The CVF3 uses a fan and inlet filter to draw clean air over the pyranometer’s domes. The fan runs continuously to reduce dust and dirt settling, to dissipate rain drops and to stabilize the dome temperature.
The CVF3 has both a 5 W and a 10 W heater. The 5 W heater raises the temperature of the dome slightly above ambient temperature to prevent the formation of dew and frost. The 10 W heater is used for more extreme climates to melt snow and ice.
|Power Supply||12 Vdc, 1.3 A (with 10 W heater)|
|Operating Temperature||-40° to +70°C|
|Ventilation Power||5 W (continuously)|
|Heating Power||5 W or 10 W|
|Heater Induced Offset||< 1 W/m2 (with CMP11)|
|Diameter||22.4 cm (8.8 in.)|
|Height||12.9 cm (5.1 in.)|
|Weight without Cable||1.6 kg (3.5 lb)|
The 27084 mounting stand is used to fasten the CVF3 to a CM220 Right-Angle Mounting Bracket or a 17953 1 in. by 1 in. NU-RAIL. The CM220 or 17953 is then attached to a mast or crossarm. The CVF3 is not compatible with the CM245 mounting stand.
The 10 W heater’s current drain is approximately 850 mA at 12 Vdc, and the 5 W heater’s current drain is approximately 420 mA at 12 Vdc. The ventilator draws an additional 5 W of power at 12 Vdc. These power requirements are large compared to most Campbell Scientific products. Because of this, the CVF3 should be connected to the 21326 Power Net 5 A Power Supply and the 7321 Crydom Relay.
The Crydom relay allows the heater power to be controlled by the datalogger program and thus reducing power consumption. For example, the datalogger program can turn on the heater only when the light level falls below 20 W/m2 or, if a measurement of air humidity is available, when the dew point of the air falls to within 1ºC of the sensor body temperature.