Campbell Scientific CNR4 Net Radiometer - Manual (Page 15)

CNR4 Net Radiometer
7. In the Confirm window, click Yes to download the program to the
datalogger.
8. Click on Wiring Diagram and wire according to the wiring diagram
generated by Short Cut.
5. Overview
The CNR4 Net Radiometer consists of a pyranometer pair, one facing upward,
the other facing downward, and a pyrgeometer pair in a similar configuration.
The pyranometer pair measures short-wave solar radiation, and the
pyrgeometer pair measures long-wave far infrared radiation. The upper long-
wave detector of CNR4 has a meniscus dome to ensure that water droplets roll
off easily while improving the field of view to nearly 180°, compared with a
150° for a flat window. All four sensors are integrated directly into the
instrument body, instead of separate modules mounted onto the housing. Each
sensor is calibrated individually for optimal accuracy.
Two temperature sensors, a thermistor and a Pt-100, are integrated with the
CNR4 body. The temperature sensor is used to provide information to correct
the infrared readings for the temperature of the instrument housing. Care has
been taken to place the long-wave sensors close to each other and close to the
temperature sensors. This ensures that the temperatures of the measurement
surfaces are the same and accurately known, improving the quality of the long-
wave measurements. A completion resistor is added in the pig tail end of the
thermistor cable providing an easy interface with dataloggers for half-bridge
measurement.
The CNR4 design is light weight and has an integrated solar shield that reduces
thermal effects on both the short-wave and the long-wave measurements. The
cables are made from Santoprene
® jacket, which is intended for outdoor use,
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