Repetier Firmware: Dual Y Steppers

Hello! While not a question about Repetier Host (which is working great for me), I hope that you might be able to help me with a Firmware question, or at least guide me to how I could start to modify things.

I have a setup which is not utilizing the extruder drivers. I have 4 steppers, with a Dual Y configuration. Before, I have driven the Y steppers together from one driver. I have now switched to a RUMBA board with Repetier Firmware. While I can still drive the Y steppers, I think that the driver is not providing enough current. The power supply I have is 24v, 150W. I can move everything just fine at Feedrates between F1000 and F2000. If I try to go higher than this, the second Y stepper makes some strange noises. I was wondering how I could make use of the extra extruder driver I have to drive the second stepper, and, if that would actually be beneficial to my situation. I know that Dual Z is supported in the RUMBA through Repetier Firmware, I was wondering how I would go about modding the firmware to get Dual Y Stepper Drivers?

I only mention this because previously I was using the R2C2 motion controller and was able to drive the Y steppers (together on one driver) quite rapidly. That being said, I was using a 24v 220W PSU (not compatible with the RUMBA power supply inputs).

So, should I:

• Get a higher power PSU?
• Modify the Repetier Firmware to support Dual Y stepper drivers?
• Both?

I am not driving any heated bed or any other peripheral at the moment, just the steppers.
Thx!
p.s. the Steppers are Nema 17, 2.8v, 1.68A / phase

Edited 1 time(s). Last edit at 12/11/2013 04:02AM by fraguada.

Not sure about 0.83 but in the development branch you have this:

/**************** duplicate motor driver ***************

If you have an unused extruder stepper free, you could use it to drive the second z motor
instead of driving both with a single stepper. The same works for the other axis if needed.
*/

#define FEATURE_TWO_XSTEPPER false
#define X2_STEP_PIN   E1_STEP_PIN
#define X2_DIR_PIN    E1_DIR_PIN
#define X2_ENABLE_PIN E1_ENABLE_PIN

#define FEATURE_TWO_YSTEPPER false
#define Y2_STEP_PIN   E1_STEP_PIN
#define Y2_DIR_PIN    E1_DIR_PIN
#define Y2_ENABLE_PIN E1_ENABLE_PIN

#define FEATURE_TWO_ZSTEPPER false
#define Z2_STEP_PIN   E1_STEP_PIN
#define Z2_DIR_PIN    E1_DIR_PIN
#define Z2_ENABLE_PIN E1_ENABLE_PIN

So no modding required, simply activate the feature:-)

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!!! I did indeed get 0.83 and did not see such code. I will check out the development branch...exactly what I was after!
Thanks a lot...will report back after testing.

Wanted to report that the Development Branch of the Repetier Firmware (0.9) is compiling and working ok. I was able to activate dual Y stepper drivers easily, and I manually flipped the Y2 stepper cabling in order for the two steppers to travel in the 'same' direction. (Maybe add in individual stepper direction inverting in the firmware?)

A word of caution to others trying it out, the dev branch defaults to a delta printer format, so be sure to go through the config. Also, I needed to flip some of the directions (z axis) whereas in 0.83 this was ok.

It does not mean I can necessarily move faster, but operation on the Y axis does seem pretty smooth with two steppers.

I guess for faster stepper movement, I should upgrade my PSU to something over 150W?

Also, the connection to Repetier Host does not seem as stable. Yesterday, when connecting, I would get just 'start.' If I tried to connect a second time, it would connect. Today, I do not get such issues, but there is definitely a slight difference in it's behavior. Thus far, this difference has not caused any issues with the printing.

Thanks for the great firmware and control software!