M584 doesn't allow multiple steppers on the same E axis?

Kiolia

I'm working on a two-stepper extruder (yes, it's extreme, yes, that's the point, and yes, it works) and I just realized after some struggles that only one of the steppers is being driven while the other sits idle. They are connected to separate drivers on a 3HC toolboard. I'm concerned that the M584 command is interpreting my attempt to assign two steppers to one E axis as instead creating two separate extruders. Here's the relevant part of my config:

; Drives
M569 P0.0 S1                                 ; physical drive 0.0 goes forwards
M569 P0.1 S1                                 ; physical drive 0.1 goes forwards
M569 P0.2 S1                                 ; physical drive 0.2 goes forwards
M569 P0.3 S1                                 ; physical drive 0.3 goes forwards ; Z upper
M569 P0.4 S1                                 ; physical drive 0.4 goes forwards ; Y upper
M569 P0.5 S1                                 ; physical drive 0.5 goes forwards ; X upper
; M569 P1.0 S1                                 ; physical drive 1.0 goes forwards (LGX) (remapped from 3 to make wiring easier)(moved to toolboard 0)
M569 P1.1 S0                                 ; physical drive 1.1 goes backwards (BoomBox A)
M569 P1.2 S0                                 ; physical drive 1.2 goes backwards (BoomBox B)
M584 X0.0:0.5 Y0.1:0.4 Z0.2:0.3 E1.1:1.2         ; set drive mapping

It does print as-is but -- as you might imagine -- the performance is somewhat limited without both motors running.

Is there a way to do what I'm trying to do without resorting to a workaround like setting this up as two mixing extruders running at 100%?

EDIT: A mixing setup does work to drive both steppers.

Phaedrux

Set them up as mixing, it's not a work around, it's exactly what you want.

Kiolia

@Phaedrux Thank you for the reply. As long as it works, I suppose that's all right! And it does. Whew! I went through a lot of effort and couldn't figure out where all the power was going. Dragging along an idle stepper explains a lot. It's more than 3x faster now

T3P3Tony

@Kiolia Glad its working. In advantage of having them setup as mixing is you adjust the mixing ratios if needed to balance the extruders (unless they are truly identical and seeing identical loads)