Specifications

CNR4 Net Radiometer
9.2 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
two-day period and, then, comparing the results. For comparison of
pyranometers, one should use a clear day. For comparison of pyrgeometers,
one should compare the nighttime results. If the deviations are greater than 6%,
the sensor should be recalibrated.
Please contact Campbell Scientific to obtain an RMA number for recalibration.
9.3 Replacing the Drying Cartridge
The CNR4 has a drying cartridge inside the sensor to help keep the electronics
dry. The manufacturer recommends that this drying cartridge be replaced
every 6 to 12 months. The three screws holding the white solar shield and the
6 screws holding the aluminium base plate need to be removed to access the
drying cartridge, as shown in Figure 9-1 below. 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 (CSI p/n 26006, CNR4 Replacement Drying
Cartridge) can be purchased from Campbell Scientific.
FIGURE 9-1. Replacing the Drying Cartridge
Rubber Gaske
t
Drying Cartridge
30