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Table 6-9: CSAT3BH factory settings
Setting
Default
Communication
settings
SDM address
3
CPI address
30
CPI/RS-485 Communication Port
Protocol
CPI Enabled
CPI Baud Rate
Auto
RS-485 Baud Rate
115200
Unprompted Output Port
Disabled
Unprompted Output Rate
10 Hz
Measurement
setting
Operating Mode
Mode 0: Data Logger Trigger |
No Filter |
Data Logger-Prompted Output
7. Operation
7.1 Theory of operation for wind and sonic
temperature measurements
The CSAT3BH uses three pairs of non-orthogonally oriented transducers that transmit and
receive ultrasonic signals. The time of flight of a sonic signal between a pair of transducers is
directly related to the wind vector component that is parallel to the sonic axis. The CSAT3BH is
able to calculate the wind vector components along each sonic axis using the time difference
between an outgoing and return sonic signal, along with the distance between sonic transducers.
Trigonometric relationships are used to calculate the wind speed in an orthogonal x-y-z
coordinate system.
The time of flight measurement is also related to the speed of sound in air, which is a function of
the air density (temperature and humidity). Through these relationships, the CSAT3BH is able to
output a measurement of sonic air temperature from which actual air temperature may be
calculated if humidity is known.
CSAT3BH Three-Dimensional Heated Sonic Anemometer
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