Rumba Microstepping Jumpers

Hi All

I am in the final assembly stages of a 3DR and have the x y and z and extruder motors wired up to my rumba board. I have downloaded and installed the marlin firmware from richrap's github and all appears o.k. The display looks good and the printer reports what I would expect in pronterface. The problem is my steppers won't move. The best I have had is that they vibrate and grind but don't go anywhere. I'm fairly new to this as my current printer (huxley) was built from a kit. I am assuming the jumpers under my pololu boards need setting. The problem is that I can't find out anywhere how they should be setup. I have jumpers (3) rather than switches under each driver board. I have already had a wisp of smoke so I think one of my driver boards is toast. I did set the pots to read 0.45V prior to connecting the motors.

Hope someone can help me.

Regards

Andy

Ps the end stops on the potentiometers are o.k

Edited 1 time(s). Last edit at 10/31/2013 02:14AM by AndyCart.

Which drivers are you using on your Rumba?

I'm about to buid one also but presently have no knowledge of the Rumba board. The vibration and grind sounds are typical of misswired motor windings with any type driver board. Sounds like the motors are not wired properly.

If you are using the new DRV8825 - it must be rotated 180 degrees from the standard driver.

[forum.reprapdiscount.com]

Edited 1 time(s). Last edit at 10/29/2013 01:00PM by Xabbax.

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You only learn when you change your mind.
[www.deltaprinter.co.za]

Thanks for the quick replies guys. I'm using the A4988 Pololu compatible driver from Reprapdiscount. I'm not sure what 'rotated 180 degrees' means ???

The driver boards I have look identical to the ones in the Rumba wiki images

Andy

Edited 1 time(s). Last edit at 10/29/2013 01:35PM by AndyCart.

AndyCart Wrote:
-------------------------------------------------------
> Thanks for the quick replies guys. I'm using the
> A4988 Pololu compatible driver from
> Reprapdiscount.
Install A4988 according to this image
[www.reprap.org]

> I'm not sure what 'rotated 180
> degrees' means ???

The DRV8825 must be rotated 180 degrees and then installed.
>
> Andy

---

You only learn when you change your mind.
[www.deltaprinter.co.za]

Yes my drivers are installed the same as the one with the yellow tick in that image. They must be the correct way round as the gnd is marked on the rumba and the gnd pin on the driver is in that hole.

One possibility - check the wiring of the motor -colourcoding - [www.reprap.org]
I have not worked with Marlin - cannot be of help there.
Tuning the motors
[reprap.org]

Some other calibration guides:
[reprap.org]
[reprap.org]
[minow.blogspot.com]

Edited 1 time(s). Last edit at 10/29/2013 02:29PM by Xabbax.

---

You only learn when you change your mind.
[www.deltaprinter.co.za]

Hi Guys

Bit of an update. Still no joy in getting any motors running. I'm using a laptop psu rated at 6.2A and 19V. I have been reading up on the Pololu A4988 and, from what I have read it should be able to deliver about 1A of current without any heatsink. My boards have heatsinks attached and even with the potentiometer set to give a vref of 0.45V, get too hot to touch when I try to drive a motor. The motor I am testing with is now out of the printer with nothing attached to it's shaft. I still get the same vibration i.e it oscillates backwards and forwards but won't turn. All my motors x,y,z and e are giving the same results. I think two of my A4988s are toast as, if I plug them into the Rumba and power up they drag the supply voltage down (I assume there must be some sort of short on them now). Two seem o.k in that if I command movement from Pronterface they at least make the motor buzz. I an running out of things I can think of to try!!! I currently have all three jumpers under the driver boards installed which, I think, means I am running at 1/16 microsteps. I have set up the Marlin firmware accordingly. The motor I am testing is connected to E0 i.e it's the extruder motor and it's microstep value in Marlin is set at 300. I have tried the other motors on the other (x,y and z) outputs with the same result and another motor on E0 with the same result so I don't think it's the motors. Could it be the Rumba or the firmware? Any help with new things to try would be really appreciated.

PS my motors are 17HS19-1684S NEMA 17 (42 x 42 mm) high torque 1.8 degree from Think3DPrint3D

Regards

Andy

Edited 1 time(s). Last edit at 10/30/2013 05:25AM by AndyCart.

This from another forum.
Quote:
"stuttering it is probably caused by exceeding the max step clock that Marlin can
drive, e.g. more than 24000 steps per second. In this case, try
reducing DEFAULT_MAX_FEEDRATE in Configuration.h from 500 to 200 or
so."

Thanks xabbax. My settings are currently :-

#define DEFAULT_MAX_FEEDRATE {380, 380, 380, 29}

As I'm using the e0 motor for testing it's already quite low !!

Andy

Power is voltage times current. You may have to reduce your current if your voltage is 19V. Then again, you could always have a defect part too.

Vibrating motor but no movement is most likely too high a step rate - feedrate or acceleration. Set the acceleration to a ridiculously low figure in the firmware setup, and in pronterface select a low feedrate. Even if you get 10 steps/sec, it will prove the connections are correct.

If you have one motor phase missing, that can lead to vibrating motor, or if the motor has a load then motion in one direction. There is also a possibility the pen config is not right.

Once you have a motor moving, then you can tweak up the rates. You can then use that channel to test other combinations of driver and motor.

If your motor is "pulsing", then it could be the driver overheating, and it shuts down for a bit then comes back. If you have no load on the motor, you should be able to set the vref quite low, say a quarter turn on the pot.

Does the hot end move freely when the motors are powered down?
Try powering just one stepper with the others unplugged to see if it is your power supply.
If your heat sinks are getting really hot you are drawing too much current. Mine get barely warm at all and I set them pretty high.


You may need to re-wire the steppers as you may be trying to drive the stepper in both directions at once. I had to rewire my connector.
do the A4988 pot endstops work? Mine did not. Do you have the pinout from the stepper manufacturer?

I tested all my A4988s separate from my ramps board before assembling and it helped a lot. There are some simple projects online for this driver board with the arduino.

Hi guys

Thanks for taking the time to reply. The hot end motor, and all the other motors turn very freely when the driver boards are unplugged from the Rumba. They stiffen up when the drivers are plugged in in much the same way as they do if you short the two pairs of coil ends together. I've checked my motor wiring with an led and it's the standard green/black for one coil and red/blue for the other. I've got to a stage where I have tried two different firmwares, marlin and repetier, I am now going to build a simple test rig in order to properly check each driver. I have an old 0.1 breadboard somewhere so it shouldn't be difficult. I can't believe 4 drivers shipped faulty so I think the issue may be with my Rumba board. I've checked the pins.h on the rumba wiki against my firmware, both versions and it seems to match. The only thing I know I did wrong was to leave all three jumpers installed under each of the drivers when I initially powered up and tested. That was trying to set 1/32 micro stepping which I now know the A4988 won't support. I'm not sure if this would damage the drivers though. They are now set with just one jumper on MS3 to give 1/16, as a last try before all of the above I will drop the max feed rate and acceleration values in firmware and try that. Wish me luck :-)

Andy

Actually, having all three jumpers connected is the correct way to get 1/16 step with A4988 drivers. See: [www.pololu.com].

Did you ever find a solution for this ? I am experiencing fairly similar issues

Are you having the same problem with the same motors and the same board? If not it might be better to start a new thread. The first thing to check is the data sheet on your motors and see what their current ratings are. The next thing would be to use a DVM to set the X and Y drivers to deliver 1/2 the rated current. You might also check you power supply.

I never actually solved it. Just sidestepped it. I swapped out my old drivers for drv8825 and went for a 12v psi. All works fine now. I have subsequently tested each of the old drivers on a breadboard test rig and they all appear to be toast!

Andy