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Z-Axis position zeros on reboot  

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Jbrizzy
(@jbrizzy)
Member
Z-Axis position zeros on reboot

After completing calibrations/tests and power cycling the Core One, I find that the z-axis will set a height of zero at whatever position the heatbed was when the power was turned off. If the heat bed was at its lowest position (276mm) when the power was turned off, it will be at 0 position when the printer is turned back on. X and Y positions are held in memory and do not have this problem.  Any way to resolve this issue and have z-axis position held in memory?

Posted : 23/11/2025 9:41 pm
miroslav.h4
(@miroslav-h4)
Prominent Member
RE: Z-Axis position zeros on reboot

You are wrong. None of the positions are stored in memory. Try a simple experiment: Set the XYZ axes to any values ​​in manual mode. Note them. Then turn the printer off and on again. Look again at the default values ​​for manual axis movement. And you will find the values ​​X=252, Y=-19 and Z=0 there, regardless of where the print head and bed are actually. That is why you need to do AutoHome after turning on the printer to reorient the printer in space.

Posted : 24/11/2025 9:53 am
hyiger
(@hyiger)
Noble Member
RE: Z-Axis position zeros on reboot

Another reason this is not done is that the motors are disengaged when the power is off. You can manually move the print head (and bed) manually anywhere. How is the printer then going to know where it is when you turn it back on?

 

Posted : 29/11/2025 12:18 am
SteinerPatrick
(@steinerpatrick)
Member
RE: Z-Axis position zeros on reboot

If autohome is required for every  powerup, I wonder if it is possible to include it in the boot up sequence?

Posted : 24/01/2026 2:22 am
hyiger
(@hyiger)
Noble Member
RE:

 

Posted by: @steinerpatrick

If autohome is required for every  powerup, I wonder if it is possible to include it in the boot up sequence?

There is really no point to do an auto home until the printer starts executing g-code or m-code commands. Also, g/m-code are interpreted by the firmware which means they can't be run until the firmware is loaded and executed by the boot loader. 

That said, I suppose it would be useful to have an optionally selectable X/Y/Z axis self test run at startup. Problem though is that if you forgot to remove a print then that could obviously cause a problem. 

Posted : 24/01/2026 4:09 pm
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