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.

Solar irradiance meters are monitoring-only devices: the EMS reads them but does not control them. They communicate over Modbus TCP.

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.

flowchart LR
    M["Irradiance meter (W/m²)"] -->|"learned curve, 30 days"| V["Expected power at this irradiance"]
    V --> O["Compare: curtailment or underperformance"]
    P["Actual inverter production"] --> O

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

All models per brand are also in the overview list.