Zero Return parameter setting procedure for Fanuc 16/18 and 16i/18i Controls

1. Move the axis to where you think zero return should be. If you can't get to the position you would like, hold in "P" and "Cancel" on power up to bypass soft overtravels or you could change the soft overtravel limits to temporarily. WARNING Do not try holding in any other keys except P and Cancel. You could blow out parameters, programs or other data.
2. Select "MDI" mode
   
3. Press the function key “OFFSET SETTING”
4. Press the soft key “SETTING”.
5. Move the cursor to “PARAMETER WRITE” . May need to page up or down to get to the top of the Parameter numbers.
6. Turn on PWE (Parameter Write) make it a 1
   
7. Press the function Hard key "SYSTEM"
8. Press the softkey "PARAM"
9. Type1815 and press "No.Search" . This should bring up parameter 1815.
10. Arrow down to whichever axis you want to change X,Y,or Z.
    
11. Change bit 4 (APZ) (make sure you count from the right starting with first space is Zero, Bits are as shown here-76543210). This will delete the current reference zero. Alarm must power down will appear, DO NOT POWER OFF
    
12. Go back to the parameter 1815 and make bit 4 a one
    
13. Power off machine for one minute and power up. New home position will be set.
    
14. Check coordinates of program and see how far you are off, if they are not correct repeat the steps. Also, make sure you handwheel the axes slowly to their overtravels. Make sure nothing binds, no servo alarms occur or destroys any way covers. If you set incorrectly, severe damage can occur. Also, remember if this is an axis that the pallet changer or Tool changer is dependant on alignment then you must check this also, because it is based off of zero return. Do not change 2nd reference position to comp for this. Always change home position.

Here is a CNC Gridshift procedure for older CNC machinery. Or if you are looking for a procedure for setting mitsubishi control home position