CNR4 Net Radiometer
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9.2 Maintenance
The CNR4 is weatherproof and intended for continuous outdoor use. The
materials used in the pyranometer and the pyrgeometer are robust and require
little maintenance. For optimal results, however, proper care must be taken.
9.2.1 Cleaning Windows and Domes
Dirty domes and windows can reduce the radiometer readings. The site
operator should check the windows and domes of the CNR4 regularly, and
clean them as needed. Use distilled water or alcohol as cleaning solution, being
careful not to scratch the windows and domes during cleaning.
9.2.2 Replacing the Drying Cartridge
The CNR4 has a drying cartridge inside the sensor to help keep the electronics
dry. The manufacturer recommends replacing the drying cartridge every 6 to
12 months. The three screws holding the white solar shield and the six screws
holding the aluminium base plate need to be removed to access the drying
cartridge, as shown in FIGURE
. Make sure that the black rubber gasket is
put in place properly before the base plate is put back to keep the compartment
sealed. The CNR4 comes with two spare drying cartridges. Additional drying
cartridges can be purchased from Campbell Scientific.
FIGURE 9-1. Replacing the drying cartridge
9.3 Recalibration
For quality assurance of the measured data, the manufacturer recommends the
CNR4 be recalibrated on a regular schedule by an authorized Kipp & Zonen
calibration facility.
The CNR4 should be recalibrated every two years. Alternatively, one can
check the sensor calibration by letting a higher standard run parallel to it over a
Rubber Gasket
Drying Cartridge
