Cant get Slicer to enable Aux fan

General Discussion
1

Basic Information:

Printer Model: Ender 3
MCU / Printerboard: BTT SKR Mini E3 V3
Host / SBC Raspberry pi 4b
klippy.log

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Describe your issue:

…

Okay, so this is a combination Slicer and Firmware issue i think.

i used a fan port and mapped it to be an aux fan in klipper with the fallowing code

[fan_generic aux_fan]
pin: PB15
kick_start_time: 0.1
off_below: 0.1
cycle_time: 0.01
shutdown_speed: 0.0

with this code i can turn on the aux fan at any point from mainsail. But i really just want the slicer to put in the gcode to turn on the aux fan when needed by itself.

I use Orca Slicer and i have it set to turn on the aux fan, but the printer never seems to turn it on, so i think there is a conflict between the slicer and how i have the firmware set up. i just dont know enough to solve this on my own.
klippy (2).zip (1.4 MB)

2

What is the aux fan supposed to do? Why do you think your slicer knows what it’s supposed to do? What is the slicer putting in the gcode?

3

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the big red thing on my x axis is my aux fan. it provides extra cooling for when i print at high speeds.

Orca Slicer does have a spot specifically for aux fans. im not entirely sure what it puts in the gcode to call on the aux fan to run.

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4

Orca addresses the extra fan as M106 P2, which Klipper does not support natively. You need to add a macro that allows you to do this:

[gcode_macro M106]
description: Enhanced M106 to handle fan scaling for a fan with fan index P2
rename_existing: M106.1
gcode:
  {% set fan_speed_raw = params.S|default(0)|int %}
  {% set fan_index = params.P|default(0)|int %}

  {% if params.P is defined and fan_index == 2 %}
    # Scale the fan speed from 0-255 to 0-1 for the Aux fan
    {% set scaled_speed = (fan_speed_raw / 255.0) %}
    { action_respond_info("Setting Aux fan speed to " ~ (scaled_speed * 100) | round(1) ~ "%") }
    SET_FAN_SPEED FAN=aux_fan SPEED={scaled_speed}
  {% else %}
    # Default fan handling if P2 is not specified
    M106.1 S{fan_speed_raw}
  {% endif %}

Adapt SET_FAN_SPEED FAN=aux_fan SPEED={scaled_speed} to call your fan.

5

when you say to adapt

Adapt SET_FAN_SPEED FAN=aux_fan SPEED={scaled_speed} to call your fan.

could you go into a bit more detail about this part? I’m not sure what it is I’m adapting.

i did go ahead an make a macro of that gcode that handles the m106 p2 situation, and added the macro to my printer.cfg.

i think i can write a simple gcode file to test if klipper can resolve that M106 02 properly with that macro.

6

You can disregard that last comment. It worked just the way you had it set up.

Hey Sineos, have I ever told you that your a genius? Cuz your amazing. Thank you so much.

1 Like