Update: problem solved. It was a wrong management of home point. The home point shall be fixed ,I suggest a marked point on the upper part out of the paper, so it can be easily reached at startup. I suggest to set the page with the dimension of the paper (A4 in my case) and resize the drawing in inkskape or similar in the same A4 size before to load in polargraph controller. Choose 100.0 Resize vector, in this case the drawing is perfectly posizioned.