[BUG] After completing Home of all three axis, the Z axis rises up about 10mm

[dmarnel]

Did you test the latest bugfix-2.1.x code?

Yes, and the problem still exists.

Bug Description

Not sure when this started happening, but after pressing Home on my Ender 3 Pro, and after all three axis have finished homing, the Z position of the print head rises up about 10mm and stops there.

If I uncomment Z_AFTER_HOMING in Configuration.h, and set it to zero, the Z axis no longer rises up after homing is completed.

Bug Timeline

Unsure

Expected behavior

I expect all three axis to remain in the "home" position after selecting the Home option from the printer display.

Actual behavior

The Z axis moves up about 10mm and remains there.

Steps to Reproduce

1. Press the Home button
2. Wait for all three axis to finish homing
3. Z axis moves up about 10mm

Version of Marlin Firmware

bugfix-2.1.x

Printer model

Creality Ender 3 Pro

Electronics

BTT SKR MINI E3 V2.0

LCD/Controller

BTT TFT35-E3 V3.0

Other add-ons

Raspberry Pi connected through USB port for WiFi & Octoprint

Bed Leveling

None

Your Slicer

Simplify3D

Host Software

OctoPrint

Don't forget to include

• A ZIP file containing your Configuration.h and Configuration_adv.h.

Additional information & file uploads

configs.zip

[ellensp]

I read this backwards

this is happening with Z_AFTER_HOMING disabled

[thisiskeithb]

Z_AFTER_HOMING is set as follows:

Marlin/Marlin/src/module/motion.h

Lines 417 to 421 in 06762db

	#ifdef Z_AFTER_HOMING
	#define Z_POST_CLEARANCE Z_AFTER_HOMING
	#else
	#define Z_POST_CLEARANCE Z_CLEARANCE_FOR_HOMING
	#endif

Since Z_AFTER_HOMING is not defined, it'll set Z_POST_CLEARANCE to Z_CLEARANCE_FOR_HOMING.

You have disabled Z_CLEARANCE_FOR_HOMING and Z_CLEARANCE_BETWEEN_PROBES is set to 5 in your config, so Z_CLEARANCE_FOR_HOMING it set to 5 (Z_CLEARANCE_BETWEEN_PROBES):

Marlin/Marlin/src/inc/Conditionals_post.h

Lines 3215 to 3221 in 06762db

	#ifndef Z_CLEARANCE_FOR_HOMING
	#ifdef Z_CLEARANCE_BETWEEN_PROBES
	#define Z_CLEARANCE_FOR_HOMING Z_CLEARANCE_BETWEEN_PROBES
	#else
	#define Z_CLEARANCE_FOR_HOMING 0
	#endif
	#endif

Z should raise by 5, not 10.

If you don't want Z to raise after homing, enable Z_AFTER_HOMING and set it to 0 instead of disabling it.

[dmarnel]

Which is exactly what I said I had to do to keep it from raising the Z axis. BTW, I haven't disabled/commented out anything having to do with homing, that is how it was set when I pulled the new changes It's been about a year since I've messed with the code. Regardless, it doesn't make sense to have to uncomment/change something to keep the axis in the home position. Maybe Z_AFTER_HOMING should be uncommented and set to zero as a default setting?