Tevo Little Monster delta endstopless homing

DomMilan

Now it homes one axis every time I G28 but a different axis every time with a net downward movement still.

Phaedrux

Two things. First, I may have made an error by removing the H2 from the G1 command to lower the heads a bit. Second, we may be experiencing a limitation of RRF2 and stall detection homing.

https://duet3d.dozuki.com/Wiki/Gcode#Section_M574_RepRapFirmware_Num_3

Ok I think we've encountered the limitation of RRF2 and stall detection. As soon as one endstop is triggered, movement stops for all axis.

You would need to use RRF3 to use multiple motor stall detection (M574 S4). See the link.

Snnn 1 = switch-type (eg microswitch) endstop input, 2 = Z probe (when used to home an axis other than Z), 3 = single motor load detection, 4 = multiple motor load detection (see Notes).

However, updating to RRF3 would take some effort on it's own since the config.g would need to be recreated with the web configurator or manually updated.

If you're not up to that, I think we could get around this limitation by homing each axis with an individual move. This gets a little tricky with a delta though because of the way the axis are linked. But if they started in a semi safe spot you should be able to home each tower individually.

So first, try this.

M400 ; make sure everything has stopped before we make changes
M915 P0:1:2 S2 F0 H200 R0
M574 X2 Y2 Z2 S3 ; set endstops to use motor stall
M913 X55 Y55 Z55 ; reduce motor current to 50% to prevent belts slipping
G91 ; relative positioning
G1 H1 X705 Y705 Z705 F4000 ; move all towers to the high end stopping at the endstops (first pass)
G1 H2 X-50 Y-50 Z-50 F7200 ; go down a few mm
G90 ; absolute positioning
G1 X0 Y0 F7200 ; move X+Y to the centre
M400 ; make sure everything has stopped before we reset the motor currents
M913 X100 Y100 Z100 ; motor currents back to normal

If that doesn't work, try this

M400 ; make sure everything has stopped before we make changes
M915 P0:1:2 S2 F0 H200 R0
M574 X2 Y2 Z2 S3 ; set endstops to use motor stall
M913 X55 Y55 Z55 ; reduce motor current to 50% to prevent belts slipping
G91 ; relative positioning
G1 H1 X705 F4000 ; move X tower
G1 H1 Y705 F4000 ; move Y tower
G1 H1 Z705 F4000 ; move Z tower
G1 H2 X-50 Y-50 Z-50 F7200 ; go down a few mm
G90 ; absolute positioning
M400 ; make sure everything has stopped before we reset the motor currents
M913 X100 Y100 Z100 ; motor currents back to normal

Also before running those try and get the carriages to be more or less even.

DomMilan

@Phaedrux Thank you for all your help on this. I bought the endstop and its coming in a few days so no need to waste both our time on this. Sorry for the inconvenience.

Phaedrux

Awww I was eager to see if that last one would work.