Dual Z Motors on Bigbox - Sanity Check
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Andyvirus,
wouldn't you want the two Z motor to actually not operate independently? How would you create a levelling bed with just 2 point adjustment?
Stephen
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the bed is on 4 rods, the z motors are center left and right of the bed (Bed is 300x200, lead screws are adjacent to X150 Y100 either side of the bed). It would level left to right. Yes front to back would still need manual adjustment if that went out of alignment but for me that rarely happens, what does happen is i wipe the bed down and if the motors have no holding current one side goes marginally out. This would fix this.
tested the above and it works a treat. never had the left and right side in such perfect alignment
My question about M569 and M906 (motor direction and voltages) is my only real question now… it seems to work fine but just want confirmation. Also speed and steps M201 and M203 and I guess M566? Do i need to reference the aditional driver at all and if so, how. If not, please could i have confirmation as i dont want Z1 all set correctly and Z2 out of step speed, voltage etc wise.
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M569 commands apply to individual motor drivers. If there is no M569 command for a driver, it defaults to forward motion and standard timing. So I guess the way you have wired the motor, forward motion is correct.
Your M906 command should come after the M584 command, then the Z current parameter will be applied to both Z motors. Your M201/203/566 etc. commands need to take account of the U axis you created, but not additional Z motors.
HTH David
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Thanks! So far all working great. Quieter Z movements too as an unexpected side effect. Happy customer
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Thanks! So far all working great. Quieter Z movements too as an unexpected side effect. Happy customer
I'm glad you're happy. You might care to share your experience on the E3D BigBox forum, because I don't think I've read of anyone else driving the two Z motors in a BigBox independently.
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Well, I've had that for some months now
Thanks to your help David 
But with the help of two extra endstops at Z max.Andyvirus, what fw are you on? I just upgraded to 1.19.2 today and have not looked at the new multi Z leveling yet.
You can read abut my setup with 1.18.1 and two endstops here: https://forum.e3d-online.com/index.php?threads/bigbox-dual-optical-z-max-endstops.2675/
I also hope to test dual Z leveling soon with the IR probe.
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Hi DC42, will do! Just upgraded to a MGN12 Rail for IDEX so will bring it up there too.
I have just found an odd issue with G32 though that you might be able to help with:In my bed.g i have:
[c]G30 P0 X20 Y100 Z-99999 ; probe near a leadscrew was x32
G30 P1 X270 Y100 Z-99999 S2 ; probe near a leadscrew and calibrate 2 motors[/c]and in config.g: [c]G31 X-33 Y-5 Z0.58 ; Set Z probe trigger value, offset and trigger height (IR Probe)[/c]
It seems that on the first probe it takes into account the z prob offset i set in G31 (Z-33) - Great
On the second probe it tries to move to 33mm more to the right than is possible. For now i have set the second probe (right) to 237 to compensate.Maybe I am using G31 wrong but seems to work perfectly in G29 (respects limits minima and maxima).
I have an IR sensor on X carriage which is 33mm to the left of the nozel (now, was at rear 60mm Y).Hi Strips, I am on 1.19.2. I will take a look at what you have done!
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You should only put G30 XY coordinates in bed.g that the probe (not the nozzle) can reach.
With an X offset of -33 in the G31 command, the head will be moved to the X offset you want to probe minus the -33mm; in other words to the X you asked to probe plus 33mm. So when you asked it to probe at X=270mm, it tried to move the head to X=303mm.
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You should only put G30 XY coordinates in bed.g that the probe (not the nozzle) can reach.
With an X offset of -33 in the G31 command, the head will be moved to the X offset you want to probe minus the -33mm; in other words to the X you asked to probe plus 33mm. So when you asked it to probe at X=270mm, it tried to move the head to X=303mm.
Ok makes sense. Probe not Nozzle. Got it. Thats what i was mistaking. Thanks!
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Thanks! So far all working great. Quieter Z movements too as an unexpected side effect. Happy customer
I'm glad you're happy. You might care to share your experience on the E3D BigBox forum, because I don't think I've read of anyone else driving the two Z motors in a BigBox independently.
Done. Quoted you post on the E3D BigBox forum anouncing the leveling fearture using 2 or more motors.
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How well does the true leveling work? I have a bed with 3x linear MGN12 rails in a triangle driven by 3x 1204 ballscrews. I’m afraid of movement when it’s powered down and then binding before it gets to auto level. Is this a true problem or should I just give it a go? Need a deux5 card to make it happen so don’t want to dive in just to fail ^^
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You can configure a maximum amount of individual leadscrew adjustment to apply in the M671 S parameter, to avoid binding. No adjustment will be performed if the adjustment to any leadscrew would exceed that limit.
You can test how well it would work before you buy a DueX by using the manual bed levelling assistant, which uses the same code. See https://duet3d.com/wiki/Using_the_manual_bed_levelling_assistant.
