We have a Victor Vturn II-26 lathe (year 2002, Fanuc 18TC). I changed the grid shift value for X -axis and after I changed it back what it was the machine won't go to reference anymore.

I have been discussing with Fanuc technician and changing grid shift has removed the reference point (Parameter 1815.4 (APZ) = 0) because this machine has absolute encoder (Parameter 1815.5 (APC) = 1). Parameter 1815.5 is now set to 0 to make movement possibly without reference point and limits are set to 999999 (Parameter 1320 X) and -9999999 (Parameter 1321 X), machine still gives error: 506 OVER TRAVEL: +X at machine POS 2.0 (about).

Interesting about this is that 506 is a hard limit and limit switches are far away from real hard limits. So, there is probably some kind of fail safe that prevents X -axis to go more than 2mm to + direction. Does anyone know how can I bypass this?

Any advice is greatly appreciated!

P.S. I'm also looking for turret correction instruction for same machine, turret type is Lio Shing LS-250SV(12).