Campbell Scientific IRGASON Integrated CO2/H2O Open-Path Gas Analyzer and 3D Sonic Anemometer - Manual (Page 44)

IRGASON ® Integrated CO
2
/H
2
O Open-Path Gas Analyzer and 3D Sonic Anemometer
Monitoring Division / National Oceanographic and Atmospheric
Administration in Boulder, CO, USA.
After an extended period of time in the field, the IRGASON gas analyzer may
need to undergo this factory calibration again to ensure valid measurements.
When recalibration is deemed necessary, contact Campbell Scientific.
The IRGASON sonic anemometer also undergoes an initial factory calibration.
Usually this calibration remains valid unless a transducer fails or damage to the
instrument leads to a change in geometry. The sonic anemometer requires
calibration when
• it develops a wind offset greater than the specification.
• it sets diagnostic flags under dry conditions with little to no wind and
with no obstruction in the ultra sonic paths.
The wind offset is tested by creating a zero wind environment by encircling the
sensor with a large plastic bag (unused refuse bag), using caution not to block
the sonic paths. See the manual CSAT3 Three Dimensional Sonic Anemometer,
Section 11.2.2, Test for Wind Offset, available at www.campbellsci.com . When
recalibration is deemed necessary, contact Campbell Scientific.
10. Datalogger Programming
The datalogger is programmed in the CRBasic language, which features two
instructions for communication with the EC100 via SDM. The first instruction
is EC100(), which reads measurement data from the EC100. The second is the
EC100Configure(), which receives and sends configuration settings.
10.1 EC100() Instruction
The EC100() instruction is used to retrieve data from the IRGASON via SDM.
The instruction syntax is:
EC100 (Dest, SDMAddress, EC100Cmd)
Dest is the input variable name in which to store data from the IRGASON.
The length (i.e., number of data elements) of the input variable array will
depend on the selected value for EC100Cmd. A value of -99999 will be loaded
into Dest(1) if a signature error on SDM data occurs.
EC100Cmd Dest Variable Length
0 8
1 12
2 13
SDMAddress defines the address of the IRGASON with which to
communicate. Valid SDM addresses are 0 through 14. Address 15 is reserved
for the SDMTrigger() instruction.
EC100Cmd is a parameter that requests data from the analyzer. The results for
the command are returned in the array specified by the Dest parameter. A
numeric code is entered to request the data, as shown in TABLE 10-1.
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