From OpenSCADAWiki
The Calendar System is Solar, year calculated from 5508 before AD, that is to the current year appended 5508, and from the current month number subtracted 2 due to the year started from Spring and not Winter.
The Calendar System is Solar, year calculated from 5508 before AD, that is to the current year appended 5508, and from the current month number subtracted 2 due to the year started from Spring and not Winter.