The CNR4 consists of a pyranometer and pyrgeometer pair that faces upward and a complementary pair that faces downward. The pyranometers and pyrgeometers measure shortwave and long-wave infrared radiation, respectively.
The CNR4 contains both an internal thermistor and an internal Pt-100 RTD. Typically, the thermistor makes the instrument housing temperature measurements used to compensate the infrared readings. Alternatively, the RTD can provide these measurements if a CR6, CR3000, or CR5000 datalogger is used