CMP6, CMP10, CMP11, and CMP21 Pyranometers
13
7.4 Programming
Short Cut
is the best source for up-to-date data logger programming code.
If data acquisition requirements are simple, you can probably create and
maintain a data logger program exclusively with
Short Cut
. If your data
acquisition needs are more complex, the files that
Short Cut
creates are a great
source for programming code to start a new program or add to an existing
custom program.
Short Cut
cannot edit programs after they are imported and edited
in
CRBasic Editor
.
A
Short Cut
tutorial is available in Section
. If you wish to
import
Short Cut
code into
CRBasic Editor
to create or add to a customized
program, follow the procedure in Appendix
(p. A-1)
. Programming basics for CRBasic data loggers are
provided in the following sections. Complete program examples for select data
loggers can be found in Appendix
(p. B-1)
.
7.4.1 Solar Radiation Measurements
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
. Programming examples are given for both average and daily total solar
radiation.
The pyranometers output a low level voltage ranging from 0 to a maximum of
up to 20 mV, in natural light, depending on the calibration factor and radiation
level.
This voltage output is measured by using either the
VoltDiff()
CRBasic
instruction or
VoltSE()
CRBasic instruction.
Nearby AC power lines, electric pumps, or motors can be a
source of electrical noise. If the sensor or data logger 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 programs.
7.4.1.1 Input Range
The output voltage is usually between 5 and 20 mV per 1000 W
•
m
–2
. When
estimating the maximum likely value of sensor output a maximum value of
solar radiation of 1100 W
•
m
–2
can be used for field measurements on a
horizontal surface. Plane-of-array irradiances can exceed 1500 W
•
m
–2
.
NOTE
CAUTION
