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Rumba controller board

Posted by JackDaniels 
Rumba controller board
May 28, 2019 11:52AM
Hi all,

I am very new to the RepRap community and have a couple of questions relating to a conversion I am trying to complete.

I am one of the unfortunate ones that purchased a Cubex Duo 5 years ago - I say this as a lot of people have given it bad reviews and with some just cause.
Over the past 5 years, I have changed over the software and completed many over mods to make the printer better and with great results but this machine has now died, both heads and main board now scrap.

So reading lots on these conversions I have started down the path of new electronics including a Hotbed.

I have purchased a Rumba board and 6x A4988 drivers and from what I have read my main problem is split into two questions;

1) The Z axis has a Nema 23 - 2.2v - 3.0A stepper and the A4988 can only drive up to 2.0A. Can anyone give me any suggestions for this problem (DRV8825 ?) or have they done this conversion?

2) The Y axis has a twin drive - Nema 17 - 2.8v - 1.68A steppers.
After looking around someone suggested stacking two A4988 drivers but I have found an expansion board (stepper driver extender A4988 DRV8825 extension stepper driver panel additional motor adapter breakout board drive expander).
From what I can make out this board would allow me to run two drivers simultaneously, one for each stepper.
Would this be correct or has anyone tried one of these?

Any help would be most appreciated. smiling smiley
Re: Rumba controller board
May 30, 2019 06:11AM
The RUMBAs six driver slots make it easy to configure a second driver for an axis. In most firmwares you just have to enable this for the specific axis and select which driver slot serves the second motor.
In Repetier look for FEATURE_TWO_YSTEPPER

Re: Rumba controller board
May 30, 2019 07:18AM
Thanks for that.

I take it as I will not be using 3 extruders I could use Extruder output 3 as the second driver.

Thanks again.
Re: Rumba controller board
May 31, 2019 05:03PM
The NEMA 23 should only require about 600ma current if driven @12V. If you set the current limit on the DRV8825 for 2 amps you will burn up the stepper and the driver.
As far as the NEMA 17's they should only require about 400ma @ 12 V

the 3 amp rating on the NEMA 23 is for 2.2V not 12V. Steppers are usually driven an higher voltages than the rated voltage.

I always calculate the ballpark current using P (watts) = I (Amps) X E (Volts)

The NEMA 23 comes out to (2.2 X 3.0) = 6.6 Watts and (6.6/12) = .550 Amps
The NEMA 17 comes out to (2.8 X 1.68) = 4.7 Watts and 4.7/12) = .391 Amps

2 NEMA 23's on the same driver would be about 1.2 Amps ( I would 1 drivers for each NEMA 23) The DRV8825 will start to run a little on the hot side at 1.2 to 1.5 Amps if you drive 2 steppers from1 driver.

However the DRV8825 will easily handle 2 NEMA 17's

The current at 12V is just to get you close, in practice the current may have to tweaked a little higher to compensate for losses.
Re: Rumba controller board
July 19, 2019 06:27PM
Hello I am also very new to 3D Printing and could really need some help. I am trying to convert my Cubex(1Printhead). I bought the following Material:

3D Drucker Teile Titan V6 Bowden Extruder Voll Kits mit NEMA 17 Stepper Motor Für 1,75mm/3mm e3D V6 Makerbot 3D drucker.

Rampen 1,4 Kit Mega 2560 R3 für arduino + RAMPS 1,4 Controller + 5 stücke A4988 Stepper Fahrer Modul + PCB Heatbed MK2B 3D Drucker kit.

My questions so far:
1)can I use the two Y motors paralel(one normal, the other one +-swapped)?
2)Is there a difference between the romba board and the raps i have got(because both use malin)?
3) is there a malin config i can use?
4) do i need to replace any ohter hardware?

I hope someone can help me.
Re: Rumba controller board
July 22, 2019 05:00AM
Rumba is a an old Atmega based board, the RAPS is a 32 bit board. Marlin is used on a large variety of platforms, 32 bit is supported since V2. Chances are you will have to specify your own Marlin configuration for your printer.

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