CNR4 Net Radiometer
8
Uncertainty in daily total:
< 5% (95% confidence level)
Instrument calibration:
Indoors. Side by side against reference
CMP3 pyranometer according to ISO
9847:1992 annex A.3.1
1
Indicates ISO specifications.
6.3 Pyrgeometer Specifications
Spectral range:
4.5 to 42 μm (50% points)
Sensitivity:
5 to 15 μV/
W/m
2
Impedance:
20 to 200 Ω (typically 50
Ω
)
Response time:
< 18 seconds (95% response)
Non-linearity:
< 1% (–250 to +250 W/m
2
irradiance)
Temperature dependence of
sensitivity:
< 4% (–10 to 40 °C)
Tilt error:
< 1% (deviation when tilted at any
angle off horizontal)
Zero offset due to temperature
change:
±4 W/m
2
(5 K/hr temperature change)
Field of view
Upper:
Lower:
180 degrees
150 degrees
Net-irradiance:
–250 to +250 W/m
2
Non-stability:
< 1% (sensitivity change per year)
Window heating offset:
< 6 W/m
2
(1000 W/m
2
solar
irradiance)
Uncertainty in daily total:
< 10% (95% confidence level) indoor
calibration
Typical signal output for
atmospheric application:
±5 mV
Temperature sensors
Thermistor:
10k Ω
Pt-100:
DIN class A
Instrument calibration:
Indoors, side by side against reference
CG(R) 3 pyrgeometer. On request
outdoors, side by side against
reference CG(R) 4 pyrgeometer
6.4 Optional CNF4 Heater/Ventilator
The purpose of the heater/ventilator is to prevent dew deposition on the
pyrgeometer and pyrgeometer window, thus enhancing the measurement
accuracy and reliability. Using the heater/ventilator will have negligible effect
on the pyranometer reading.
