How to define bed location and size?

[TechButterfly]

My x endstop is 15mm to the left of the edge of the bed - how do I define where the bed actually is?

[fcwilt]

@techbutterfly said in How to define bed location and size?:

My x endstop is 15mm to the left of the edge of the bed - how do I define where the bed actually is?

There are a couple of ways.

You can specify X min as a negative value so that X = 0 ends up where you want it to be. This is a fairly common approach.

I prefer to set the axis min/max to the actual printable area.

But this means that when the endstop is triggered the logical axis position is set to axis min or max (depending on the location of the endstop) regardless of where the endstop actually is.

This is easily dealt with. Assume the endstop is at X = -15. When the endstop is triggered the logical X position is set to 0 when the physical X position is -15.

So just do a relative move G1 X15 which sets the physical X position to 0 but the logical X position is 15 as displayed in the DWC.

Then you do a G92 X0 which sets the logical X position to 0 and it is now in sync with the physical X position.

Frederick

[TechButterfly]

@fcwilt Thank you very much! That's what I needed!

[TechButterfly]

@fcwilt So I did set up my X homing as you suggested. The actual offset was 30mm, so I'm homing X, moving to X30 and then M92 X0 to set that as the new zero point. Worked great except that when I went do a mesh bed level, it says the probe can't reach the first point, which is X20 (my probe has a 37mm offset on X). Is there a way to make the mesh leveling know that the probe can reach X20, because there's 30mm of dead space beyond X0?

Or is the solution the other option you mentioned - define the bed as X-30 on the left side?

[fcwilt]

@techbutterfly said in How to define bed location and size?:

@fcwilt So I did set up my X homing as you suggested. The actual offset was 30mm, so I'm homing X, moving to X30 and then M92 X0 to set that as the new zero point. Worked great except that when I went do a mesh bed level, it says the probe can't reach the first point, which is X20 (my probe has a 37mm offset on X). Is there a way to make the mesh leveling know that the probe can reach X20, because there's 30mm of dead space beyond X0?

Or is the solution the other option you mentioned - define the bed as X-30 on the left side?

Aside from just setting the axis min/max to expand the area that can be probed there are three other ways to deal with this:

• pick points the probe can reach even if it does prevent access to some of the bed
• execute a M564 S0 before creating the mesh, execute a M564 S1 when done
• expand the axis min/max before creating the mesh to allow probing the desired points, reset the axis min/max when done

I usually just pick points that can be reached but I have done the last one, expanding the axis min/max temporarily.

Frederick

[dc42]

@techbutterfly said in How to define bed location and size?:

Or is the solution the other option you mentioned - define the bed as X-30 on the left side?

Yes.