Campbell Scientific EC150 CO2 and H2O Open-Path Gas Analyzer and EC100 Electronics with Optional CSAT3A 3D Sonic Anemometer - Manual (Page 22)

EC150 CO
2
/H
2
O Open-Path Gas Analyzer
The mounting bracket for the EC50 with CSAT3A, pn 26786, allows the intake
source of the CSAT3A and EC150 to be positioned at varying degrees up to
approximately a 5.0 cm (2.0 in) offset. The positioning and offset is illustrated
in FIGURES 6-3 and 6-4. The change in positioning allows a small but
significant difference in the flux attenuation ratio. Campbell Scientific
generally recommends that the EC150 is positioned in the most forward
position to minimize errors caused by sensor separation. The tradeoff,
however, is greater flow distortion. The effect of spatial separation on flux
attenuation is greatest at lower measurement heights as shown in FIGURE 6-2.
A Campbell Scientific application engineer can help determine the best
positioning of the EC150 relative to the CSAT3A in scenarios where the
measurement height is below 10 meters.
FIGURE 6-2. Changes in flux attenuation ratio relative to sensor height
at the most fore and aft positions
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