[Solved] Stepper Motor wont turn...

Hey everybody,
I am getting so close to finishing this project!! The major structure of the prusa is assembled and all I have to do is get the electronics working. But I have hit a brink wall. The motors wont turn. I tried to use resnapper, but had problems connecting with the arduino. So I am now using Replictor-g on an Ubuntu[11.04]. I only have one motor control and its motor connected to a pre-assembled RAMPS 1.3. When I try to move the motor it "vibrates", but it doesn't turn. It makes a noise and shakes but there isn't any real movement going on. I have everything set on default. I have the motor control on the lowest setting and I haven't changed any of the jumpers on the ramps board. I just tested the motor again and discovered that it only wants to move in the positive direction. I thought the wires might have been wrong, but i have checked it a few times and tried it a couple of different ways.

I bought my used motors from Tony on ebay and the wiring is as follows:
PIN5 / RED = A
PIN3 / BLUE= B
PIN4 / YL = A-
PIN2 / ORG = B-

PIN1 / WHT = COMMON
PIN6 / BLK = COMMON

I have tried to wire the motors in order: Red, Blue, Yellow, Orange.
But I recent read a post that said it should be: Red, Yellow, Blue, Orange. This is how it is setup now.

I haven't had any luck and I really hope I am missing something obvious. Has anyone had any of these problems before? I would really appreciate any help you can offer. Thanks in advance.

-Robert

Edited 1 time(s). Last edit at 10/25/2011 02:47AM by Hawkeye13.

I suggest you use pronterface, which Just Works(TM), at least for me.

You might have to increase the pot meter on the pololu a little bit to make the motor move.

What firmware do you use? You may need to connect an endstop for the motor to turn both ways.

The wire colors/motor coils is important to get right, and it can be different for every make of motor. If you disconnect the motor and short two leads together the shaft should be harder to turn if they are the same pair. This way you can find pair A and B, and wire accordingly. I've heard different things about the importance of getting them all in the right order, but theoretically it should be enough if you at least have the correct pairing. Though I don't know if this is true for 6 wire motors?

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-Nudel
Blog with RepRap Comic

I just tried to increase the meter on the pololu and the motor simply moves back and forth. Hey, its movement!! But not quite what I am looking for. Adding this new issue, does anyone have any other ideas?

I am going to try Pronterface and see if it makes a difference.

Thanks!

If the motor move in one direction and not the other then in 99.9% of the cases you don't have your end stop connected.
Or the end stop must be inverted, or the end stop is defective.

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

Very big update. I found out that it was the end stops that was causing the problem. I had to change the "Endstops_Inverting" to "True". The motor now moves both ways. I am still having a problem with the movement though. Every time I click +10 the motor moves in the direction but it is not smooth. It more shakes in that direction rather than turns. When I click +.1 it only moves in one direction. But that direction seems random each time I click the button; though it goes more in the direction I clicked. Its like two steps forward and one step back. When I click +100 the motor seems to simply vibrate. I feel like I am so close to getting this to work. I just need a little more help!! I would appreciate any more advice that I can get. Thanks in advance!

-Rob

You might have wired your endstop switches backwards so you had to change the polarity to inverting.

It also sounds like you need to adjust the trimpot on the Pololu that limits the current to the steppers.

Change it how? I have is some where between 33% and 45-ish%. I thought that might have been a bit high...Would that cause an issue with movement?

I just decreased the Pololu quite a bit. I turned it down to 15% or so. Now it is just vibrating. There is no real movement at all. I am really not sure what is wrong. I am also scared of turning it up to full. I think that might do more damage and cause more problems. I am using Sprinter. I double checked that and everything looks right, but honestly, if there was a problem there I doubt I could find it. I truly am at a loss here...

sounds like to me your driver can't handle the speed of pulses for the stepping. if using sprinter, be sure the delays are enabled for steps. i don't remember the exact setting, but it puts some microsecond delay in there..

an other option is to look for step pulses in firmware and add

microsecondsDelay(3);

between the pulses

Good god it works!!! I want to thank everybody for the help!! I can finally get everything put together.

Thanks again!! I am SO excited. ><
-Rob

hello there,
can anybody help me?? i m making my FYP and the problem is the motor is just vibrating not moving

I had something similar happen when my extruder stepstick blew. The X axis locked and nothing else would respond.

Hi,
I am having a similar problem.

I have recieved my sanguinololu 1.3a complete circuit and my Stepper motors type 103h5208-10u41.

They are Sanyo Denki 103H5208-10U41 Stepper Motor 1.8 Deg Nema 17. Red and black wires were swapped on the connector for the sanguinololu but i changed them to be back in order from left to right.

I am using Pronterface with x/y feedrate set at 30mm/sec and z set at 10mm/sec.

When I connect the Sanguinololu board, it is recognised in Pronterface and connects ok.

When I try to home my x axis, the motor vibrates but will not turn. It is difficult to turn by hand as if it is locked up but turns ok with power dissconected.

I have wired up my stepper as in The wiring diagram included as a pic.

I have wired up my end stops and they stop the motors shuddering when I try to send motors home so I assume they are working.

My steppers have six wires but I have only used 1 to 4 looking from left to right with wires facing you as per drawing.

My sanguinololu came assembled with Atmega644p and bootloader and sprinter installed and had been tested.

The red led comes on when i connect to usb or power from atx supply. My power supply is 500w.

I have looked everywhere on the net but can't get any clear instructions on how to fix my problem.

Any help appreciated.

Greg

Swap the centre pair of wires on the motor that wont turn.

Thanks for the quick reply.

Do you mean the centre of the four that I am using as in second from left with 3rd from left or the centre 2 of the 6 that my stepper came with.

Thanks again for your help.

Greg

I don't think swapping the center wires would fix the problem. The fact that the motors vibrate probably mean the the wire sequence on the controllers are correct. But did you check to make sure that you used the end taps of the motor wires and not the center taps? Usually the end taps are red, blue, green and black as shown in the wiring diagrams but I don't know if that's the case for that motor. You can always check the resistance with a multimeter. The end taps would give you the highest resistance but not infinity.

You are using +12V, right?

If you're sure about your wiring, then try turning the trimpot down to around the 10 O'Clock position. If it sill vibrates, try turning a bit lower until the vibration stops.

If that doesn't work, then try adding a delay in the firmware as James wrote earlier.

According the to datasheet here: [www.interinar.com] you should wire them in the order:

red, yellow, blue, orange.

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[www.hydraraptor.blogspot.com]

Problem solved ( I think )

I plugged the connector that came with the motors into the sanguinololu board using the middle four wires and everything turns and steps... Whew... At Last

The only problem now seems to be that the driver chips get too hot to touch after a short while driving the motors.

I have fitted the little heatsinks that came with the board but they too get very hot.

I haven't wired up as per nopheads link yet so will try that and see how that affects the heat situation.

Straight out of the box they are wired left to right with wires facing you as follows...
Black, red, yellow, blue, orange, white.

Red and black are crossed over before they connect to the circuit board as are white and orange.

The 2 middle wires, yellow and blue, remain in line.

The curious thing is that it doesn't make any difference whether I plug the connector upside down or the right way up.
The motors still run and behave..

Thanks all for the suggestions and advice.

Greg

You should follow Nophead's wiring instructions. Reversing the plug will reverse the direction of the motor. When you jog the axis and it moves in the wrong direction, you can plug the connector backwards to correct it or edit the firmware. In RAMPS, it's easy to reverse the plug since it's not polarized.

If you connect the middle four pins then you have wired them as I described.

If you put the plug on the other way round the motor will spin in the opposite direction.

If the drivers get too hot reduce the current by turning the pot anti-clockwise.

Edited 1 time(s). Last edit at 04/23/2012 10:19AM by nophead.

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[www.hydraraptor.blogspot.com]

Wired as per nophead suggestion and all seems good.

The only problem I have now is getting the gears off the shafts of my steppers.

It looks like they are just pressed on so i will take them to the local electrical repair shop tomorrow and see if they agree and then work out how to press them off.

Thanks all again but I'm not printing yet so more questions to come.

Greg

Pic of motors included

What kind of gears are those? The teeth look awfully close to the T2.5 gears that I'm using. Perhaps you should find out if you can get the right belt for those gears and use them instead for the x and y.

All seems ok so far.

I just ran the hollow calibration cube from thingiverse and all motors seem to be operating as they should.

Another question though for future reference.

Where do I find the pot to adjust it? Do I have to unplug the stepper driver board? I can't see any pot on the board.

Greg

Yeah. I thought they looked like the 2.5 gears i've seen on the net.

If so, I will leave x and y alone. I still have to get rid of the gears for the extruder and z axis though.

Might have found the adjust trimpot on my a4988 pololus board.

Are they the small screws beside each heatsink as indicated in the photo?

If this is correct, do I turn them to the left until the motors stop turning and turn them back up until the motors start to turn plus a bit to get the lowest current setting and avoid overheating?

Pic included

Thanks

Yes, that's the trimpot, and yes that's the way I adjust them. Use a jewelers screwdriver or eyeglass repair screwdriver. Don't touch anything except the trimpot while doing so.

I go for the highest current that does not give overheating because that gives the most accurate positioning.

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[www.hydraraptor.blogspot.com]

nophead Wrote:
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> I go for the highest current that does not give
> overheating because that gives the most accurate
> positioning.

Interesting. I seem to learn something new from you every week. I haven't noticed any lack of accuracy, but will try adjusting the trimpots on my white Sells Mendel made from your parts to see if very small fine parts look any better. Before I do, tho, by "overheating" do you mean too hot to comfortably leave your hand on the motors, or having the stepper drivers themselves go into thermal shutdown (observable by having the motors "stutter")? I do have heatsinks on the Pololus.

I like both motors and the drivers to be not too hot to touch, but perhaps too hot to hold on to.

There are three reasons why lower current produces less accuracy.

1) The Allegro drivers have a fixed off-time and a minimum on-time, which means they can't produce less than a certain current. That means when microstepping the lower current part of the sinusoid cannot be achieved, so the steps become uneven with some steps microsteps missing altogether. See [hydraraptor.blogspot.co.uk]

2) Even if the current is high enough to produce all the microsteps the current waveform has a ripple on it due to chopping, which has a fixed amplitude for a given motor and supply voltage. Since it is the peak current that is controlled, the average current and hence the torque is offset by half the ripple. If the current is lower this offset is more significant.

3) There is inevitably some friction in the axis. A stepper motor only produces torque when its rotor is not at its target position. That means it tends to stop a little short (where the torque equals the friction) causing backlash. Increasing the current increases the torque and so reduces the backlash caused by friction.

How much these effects affect print quality I don't know, but the advice to set the current just high enough not to lose steps seems daft to me. I set it just low enough to not overheat something. That way I get the best performance my motors and electronics are capable of. The only down side is using a bit more electricity, but that is insignificant compared to the power taken by the heaters and the cost of plastic.

Edited 2 time(s). Last edit at 04/25/2012 03:34AM by nophead.

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[www.hydraraptor.blogspot.com]

Can somebody clarify which pins need to be attached from the pololus boards to tha sanguinololu?
The wiki suggests in the photograph that only some pins need soldering on the side facing outward and
That none of the inner pins are connected. All the photographs of finished boards look like all pin are connected.