4x Z motors moving different amounts for one Z command

michaelr123

Problem is that I’ve got 4x motors on the x and y for an awd setup. I don’t want to run into the same issue on my gentry system either.

Here’s an idea, what if I do 2x X motors on the 6HC and 2x Y motors on the 3HC? Then keep all the z motors together on the 6HC?

Any body that’s done an AWD setup have any input here?

jay_s_uk

@michaelr123 that's what I said. Move either the X or Y to the 3HC.
I've done 4WD but I was running a board with 8 driver sockets and only needed 1 z

michaelr123

@jay_s_uk

Seems to be working well now, thanks for the recommendation!

Unfortunately, sensorless homing isn't working now. I can home to Y no problem, but when I home to X it will not trigger as an endstop. If I turn on R1 parameter it's definitely reading that motors are stalling. Is there any chance I have the X and Y motors flipped and backwards or something like that and the sensorless endstop is looking for stalls on the wrong motors? Or does S4 on a corexy look at all the X and Y motors?

; Endstops
M574 X1 S4 ; setting up sensorless homing
M574 Y1 S4 ; setting up sensorless homing
M915 X Y R0 F0 S3

Phaedrux

Firmware version?
Can you post your full config and homing file?

michaelr123

@Phaedrux

3.4.6 all the way through.

Yep can do:

homey.g homex.g config.g

jay_s_uk

@michaelr123 I don't think sensor less works with expansion boards yet
https://docs.duet3d.com/en/User_manual/RepRapFirmware/CAN_limitations#temporary-limitations

michaelr123

@jay_s_uk

ahhh that's definitely what it is. So the motors on the expansion board aren't being red as an endstop... Any chance 3.5 is adding that feature?

Might have to using one wire on the gantry for endstops after all...

jay_s_uk

@michaelr123 looks like it's planned for 3.6

michaelr123

@jay_s_uk

Gotcha,

I tried moving 2 z motors back to the HC3 so I could get the 4 XY motors on the 6HC. Sensorless homing works great and after power cycling the board I'm not getting the weird behavior where one set of of Z motors moves at a different rate than the other two. It's definitely something going on over the CAN connection as I saw 2 motors display the weird behavior instead of just the one.

I'll keep running it this way so I can avoid the extra wire

michaelr123

@jay_s_uk

Update on this, it seems like anytime you change config code that affects the endstops or the drive mapping you get this weird behavior when you just run the config file. If you completely reset the board or power cycle it everything behaves just fine.

Long story short you can run 4x Z motors split across a can connection, but you need to fully power cycle between config updates.

gloomyandy

@michaelr123 Remember that running config.g does not reset things back to the default state before you run it. So anything that you do not explicitly set in the config.g will just keep whatever setting it may have had before you ran the config.g. Some commands may also not execute correctly (for instance if you had already assigned a pin in the old config.g, it may not be free if you try to use it for some other purpose in the new config.g). Personally I always reset things when making changes to config.g, just to be sure.