The VHS is designed for unattended routine operation of pyranometers and pyrgeometers under all weather conditions. The VHS, which is mounted below the lower plate, blows ambient air upwards to the radiometer where a circular heating element slightly pre-warms the air.
As a result, the dome window is largely kept free of dust, dew and water droplets. In cold weather conditions below the freezing point, the dome window will also remain free of ice or snow. The system has been used in harsh alpine environments for extended time periods without failure.
Mechanical Specifications
| Height | 125 mm |
| Width | 210 mm (diameter) |
| Weight | 1.24 kg |
Electrical Specifications
| Voltage | 12 VDC |
| Current | 1 A (max.), 240 mA (ventilation), 680 mA (heating) |
Environmental Conditions
| Operating Temperature | -20°C to +75°C |
| Storage Temperature | -20°C to +75°C |