CSD3 measures sunshine duration. Sunshine duration is defined by the World Meteorological Organization as the time during which the direct solar radiation exceeds 120 W/m². It has no moving parts and uses 3 photo-diodes with specially designed diffusers to make an analogue calculation of when it is sunny. The output is switched high or low to indicate sunny or not sunny conditions. The calculated direct irradiance value is available as a voltage output.
- No moving parts
- Large drying cartridge for low maintenance at long intervals
- Glass tube for improved resistance to scratching by storm blown sand and ice
- Low power consumption, suitable for remote stations
- Two heater levels, increasing accuracy and reliability
Sunshine Duration Sensors are widely used in weather networks and holiday resorts to provide the number of sunshine hours per day for tourist information. In health spas and clinics they contribute to the measurements used in treatment and recovery. In agronomy the amount of sunshine received by crops can be used to help forecast yields. In building automation the CSD 3 can be used as an input to the systems for the control of the internal environment, such as the deployment of sun blinds.
The instrument is designed for continuous outdoor use and the waterproof plug-and-socket cable connection provides for easy installation and servicing. A humidity indicator progressively changes color to show when it is necessary to change the drying cartridge, which is located under a screw-on cover. The recommended recalibration interval is 2 years.