how can i move my z motors independently ?
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hi i wonder if i can with a G0 command move only one of my Z motor and not the other ?
i thought at first using the G0 H2 Z parameter but how can i specify z1 or z2 ??thanks
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@psychotik2k3 said in how can i move my z motors independently ?:
hi i wonder if i can with a G0 command move only one of my Z motor and not the other ?
i thought at first using the G0 H2 Z parameter but how can i specify z1 or z2 ??thanks
Why do you wish to do this? The "why" makes a difference in how it's done.
Thanks.
Frederick
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@fcwilt oh it's quite simple, sometimes when i remove parts form the bed (or other situation) my bed is not well aligned at all, and a call to the bed levelling fails because the difference between the 2 sides is more than 3mm.
i don't want to change this limit, what i want to do is create 2 macros one to raise 1mm left motor and one to lower 1mm left motor.
this way if the bed levelling tells me taht the left side is 5mm lower than right side i run 4 times my macro.right now i have to reset the printer (or disable stepper motors) push the gantry far left and raise by hand the bed up to the highest limit, then lower it 5cm so the head wont crash onto it when i'll do a homing or bed levelling.
thanks anyway
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If you equip each Z axis with it's own Z endstop sensor the firmware will move the Z steppers as needed to get both endstops triggered.
If the endstops are carefully positioned the bed will end up nearly level and you can then follow up with G32 to "fine tune" the bed leveling.
Here is a quick-and-dirty video of my 3 Z stepper printer with 3 Z endstops. I have intentionally put the bed very out of level to demonstrate.
If you don't wish add the endstop sensors you have to use M584 to change from Za:b to something like Za Wb which gives you access to the steppers as Z and W.
Then when done you need to use M584 to put back Za:b.
Frederick
Printers: a E3D MS/TC setup and a RatRig Hybrid. Using Duet 3 hardware running 3.4.6
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@psychotik2k3, had similar situation with my printer which had 2 Z motors and no z end stops, just a BL touch for homing and auto leveling.
I created a macro that reduces Z current and lower the bed by 100mm. Then I used to run that macro until it mechanically bottomed on both sides which was a good starting point for the auto bed leveling.
Never had a problem with it and the motors didn't need much current to lower the bed.
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@zapta yeah i could do that but right now below my bed there a lot of mess that i remove if i have to print tall objects
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@fcwilt said in how can i move my z motors independently ?:
If you don't wish add the endstop sensors you have to use M584 to change from Za:b to something like Za Wb which gives you access to the steppers as Z and W.
Then when done you need to use M584 to put back Za:b.thanks, didn't though about that changing the config to only one motor then put it back to 2.
i will try to do that... humm tomorow, coding at 1:30AM is usually not so good. -
@psychotik2k3 said in how can i move my z motors independently ?:
@fcwilt said in how can i move my z motors independently ?:
If you don't wish add the endstop sensors you have to use M584 to change from Za:b to something like Za Wb which gives you access to the steppers as Z and W.
Then when done you need to use M584 to put back Za:b.thanks, didn't though about that changing the config to only one motor then put it back to 2.
i will try to do that... humm tomorow, coding at 1:30AM is usually not so good.Give some thought to adding an endstop sensor to each Z axis. It will make the whole process of getting the bed back to nearly level simple and quick.
Frederick
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@psychotik2k3 An alternative approach is to modify your bed.g to have two stages. An initial stage probes the bed only along a short line between your two bed mount points/motor locations and allows for larger corrections than 3mm. The second stage uses your existing bed levelling points. The idea is to allow the initial correction to get the bed roughly level with no danger of crashing part of the hot end/probe into the bed if the bed is really at an angle. So basically you probe the bed at the centre to get a zero/home point then probe at two points either side of that towards your motors but not that far from the centre of the bed (so that movement of the head is still safe with a heavily skewed bed), this then provides a crude correction. Then rehome Z in the centre of the bed and continue with the more accurate (but smaller) bed correction taken at points near to your motor mounts.
I've been using something similar to this for a long time and it works very well for me, my bed has a habit of dropping a fair bit when the motors are not powered, but only on one side and this procedure handles this very well without manual intervention.
