Campbell Scientific's EC155 closed-path analyzer incorporates vortex technology for reduced maintenance, an absolute pressure sensor in the sample cell for more accurate measurements, and a sample cell with improved corrosion protection. The EC155 can be combined with the CSAT3A sonic anemometer, as shown in the main image. The revised CSAT3A has a more aerodynamic and rigid design.
The EC155 is ordered as part of a CPEC300-series system (CPEC300, CPEC306, or CPEC310), which also includes the sample pump, data logger, optional valve module, and optional scrub module to provide a zero air source. The EC155 with anemometer simultaneously measures absolute carbon dioxide and water vapor mixing ratio, sample cell temperature and pressure, and three-dimensional wind speed and sonic air temperature.
Read MoreThe EC155 has the following outputs:
*Requires a CSAT3A Sonic Anemometer Head.
Operating Temperature Range | -30° to +50°C |
Operating Pressure | 70 to 106 kPa |
Input Voltage Range | 10 to 16 Vdc |
Power | 5 W (steady state and power up) at 25°C |
Measurement Rate | 60 Hz |
Output Bandwidth | 5, 10, 12.5, or 20 Hz (user-programmable) |
Output Options | SDM, RS-485, USB, analog (CO2 and H2O only) |
Auxiliary Inputs | Air temperature and pressure |
EC100 Barometer Accuracy |
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Sample Intake/Sonic Volume Separation | 15.6 cm (6.1 in.) |
Warranty | 3 years or 17,500 hours of operation (whichever comes first) |
Cable Length | 3 m (10 ft) from EC155/CSAT3A to EC100 |
Weight |
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Gas Analyzer |
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Sample Cell Thermistor Accuracy | ± 0.15°C (-30° to +50°C) |
Sample Cell Pressure Accuracy | ± 1.5 kPa (> 0°C ), increasing linearly to ±3.7 kPa at -30°C |
Gas Analyzer - CO2 Performance |
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Accuracy |
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Precision RMS (maximum) |
0.15 µmol/mol Nominal conditions for precision verification test: 25°C, 86 kPa, 400 μmol/mol CO2, 12°C dewpoint, and 20 Hz bandwidth. |
Calibrated Range | 0 to 1,000 μmol/mol (0 to 3,000 µmol/mol available upon request.) |
Zero Drift with Temperature (maximum) | ±0.3 μmol/mol/°C |
Gain Drift with Temperature (maximum) | ±0.1% of reading/°C |
Cross Sensitivity (maximum) | ±1.1 x 10-4 mol CO2 /mol H2O |
Gas Analyzer - H2O Performance |
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Accuracy |
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Precision RMS (maximum) |
0.006 mmol/mol Nominal conditions for precision verification test: 25°C, 86 kPa, 400 μmol/mol CO2, 12°C dewpoint, and 20 Hz bandwidth. |
Calibrated Range | 0 to 72 mmol/mol (38°C dewpoint) |
Zero Drift with Temperature (maximum) | ±0.05 mmol/mol/°C |
Gain Drift with Temperature (maximum) | ±0.3% of reading/°C |
Cross Sensitivity (maximum) | ±0.1 mol H2O/mol CO2 |
Sonic Anemometer - Accuracy |
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-NOTE- | The accuracy specification for the sonic anemometer is for wind speeds < 30 m s-1 and wind angles between ±170°. |
Offset Error |
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Gain Error |
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Measurement Precision RMS |
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EC100-Series Support Software.
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 11 or 10 (Both 32 and 64 bit)
Number of FAQs related to EC155: 8
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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.
The EC155 requires a barometer for several reasons. First, the EC155 calculates CO2 as a concentration, and these values must be multiplied by the air density to get the CO2 flux. Second, the closed-path analyzer measures the number of CO2 molecules in the path and converts them to a concentration. This conversion requires a measure of sample cell pressure, which in older EC155 models (serial numbers less than 2000) is the sum of the barometer and differential sensor. In newer EC155 models (serial numbers 2000 or greater), this conversion still requires a measure of sample cell pressure, but it is done with an absolute pressure sensor in the sample cell. Finally, the EC155 has been calibrated at the factory over a range of barometric pressures.
The molecular sieve is a non-hazardous material that can be shipped to any country.
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:
Precipitation can block the infrared beam of an open-path IRGA—primarily through accumulation on the windows and by falling through the measurement path. The EC155 is a closed-path IRGA that is protected from rainfall by taking its measurements within a sample cell assembly. Older EC155 models (serial numbers less than 2000) have a heated intake assembly with a rain diverter to prevent precipitation from entering the sample cell. Newer EC155 models (serial numbers 2000 and greater) have a heated inlet and vortex intake (U.S. Pat. No. 9,217,692), which significantly improve performance during precipitation events and in conditions of high particulate concentrations, such as dust storms. However, measurements from sonic anemometers can also be affected by rainfall, especially if droplets accumulate on transducer faces. Therefore, it is important to continue monitoring data during rainfall events to ensure quality measurements are included in final calculations of flux.
Newer EC155 models (serial numbers 2000 and greater) take advantage of the new vortex intake technology (U.S. Pat. No. 9,217,692), which significantly reduces the frequency of maintenance required, especially in dustier, more polluted conditions. The new models also have an absolute pressure sensor instead of a differential one, which improves the pressure measurements. Finally, the new design uses a stainless-steel sample cell, which provides added protection against corrosion.
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:
For more information, see the white paper “EC150, IRGASON, or EC155: Which CO2 and H20 Eddy-Covariance System Is Best for My Application?”
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