SunSpec model 303 Back of Module Temperature Model

SunSpec model 303 is the SunSpec information model for back-of-module (BOM) temperature sensors. It defines how the readings are laid out in registers and does not specify the wire or bus they travel over. The model starts with a read-only header: an ID register holding the value 303 and a length register. A repeating block follows, so a device can report a variable number of BOM temperature readings. Each repeated point is TmpBOM, a read-only int16 value in degrees C with a scale factor of -1. The RainWise PVMet 500 weather station is SunSpec compliant and supports model 303 alongside irradiance model 302 and meteorological model 307. When installing a module temperature probe, stick it to the centre of the module's back, away from the edge of the array. A measured back-surface module temperature can be fed into a performance model, which avoids the uncertainty of estimating it from weather data. Cell temperature can then be worked out from the back-surface temperature.

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• sentence 1: support check: partial - The BOM purpose and register layout are stated, but nothing in the passages says the model does not specify the wire or bus (the Modbus RS-485 table is only mentioned, not contrasted).
• sentence 1: review: partial - The BOM temperature purpose and register identification are supported, but nothing in the passages says the model leaves the wire or bus unspecified. -->