Dual / Two z stepper motor for Ender 3 using SKR mini e3 v2

General Discussion
1

Basic Information:

Printer Model: Ender 3
MCU / Printerboard: SKR mini e3 V2
klippy.log
klippy.zip (756.0 KB)

Describe your issue:

Hello,

I want to use a dual z stepper motor on my Ender 3 with SKR mini e3 V2 board. This board has the possibility to drive 2 Z motors (ZAM, ZBM), but Im not sure how to configure it.

My current, single z-motor, config is the following (i.e. the default config provided by klipper)

[stepper_z]
step_pin: PB0
dir_pin: PC5
enable_pin: !PB1
microsteps: 16
rotation_distance: 8
endstop_pin: ^PC2
position_endstop: 0.0
position_max: 250

[tmc2209 stepper_z]
uart_pin: PC11
tx_pin: PC10
uart_address: 1
run_current: 0.580
stealthchop_threshold: 999999

From the pinout it seems that both Z motor use the pins PB1 PB0 PC5 for Enable/Step/Dir. However, when I configure a [stepper_z1] with those pins I get an error that those pins are already used.

I face a similar situation when defining the [tmc2209 stepper_z1], but then concerning the uart_address. I know that the uart_pin and tx_pin are all the same, but the uart_address should be unique. Since this number can only be 0, 1, 2 and 3, and since all of these are already given to motor x, y, z, and e, I think I should also re-use the uart_address for the second z motor.
Besides, it is a very desirable property to control motor z and motor z1 in exactly the same way of course.

Can someone guide or give me the correct config for a second z motor? Also if I have not provided sufficient information, please let me know

2

Hello @zwep !

You can find information here:
https://www.klipper3d.org/Config_Reference.html#stepper_z1

3

Hello,

thank you for you answer. I am aware of that page and that helped me to give at least the required syntax for the definition of the second z stepper motor. However, this does not tell me what to do if the pins are the same, or how to deal with the uart_address overlap.

5

You do not need a second z-stepper configuration in your printer.cfg. The two z-stepper ports in this board are wired in parallel and driven by the same TMC

  • Remove the z1 from your cfg
  • Remove the z1 TMC configuration
  • Double the run_current to what you typically need for one of your steppers
6

Ah great, thanks! That explains a lot.

I now remember looking at an Anet A8 config with the SKR mini… but I was surprised that it did not have a definition for the second z stepper motor. Didnt think much of it, and attributed it to an error…

Anyway, thanks again :slight_smile:

7

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