I want to control respectively 4 motors already mapped to Z-axis

psyblue

Four motors are used on the z-axis. The bed is 1000mm by 500mm, 10mm thick aluminum, very rigid.

I'm struggling to automate bed leveling.

The procedure I want to try is :

Mapping 2 out of 4 motors as if they were one
Automatic 3 point bed leveling
Manually adjust gap where the bed is floating.

To do this, we need a method of bundling two motors and treating them as one motor.

PCR

you can easily map them.

for example

M569 P0 S0                                     ; physical drive 0 goes backwards
M569 P1 S0                                     ; physical drive 1 goes backwards
M569 P2 S1                                     ; physical drive 2 goes forwards
M569 P3 S1                                     ; physical drive 3 goes backwards
M569 P4 S1                                     ; physical drive 4 goes backwards
M569 P5 S1                                     ; physical drive 5 goes backwards
M569 P6 S1                                     ; physical drive 6 goes backwards
M584 X0 Y1 Z2:3:4:5 E6                               ; set drive mapping

In the M906 you need only one Z parameter

M906 X800 Y800 Z800 E1000 I50                  ; set motor currents (mA) and motor idle factor in per cent

After that you can use this wiki entry

https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors

psyblue

@PCR

Thank you for your reply.

I'm already doing it the same way you do, and I already know the wiki.

My question is some sloppy, so I want to change the question,

what if I want to control respectively the four motors already mapped to Z-axis?

3 Z-axis bed leveling is so simple, but leveling 4 Z-axis has many limitations with rigid not flat bed.

Veti

@psyblue

you could try assigning each of the z mother additional axis. to U, V, W, A and setting the P value so they are visible

then you can manually control them as well.

big but, it might be better if you convert one axis to just a support axis as 4 point bed levelling is problematic. see https://drmrehorst.blogspot.com/2017/07/3-point-print-bed-leveling-vs-4-point.html