> For the complete documentation index, see [llms.txt](https://docs.yudash.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.yudash.com/felyx/si/solar-radiation.md).

# Solar Radiation

Solar radiation sensors measure the energy received from the sun and are widely used in weather and hydromet stations, agriculture, ecological research, evapotranspiration studies, solar-energy monitoring, and surface energy-balance studies. Depending on the sensor type, measurements may include global shortwave radiation, net radiation, reflected radiation, PAR/ePAR, or spectral irradiance.

Radiation sensors are commonly available with **Modbus/RS485, SDI-12, 4–20 mA, or voltage outputs such as 0–5 V**, depending on the sensor model. FELYX can interface directly with these supported digital and analog outputs. Apogee, for example, offers pyranometer variants with 4–20 mA, 0–5 V, SDI-12 and Modbus outputs.

### Apogee SN-522-SS Net Radiometer

<figure><img src="https://1858257737-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FToww5EM1cml3ouN6fvnJ%2Fuploads%2F1kAakgUzQ5f3biultaQa%2Fapogee_sn522.jpg?alt=media&amp;token=66d34f92-d287-464c-b860-7c443eefdb58" alt=""><figcaption></figcaption></figure>