Strange home values on delta

When I use Repetier Host manual control to zero all axis, I get Z=326, X=-135, Y=-135. If I advance the head from the stop position by using the positional control to advance say 50mm down and then say X + 50mm, the display will now show X=-85mm. Trying to move minus 50mm from the center position will result in no move. The Y axis behaves the same.
If I home all axis and then move down using say G0 Z0, the moment I give a required position on X or Y, say "G0 X0", the display changes from -135 to 0 and the manual controls can now be used to move to minus positions
I think that the printer will now print, but where does the -135 come from? Is it best to just live with it or can it cause problems?

Further info: More or less standard Rostock printer with Ramps 1.4, Repetier-Firmware-Development downloaded and installed yesterday, previous Arduino sketch lost with disk crash a few months ago so all settings are my best interpretation.

Thanks for any help,

Mike

That does not sound correct, also I do not understand what buttons you press, when you say:
> When I use Repetier Host manual control to zero all axis, I get Z=326, X=-135, Y=-135.

The only valid action is homing at the start or everything is undefined. Only after homing moves make sense and should be executed like you think they should. Manual moves will never help on delta printer.

Also be aware that the new version supports bed leveling. If you have none make sure it is disabled:

M321 S2

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Sequence of actions:

Open Repetier-Host V0.90C from Windows, click connect, click on Manual Control tab. Display next to homes are red and show X=0.00, Y=0.00 and Z=0..00. Click on home all symbol and all three sets of legs lift until limit switches reached, moves down 2mm then up again. Display next to homes now black and show Z=326.00, X=-135.00, Y=-135.00.

Using M114 in the G Code box causes the X and Y values to go to 0.00 (Z shows 325.98mm, but twenty microns is not a lot)

Bed leveling is disabled. I wanted to use the manual controls to find hotend to bed clearance at successive points but entering coordinates works.

I am pretty sure that everything is working, but am still intrigued by the value -135 as it doesn't appear in the Configuration.h.

Thanks,

Mike

ok, i understand. it's a misconfiguration in the host. Open printer settings and change the homing position for x and y to zero instead of min.

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