Duel Z movement weirdness
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I am building a hypercube evolution and just got to the z motors connected. I attempted to run a test of the z homing but it is moving very oddly and causing binding. In the attached video you can see the left side move down, then the right side and then the left moves back up causing the whole thing to bind. I have both motors connected to the standard z connectors on the board. I can move it freely by manually rotating the leadscrews and moves without issue if I remove the leadscrews. Any ideas?
https://www.dropbox.com/s/grhnbq6od0042mv/VID_20190826_183700[1].mp4?dl=0
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It looks like binding to me.
Can you post your config file?
What commands are you sending to try and move it?
Have you tried leveling each side manually first to get it close? -
The binding is coming from the weird movement. Why is the left side, moving back up? The axis in the video is level. It's raised as high as it can go and is leveled. Config file is attached. I am using standard G28 Z to do the z homing
[0_1566867261162_config.json](Uploading 100%)
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Try uploading the config.g file instead. Or copy and paste it's contents.
It's possible that the movement speed or acceleration is too high or the motor currents too low.
Are the lead screws lubricated?
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COnfig.g is attached. I haven't lubricated them myself but I can also move it without any resistance manually.
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If you test each motor when connected individually do they turn in the same direction?
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Well it's stopped working all together now. I just get a motor phase may be disconnected message every time I try
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Double check the phases of your wiring. Test one motor at a time.
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What is the max rated current for the motors?
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I'm unsure of the current limit. They are generic nema 17 motors so I would assume the usual 1.5-1.8. It's curious that is started so suddenly with both motors on bot connections.
Edit: I was able to track down my order(I bought the parts over a year ago). These motors were both from Abycubic and were purchased at the same time but appear to have different pinouts.
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The z connectors are wired in series to a single connector.
You may be able to find a label for model number on the motor itself. Googling it may turn up a special sheet to find the max current. Then you can set the current for the z axis in config.g to be about 70-85% of that rated max.
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@agentnoise said in Duel Z movement weirdness:
I'm unsure of the current limit. They are generic nema 17 motors so I would assume the usual 1.5-1.8
measure the resistance of each phase. then look up similar stepper motors with resistance in that range.
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I think I'm losing my mind. Today, the motor that was working, doesn't. I didn't unplug it or swap cables but it's back to getting the error message that the motor phase a and b may be disconnected. I have tried every possible wiring combonation and I get the same error no matter what. I've tested 3 different motors, same results.
How can I tell which pin is ground and what is voltage? I used a multi-meter to find the pins on the same coils
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Can you test each motor on a different driver? And test a working motor on the z driver to see if the problem is with the driver or the motor.
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I've tested 3 motors on all the drivers. The only results I can get are a a brief stuttering of movement and then a short to ground message or the same Phase A and B might bot be connected message
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If you have a multi meter, measures resistance between the motor phases. On your motor 2 and 2 phases should have similar resistance (probably around 0.9 to 1.5ohm) but from one phase to the other there should be really high resistance (mega ohms).
Once you have identified the phases, connecting them should be straight forward.One way to rule out any mechanical problems is disassemble the motors from the printer and just have a piece of tape on the motor shaft and test if everything moves the correct direction(remember to never connect or disconnect a motor when the driver has power).
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I figured this out. It was just the weird motor wiring not being the same on both motors so they weren't moving in the correct directions.
Now the Z axis is moving way to much. 10mm is closer to 100. I set the steps per mm to 13 just for kicks but it didn't seem to change anything. I have the z homing at the high end but can only move it down 30mm despite my size being 300mm.
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@agentnoise said in Duel Z movement weirdness:
I set the steps per mm to 13 just for kicks but it didn't seem to change anything...................
Assuming you are using 1.8 degree motors which have 200 full steps per revolution and you are using the default micro-stepping of 16X, then setting the steps per mm to 13 means that 1 revolution of the motor would equate to 246mm of linear motion. Again, assuming that the motor directly drives the screw without any gearing, this would imply that you have screws with a lead of 246mm. If they happen to be single start screws, then the pitch will also be 246mm. I somehow doubt that is correct which explains your problem.
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@deckingman Thanks, I'll try that. I attempted 400 steps per mm. It was default set to 4000
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@agentnoise Do the maths. It's easier than guessing. One turn of a motor is 200 full steps assuming it's a 1.8 degree motor. So that's 3200 steps per revolution at default 16x micro stepping. Divide that by how far a nut attached to the screw will travel in 1 revolution (the lead) and you have the steps per mm.
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Does the interpolation to X256 micro-stepping come into play in this calculation? The default 4000 steps per mm was moving too far as well.
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@agentnoise No it does not...you set the steps based on the x16 microsteps if that is how you have your config set up....the interpolation is done by the stepper driver.
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OK I see what I was doing wrong I was setting the steps per mm in the config.json only but I needed to update it in the config.g too. That's why none of my changes were making a difference
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The .JSON file is for the configurator only if you want to re import your config into it again to make some changes.
The typical way of doing things is to edit config.g directly.
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Also worth noting, after you edit the config.json file to make changes manually it may not be imported properly in the online configuration tool. I.e. if you can't change it online, odds are it won't import either.
