Implementing Z offset

sbk

Repetier/Marlin.
Hi. I am trying to use Repetier with a Marlin-based printer, but the print keeps starting with the mechanical endstops as the reference rather than the offset soft endstops. Can anyone advise if this is a Marlin problem, or a Repetier one ? Sending G28 sends the carriage to -10, -10, -3 on the printer display. 0, 0, 0 Is the reference I want for printing
G851 provoked an "Unknown Command, so I used M428, but no change
Snip
The following strategy must be followed to specify the Z offset:

Heat your printer up to your printing temperature and allow a few minutes for it to expand and settle
Reset the existing Z-offset to zero M851 Z0
Home all axes G28
Move the nozzle to the middle of the bed G1 X110 Y110 (if your bed is 220 x 220)
Turn off the software endstops with M211 S0
Move the nozzle down so it is just gripping a piece of standard printer paper
Set the Z-offset to the displayed value. E.g. if the printer displays a Z-Value of -1.23 enter M851 Z-1.23
Store it to the EEPROM M500
Important notice! Enable the endstops again with M211 S1 or the printer head will collide with the bed on the next G28 command

Repetier

Repetier just sends G28 for homing. It is printer internal how this is handled.

I'm not sure what you do with software endstops. These are for opposite side and just prevent moves outside reachable area after moving to physical endstops. I think you want to set an endstop offset defining that it shoudl move away x mm after hitting endstop. But that is marlin internal stuff.