[BUG] Runout uses FILAMENT_MOTION_DISTANCE_MM after #28074

[vovodroid]

Did you test the latest bugfix-2.1.x code?

Yes, and the problem still exists.

Bug Description

After Trigger instant runout on filament jam #28074 BTT Microprobe uses FILAMENT_MOTION_DISTANCE_MM value in the case of runout.

Bug Timeline

After #28074

Expected behavior

When BTT SFS is used and filament is runout FILAMENT_RUNOUT_DISTANCE_MM is used.

Actual behavior

When BTT SFS is used and filament is runout FILAMENT_MOTION_DISTANCE_MM is used instead of FILAMENT_RUNOUT_DISTANCE_MM

Steps to Reproduce

Configure small FILAMENT_MOTION_DISTANCE_MM, and larger FILAMENT_RUNOUT_DISTANCE_MM, remove filament from the sensor while printing.

Version of Marlin Firmware

bugfix-2.1.x 29-09-25

Printer model

No response

Electronics

No response

LCD/Controller

No response

Other add-ons

No response

Bed Leveling

None

Your Slicer

None

Host Software

None

Don't forget to include

• A ZIP file containing your Configuration.h and Configuration_adv.h.

Additional information & file uploads

Marlin.zip

[ellensp]

Please actually fill out the template.

please fillout Expected behavior and Actual behavior because your one line description does not tell us what is wrong with using FILAMENT_MOTION_DISTANCE_MM

[vovodroid]

Filled.

[thinkyhead]

The purpose of FILAMENT_RUNOUT_DISTANCE_MM is to let the extrusion continue after a typical runout is detected, as when the filament is no longer triggering a toggle switch. And then, the filament motion sensor is meant to detect that a jam has occurred once FILAMENT_MOTION_DISTANCE_MM has accumulated, in which case the filament should not continue to try to extrude the slipping or jammed filament.

So FILAMENT_MOTION_DISTANCE_MM is part of the actual detection, and FILAMENT_RUNOUT_DISTANCE_MM is for post-runout behavior. Two entirely different purposes.

Is your sensor set up to detect both runout switch and lack of motion at the same physical place? Typically the switch would be in front of the extruder, and then the motion sensor would be close to the nozzle.

So maybe we need to add an option to deal with different usage patterns.

[vovodroid]

Is your sensor set up to detect both runout switch and lack of motion at the same physical place?

Exactly! It's BTT Smart filament sensor - 2 in 1: