CSAT3BH Heated, 3-D Sonic Anemometer with Integrated Electronics
Easy-to-Use Sonic Anemometer with Smart Heater Option
Provides continuous, reliable data year-round in harsh environments
weather applications water applications energy applications gas flux and turbulence applications infrastructure applications soil applications

Overview

The CSAT3BH is ideal for stations that are deployed in cold climates. The easy-to-use CSAT3BH sonic anemometer features smart heating that delivers just the right amount of heat to keep the instrument free of ice and snow, enabling continuous and reliable measurements in cold environments. The CSAT3BH is designed to prevent ice accumulation on the sensor, avoiding prolonged periods of data loss.

The CSAT3BH features variable power, only delivering power when needed—as opposed to the common method of providing two-way heating (on/off). Moreover, there are real-time data flags when the heaters are turned on, which is crucial to post-processing your data files.

The CSAT3BH is a heated version of the CSAT3B 3-D Sonic Anemometer with Integrated Electronics. The specifications of the CSAT3BH are the same as the CSAT3B with regard to wind measurements. 

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Benefits and Features

  • New conformal coating helps protect sonic transducers in corrosive environments
  • Two-zone heating to keep both the transducers and body of the sonic anemometer free of snow and ice
  • Heating controller using environmental feedback to ensure power budgeting
  • Streamlined heater integration to ensure maintenance of sonic aerodynamics
  • Integrated data flagging, providing critical information when heaters were operational

Images

CSAT3BH with snow
CSAT3BH with snow
CSAT3BH with snow
CSAT3BH
CSAT3BH Heated Controller
Connectors on the CSAT3H Heater Controller
Exploded view of the CSAT3BH boom
CSAT3BH with lit status light
CSAT3BH system (items sold separately)

Detailed Description

The CSAT3BH provides integrated two-zone smart heating: 

  • Zone 1 consists of the arms and strut.
  • Zone 2 provides heating to all the transducers.

The smart heating uses environmental conditions and a controller to apply variable heating to the sonic anemometer to keep the body and transducers free of ice and snow. The CSAT3BH is designed to prevent ice from forming on the arms and fingers of the system. The block has no heating in it. The CSAT3BH has a separate controller that is used to control the heating algorithm of the sensor. The controller requires a temperature/RH input. There is an ambient temperature and relative humidity sensor that is standard for use with the controller, or the data can be provided through a user-supplied temperature/RH sensor.

Physical

The CSAT3H heater controller is a polycarbonate enclosure sized 20.32 x 25.4 x 15.24 cm (8 x 10 x 6 in.). The enclosure uses connectors for incoming power, heaters, temperature sensors, temperature/RH, RS-485(2), and USB.

Electrical

The heaters are controlled on two zones and require 150 W at full power. The controller controls the heaters by increasing or decreasing the voltage to get the appropriate wattage to keep ice from forming on the sensor.

Specifications

Sensor 3-dimensional sonic anemometer
Measurement Description Highest-quality wind speed and direction
Operating Temperature Range -40 to +50°C (equivalent to 305 to 368 m s-1 in speed of sound)
Outputs ux, uy, uz, Ts (ux, uy, uz are wind components referenced to the anemometer axes; Ts is sonic temperature in degrees Celsius.)
Speed of Sound Determined from three acoustic paths. (Corrected for crosswind effects.)
Wind Direction Range 2.5 to 357.5° in CSAT3B coordinate system (0 to 360° customized)
Filter Bandwidths 5, 10, 20, or 25 Hz
Measurement Path Length 10.0 cm (3.9 in.) vertical; 5.8 cm (2.3 in.) horizontal
Transducer Angle from Horizontal 60 degrees
Transducer Diameter 0.64 cm (0.25 in.)
Transducer Mounting Arm Diameter 0.84 cm (0.33 in.)
Support Arm Diameter 1.59 cm (0.63 in.)
Anemometer Head Weight 1.9 kg (4.2 lb)
Anemometer Dimensions 63.1 x 12.3 x 43.3 cm (24.8 x 4.9 x 17.0 in.)

Power Requirements
Anemometer Voltage Requirement 9.5 to 32 Vdc
Current Required for 10 Hz Measurement Rate
  • 110 mA (@ 12 Vdc)
  • 65 mA (@ 24 Vdc)
Current Required for 100 Hz Measurement Rate
  • 145 mA (@ 12 Vdc)
  • 80 mA (@ 24 Vdc)
Heaters 6.2 A (@ 24 Vdc)
Arms and Strut
  • 0.74 A nominal (@ 24 Vdc)
  • 2.46 A at maximum heating (@ 24 Vdc)
Transducer Fingers
  • 1.13 A nominal (@ 24 Vdc)
  • 3.75 A at maximum heating (@ 24 Vdc)
Total System Power
  • 1.86 A nominal (@ 24 Vdc)
  • 6.2 A at maximum heating (@ 24 Vdc)
Controller Current Required 30 mA (heaters off [quiescent] @ 24 Vdc)

Wind Accuracy
-NOTE- Accuracy specifications assume the following:
  • -40° to +50°C operating range
  • Wind speeds < 30 m s-1
  • Wind angles between ±170°
Maximum Offset Error < ±8.0 cm s-1 (ux, uy), < ±4.0 cm s-1 (uz)
Maximum Gain Error
  • < ±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)

Measurement Resolution
ux, uy 1 mm s-1 RMS
uz 0.5 mm s-1 RMS
Ts 0.002°C RMS (at 25°C)
Wind Direction < 0.058° (ux = uy ≤ 1 m s-1)

Measurement Rates
Data Logger Triggered 1 to 100 Hz
Unprompted Output (to PC) 10, 20, 50, or 100 Hz
Internal Self-Trigger Rate 100 Hz

Measurement Delay
Data Logger Triggered (no filter) 1 trigger period (1 scan interval)
Unprompted Output (no filter) 10 ms
Filtered Output (data-logger-prompted or unprompted to PC)
  • 795 ms (with 5 Hz bandwidth filter)
  • 395 ms (with 10 Hz bandwidth filter)
  • 195 ms (with 20 Hz bandwidth filter)
  • 155 ms (with 25 Hz bandwidth filter)

Internal Monitor Measurements
Update Rate 2 Hz
Inclinometer Accuracy ±1°
Relative Humidity Accuracy
  • ±3% (over 10 to 90% range)
  • ±7% (over 0 to 10% range)
  • ±7% (over 90 to 100% range)
Board Temperature Accuracy ±2°C

SDM
-NOTE- Used for data-logger-based data acquisition.
Bit Period 10 µs to 1 ms
Cable Length
  • 7.6 m (25 ft) max (@ 10 µs bit period)
  • 76 m (250 ft) max (@ 1 ms bit period)
Address Range 1 to 14
Bus Clocks per Sample ~200

CPI
-NOTE- Used for data-logger-based data acquisition.
Baud Rate 50 kbps to 1 Mbps
Cable Length
  • 15 m (50 ft) max (@ 1 Mbps)
  • 122 m (400 ft) max (@ 250 kbps)
  • 853 m (2800 ft) max (@ 50 kbps)
Address Range 1 to 120
Bus Clocks per Sample ~300

RS-485
-NOTE- Used for anemometer configuration or PC-based data acquisition.
Baud Rate 9.6 kbps to 115.2 kbps
Cable Length
  • 305 m (1000 ft) max (@ 115.2 kbps)
  • 610 m (2000 ft) max (@ 9.6 kbps)
Bus Clocks per Sample ~500 (ASCII formatted)

USB
-NOTE- Used for anemometer configuration or PC-based data acquisition.
Connection Speed USB 2.0 full speed 12 Mbps
Cable Length 5 m (16.4 ft) maximum

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 (retired)
CR1000X
CR300
CR3000 (retired)
CR310
CR6
CR800 (retired)
CR850 (retired)

Downloads

CSAT3BH CR1000X Programs v.2.03 (9 KB) 20-11-2020

CR1000X datalogger programs for the CSAT3BH with SDM and CPI communications protocols. 

Warning: This program is not intended for the CSAT3H Heater Controller Enclosure. Please contact Campbell Scientific for any questions regarding the CSAT3H Heater Controller program.

CSAT3B OS v.3.02 (548 KB) 14-10-2019

Current CSAT3B Operating System.

View Update History

CSAT3H Heater Controller v.14.2 (46 KB) 02-02-2021

The CSAT3H Heater Controller ships with this encrypted program. This program is for the unlikely event that the program needs to be re-installed or updated to a newer version. Please contact Campbell Scientific if you have questions about the program or would like the algorithm modified for a specific application.

Frequently Asked Questions

Number of FAQs related to CSAT3BH: 15

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  1. Is the CSAT3A, CSAT3AH, CSAT3B, or CSAT3BH anemometer measurement limited by precipitation?

    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. Sonic wicks, which come with all sonics, can be placed on the transducers to wick away moisture from the faces of the transducers. Ensure that these wicks are removed during cold conditions to prevent ice from building up around them.

  2. If the polymer coating at the ends of the CSAT3A, CSAT3AH, CSAT3B, or CSAT3BH transducers starts coming off, is that a problem?

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

  3. Are there any mounting options for the CSAT3A, CSAT3AH, CSAT3B, or CSAT3BH that lend themselves to frequent repositioning?

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

  4. What are the calibration procedures for the CSAT3A, CSAT3AH, CSAT3B, and CSAT3BH, and how are they traceable to the National Institute of Standards and Technology (NIST)?

    The CSAT3A, CSAT3AH, CSAT3B, and CSAT3BH are calibrated over temperature for the effects of transducer delays on the wind speed, and to a lesser extent, for the speed of sound measurements.

    There is no NIST-traceable standard for ultrasonic anemometers.

  5. Can the CSAT3A, CSAT3AH, CSAT3B, or CSAT3BH be used in low-speed conditions, such as less than 5 cm/s? If so, what are the resolution and accuracy at these low speeds?

    The sonic anemometer 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.

  6. Can the CSAT3B or CSAT3BH measurement frequency be changed? If so, what frequencies are supported by these sensors?

    Yes. The CSAT3B and CSAT3BH measurement frequency can be changed by the user. The user can either choose a prompted or unprompted output rate. The prompted output rate is based on the scan interval of the data logger, which must be an integer. Therefore, the measurement frequencies supported would be 1, 2, 4, 5, 8, 10, 20, 25, 40, 50, and 100 Hz. The unprompted output rate allowed is 10, 20, 50, and 100 Hz.

  7. Is there a way to determine the time at which the CSAT3A, CSAT3AH, CSAT3B, or CSAT3BH started reporting data with sub-second precision?

    No. The sonic anemometer 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.

  8. How sensitive are the CSAT3A, CSAT3AH, CSAT3B, and CSAT3BH velocity measurements to sea spray in periods of high wind speed?

    The CSAT3A, CSAT3AH, CSAT3B, and CSAT3BH—like other sonic anemometers—measure wind speed along the sonic path using ultrasonic signals. If the salt spray blocks the sonic path, the sonic anemometer will not be able to make measurements. The same is true if a thick layer of salt is deposited on the transducer faces.

  9. Is the offset relatively constant for a single CSAT3A, CSAT3AH, CSAT3B, or CSAT3BH?

    No. The offset is a function of temperature and time. Once a year, spot-check the sonic anemometer wind offset using the procedure outlined in the CSAT3B instruction manual. If the measured offset is outside the specification, return the sensor to the factory for calibration. To request a return material authorization (RMA) number, follow the steps listed on our Repair and Calibration page. 

  10. What is the natural frequency of the CSAT3A, CSAT3AH, CSAT3B, or CSAT3BH?

    100 Hz.

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