Jonathan,
the setup page on USBCNC for acceleration shows Acc.[AU/S^2]. In this box I have left it set to 50 which is the default setting. I cant remember what this setting means. I think I did ask Gary at Zapp about this a while ago and I have been looking through some old emails trying to find the answer but cant find it so I dont really know what Ive got it set to. I think I will have to email Gary again about it.

Ian