> For the complete documentation index, see [llms.txt](https://docs.voltmasters.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.voltmasters.io/device-integrations/solar-irradiance-meters.md). # Solar irradiance meters A **solar irradiance meter** (pyranometer) measures the solar irradiance reaching the plane of your PV panels, in **W/m²**. Our EMS uses this live measurement to estimate how much PV power the installation *should* be producing at that moment. ### Why add one By comparing the measured irradiance against the actual production of a PV inverter, the EMS can: * Estimate the **achievable PV power** from the current sunlight. * Detect **curtailed or underperforming** production (for example, a string that is offline or soiled), because real production falls short of what the irradiance predicts. The EMS learns an **irradiance-to-power curve** for each PV inverter that has an irradiance meter linked to it: over a rolling 30-day window it records the typical (median) power the inverter produced at each irradiance level, ignoring periods where curtailment was active. That curve is then used to judge live performance against the current irradiance. ### Linking to a PV inverter An irradiance meter is added as its own device and then linked to a PV inverter through the inverter's **Solar Irradiance Meter** parameter in the device settings. One meter can be used as the reference for the inverter(s) it is linked to. ### Supported brands Select a brand below for the supported models, or see the [Overview list](/device-integrations/overview-list.md) for all supported brands and models. * [Soluzione Solare](/device-integrations/solar-irradiance-meters/soluzione-solare.md) * [IMT Technology](/device-integrations/solar-irradiance-meters/imt-technology.md) Solar irradiance meters are **monitoring-only** devices: the EMS reads them but does not control them. They communicate over Modbus TCP. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.voltmasters.io/device-integrations/solar-irradiance-meters.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.