Campbell CSAT3B, Инструкция по эксплуатации, Страница: 28 / 88

CSAT3B Three-Dimensional Sonic Anemometer
CSAT3B before the wind speed is transformed into orthogonal coordinates.
Because of this correction, it is not necessary to apply the speed of sound
correction described by Liu et al., 2001 (see Section10.1, References ).
The CSAT3B has several operating modes to suit different applications. The
anemometer can be configured to make a single measurement per datalogger
trigger, or it can operate in a self-triggered mode. When self-triggering, the
CSAT3B will make measurements at a high rate and provide the latest output
upon receiving each datalogger trigger. In either operating mode, various
filters can be applied to the output samples to limit the bandwidth of the output
data. The default of the CSAT3B is to make measurements when triggered by
a datalogger (SDM or CPI) and not apply any low-pass (high-cut) filtering.
See Section 4.2, Communications Connections , for a list of all default settings.
6.1 Measurements
Operating Temperature
Standard:
–30 to 50 °C
Wind Accuracy (–40 to 50 °C, wind speed < 30 m·s –1 , azimuth angles between ± 170 °C)
Offset Error
u
x
: ± 8 cm·s
–1
max
u
y
: ± 8 cm·s –1 max
u
z
: ± 4 cm·s –1 max
Gain Error
Wind Vector ±5° of horizontal: ± 2% of reading max
Wind Vector ±10° of horizontal: ± 3% of reading max
Wind Vector ±20° of horizontal: ± 6% of reading max
Wind Resolution
u
x
: 1.0 mm·s –1 RMS
u
y
: 1.0 mm·s –1 RMS
u
z
: 0.5 mm·s
–1
RMS
Wind Full Scale Range: ± 65 m·s –1
Sonic Temperature Resolution: ± 0.002 °C RMS at 25 °C
Sonic Temperature Reporting Range: –30 to 50 °C
Measurement Rates
Datalogger Triggered: 1–100 Hz
Unprompted Output (to PC): 10, 20, 50, or 100 Hz
Internal Self-Trigger Rate: 100 Hz
Measurement Delay
Datalogger-Triggered (no filter): 1 trigger period (1 scan interval)
Unprompted Output (no filter):
10 ms
Filtered Output (Datalogger-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
Filter Bandwidths: 5, 10, 20, or 25 Hz
18