Help understanding why I have trouble with setting my Z height

Threepwood

@phaedrux Thanks for that. I'll have a play with M558 commands. Problem is, I suspect that this will cause the bed mesh to probe 3/4 times at each point unless I add another M558 command to go back to default values.

I do have another question relating to probing and meshing. Let me know if I should make another thread about it and I will do that.

When I do quad gantry leveling on the Voron, I want quite a large dive height like 5 mm (ideally I'd like to go heigher, but that would really slow down meshing) because when the power cuts the E3D "Super Whopper Motors" cause the back of the gantry to drop slightly, or worse, if I've been working on the gantry it can end up far off parallel.

However, after this point when meshing the bed I only need to lift the gantry enough to be comfortably past the probe trigger point (the bed has a deviation of ~0.068mm). I just tried setting the dive height to 1mm and got a 121 point mesh in 50 seconds.

Is there a way I can set separate dive heights for normal probing and mesh leveling? M557 doesn't seem to have a dive height parameter, so I guess not. So I suppose I can just put M558 P5 C"io4.in" H1 F800 T27000 between the gantry leveling and the mesh leveling in my slicer start gcode, then M558 P5 C"io4.in" H5 F800 T27000 after the mesh leveling. You may have noticed that I have a thing for trying to make my Voron a speed machine (without losing any significant precision).

Does that sound like it would be the best way to achieve what I want?

It would be handy if the Duet would allow us to set a separate dive parameter for meshing. Maybe I should submit a feature request... Or maybe I've just missed how to achieve it.

Threepwood

So I've tried inserting M558 in to a "Full homing and leveling" macro like this:

G28
G32
M558 P5 C"io4.in" H1 F800 T27000
G32
G32
G28 Z

But when I do this, it messes up the offsets of the probe. It's no longer moving the nozzle 24mm forwards.

Does M558 being run reset the G31 offset values? I guess I can paste my G31 line right after. There's probably a better way to do this...

Phaedrux

I would question why you would want to put that there in the first place. What are you trying to do with that command? Which value are you trying to modify?

If you remove the P5 and C"io4.in" from that line it shouldn't reset the G31 values.

Threepwood

@phaedrux You make a good point. I was being lazy and keeping the whole line, and only changing the Z dive height, instead of finding out what values are optional in a M558 command.