If your using Windows and need to modify the scale of what’s plotted, you will probably have to set the permissions for the axidraw_conf.py file so you have full control.
In my setup the file was found under C:Program FilesInkscapeshareextensions
Next open the file and look for “#Machine resolution: Used in converting drawing size to motor steps.”
Muck with the settings until you get the correct scale. I had to reset it to 2500 so the Inkscape 100mm scale matched what was plotted.