Stepper won't go in consistent direction

tioJim
Posts: 135
Joined: Sun Apr 22, 2012 11:31 am

Stepper won't go in consistent direction

Post by tioJim » Sun Aug 12, 2012 6:45 pm

Is it possible for the steppers to get confused about direction as well as stall?

I can get a single isolated stepper to turn in either direction but there's no rhyme or reason to it

Assuming X=0

Send X10

Clockwise

Send X15

Clockwise

Send X0

Anti-clockwise

Send X100

Clockwise

Send X50

Wham! It just went clockwise it should have gone anti-clockwise no?

Let's continue

Send X0

Clockwise

Send X-100

Anti-clockwise

Send X0

Anti-clockwise ...

What settings are related to this direction problem? It does judder before it starts turning ...

jchen
Posts: 6
Joined: Tue Sep 04, 2012 3:30 am

Re: Stepper won't go in consistent direction

Post by jchen » Tue Sep 04, 2012 3:45 am

I just assembled my Inventables batch #2 ShapeOko (serial# 583), and am having the same issue, but at the Z-axis stepper motor. I am using manual control in the Universal Gcode Sender running on a Linux laptop. X and Y manual control functions normally, but Z control seems to randomly go in different directions even though I am just pressing the "Z+" button. Could it be that I got a bad grblShield?

Colecago
Posts: 136
Joined: Fri Jun 08, 2012 5:31 pm

Re: Stepper won't go in consistent direction

Post by Colecago » Tue Sep 04, 2012 12:20 pm

I assume its in absolute positioning mode so you are telling it to go to z50, it does clockwise lets say, then you say z25, it returns to z25, it doesn't go another 25 clockwise.

As for the second poster, not sure why z+ would make it change direction unless it wasn't keeping track of its position in the sender correctly.

Will Winder
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Re: Stepper won't go in consistent direction

Post by Will Winder » Tue Sep 04, 2012 12:52 pm

Colecago wrote:As for the second poster, not sure why z+ would make it change direction unless it wasn't keeping track of its position in the sender correctly.
The sender should work fine on linux, especially since the X/Y are working.

Double check your wiring for the Z-Axis motor, with micro-stepping enabled and a mis-wired stepper you could see erratic movement.
ShapeOko #367: Dual-Y drive, Belt on outside, 1000mm Y-Axis, DW660 Spindle, Nema-23 X/Y motors.

Primary developer on Universal Gcode Sender.

jchen
Posts: 6
Joined: Tue Sep 04, 2012 3:30 am

Re: Stepper won't go in consistent direction

Post by jchen » Tue Sep 04, 2012 6:00 pm

Thanks Will,

I will double check that this weekend since I am out of town for the rest off this week. Is it a forgone conclosion that if the stepper motors moves at all via gcode sender, that the grblShield is working properly and I just have it wired incorrectly somewhere? Just want to get a sense of what I am dealing with when I am going back to troubleshoot it.

Thanks again,
John.

Will Winder
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Location: Hudson, MA
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Re: Stepper won't go in consistent direction

Post by Will Winder » Tue Sep 04, 2012 6:09 pm

You could also swap the Z-Axis with the X or Y. That way you can test if there is a problem with the driver or the wiring.

So if you swap Z and X, (1) use the Z buttons to move the X which will verify that the Z driver is working then (2) use the X buttons to see if the Z axis moves to verify if the Z wiring works.
ShapeOko #367: Dual-Y drive, Belt on outside, 1000mm Y-Axis, DW660 Spindle, Nema-23 X/Y motors.

Primary developer on Universal Gcode Sender.

jchen
Posts: 6
Joined: Tue Sep 04, 2012 3:30 am

Re: Stepper won't go in consistent direction

Post by jchen » Wed Sep 05, 2012 4:47 am

Thanks again Will for your troubleshooting tips. I will give it another try this weekend and report back. - John.

jchen
Posts: 6
Joined: Tue Sep 04, 2012 3:30 am

Re: Stepper won't go in consistent direction

Post by jchen » Sat Sep 08, 2012 11:07 pm

Hi Will,

I finally got to troubleshoot this again. I first swap the X and Z axis cables from the motor to the terminal block and the Z axis behaved correctly going in the correct direction as set by the either the "X+" or "X-" manual control buttons (but very slowly since it is now turning a screw as suppose to a belt), while now the X axis goes in random directions when pressing the "Z+" and "Z-" buttons (going very fast). I then swap the X and Z axis cables at the grblShield terminals and now the X and Z axis behaves as when I first started (X and Y manual control operates normally, but Z control goes in random direction.) Is there anything else I can try to fix this?

Thanks for helping out,
John.

jchen
Posts: 6
Joined: Tue Sep 04, 2012 3:30 am

Re: Stepper won't go in consistent direction

Post by jchen » Sun Sep 23, 2012 2:30 am

Can anyone help? Should I just buy a replacement grblShield?

Thanks,
John.

cvoinescu
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Re: Stepper won't go in consistent direction

Post by cvoinescu » Sun Sep 23, 2012 10:42 am

So you know it's not the GRBLShield, because all three of its channels work correctly when fed the X and Y signals, but any axis works incorrectly when fed the Z signals. So I would say it's whatever you have upstream of the GRBLShield. I would check the wiring and continuity of the Z direction pin.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

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