@wayne530 shared in this thread
https://diysolarforum.com/threads/lv6548-output-charger-source-priority-timer-settings.42163/
the link to the download of the Voltronic's Command Tool (http://ftps.voltronic.com.tw/C/Communication_tool-13A957D3F9AB41B59CCB/)
It allows basic RS232 communication...