Home Z in Repeiter host

I have my LR setup with dual end stops for Z. When I hit home on repetier host it moves the Z axis up until it hits both the limit switches and everything seems to be ok. However I think it thinks this is 0. How do I get repeiter host to set the home position greater than zero?

Since I don’t own a LowRider, this info is based on my general understanding of the MPCNC and reading on the forum.

To set the position at the end of Home Z to something other than Z=0, you can execute a G92. In Repetier-Host, under Manual Control, you can type “G92 Z110” in to the G-Code field and hit send. This would set the current Z position to 110 mm (arbitrary example value).

If you want to automate this process, you can define one of the custom buttons. Got to the Repetier-Host Config menu and select Printer Settings. Select the Scripts tab. From the Script dropdown, select Script 1. You can put something like this in for the script:

G28 Z
G92 Z110

Now clicking on button 1 will execute this code. Note that the height when you squired your Z axis on a LowRider is arbitrary since the length of the bit is part of the equation and it changes. Rather than worry about Home setting Z to 0 at the top, perhaps you want to install a touch plate and get probing downward working. On a LowRider with dual end stops, this is accomplished using a G38.2 g-code.

Are you sure the Z axis is moving the right way? When it homes up, it should set the position to 200 (which isn’t right either, but it makes me think your Z is backward).

When you command Z+10mm does it move up? If not, you’ll have trouble running gcode.

Also, which board do you have?

It rises up when I home it and after it’s done it does show 200 when I home it. When I send g0 z190 it goes down 10 mm. It’s the Rambo 1.4.

Oh, stupid RH. It thinks home is at zero and then when you hit the +10mm button, it goes into the ground?

Yes. Is there a setting in RH to tell it where it is when its done homing?

I’m not sure. At some point we found out that sending @isathome in the console would tell it you were at zero. But I didn’t find any documentation for it, or any similar commands.

Repetier host (for some reason) doesn’t ever ask the printer for it’s coordinates. It just thinks it knows better (ok, maybe I’m anthropomorphising). Maybe try cncjs?

Thank you. I will try it. I have a v1 pi about ready to try out, but I am just getting started and am slowing learning!

I will definitely try to get the touch plate and try that out. That sounds like the way to get things setup.

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You can also set the “Printer shape” in Repetier to explain where endstops are relative to travel envelope. This is only for Repetier’s understanding, won’t help when you switch to a new gcode sending method.

In Windows - Config menu -> Printer Settings -> Printer Shape tab.