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2 stepper drivers in one slot.

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As mentioned in the topic, do you think there will be any issue driving 2 stepper drivers from same slot on 3dprinter board? I need 2 motors driven by same signal but be able to control current separately.

What I would try would be to use two separate drivers to avoid issues with heat sinking, but bridge the data lines on the pcb so that one signal switches both drivers.

It should work just fine. You'll be able to control the current output through each driver with the switching on and off being done with the same signal.

It ought to work. The only inputs that should be chained together are the step and direction inputs, everything else keep separate.

I see people are going off topic here, I will explain again:

I DON'T want:

  • Dual Z axis
  • Driving 2 motors from same driver

What I want:

  • To drive 2 stepper DRIVERS - small pcb boards on your 3dprinter board (not motors) from E0 (extruder0).
  • Do it by connecting 2 DRIVERS to E0 socket or by configurating E1 to do the same thing as E0 at the same time.

Looking at the diagram for the DRV8825 driver (see attached image), the control signals are all inputs to the drivers, therefore, you should be able to use the same control signals for multiple drivers. The only limitation would be the source/sink capability of the chip generating the control signals (Arduino). Also, take a look at the minimal wiring information provided by Pololu.

I see what you mean, so if I would identify chip that delivers power to that particular driver and find way too cool it down it would work. I'm wondering what's power delivery of these chips and if they could just handle 2 drivers without any mods.

Taking the Ramps 1.4 schematic as example, you can see that digital IO lines control the STEP/DIR for each stepper driver. The Arduino can source/sink 20mA and 10mA at 5V and 3.3V respectively. The A4988 stepper driver, found on the ramps, requires only 1uA typical, 20uA max. Hence, no issues driving several chips from one set of pins.

Great, thanks for that !

You're on the edge of my Marlin experience. Marlin sees E0 and E1 as two separate extruders. There is no configuration I'm aware of to set up a dual connection like on the X, Y , or Z steppers. The only thing I can think of is to configure the E0 and E1 as extruders and then configure them to feed a MIXING_EXTRUDER.

This is what Marlin has as a comment in Configuration.h

/**
 * "Mixing Extruder"
 *   - Adds a new code, M165, to set the current mix factors.
 *   - Extends the stepping routines to move multiple steppers in proportion to the mix.
 *   - Optional support for Repetier Firmware M163, M164, and virtual extruder.
 *   - This implementation supports only a single extruder.
 *   - Enable DIRECT_MIXING_IN_G1 for Pia Taubert's reference implementation
 */

Since all my printers are single extruders I have no knowledge of how this works.

Also, in answer to your question clarification I found this forum post.

Hope this helps.

That's great, you just found option in Marlin exactly for what I need. That puts me in the right direction and I can research this topic more.

Thanks your help, looks like edge of your knowledge was what I needed :)

Comments deleted.

If you're using Marlin, and have an E1..... it can be configured for two Z stepper motors. Remove the commenting from "Z_DUAL_STEPPER_DRIVERS" in Configuration_adv.h. Never tried it myself but it's supposed to allow identical step signals to the Z and E1 drivers. There may be other configuration needed, of which I'm unaware, since I've never used it.

That's looks like what I'm looking for. I'm building ceramic paste extruder and It will require 2 stepper motors working at different speeds.
I hope its possible to make it in the way that E1 would be configured for two E0 motors.

I may have made a wrong assumption. My bad. I was believing that this was for dual Z's, as was stmorgan. Marlin has configurations for dual X, Y, and Z. But, as far as I know, they all supply the same stepper signals to both stepper drivers. Therefore, the dual motors would both turn at the same rate. I'm unaware if it's possible to configure different axis steps for each of the dual motors. Failing that, different rates would need to be handled in the gearing of your design. But the dual config does allow different currents to each motor.

Basically what you explained sounds like it might work, you said that removing commenting in marlin will send identical step signals to the Z and E1 drivers. Why wouldn't it be possible to change signals for E0 and E1 to be indentical? I have planned mechanical gearing but I wanted to be able to control power of the motor too.

You won't be able to control current separately if they're both tied to the same output. I think you can get stepper Y-cables, and I'm fairly sure the dual Z plugs on a RAMPS board are just wired in parallel.

I don't want to connect stepper motors to same driver, I'm about connect 2 stepper drivers to same socket on the board, question is mostly if 3d printer board can handle power for 2 stepper drivers on that slot.