Z Axis not moving during print April 07, 2016 02:01PM |
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Re: Z Axis not moving during print April 08, 2016 07:17AM |
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Re: Z Axis not moving during print April 08, 2016 08:00AM |
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Re: Z Axis not moving during print April 08, 2016 08:26AM |
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Re: Z Axis not moving during print April 08, 2016 09:27AM |
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Re: Z Axis not moving during print April 08, 2016 09:42AM |
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Re: Z Axis not moving during print April 08, 2016 10:18AM |
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Re: Z Axis not moving during print April 08, 2016 01:45PM |
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Re: Z Axis not moving during print April 08, 2016 02:23PM |
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Re: Z Axis not moving during print April 08, 2016 07:01PM |
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White.Renard
I don't have access to an Oscilloscope unfortunately... They're pricey!
And I don't think my multimeter has frequency or duty cycle modes. How would I do it with a an LED?
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Well I mesearued the Vref on the drivers and for X and Y axis, they are 0.06 and for Z axis I've set it to 0.11. The motors don't get hot at all, just a little warm.
These motors are hacked to be bipolar, using this guide: http://www.electronicsmayhem.com/?p=13
The resistance is doubled after doing this.
Both of my Z motors are connected directly to Ramps, this would be parallel, right?
Re: Z Axis not moving during print April 09, 2016 06:50AM |
Registered: 8 years ago Posts: 22 |
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JamesK
For checking voltage output from an IO pin you could just use a LED in series with a 1k resistor - that would draw about 4mA and should be visible, and the IO pins should supply that easily. Connect the negative side of the probe to the supply 0 and solder some sort of mostly insulated probe pin to the positive side of the LED (a piece of solid core wire would do). Then carefully hold the pin to the enable, dir and step pins in turn and see if there are signs of life. You can compare with the x or y axis to check what it looks like when things are working, but I would expect the enable pin to be on all the time, the dir pin may or may not be on depending on which way the motor turns and the step pin should flash (but probably too fast to see, may just look dimmer than solid on) when moving.
What voltage power supply are you using? You can probably use the same 1k resistor for a 12v setup, the led will just be brighter. To check for output from the stepper driver you would connect the probe across each of the motor output pairs. I don't know which will be positive and which negative, so you'd either have to try it both ways or solder a second led back to back with the first one so that one or the other always lights up.
Be careful not to accidentally disconnect the motor, the stepper drivers can be damaged if disconnected while powered up. It may be tricky to find a good place to connect the probe to to test this, it's not something I've tried. You don't want to short anything out either.
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JamesK
Yes, the Z driver on the ramps has the two sets of output connectors in parallel, so you set the Vref to deliver 2x the current of a single motor. If the motors are only just warm you can probably afford to increase the Vref a little. The motors will survive being quite warm, but not burning hot. 40C or so should be ok.
Re: Z Axis not moving during print April 09, 2016 08:17AM |
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Re: Z Axis not moving during print April 09, 2016 09:29AM |
Registered: 8 years ago Posts: 22 |
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JamesK
Sorry, I should have been more clear. I just meant the 0V or sometimes marked as -V side of the supply. You can connect to it anywhere that's convenient, but it's often easiest if there's a spare connector at the power supply to wire the probe in there so you don't have to try and hold two connections in place by hand. You want to be able to concentrate on the + side of the probe and not worry about the other end.
Yes, whining stepper motors tends to be normal. It can be quite amusing if you have any musical tendencies - I often hear melodies as my printer does it's thing
What sort of stepper drivers are you using?
Re: Z Axis not moving during print April 09, 2016 09:45AM |
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Re: Z Axis not moving during print April 09, 2016 10:30AM |
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Re: Z Axis not moving during print April 09, 2016 10:40AM |
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Re: Z Axis not moving during print April 09, 2016 10:57AM |
Registered: 8 years ago Posts: 22 |
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JamesK
Now to check for output from the driver to the motor. My first thought was to connect the probe between pairs of output pins from the driver, but I guess you could keep the -ve side of the probe connected to 0V and work your way along the 4 pins in turn. All you're looking for is some sign of changing output when the Z axis should be moving and isn't, so any one pin is probably enough.
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JamesK
OK, that all sounds good for signals getting through. You took the 1/2 step setting into account when you calculated the steps/mm for Z? As long as it matches up ok 1/2 step should be fine, if a bit noisy.
Re: Z Axis not moving during print April 09, 2016 01:39PM |
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Re: Z Axis not moving during print April 09, 2016 03:15PM |
Registered: 8 years ago Posts: 22 |
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JamesK
Yes, those are the pins. So I think you've proved that everything is working like it's supposed to in terms of getting signals from the controller to the motor, but for some reason the motor decides it doesn't want to play, but only sometimes. I think that takes us to the speed, acceleration and jerk settings. Try setting the Z jerk to 0, and the Z accel to 0.1 and see if it makes any difference. And bump up the current to the definitely warm but not burning hot level, even if it's noisy
Re: Z Axis not moving during print April 09, 2016 05:14PM |
Registered: 9 years ago Posts: 1,873 |