z-offset increasing 3mm on every subsequent calibration
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Thanks!
Perhaps a note on https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe should be added that mesh calibration should be off, or that at least you should test at a point where the calibration has 0 effect...?
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@VJ Done.
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Hi,
Perhaps the firmware could handle this automatically by ignoring any active mesh calibration when setting Z=0 using a Z probe?
Frederick
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I'm not sure that that is so straightforward... Also, it is nice that the firmware just does what the command tells it to do, without performing additional steps behind the user's back. Sure you have to know more what you do, but at least it allows you to do what you want.
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@VJ said in z-offset increasing 3mm on every subsequent calibration:
I'm not sure that that is so straightforward... Also, it is nice that the firmware just does what the command tells it to do, without performing additional steps behind the user's back. Sure you have to know more what you do, but at least it allows you to do what you want.
But when would you ever want to set Z=0 with mesh compensation active since it doesn't accomplish anything useful?
As it is you need to remember/know to use G92 S2 before G30 for it to work right.
And as we see that need can cause problems.
Frederick
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Or you can just include a M561 in your homez.g and homeall.g files before your G30 ever gets called. This wipes out anything a G29 may have set.
Personally, I like the fact the machine doesn't make assumptions in the firmware. Assuming to ignore the G29 could be bad for certain applications but good for others. Making the user use the available Gcode commands to wipe or remember settings is a positive and makes RepRapFirmware very flexible for multiple platforms outside 3D printers.
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Can you provide an example of when executing a G30 when mesh compensation is active makes sense?
As pointed out the result is not meaningful.
Frederick
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A laser engraver would be one example where you might use G29 to measure your bed surface, and then perform a G30 to re-zero your Z axis against an object your going to engrave to set the proper z height for the correct focus length. You want the laser to move in a consistent plane, but will want a different Z position for laser focus against an object.
The same can be said for a 3D engraver or a small milling machines.
