Logging Analog Data from the CSAT3

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Instructions for configuring the CSAT3 for LI-COR EC systems.

The CSAT3 sonic anemometer (Campbell Scientific, Inc., Logan, UT) can be configured to log raw flux data in conjunction with an LI-7500RS or LI-7200RS gas analyzer from LI-COR in a compressed .ghg file format. The .ghg file format makes it possible to continuously collect raw flux data for more than two months on a single 4 GB USB drive and to process data conveniently with LI-COR’s EddyPro flux data processing software.

  1. The CSAT3 is connected to an LI-7550 Analyzer Interface Unit through analog output/input channels. There are three cabling options for interfacing the CSAT3 to the LI-7550:
    1. The LI-7550 to CSAT3 interface cable (p/n 9975-035) provides a direct cable connection (shown below). This cable is not included with the LI-7500RS and LI-7200RS but can be ordered separately.
    2. The 9975-035 cable from LI-COR can be used to connect the CSAT3 to the LI-7550.
    3. The CSAT3 analog output cable can be wired into the LI-7550 auxiliary sensor interface box (LI-COR p/n 7550-101).
    4. The LI-7550 analog input/output cable (p/n 392-10109) can be spliced into the CSAT3 analog output cable, or soldered into the CSAT3’s analog connector.
  2. Analog outputs from the CSAT3 are turned off by factory default. To turn them on, use the CSAT32 software, which can be downloaded from:
  3. http://www.campbellsci.com/19_1_9999_68
  4. Set the Measurement Rate of the CSAT3 to 60 Hz for better data synchronization with the outputs from the gas analyzers.
  5. Scale the CSAT3 analog outputs. Choose Low or High and set the offsets and multipliers for the output range.
  6.   Slope, Low range (m s-1 v-1) Slope, High range (m s-1 v-1) Offset (m s-1)
    ux 6.5536 13.1072 0
    uy 6.5536 13.1072 0
    uz 1.6384 1.6384 0
    c 6.5536 13.1072 340
  7. Follow the quick start guide to set up LI-COR gas analyzers to log eddy covariance data in the .ghg file format. The CSAT3 provides the analog outputs as U, V, W, and Speed of Sound (SOS). The LI-7550 will need to be configured to read SOS, rather than sonic temperature (Ts), for a CSAT3.