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CoreXY sensorless homing Marlin

Posted by Dee_lay 
CoreXY sensorless homing Marlin
February 23, 2020 01:12PM
Hey, I have bulit a custom coreXY printer and the hardware is working fine so far, however I have a problem with homing. I have set up sensorless homing for X+Y. For the Z-axis I’m using a normal endstop. I can home all axes separately in Pronterface. Homing all axes simultaneously fails (motors won’t stop on XY). To avoid this issue I tried to set up G28 for each axis separately in Cura, however only X and Z axes home while the Y axis stays at its current position. I tried to put M400 in between but the problem remains. Has anyone experienced the same problem or has any idea how to fix this?
Thanks in advance
Re: CoreXY sensorless homing Marlin
February 24, 2020 01:23PM
Unfortunately, sensorless homing is not yet ready for prime time. There are too many variables that can affect the behavior.
Re: CoreXY sensorless homing Marlin
March 02, 2020 04:22PM

I got the same problem since I updated Marlin about a week ago. Before sensorless homing worked perfectly.
G28 X : works perfectly
G28 Y : works perfectly
G28 XY : does not work

I also have a CoreXY printer and am homing X and Y independently. (first X then Y). When doing a G28 XY the printer homes X and than tries to home Y, but stops immediately as if it would have hit the end already. It seems like the trigger from the successful X Bump is still active an is registered again for the Y homing routine.

Is there something wrong with my setup? I noticed that there were some code changes regarding the TMC Drivers. (in the Marlin code as well as in the TMC Sepper library) Could this be connected? Does the new code require a specific setting/config?

I am using TMC5160 driver boards on a SKR 1.3 board.

I am thankful for any help.
Re: CoreXY sensorless homing Marlin
March 06, 2020 10:51AM
I am using an SKR 1.3 too and 2130s from Watterott.
When homing XY both axes move at the same time and the motors won't stop after bumping into the frame.
Do you have the files from the version you were using before?
Re: CoreXY sensorless homing Marlin
March 06, 2020 06:01PM
When trying to home a CoreXY via sensorless homing you need to drive the axis individually as both XY motors are used for moving the carriage. So you first need to home one axis an "listen" for either motor stalling. Then you need to move the other one and also wait until either motor stalls. (Ideally they should stall at the same time)
So the QUICK_HOME option should be disabled. The print head has to move in the X and than the Y direction individually.
Edit: To be more clear: The print head must not move diagonally.

Unfortunately I updated my Marlin sources and i cannot simply go back. However I will try an older release of Marlin probably this weekend.

I also found some people on GitHub with the same issues: [github.com]

Edited 1 time(s). Last edit at 03/07/2020 03:43PM by Camaro.
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