SunSpec model 123 Immediate Controls

SunSpec model 123 Immediate Controls is one of the SunSpec information models, which group device registers into models that each start with a header giving the model ID and length. The first register at 40290 is a read-only uint16 holding the model number 123. The block also carries a read-only reactive power percent scale factor, VArPct_SF, at 40315 with a value of -1. On the XGI 1500, not every register in a model is supported; unsupported ones are marked Reserved and should not be used.