Maestro CR-10S Separated Z Axis & Endstops Question

PuterPro

I'm setting up my CR-10S with a Maestro and am running the Configurator but I see no place to specify a 2nd Z Endstop, and am a bit confused on the Z motor setup as well.

I've read all I can find on this subject but have just reached the "Eyes crossed" point you get from TOO much research, LOL.

So 1st Q - I have assumed {ahem} that it's preferable to add a second Endstop for the second Z motor, or is that just nuts?

Part of my logic is that the CR-10S has a problem of Axis shift where the right side sags when the steppers are released, causing in effect an "unlevel bed" when the X Axis rail sags a bit only on one end.
(Note I have addressed the mechanical alignments as much as this printer will allow, MANY hours spent, and it's accurate as heck when running)

I figure if the two sides are being driven separately, with seperate endstops, it will automatically be aligned when homed, fixing the problem. Am I just mad?

2nd Question - I see people have configured the second Z motor to work on E0 and the Extruder on E1.
Is there a reason for using that way I was defining the Extruder on E0 and the Z motor on E1.

3red Q - I also see people defining it as a new axis "U". Doesn't just assigning it as a second extruder in the RepRap Configurator with the proper values (same as Z drive) then plugging it in to E1 do the same thing?

Be gentle, I'm a n00b in the RepRap world ...

Phaedrux

Have you seen this? https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors

PuterPro

@phaedrux said in Maestro CR-10S Separated Z Axis & Endstops Question:

Have you seen this?

Of course, but thanks!
I read about every post I could find about the CR-10S and dual Z, but it doesn't handle my confusion points...

JamesM

If the maestro is similar to the duet wifi you don't need a second endstop or to map another stepper for the second z motor. I have an ender 3 and added a second z to it(one actually for the cr-10)..you just use the existing z endstop, plug the second stepper into the second z plug and they work synchronous. You just have to measure from the x-axis cross bar to the frame and turn the second leadscrew until the cross-beam is at the same height as the left side. Then re-level(tram) the bed and you're golden.

Phaedrux

@jamesm said in Maestro CR-10S Separated Z Axis & Endstops Question:

If the maestro is similar to the duet wifi you don't need a second endstop or to map another stepper for the second z motor. I have an ender 3 and added a second z to it(one actually for the cr-10)..you just use the existing z endstop, plug the second stepper into the second z plug and they work synchronous. You just have to measure from the x-axis cross bar to the frame and turn the second leadscrew until the cross-beam is at the same height as the left side. Then re-level(tram) the bed and you're golden.

Yes you can do it like that, but then you have to manually adjust the Z axis to keep it true, which is what he's trying to avoid.

@PuterPro I'll try to answer your questions then, and hopefully that will clear up what's in that article. Since it's describing exactly what you want to do.

Yes you need to add another endstop to make best use of independent leveling. You also need to have the second z motor on it's own driver. The Za and Zb connectors won't work for this. 1 motor will go to Za and the other motor to E1 and the endstops will go to Z and E1.
You can use either E1 or E0, it's totally up to you as long as you keep it consistent.
The way the leveling works, is that it splits to Z axis from being both motors controlled together into a Z and a U axis, which can then be homed independently to each endstop in turn. Then combined back to the Z axis for normal operation.

Re-read that article, and see what specific questions remain.

There's also this thread discussing the same thing going on might give you some insight: https://forum.duet3d.com/topic/8998/2-z-motors-to-endstops

dc42

Does the printer have a Z probe? If so then you can use just 1 endstop and use the Z probe to level the 2 motors. https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe#Section_Duet_2_WiFi_Ethernet_without_a_Duex_2_or_Duex_5_expansion_board

PuterPro

@JamesM - Thanks so much for your reply! I get what you're saying, I've lived with this sweet but annoying beast since Nov 2017 and as @Phaedrux says that's what I'm trying to avoid.

Having to level the X rail then re-level the bed every time you stop printing is like having to pump air into two tires everytime you want to drive somewhere! I've minimized it to a small amount mechanically, but it's a frame & wheels problem and I can't get it perfect.

Additionally, as I understand it, the Za & Zb setup you're using puts the motors in series not parallel as the CR-10S Melzi board does and that's not ideal for the NEMA 17 motors we're using, working better with larger motors like NEMA 23. But again, thanks for jumping in!!

@Phaedrux - Thanks for the simplification! OK, I re-read the article after reading more about M584 in the Duet3D Wiki G-Code section. I had read about it in the RepRap G-Code and there's a big difference in explanation levels. I also go a better understanding from a thread on "Incorrect Z microstepping" where @Surgikill was having CoreXY problems.

Makes sense now. Part of it was just brain overload trying to grasp everything I have to do to get this into my CR-10S, LOL.

Still have a confusion on this:

In the RRF Configuration Tool when I specify I want E1 to drive Zb, then move on to Endstops, there's no way to ADD the endstop for Zb. It only shows X,Y & Z. Do I have to define it manually in the config.g file after the RRF tool is done? No problem I think I can do that, but ...
Note - I do not currently have a probe. Plan on a BLTouch soon once the ~~Wife~~ Finance Committee recovers from all the other purchases

@dc42 - No probe yet, soon tho' Thx. And get some sleep, will ya. Even with the time difference to the East Coast US you're still working too late.