Stepper Motor Twitching

Hi,
I got some Problems running my Stepper Motor. So far neither Forum nor IRC-Channel could help.
So I'll try to recap what the symptoms are and I've already tried.

First the setup:
* RepRap Mendel
* Gen3 Techzone Remix Electronics running FiveD Firmware 20100806
* 4th Stepper Driverhooked up to SDA/SCL on Mainboard and shares power lines with extruder board.
* Stepper Driver Pin 5 hooked to Gnd on Pin 10.
* Stepper Driver Pin 3/4 to mainboard Step/Dir
(like described here: [www.reprap.org])

The Problem is, that the stepper doesn't run. Instead it twitches back and forth.

Already tried:
- connecting the stepper driver to Z-axis of mainboard to verify it's functionality (ran smooth)
- connecting the stepper motor to the Z-axis stepper driver board (also smooth)
- connecting enable to powersource Gnd (didn't do anything)
- connecting Dir to GND (didn't do anything)
- measure the resistance of the Ground pins like described here [http://reprap.org/wiki/File:Tech_zone_remix_ground.jpg] (all under 0.3Ohm)
- running via RepRap Host, Repsnapper (no difference, except startup waittime)
- running on different speeds in repsnapper, 0-9999 in increments of 500 (didn't do anything)
- recompiling Mainboard Firmware to use 40 steps per mm instead of the default of 2.2 (only twitched faster)
- pinged wiring between mainboard and stepper board (all fine)
- connected a LED on Step and Gnd to see the pulses (saw the pulses in slow speed, also moving the led showed blinking in higher speeds)
- turning the pot on the board (only changes the intensity of the twitching)
- connecting an working axis controller to SDL/SCL (strangely didn't do anything, the motor didn't even energize)

There were some ideas about the header being the wrong way around on the driver board, but thats not possible after I verified that it runs on Z-axis.

ok I think that was all. If I had forgotten anything I will edit it later.
Sure hope somebody can show me how stupid I am for doing it wrong...

Wanna print so badly after 9 months...

Edited 3 time(s). Last edit at 09/22/2010 05:08PM by mostley.

Maybe the current it too high on the motors? My RAMPS setup twitches when the current is too high.

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-Steve

Well turning the pot on the board only changes the intensity of the twitching, so if there's no other way to do that I think thats not it :/

Steppers twitch if one coil is not connected, or one half of the driver is fried, or if they are wired incorrectly. Try connecting only two of the wires. You can probably do that by shifting the connector along two places. It should then twitch. Then try just the other two. If one of the combinations does nothing then one half of the driver is duff.

Make sure you don't plug or unplug with the power on as that will blow the driver.

---

[www.hydraraptor.blogspot.com]

Well like I said I think the wiring is correct because the motor turns if connected to the main board as an axis.
I just switched the SDA/SCL -> 10pin-header connection to z-axis -> 10pin-header and it ran perfectly. So I figured its neither the wiring nor the motor, right?

just remembered I also already tried to connect an axis controller to SDA/SCL but strangely didn't do anything, the motor didn't even energize.

I think I could do a live stream while in IRC or something perhaps some visuals could help?

The motor will only energise when you connect the enable signal to ground.

The problem could be a bad ground, 0.3R is way to high. You need a solid ground between between the stepper board and the mother board as well as SCL and SDA.

---

[www.hydraraptor.blogspot.com]

I think 0.3 is the measurement failure of my multimeter....but will check that tomorrow again.

oh another thing I saw is whatever I set in repsnapper, reverse or normal Direction always is the same. The exact number I will test again tomorrow too.

Thanks so far for the new input.

sure sounds like a poor ground connection to me.. the logic can't tell the difference between a poor ground connection and your signals bouncing all over the place, and if it looks like the signals are bouncing all over the place, twitching is what you will see.

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-----------------------------------------------
Wooden Mendel
Teacup Firmware

so, I should try and connect any ground connection on the stepper board and the mainbaord with the ground from the power source? Or are there some ground connections better suited for this task?

So, I connected one Mainboard pin, one pin on the stepper driver board and the stepper driver enable directly to gnd on the power source.
It doesn't change the behaviour at all.

I think that the 0.3R is just my crappy multimeter.

I have the exact same issue.

Hi,

In my Gen3 electronics the analog ground and digital ground was not connected and that caused the problem.

[grrf.de]

br
Gerald

Just solved my issue. The gen 3 remix motherboard is powered via usb. I checked the motherboard ground and it read 7.6! I wired the the usb ground to my psu ground and it now reads 00.1 with the meter on 200k. The motor works perfect powered from the extruder (minus the whine). In all my testing i managed to fry one of my stepper drivers so i just purchased two more (one to replace and one to try with the extruder.

I have similar problem.

First, the motor just twitched so I tried to unplug one coil at a time. And yes, one of them had bad connection so I rewired it again and now the motor rotates.

But only for a while, say a few second. The extruder controller's 4 LEDs blink, they blink too fast but it seems to me that when some LED is off some other is on, etc, sort of they blink in a synchronized way. But then two of them stay on, the other one off, the motor starts to make this high pitch noise and it ceases to rotate.

Please, does anyone know what could that be? How should I measure this ground and what is "7.6"? And how do I connect motherboard (?) gnd to powersource gnd? Just by a wire? I mean, just to connect GND from motherboard (say the one next to SDA) to controller (where? "-" from power, just next to "+"?)?

I'm using Gen3 electronics, I have D9 connected to SDA, D10 to SCL, and RS485 on both boards (I mean first two wires connected as: 1. to 1., and 2. to 2.).

I've created an image to show how my electronics are wired. The big black wire is what i added to fix the grounding issue.

[[url=http://i.imgur.com/QDQyB.png]Electronics Wiring[/url]

Ecir Hana Wrote:
-------------------------------------------------------
> I have similar problem.
>
> First, the motor just twitched so I tried to
> unplug one coil at a time. And yes, one of them
> had bad connection so I rewired it again and now
> the motor rotates.
>
> But only for a while, say a few second. The
> extruder controller's 4 LEDs blink, they blink too
> fast but it seems to me that when some LED is off
> some other is on, etc, sort of they blink in a
> synchronized way. But then two of them stay on,
> the other one off, the motor starts to make this
> high pitch noise and it ceases to rotate.
>
> Please, does anyone know what could that be? How
> should I measure this ground and what is "7.6"?
> And how do I connect motherboard (?) gnd to
> powersource gnd? Just by a wire? I mean, just to
> connect GND from motherboard (say the one next to
> SDA) to controller (where? "-" from power, just
> next to "+"?)?
>
> I'm using Gen3 electronics, I have D9 connected to
> SDA, D10 to SCL, and RS485 on both boards (I mean
> first two wires connected as: 1. to 1., and 2. to
> 2.).

ensgrp, thanks a lot!

It turns out, this is a bit embarrassing, I was was using default host software and there is this "extruder" tab. And I hit "extrude" button to test it and to see if it works but it stopped after a while. Well, the thing is, the field next to the button says, how long it will print during the test. So I just typed-in larger dumber and it prints longer. Sorry for the false alarm, I feel a bit stupid...

You shouldn't feel stupid. It's not like the reprap comes with any instructions.

Ecir Hana Wrote:
-------------------------------------------------------
> ensgrp, thanks a lot!
>
> It turns out, this is a bit embarrassing, I was
> was using default host software and there is this
> "extruder" tab. And I hit "extrude" button to test
> it and to see if it works but it stopped after a
> while. Well, the thing is, the field next to the
> button says, how long it will print during the
> test. So I just typed-in larger dumber and it
> prints longer. Sorry for the false alarm, I feel a
> bit stupid...