I have found that G29 is NOT the same as G29 S0.
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@fcwilt no need to repeat yourself. It’s becoming a bit snarky. You also keep talking about the three times z=0 datum is required, yet I feel you’re not paying attention to the multitude of times I’ve said I’m doing that. You’re also contradicting yourself, relative to what I’ve already explained I do at each step from turning on my printer to starting to actually print. Specifically, you stated earlier on (which I agree with) that...
“ The center of the bed, on the other hand, is always the same, barring some physical change in the printer, and is independent of the grid settings.”
So probing at startup, as part of my z axis homing process in homez.g accomplishes that, before or after autoleveling, since as you point out, will remain the same geometrically. Sure it may be off from the central point by a bit, but it’s reasonable to say that variance is negligible at best. If the center is as you say, always the same short of some physical change to the printer geometry, then always probing at the middle more than once to set z=0 datum is redundant. Once would suffice to establish the baseline.
As I’ve said, I have zero printing issues (particularly with my first layer) even when the compensation was not active. The initial post was an observation, not a detrimental issue. I feel like we will only circle the drain, so unless you’re telling me (again) I’m doing it wrong with no factual evidence the results are due to the defect you’re asserting, I will just move on from this topic.
Just in case you missed it, I am performing a G30 in the course of the machine running and starting up. That isn’t and hasn’t been an issue, even though a large chunk of your responses are devoted to it (not even sure why you’ve fixated on that at all), even when discussing the use of G30 s-3 somehow became a major concern. This entire thread was initially about G29 and could have concluded much earlier on.
Also to clarify (and go back to the original point), on my Duet3 v1.0 with toolboard v1.1, with and without mesh.g, initiating a G29 alone will not activate mesh compensation, but only when I stipulate G29 S0.
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Setting the Z=0 datum once may not be sufficient because it can change as things heat up/cool down.
Thus it is best to do it at the times I have stated.
As to G29 not working I don't understand how that is possible since the hardware being used should make no different, only the firmware.
But that is assuming that the firmware builds are the same for each platform. That is not something I can determine.
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@nuramori said in I have found that G29 is NOT the same as G29 S0.:
The G30 S-3 has removed my need to deal with z axis calibration every time I swap them, so after having the command work for me based on a lengthy experimentation period (eliminating having to deal with the nozzle height changes), led to me just leaving it in.
I think this is only working out for you by accident. You can't calibrate the trigger height unless you're the one providing an accurate Z0 point manually. That's where you would jog the nozzle to touch the bed and send G92 Z0 to set the known position and then measure the trigger height either with G30 S-1 (report trigger height) or G30 S-3 (set the current trigger height to what it measures).
Just doing G30 S-3 after a G30 will only give you the same trigger height you had when you initially measured it and set it in G31 Z.
So it's not hurting, but it's not really doing anything.
The intention of G30 S-3 was for use in macros where you would have prompts to set Z0 and then to the trigger height measurement and have it applied automatically, you could also add M500 P31 to save the resulting G31 Z trigger height to config override to be reloaded at each power up.
Regardless, the main point of the thread was around the functioning of G29 and G29 S0.
Can you confirm again for me whether sending G29 with mesh.g not present functions to probe the bed and activate the mesh?
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@arnold_r_clark said in I have found that G29 is NOT the same as G29 S0.:
Very Interesting, can you please provide a link to the documentation which provides citation of that fact, I would like to research this further.
From the Duet Gcode documentation:
If G29 is commanded with no S parameter, then file sys/mesh.g is run if it exists, otherwise the command behaves like G29 S0.
I know this is the case on my Duet hardware for firmware 3.2.2 and 3.3.0 with no SBC connected.
Frederick
Printers: A FT-5 with the 713 upgrade bits, a custom MarkForged style, a small Utilmaker style, a small CoreXY from kit and a E3D MS/TC setup. Various hotends. Using Duets (2 and 3) running 3.4.6
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@fcwilt Thanks for testing.
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@phaedrux said in I have found that G29 is NOT the same as G29 S0.:
@fcwilt Thanks for testing.
I suppose it is possible that the firmware build for hardware other than mine (Duet 2 WiFi, Duet 3 Mini 5+, Duet 3 MB6HC) might have a bug but of course I cannot test that.
What I haven't tested is what happens if you execute a G29 inside mesh.g - that could be interesting.
I use mesh.g for my printer but inside is a G29 S0.
Frederick
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@arnold_r_clark said in I have found that G29 is NOT the same as G29 S0.:
Thank you for the information.
So from the documentation the key word is "IF" as IF no mesh.g file exists then G29 (no additional parameter) automatically morphs into G29 S0 .
Correct.
And if you have a mesh.g file without a G29 S0 (create height map) or a G29 S1 (load height map) then executing G29 will run the file but mesh compensation will not be enabled.
Frederick
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@phaedrux I should note I am using an SBC with my duet3. Perhaps that’s the one element that’s making a difference in the results.
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@nuramori said in I have found that G29 is NOT the same as G29 S0.:
@phaedrux I should note I am using an SBC with my duet3. Perhaps that’s the one element that’s making a difference in the results.
Could certainly be the case.
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@nuramori Thanks for the report, I am looking into it.
