CNR 1 has several output signals: two voltages for the model type CM 3 pyranometers, two
voltages for the model type CG 3 pyrgeometers, and a 4 wire Pt-100 connection. A heater is
incorporated. The heater is intended to prevent dew and frost deposition at night. Heating generally
improves accuracy but at the same time introduces some measurement errors. It is not a necessity.
An electrical diagram of CNR 1 is depicted in figure