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FIGURE 7-3. Example of unprompted RS-485 or USB output to computer
Table 7-3: CSAT3BH synchronicity errors
Mode
Synchronicity error
0
0 ms
1
–5 to +5 ms
2 and 3
Output
rate
10 Hz
0 to 100 ms
20 Hz
0 to 50 ms
50 Hz
0 to 20 ms
100 Hz
0 to 10 ms
7.3.4 Operating mode recommendations
Due to the advantages in making synchronous measurements, Campbell Scientific recommends
using a data logger that supports SDM or CPI communications to collect data from the CSAT3BH.
If flux measurements are the primary interest, Campbell Scientific further recommends that the
CSAT3BH be operated in Mode 0 where the data logger triggers the measurements, no filters are
applied, and the data is collected by the data logger. If unaliased spectra are desired for
characterization of the system and site, Mode 1 is recommended in which the measurements are
self triggered, a filter is applied with a bandwidth that is half the data logger scan rate, and the
data is down-sampled by the data logger. If flux measurements and spectral characterizations
are of interest, then Campbell Scientific recommends unaliased data using Mode 1, along a
sample rate sufficient to capture the high-frequency variations that contribute to fluxes.
7.4 Synchronization with other sensors
As a delay exists between the CSAT3BH measurement and output to a data logger or computer
(see
(p. 67)), the CSAT3BH data will be slightly older than the record timestamp (recall
CSAT3BH Three-Dimensional Heated Sonic Anemometer
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