Sensorless homing - tuning the stallguard value

[drpeej]

My first attempt at sensorless homing a couple of years ago was a failure as I just couldnt get it to work.

Due to a stupid mistake on my part, I have recently had to reinstall clipper and rebuild my configuration.

I decided to try sensorless again using https://docs.vorondesign.com/tuning/sensorless.html. This time it worked first time and was so straightforward that I dont know what went wrong first time.

I am puzzled about how to adjust the stallguard value. Following the instructions, the MAX value was easy enough to find. However I am not sure how to find the minimum value. I reduced the value and reached a point where I could hear the carriage hit the limit. However it was really vague and not as obvious as finding the MAX value. I have chose a MIN value 30 less than the MAX so my stall guard value is 15 which seems to work. Does this sound about right? It all seems to be working well.

 

[StefanT]

The only thing I had to adjust was the driver_SGTHRS value.
Which min/max values do you mean?

 

[drpeej]

The instructions suggest finding a MAX value and a MIN value of driver_SGTHRS where the virtual endstop is triggered and then you set the final value at the midpoint. I guess its no too important if it works

 

[StefanT]

Well ... seems like I skipped that part. I found the max value, reduced it like 10%, and went with that.

 

[drpeej]

Well ... seems like I skipped that part. I found the max value, reduced it like 10%, and went with that.

Thats probably a sensible plan. The MIN value is really not easy tio identify

 

[5twenty]

Yeah, I got mine tuned just enough to be repeatable, but still need to fine tune it. I figured it's good enough for now, and stopped chasing that particular unicorn for the time being...but I'll be back at it again one day. Once I finish these other printers.

Keep at it, but don't pull your hair out. If it is homing fine...it is homing fine.

 

[claudermilk]

I recently had to switch my Trident over to sensorless (X switch finally died). I just followed the instructions on t he Voron docs site. The only setting I had to tweak was driver_SGTHRS. I have no min, max, or stallguard set. Just tweaked the mentioned setting until I got a good repeatable stop without slamming & left it at that. It really was surprisingly easy.

So, as @5twenty said: if it's working then it's working.