morningstar-0.1.3 doesn't have any documentation.
morningstar-rs
Gather stats from, and control morningstar solar charge controlers. Currently only the Prostar MPPT is supported, because that's the only one I have physical access to.
see document http://support.morningstarcorp.com/wp-content/uploads/2015/12/PSMPPT_public-MODBUS-doc_v04.pdf for details on the modbus interface.