Question Need help with sensorless homing

[BOSSJoe]

Printer Model

Voron 0.2 mixed with Voron 0.1

Extruder Type

Galileo

Cooling Type

Other

Hello everyone,

I could use your help. I can't see the wood for the trees.
I'm currently building a formbotkit of a Voron 0.2 and am in the process of setting up the printer.cfg. Unfortunately I have some problems with the sensorless homing.
I think this is because I have built a wild mixture of a 0.1 and a 0.2. Specifically I mean I have used CNC parts which are actually meant for a 0.1. That means I don't have the Z-Home switch at the bottom of the Z-axis but at the top.
I can actually home Z quite well. I have simply entered -0.10 for "position_endstop" as in the Voron 0.1 sample configuration.

My problem now is that the X and Y axes cannot be homed correctly with sensorless homing. The axes move a bit and then think they are homed. At the same time, Z keeps moving down a bit.

I'm really stumped right now and can't figure out what's wrong. A nudge in the right direction would be great.
Thank you very much.

Greetings
Joe

 

[NoGuru]

Okay this is easy, you have your SGTHRS set to the weakest setting.

Follow this guide to test the strength of the the sensorless. https://docs.vorondesign.com/community/howto/clee/sensorless_xy_homing.html

 

[BOSSJoe]

Okay this is easy, you have your SGTHRS set to the weakest setting.

Follow this guide to test the strength of the the sensorless. https://docs.vorondesign.com/community/howto/clee/sensorless_xy_homing.html

Perfect, thank you very much.

After a little sleep and a little more thinking, I came up with it.
The problem with my understanding was that I had to go quite far down with the values.
I started at 255 and then went down in steps of 50. I think that's what the instructions say. When I got to 100 and still nothing had changed, I got nervous. Now I'm at 58 and I still had similar behavior up to 60 as I did at 255.

Thanks again anyway.

Perhaps another question. In my printer.cfg, which comes more or less directly from the Voron Github, there are quite a few macros regarding homing. I am not so good at reading and understanding these macros. Hence the question, do I get problems if I home the Z-axis at the upper end of the Z-axis like I do with a Voron 0.1?

Thanks a lot
Greetings
Joe

 

[NoGuru]

I do sensorless in jumps of 20 then 10 when I get close then I dial it right in to the final number 1 number at a time. Some machines and stepper driver require this and some give you lots of wiggly room. I can tell you on most machines your values are going to be pretty close to 0

 

[BOSSJoe]

I do sensorless in jumps of 20 then 10 when I get close then I dial it right in to the final number 1 number at a time. Some machines and stepper driver require this and some give you lots of wiggly room. I can tell you on most machines your values are going to be pretty close to 0

I did something similar at the end.
I started at 120 and then went down to 100, then in steps of 10 down to 60 and then to 58.

As I said, I have very little experience with sensorless homing and I was unsure when I went that low.

But now I've learned something again. Not bad either.

Joe