure

Dimensions 54 x 44.5 x 29.7 cm (21.3 x 17.5 x 11.7 in.)
  • 15.36 kg (33.85 lb)
  • 16.24 kg (35.8 lb) with optional CDM-A116 module

Pump Module

Inlet Connection 3/8-in. Swagelok
Pressure Sensor Range 15 to 115 kPa
Pumping Speed 3 to 9 LPM (automatically controlled at the set point, typically 7 LPM)
Cable Length 3.0 m (10 ft)
Dimensions 35.6 x 29.2 x 13.5 cm (14.0 x 11.5 x 5.3 in.)
Weight 5.4 kg (11.8 lb)

Three-Valve Module

Inlets for Module Zero, CO2, and H2O span
Outlets Analyzer and H2O bypass
Connections ¼-in. Swagelok
Dimensions 14.0 x 12.7 x 14.0 cm (5.5 x 5.0 x 5.5 in.)
Weight 1.5 kg (3.3 lb)

Scrub Module

  • 0 W (quiescent)
  • 2 W (with pump running)
  • 8 W (with heater running)
Cylinder Volume 480 cm3 each (29.29 in.3 each)
Molecular Sieve Size 1.6 to 2.5 mm beads (0.063 to 0.098 in. beads)
Enclosure Dimensions 39.4 x 34.3 x 20.3 cm (15.5 x 13.5 x 8.0 in.)
Weight 9.6 kg (21.1 lb)


CR6 OS v.8.00 (6.87 MB) 27-06-2018

(WARNING) If updating the dataloggers operating system from a version prior to 7.0, the user will need to install updated USB drivers for the CR6. The new drivers are available in Device Configuration Utility version 2.16 (or greater) which is available on the Campbell Scientific website.

Execution of this download installs the Operating Systems for the CR6 and all integrated communication options to your computer. It also updates the CRBasic Editor compiler and support files. The Device Configuration Utility is used to upload the Operating Systems to the CR6.

Note: Upgrading the Operating System will reset all the CR6’s settings back to the factory defaults.  Sending this OS remotely is not recommended.  To restore settings after the update, it is recommended that a backup be made of the current logger settings or take programmatic measures to ensure your settings can be restored. This can be done using the DevConfig backup utility or CRBasic instruction SetSetting.

Watch the Video Tutorial: Sending an OS to a Local Datalogger.

View Revision History

EC100 OS v.8.01 (561 KB) 07-05-2018

EC100 Operating System.

Watch the Video Tutorial: Updating the EC100 Operating System.

View Revision History

ECMon v.1.6 (10.7 MB) 29-03-2016

EC100-Series Support Software.

Device Configuration Utility v.2.19 (33.2 MB) 06-12-2018

A software utility used to download operating systems and set up Campbell Scientific hardware. Also will update PakBus Graph and the Network Planner if they have been installed previously by another Campbell Scientific software package.

Supported Operating Systems:

Windows 10, 8.1, 8, and 7 (Both 32 and 64 bit)

View Revision History

EasyFlux DL for CR6CP v.1.01 (105 KB) 19-09-2018

CR6 datalogger program for Campbell closed-path eddy-covariance systems.

FAQs for

Number of FAQs related to CPEC310: 6

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  1. The molecular sieve is a non-hazardous material that can be shipped to any country.

  2. No. A valve module is required to use the Scrub Module. Only the CPEC310 comes with a valve module.

  3. The molecular sieve is a direct replacement for the old magnesium perchlorate bottles. The molecular sieve may be used for any Campbell Scientific analyzer that used the old bottles.

  4. The molecular sieve has been demonstrated here by our engineering department to be effective at removing CO2 and H2O from the air sample. The change was made for two reasons:

    1. It was a safer alternative than using the previous chemicals.
    2. Increased shipping regulations for the chemicals limited the number of suppliers. 
  5. The bottles of sieve for drop-in replacement contain the pellets and a membrane on top. The membrane is necessary to keep the pellets contained while allowing gas to pass over the zeolite. The bottle has the same footprint as the old magnesium perchlorate bottles. The amount in each bottle is listed on the bottle. The amount of sieve needed for each analyzer is the following:

    • The EC150 needs 22 g (drop-in bottle).
    • The IRGASON® needs 22 g (drop-in bottle).
    • The EC155 needs 22 g (drop-in bottle).
    • The AP200 needs 500 g (refill).
    • The 27423 needs 1000 g (refill).
    • The 31022 needs 500 g (refill).