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[BUG] Probe temperature compensation does not apply to Z Wizard, UBL, etc. #23047

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tombrazier opened this issue Oct 30, 2021 · 4 comments
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@tombrazier
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tombrazier commented Oct 30, 2021

Did you test the latest bugfix-2.0.x code?

Yes, and the problem still exists.

Bug Description

Probe temperature compensation has effect in exactly one place: in G29 for AUTO_BED_LEVELING_LINEAR and AUTO_BED_LEVELING_BILINEAR.

I propose to submit a PR moving the compensation code into probe.probe_at_point() with an option disable PTC in a few specific instances.

The following would benefit from this:

  • G29 for levelling algorithms AUTO_BED_LEVELING_3POINT and AUTO_BED_LEVELING_UBL. Also any future G29 algorithm anyone invents.
  • The Z Probe Wizard: presently the Z Offset found by the wizard is incorrect unless the wizard is used at the temperatures defined by PTC_PROBE_START, PTC_BED_START and PTC_HOTEND_START.
  • G33 - Delta Auto Calibration.
  • The Tramming Wizard - if you take long enough using it for temperatures to change.
  • DWIN_CREALITY_LCD_ENHANCED has a menu option that reports bed height.

In other cases it wouldn't make any difference one way or the other:

  • G35 - Tramming Assistant.
  • G34 - Z-Stepper automatic alignment.
  • DWIN_CREALITY_LCD_JYERSUI has a menu option where Z heights are compared with each other.

In two cases, it might make sense for the user to specify whether to apply PTC:

  • G30 - Single Z-Probe.
  • M48 - Probe Accuracy Test.

Finally, G76 - PTC calibration needs to run without PTC being applied.

Bug Timeline

It has always been there.

Expected behavior

I expect UBL, for example, to apply PTC. And I expect the Z Probe Wizard to give me a correct value.

Actual behavior

They don't.

Steps to Reproduce

Enable PROBE_OFFSET_WIZARD.
Enable and calibrate PTC.
Use the Z Wizard at different temperatures: the result should be pretty much the same because of PTC but they aren't.

Version of Marlin Firmware

Latest bugfix branch

Printer model

No response

Electronics

No response

Add-ons

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Bed Leveling

UBL Bilinear mesh

Your Slicer

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Host Software

No response

Additional information & file uploads

configs.zip

@tombrazier
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So if G30 and M48 need an option to enable/disable PTC when probing, any suggestions for a parameter letter? P is already taken for M48. How about C which can take a 0 or 1 to disable or enable PTC respectively and defaults to 1?

@tombrazier
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Just in case anyone wonders, I have not forgotten this. I am just getting inconsistent results in testing which I think is related to my machine's hardware. Working on it slowly.

@thisiskeithb
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#23764 has been merged.

@github-actions
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This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.

@github-actions github-actions bot locked and limited conversation to collaborators Apr 23, 2022
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