should homing be using offsets like z_tilt?

Z homing, centers the nozzle , so probes offset (not dead center) for the final Z homing. Z_Tilt.... uses the probe points from printer.cfg., as to for the mesh point locations. Why doesn't normal homing use that same offset.
I pose the question as what if there is a mesh diff between the offest point and the Z homing centered point that one would think sets the ref for the mesh center. Wouldn't that possibly add to mesh thickness issues across the bed?
6 Replies
miklschmidt
miklschmidt16mo ago
It makes no difference Neither homing nor z_tilt cares about probe offets. Also the bed mesh reference is now the coordinate where Z was homed, all of that changed recently.
ptegler
ptegler16mo ago
I guess that was kind of my Q.... if the probe for Z homed is not dead center, is the mesh grid offset to match where the probe touched down for Z home (is it based on the probe offset coordinates) tia
miklschmidt
miklschmidt16mo ago
The zero_reference_position expects an (X, Y) coordinate matching that of the reference position described above. If the coordinate lies within the mesh then the mesh will be offset so the reference position applies zero adjustment. If the coordinate lies outside of the mesh then the coordinate will be probed after calibration, with the resulting z-value used as the z-offset. Note that this coordinate must NOT be in a location specified as a faulty_region if a probe is necessary.
Note, this is only useful if you use a z-endstop. What it does is offset the mesh in Z by comparing the z-endstop offset and the probe results from that coordinate. By default (like in stock RatOS), no translation is done. So it's irellevant for us. We use the probe for everything. So when you home you printer (regardless of where you probe Z), that will be zero. Everything in your bed mesh is relative to that zero (because it's the same probe). It's much easier to understand if you forget that zero reference offset is a thing, because it literally is completely irrelevant when you only use a probe. It also has nothing to do with x/y probe offset Just realized i may have misunderstood what you meant. You're asking if bed_mesh is offset compared to the z-home. In other words, does bed_mesh know where you homed and did the klipper guys "forget" to compensate for x/y probe offset. The answer is no. Don't let the fact that bed_mesh uses probe coordinates instead of nozzle coordinates fool you. That is of course handled internally IT would be insane if it wasn't.
ptegler
ptegler16mo ago
Again...perhaps all more complicated than needed.... was simply asking that when you finish 'home all' the nozzle is centered based on your bed size config settings...and the z probe is offset when it touches down, as the nozzle is centered not the probe. In a round about way I believe you answered my Q... was just trying to ref in my mind, what (and only what) is actually effected by that probe offset settings. all this has to do with my 300 sized (idex config) bed mounted in my VC500 frame. Coordinates had to be manipulated to ref the 500 frame 'zeros' rather than min/max'es. So for my 300 bed (in a 500 frame) for instance.... the primeblob location is actually at 110, 80, which on the 300 bed, is actually 10, 15. finding locations for proper config...I just did a 'home all' then moved the head to the actual center of the 300 bed, noted the coords, then the same for the primeblob locations, new min/maxs etc. The first time I did a bed mesh it appeared to run skewed to the right, by the amount of my probe offset. I'll have to verify my mesh positions were correct (probably my error) but is what caused my confusion of what is actually effected by the probe offsets.
eager-peach
eager-peach12mo ago
The coordinates of my machine's nozzle and probe are like this. all 3 ball points. Please help me setup z_tilt. Thank you
No description
blacksmithforlife
please start your own post
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