Campbell Scientific CNR4 Net Radiometer - Manual (Page 10)

CNR4 Net Radiometer
4. Quickstart
Please review Section 7, Operation, for wiring and CRBasic programming.
Appendix B, CNF4 Heater/Ventilator, provides information about using the
CNF4 heater/ventilator.
4.1 Siting Considerations
1. Mount the sensor so no shadow will be cast on it at any time of day from
obstructions such as trees, buildings, or the mast or structure on which it is
mounted. If the instrument is h meters above the surface, 99% of the input
of the lower sensors comes from a circular area with a radius of 10h.
Shadows or surface disturbances with a radius < 0.1h will affect the
measurement by less than 1%.
2. To avoid shading effects and to promote spatial averaging, the CNR4
should be mounted at least 1.5 m above the ground surface. It is
recommended that the CNR4 be mounted to a separate vertical pipe at
least 25 ft from any other mounting structures.
3. Orient the sensor towards the nearest pole to avoid potential problems
from shading.
4.2 Mounting
A mounting bracket kit, pn 26120, is used to mount the CNR4 directly to a
vertical pipe, or to a CM202, CM203, CM204, or CM206 crossarm. Mount the
sensor as follows:
1. Attach the mounting rod to the CNR4 (see FIGURE 4-1).
FIGURE 4-1. Attaching the mounting rod to the CNR4 body
2