The CSAT3A sonic anemometer head is similar to the sensor head from the CSAT3 sonic anemometer, but its cable is modified to connect to the EC100 electronics. It is used as part of the EC150 open-path analyzer and the CPEC200 closed-path eddy-covariance system.Read More
|Measurement Path Length||
|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|
|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 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)|
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|
|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).|
Number of FAQs related to CSAT3A: 23
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No. The standard CSAT3 operating temperature is -30° to +50°C. The CSAT3 operating temperature range can be shifted by 10 degrees to cover the range of -40° to +40°C. Operating a CSAT3 with a shifted temperature range requires collecting the speed of sound and applying a different multiplier.
With a data logger, collect the CSAT3 data with the option …Get wind & c-340 data. Compute the speed of sound using the following formula:
Ts is the CSAT3 sonic temperature;
c is the CSAT3 speed of sound, less an offset;
x is the speed of sound offset (337.0 for a CSAT3 with a -40° to +40°C shifted calibration);
γd is 1.4 (the ratio of the heat capacity of dry air at constant pressure to heat capacity of dry air at constant volume); and
Rd is 287.04 J kg-1 K-1, the gas constant for dry air.
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 offset specification is ±8 cm/s. Therefore, it cannot be used in an application where the expected wind speed is in the range of ±5 cm/s.
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.
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.
The sensors used in the eddy-covariance application are not compatible with SCWin. An open-path eddy-covariance program is available for purchase as pn 18442, CRBasic Basic Eddy Covariance Program. This is the program without energy balance sensors. Also available is pn 18443, CRBasic Extended Eddy Covariance Program, with energy balance sensors. To order a custom configured program, contact the Micrometeorology Flux group for assistance.
No. The CSAT3 is a sensor. Time stamps are assigned to the CSAT3 data by the data acquisition system—typically a Campbell Scientific data logger or PC.
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.
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.