CSAT3A 3-D Sonic Anemometer, Head Only
Precision Measurements
Best instrument for flux and other high-level turbulence research projects
weather applications water applications energy applications gas flux & turbulence applications infrastructure applications soil applications

Overview

The CSAT3A 3-D Sonic Anemometer is the 3-D sonic anemometer of choice for eddy-covariance measurements. It has an aerodynamic design, a 10 cm vertical measurement path, operates in a pulsed acoustic mode, and withstands exposure to harsh weather conditions. Three orthogonal wind components (ux, uy, uz) and the speed of sound (c) are measured and output at a maximum rate of 50 Hz. The CSAT3A head is operated by the EC100 electronics, which also control either an EC150 or EC155 gas analyzer.

Measurements can be triggered from two sources:

  • Datalogger’s SDM command
  • EC100’s internal clock

The SDM protocol supports a group trigger for synchronizing multiple CSAT3As.

Read More

Benefits and Features

  • Innovative design provides precision turbulence measurements with minimal flow distortion
  • Usually combined with EC150 or EC155 gas analyzers giving near complete colocation for eddy-covariance measurements
  • Compatible with most Campbell Scientific dataloggers
  • Measurements can be used to calculate momentum flux and friction velocity
  • Campbell Scientific’s fine wire thermocouples are an option for fast-response temperature measurements
  • Field rugged
  • Innovative signal processing and transducer wicks considerably improve performance of the anemometer during rain events
  • Sealed sonic transducers and electronics

Images

CSAT3A lower transducer assembly top view

Detailed Description

The CSAT3A is an optional component of an EC150 open-path or EC155 closed-path CO2/H2O gas analyzer. It attaches to a common mounting bracket and connects to the gas analyzer's EC100 electronics module.

Specifications

Measurement Path Length
  • 10.0 cm (3.94 in.) vertical
  • 5.8 cm (2.3 in.) horizontal
Path Angle from Horizontal 60°
Construction Sealed sonic transducers and electronics
Anemometer Head Materials Stainless-steel tubing
Electronics Box Materials Welded aluminum
Operating Temperature Range -30° to +50°C
Voltage Supply 10 to 16 Vdc
Current
  • 200 mA (60 Hz measurement rate)
  • 100 mA (20 Hz measurement rate)
Digital SDM Output Signal CSI 33.3 k baud serial interface for datalogger/sensor communication. (Data type is 2-byte integer per output plus 2-byte diagnostic.)
Support Arm Diameter 1.59 cm (0.63 in.)
Transducer Diameter 0.64 cm (0.25 in.)
Transducer Mounting Arm Diameter 0.84 cm (0.33 in.)
Anemometer Head Dimensions 47.3 x 42.4 cm (18.6 x 16.7 in.)
Anemometer Head Weight 1.7 kg (3.7 lb)

Measurements

Outputs ux, uy, uz, c
(ux, uy, uz are wind components referenced to the anemometer axes; c is speed of sound.)
Speed of Sound Determined from three acoustic paths; corrected for crosswind effects.
Measurement Rate Programmable from 1 to 60 Hz, instantaneous measurements. Two over-sampled modes are block averaged to either 20 Hz or 10 Hz.
Output Bandwidths 5, 10, 12.5, or 20 Hz
Output Rate 10, 20, 25, or 50 Hz
Measurement Resolution
  • Resolution values are for instantaneous measurements made on a constant signal; noise is not affected by sample rate.
  • 1 mm/s rms (ux, uy)
  • 0.5 mm/s rms (uz)
  • 15 mm/s (0.025°C) rms (c)
Offset Error
  • Offset error and gain error values assume the -30° to +50°C range, wind speeds of < 30 m/s, and wind angles between ±170°.
  • < ±8.0 cm/s (ux, uy)
  • < ±4.0 cm/s (uz)
Gain Error
  • Offset error and gain error values assume the -30° to +50°C range, wind speeds of < 30 m/s, and wind angles between ±170°.
  • < ±2% of reading (wind vector within ±5° of horizontal)
  • < ±3% of reading (wind vector within ±10° of horizontal)
  • < ±6% of reading (wind vector within ±20° of horizontal)
Rain Innovative ultrasonic signal processing and user-installable wicks considerably improve the performance of the anemometer under all rain events.

Digital USB and RS-485 Output Signal

Baud Rate 230400 bps (maximum)
Data Type Comma-delimited ASCII

SDM, USB, & RS-485 Digital Outputs Reporting Range

Full-Scale Wind ±65.535 m/s autoranging between four ranges (Least significant bit is 0.25 to 2 mm/s.)
Speed of Sound 300 to 366 m/s (-50° to +60°C) Least significant bit is 1 mm/s (0.002°C).

Compatibility

Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.

Data Loggers

Product Compatible Note
CR1000
CR200X (retired)
CR206X (retired)
CR211X (retired)
CR216X (retired)
CR295X (retired)
CR3000
CR5000 (retired)
CR800
CR850
CR9000X

Frequently Asked Questions

Number of FAQs related to CSAT3A: 23

Expand AllCollapse All

  1. No. The CSAT3 is a sensor. Time stamps are assigned to the CSAT3 data by the data acquisition system—typically a Campbell Scientific datalogger or PC.

  2. No. The CSAT3 does not report time with the wind measurements. A time stamp will be assigned to the wind data by the data acquisition system—either a datalogger or a PC.

  3. Campbell Scientific does not offer any mounting booms or hardware that enable easy and frequent positioning of the CSAT3 sensor head. This type of hardware must be provided by the user.

  4. The CSAT3, like other sonic anemometers, measures wind speed along the sonic path using ultrasonic signals. If the salt spray blocks the sonic path, the CSAT3 will not be able to make measurements. The same is true if a thick layer of salt is deposited on the transducer faces.

  5. No. The offset is a function of temperature and time. Once a year, spot-check the CSAT3 wind offset using the procedure outlined in the CSAT3 instruction manual. If the measured offset is outside the specification, return the CSAT3 to the factory for calibration. To request a returned material authorization (RMA) number, follow the steps listed on our Repair and Calibration page. 

  6. Yes. The bubble level can be replaced in the field using pn 31962, 1-Ring Replacement Bubble Level with Mounting Bumper and Hardware.

  7. Ultrasonic anemometers are unable to make measurements if the sonic path is blocked. The path may become blocked by water that puddles on the lower transducer face or droplets that hang from the upper transducers.

  8. The CSAT3 is compatible with three output signals: analog, RS-232, and Synchronous Device for Measurement (SDM). The CSAT3 can be interfaced to any data acquisition system that is compatible with analog measurements or RS-232 serial communications. SDM is used with Campbell Scientific dataloggers.

  9. Yes. If the matching layer is damaged or missing, return the CSAT3 to the factory for repair. Follow the steps listed on our Repair and Calibration page to request a returned material authorization (RMA) number. 

  10. Yes. The CSAT3 measurement frequency can be changed by the user. It is set by the Execution Parameter. This parameter is described in detail in the CSAT3 instruction manual in the “Datalogger Instruction Parameters” section, as well as in the “CSAT3 RS-232 Commands” section of Appendix B.

Case Studies

Canada: Forest Carbon Sequestration
Forest habitats contribute more than any other terrestrial biome to carbon cycles and processes. It......read more
Alaska: Eddy Covariance
Scientists and land-use managers have long recognized the importance of forest lands for their role......read more

Privacy Policy Update

We've updated our privacy policy.  Learn More