The CSAT3 is a three-dimensional sonic anemometer that measures three orthogonal wind components and the speed of sound. In eddy covariance systems, it can measure the turbulent fluctuations of horizontal and vertical wind. These measurements are then used to calculate momentum flux and friction velocity. This sonic anemometer can also provide average horizontal wind speed and direction measurements. The CSAT3 comes with 25 ft cables.Read More
Whenever possible, use the CSAT3B (the CSAT3's replacement) instead.
The CSAT3 has a 10 cm vertical measurement path and operates in a pulsed acoustic mode. The three orthogonal wind components (ux, uy, uz) and the speed of sound (c) are measured and output at a maximum rate of 60 Hz. Analog outputs and two types of digital outputs are provided.
Measurements can be triggered from from the CSAT3’s internal clock, the PC-generated RS-232 command, or the data logger’s SDM command. The SDM protocol supports a group trigger for synchronizing multiple CSAT3s.
The FW05 fine wire thermocouple (12.7 μm diameter) is available as an option for fast response temperature measurements.
|Measurement Path Length||
|Path Angle from Horizontal||60°|
|Construction||Sealed sonic transducers and electronics|
|Anemometer Head Materials||Stainless-steel tubing|
|Electronics Box Materials||Cast aluminum|
|Operating Temperature Range||-30° to +50°C|
|Voltage Supply||10 to 16 Vdc|
|Digital SDM Output Signal||CSI 33.3 k baud serial interface for data logger/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 Fingers Diameter||0.84 cm (0.33 in.)|
|Cable Length||7.62 m (25 ft)|
|Anemometer Head Dimensions||47.3 x 42.4 cm (18.6 x 16.7 in.)|
|Anemometer Head Weight||1.7 kg (3.7 lb)|
|Electronics Box Dimensions||26 x 16 x 9 cm (10.24 x 6.3 x 3.54 in.)|
|Electronics Box Weight||3.8 kg (8.4 lb)|
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.|
|Wind Direction Accuracy||±0.7° at 1 m/s (for horizontal wind)|
|Rain||Innovative ultrasonic signal processing and user-installable wicks considerably improve the performance of the anemometer under all rain events.|
Digital RS-232 Output Signal
|Baud Rate||9600, 19200 bps|
|Data Type||2-byte integer per output plus 2-byte diagnostic|
|Number of Outputs||4|
|Voltage Range||±5 V|
|Number of Bits||12|
SDM & RS-232 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).|
Analog Outputs Reporting Range
|ux||±30 m s-1, ±60 m s-1|
|uy||±30 m s-1, ±60 m s-1|
|uz||±8 m s-1|
|c||300 to 366 m s-1 (-50 to +60°C)|
Analog Outputs LSB
|ux||15 mm s-1, 30 mm s-1|
|uy||15 mm s-1, 30 mm s-1|
|uz||±8 m s-1|
|c||16 mm s-1 (0.026°C)|
Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.
|Data Logger Model||Data Logger Operating System (OS)
or PROMs Required
|CSAT3 OS Required|
|21X||1K 6145-3, 6146-5, 10006-1||2.1 or higher|
|21X||2K 6148-5, 6149-7, 6070-64||2.1 or higher|
|CR800, CR850||All OS||3.0 or higher|
4K is a Library Special
|2.1 or higher|
|CR10X||OS 1.4 or higher||2.1 or higher|
|CR1000||All OS||3.0 or higher|
|CR23X||All OS||2.1 or higher|
|CR3000||All OS||3.0 or higher|
|CR5000||All OS||3.0 or higher|
|CR9000||2.01 or higher||2.1 or higher|
|CR9000X||All OS||2.1 or higher|
Number of FAQs related to CSAT3: 26
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The CSAT3 has been optimized for most terrestrial applications. If the CSAT3 is to be used in a marine environment or in an environment where it is exposed to corrosive chemicals (for example, sulfur-containing compounds in viticulture), expect the sonic transducers to age more quickly and require replacement sooner than a unit deployed in an inland, chemical-free environment. If possible, mount the CSAT3 in a way that reduces exposure to saltwater spray/splash and/or corrosive chemicals.
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.
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.
The CSAT3 measures three-dimensional wind in a right-handed Cartesian coordinate system. From these measurements, use trigonometry to compute the wind flow angle, horizontal angle, and wind speed.
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.
The CSAT3 is calibrated over the temperature range of -30° to +50°C. The CSAT3 operating temperature range can be shifted by 10 degrees to cover the range of -40° to +40°C.
The instrument will continue to operate outside the calibrated temperature range; however, the proper calibration will not be applied to the measurements because it does not exist in the CSAT3 electronics.
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.
Yes. The CSAT3 electronics contain unique calibration and sensor head geometry information. The sensor head and electronics are a matched set. (The serial number on the sensor head must match the electronics to make valid measurements.)
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 data logger or a PC.