LI200X Pyranometer
A
Short Cut
tutorial is available in Section 4,
Quickstart
. If you wish to import
Short Cut
code into
CRBasic Editor
to create or add to a customized program,
follow the procedure in Appendix A.1,
Importing Short Cut Code into a
. Programming basics for CRBasic dataloggers are provided in
the following sections. A complete program example for a CRBasic datalogger
can be found in Appendix B,
Example Program
. Programming basics and
programming examples for Edlog dataloggers are provided at
www.campbellsci.com/old-manuals
Output from the LI200X is 0.2 kW m
–2
mV
–1
, which is measured by the
datalogger using the VoltDiff CRBasic instruction. CRBasic is included in
PC400 and LoggerNet datalogger support software.
Nearby AC power lines, electric pumps, or motors can be a source of electrical
noise. If the sensor or datalogger is located in an electrically noisy
environment, the measurement should be made with the 60 or 50 Hz rejection
integration option as shown in the example program.
Solar radiation can be reported as an average flux density (W m
–2
) or daily total
flux density (MJ m
–2
). The appropriate multipliers are listed in TABLE 7-2.
Programming examples are given for both average and daily total solar
radiation. Negative values should be set to zero before being processed.
TABLE 7-2. Multipliers Required for
Average Flux and Total Flux Density in Sl
and English Units
UNITS
MULTIPLIER
PROCESS
W m
-2
200
Average
MJ m
-2
t * 0.0002
Total
kJ m
-2
t * 0.2
Total
cal cm
-2
min
-1
0.2 * (1.434)
Average
cal cm
-2
t * 0.2 * (0.0239)
Total
t = datalogger execution interval in seconds
7.4.1 Total Solar Radiation
If the solar radiation is totalized in units of kJ m
–2
, there is a possibility of
overranging the output limits. For CRBasic dataloggers, you can avoid this by
using the IEEE4 or long data format.
8. Maintenance
On a monthly basis, the level of the pyranometer should be checked. Any dust
or debris on the sensor head should be removed. The debris can be removed
with a blast of compressed air or with a soft bristle, camel hair brush. Check
that the drain hole next to the surface of the sensor is free of debris.
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