IRM-1

The Sonel IRM-1 is a compact, field-hardened solar irradiance and temperature meter built specifically for photovoltaic commissioning and O&M testing. Its primary role is to provide the plane-of-array irradiance and module temperature data required to convert PV electrical measurements to standard test conditions (STC) per IEC 60891 — data that is essential for any meaningful comparison of field results to nameplate values.

The instrument measures three parameters simultaneously: solar radiation intensity in the plane of the module (in W/m² or BTU/ft²·h), PV module temperature via an external probe, and ambient temperature. A built-in inclination sensor confirms the measurement angle relative to the reference surface, and a built-in compass provides geographical orientation — both useful for documenting the exact measurement conditions and for initial array orientation work during design or commissioning.

Communication with the PVM-1530 master meter is via LoRa, which provides significantly greater wireless range than Bluetooth — a meaningful advantage on large utility-scale arrays where the IRM-1 may be mounted at the test module while the technician walks combiner rows. The reSYNC function handles connection gaps automatically: if the IRM-1 moves out of range, it continues logging environmental data internally and transfers it to the master meter when the connection is restored, ensuring no measurement is left without environmental context. The IRM-1 also functions as an independent datalogger with 999 cache cells and 5000 recorder records — useful for pre-construction irradiance surveys and shading analysis before a PVM is on site.