Background:
I bought the Rambo dual endstop kit from V1, with firmware pre-flashed around december 2019. My MPCNC has been working well since then but recently I wanted to be able to save a setting to EEPROM, which I noticed was disabled in my firmware. I went on the github and noticed that Ryan made some updates to the dual endstop firmware in April. I figured it was worth updating, and the flashing process went smoothly.
The problem:
My issue now, since updating firmware, is that when I send the commands G28 X0 (home the X axis) or G28 Y0 (home Y axis) the Z axis always moves up (around 10mm or so) before executing the command. I’m very confused by this behavior, and it’s messing up my workflow.
To clarify, if I send G28 X0, I want only the X axis to move.
Has anyone else discovered this and/or does anyone have any ideas for a fix? I assume any recent dual-endstop Rambo builds would also be experiencing this behavior.
I am happy to edit the firmware files and re-flash if there are any ideas as to what lines to edit.
…SOLVED.
OK so it turns out that if I home the Z axis (using a touch plate) FIRST, then the machine no longer moves up in the Z axis prior to executing the G28 command. This is definitely different than the functionality of the previous firmware, but I’m fine homing the Z axis before the others, I’m just not sure why this happened… or why this fixed it.
I would just delete this post, but in case anyone else thinks they have run into a similar problem I figured I’d leave it up.
in configuration.h, there is Z_HOMING_HEIGHT which is intended to move away from the bed to clear any fixtures before homing. If this is not defined, which is how the github firmware currently has it, I believe it will use the Z_CLEARANCE_BETWEEN_PROBES distance instead (set to 5mm as a default). Setting one of these to 0 will prevent any raise. But it does come with the risk of dragging your bit across the surface of your workpiece.