Stall detection fails after calibrating steps/mm
Hello! I have been doing some calibrations on my CoreXY printer and I have ran into some issues with my sensorless homing setup.
I simply can't get the stall detection to work after changing the steps/mm on each motor for X and Y.
I used this before the calibration:
M92 X80.00 Y80.00 Z400.00 E2771.50
And changed it to this:
M92 X79.24 Y79.64 Z400.00 E2771.50
Stall detection settings:
M915 X Y S3 F0 H300 R0
The stall detection works perfect with 80 steps/mm but with the lower ones(79.**) does not make the stall detection trigger at all. I have tried to change up the S parameter all the way down to -50 but there are no visible changes. The motors drag the extruder to the end of its axis and the belts start slipping.
I can't find anything about this in the limitations section of stall detection. Is there anything im missing here?
What speed do you use in the homing move? How does the minimum speed for stall detection reported by M915 compare with that speed?
@dc42 Im running it on 3600.
My homing file looks like this:
; homeall.g ; called to home all axes ; M400 ; make sure everything has stopped before we make changes M913 X50 Y50 ; reduce motor current to 50% to prevent belts slipping G91 ; use relative positioning G1 S1 X-400 F3600 ; move back 400mm, stopping at the endstop G1 X5 ; move away from home G1 S1 Y-400 F3600 ; move back 400mm, stopping at the endstop G1 Y5 ; move away from home G1 S1 X-400 F3600 ; move towards axis minimum G1 S1 Y-400 F3600 ; move towards axis minimum G1 X5 Y60 ; move away from home G92 X0 Y0 ; set coordinates to 0,0 M400 ; make sure everything has stopped before we reset the motor currents M913 X100 Y100 ; motor currents back to normal ;G90 ; absolute positioning ;G1 X0 Y60 F6000 ; go to first bed probe point and home Z ;G30 ; home Z by probing the bed
M915 Driver 0: stall threshold 3, filter off, steps/sec 300, coolstep 0, action: none Driver 1: stall threshold 3, filter off, steps/sec 300, coolstep 0, action: none Driver 2: stall threshold 1, filter off, steps/sec 200, coolstep 0, action: none Driver 3: stall threshold 1, filter off, steps/sec 200, coolstep 0, action: none Driver 4: stall threshold 1, filter off, steps/sec 200, coolstep 0, action: none
You are running older firmware, so M915 is not translating the full steps/sec into mm/sec. However, we can do that by hand. Assuming you are using x16 microstepping, 300 full steps/sec is 4800 microsteps/sec, divided by 80 steps/mm is 60 mm/sec, times 60 is 3600 mm/min. So your homing speed is exactly the same as the minimum stall detection speed. When you reduce the steps/mm, the minimum stall detection speed is slightly higher than your homing speed.
So you need to reduce the M915 H parameter.
@dc42 I will update the firmware right away. Been a while sinse I updated last.
Thanks alot for the explanation. You were 100% right! I was a bit too quick to overlook that
It triggered right away when I reduced the H parameter.