Z-stall as Z-probe, but until then...

matteo2u

Hello all,

I want to use stall detection on my z-axis as a probe, but I am not sure how to set it up using the RepRap Configurator. Can that even be done, or does it need to be done manually in G-code? I have read enough to know that if I don't have appropriate motor current and steps/mm defined while doing this, I can cause some damage, so I'm just trying to avoid that. Anybody have a step-by-step procedure on setting that up?

Until I can get that figured out, how do I set up manual bed levelling? If i just set the probe type to No Probe, will the web interface have a walk through to develop a mesh?

Any guidance would be helpful, thank you!
Matt

oliof

Yes, see https://duet3d.dozuki.com/Wiki/Using_the_manual_bed_levelling_assistant

matteo2u

@oliof thank you

Phaedrux

@oliof said in Z-stall as Z-probe, but until then...:

https://duet3d.dozuki.com/Wiki/Using_the_manual_bed_levelling_assistant

Actually, manual bed leveling assistant is different to using the M558 P0 (no probe) probe type. The assistant helps you find how much to adjust the leveling screws by using the probe. You are correct that if you choose P0 as your probe type it will pop up a dialogue box to manually jog the print head down to the bed when a G30 is called.

dc42

@matteo2u said in Z-stall as Z-probe, but until then...:

Hello all,

I want to use stall detection on my z-axis as a probe, but I am not sure how to set it up using the RepRap Configurator. Can that even be done, or does it need to be done manually in G-code? I have read enough to know that if I don't have appropriate motor current and steps/mm defined while doing this, I can cause some damage, so I'm just trying to avoid that. Anybody have a step-by-step procedure on setting that up?

Until I can get that figured out, how do I set up manual bed levelling? If i just set the probe type to No Probe, will the web interface have a walk through to develop a mesh?

Any guidance would be helpful, thank you!
Matt

You can use the manual bed levelling assistant (see link above) with the probe type set to zero (P0 in your M558 command).

To try stall detection, use P10 in your M558 command. You will need to experiment with the stall threshold (M915), the motor current fraction (M913) and the speed (M558 F parameter).

matteo2u

@dc42 Thank you! Please forgive my ignorance, but would i be putting these codes in the bed.g file, or where? Start low with the stall threshold, motor currents, and speed?

Also, are the same parameters tunable if using stall detection as the z-endstop? Is there any reason to not do that if I only have a single nozzle? Is there any long-term damage to the z-motor to be expected? I currently have a simple switch at the low end of the range for Z-range for an endstop, but it seems kind of pointless there and would better serve at the high end if I can use the stall detection as a low range endstop. Sound liek a wise plan?

Thanks again for your help!
Matt

oliof

All the settings are live tunable. If you search the forum for Z stall detection you will find some macros by @Phaedrux which will allow you to test this feature without touching your config.g or bed.g directly until you're satisfied with the values (here is the direct link https://forum.duet3d.com/post/51413)

It's very important that your nozzle installation is very rigid (my 3 wheel x gantry flexes waaaay too much before any z stall registers).

Bravewildheart

Hello All,

I am also having trouble stetting up Autobed Leveling / Mesh Compensation G29 using stall detection.

I manage create a Home All file successfully.

; homeall.g
; called to home all axes
G91 ; relative positioning
G1 Z5 F6000 S2 ; lift Z relative to current position
; x and y Sensor less homing
M400 ; make sure everything has stopped before we make changes
M913 X80 Y100 ; XY motors % current
M915 X S2 Y S3 R0 F0 ; set X and Y sensitivity, do nothing when stall, unfiltered
M574 X1 Y1 S3 ; set endstops to use motor stall
G1 S1 X-500 Y-500 F5000 ; move X and Y back, stopping at the end stop
M400 ; make sure everything has stopped
M913 X100 Y100 ; XY motors to 100% current
G90 ; back to absolute mode
G1 X250 Y250

; z Sensor less homing
M400 ; make sure everything has stopped before we make changes
M913 Z60 ; z motors % current
M915 Z S1 R0 F0 ; set Z sensitivity, do nothing when stall, unfiltered
M574 Z1 S3 ; set endstops to use motor stall
G1 S1 Z-150 F600 ; move Z back, stopping at the end stop
M400 ; make sure everything has stopped
M913 Z100 ; Z motor to 100% current
G90 ; back to absolute mode
G1 Z10

I am just not sure to set the Mesh compensation up correctly.

What do I need to do in my Config file?
Do I need to create additional files?
How do I set the current up and down before and after G29 command?

Any guidance would be helpful, thank you!
Jacques

Phaedrux

@Bravewildheart the m558 and g31 commands define the probe. M557 defines the mesh size. M558 P10 is for stall detection probing. Then g29 will start the routine and create the heightmap.csv.