Incorrect Stealthchop Setting in the Default Config

[hyperphonic0]

There is quite a lot of discussion on Discord right now, with people having problems with the wrong default setting in the repo. This has lead to many turning off Stealthchop entirely, meaning they will not benefit from near-silent - and skip free - steppers.

Klipper docs are fairly clear that Stealthchop should either be always on, or always off:

Enabling "Stealthchop" mode¶

By default, Klipper places the TMC drivers in "spreadcycle" mode. If the driver supports "stealthchop" then it can be enabled by adding stealthchop_threshold: 999999 to the TMC config section.

It is recommended to always use "spreadcycle" mode (by not specifying stealthchop_threshold) or to always use "stealthchop" mode (by setting stealthchop_threshold to 999999). Unfortunately, the drivers often produce poor and confusing results if the mode changes while the motor is at a non-zero velocity.

So I would suggest changing the default configuration for stepper_x, stepper_y and stepper_z to:

stealthchop_threshold: 999999 # Comment out to turn off StealthChop

I doubt that using Stealthchop on the extruder motor is going to provide any benefit, and because it can reduce the motor torque at higher speed it may cause problems. I would suggest turning it off for the extruder.

[Stephan3]

https://github.com/Klipper3d/klipper/blob/5c10001bc525701f0ef004041cbbf093522f6de6/klippy/extras/tmc.py#L512

Take a look at the code. If value is 0, pwm mode is false and therefor the field in the register is too. With a value of 0 stealtchop is disabled.

[hyperphonic0]

I'm not quite sure what you're saying, but I'm suggesting the default config should have Stealthchop turned on by default, with the included comment explaining how Stealthchop can be turned off, if that is what is desired.

I believe setting stealthchop_threshold: 0 would also turn it off, as would excluding the setting from the config.

[Stephan3]

Oh okay. NVM that people using stealthchop by default.

[eddietheengineer]

I'm not quite sure what you're saying, but I'm suggesting the default config should have Stealthchop turned on by default, with the included comment explaining how Stealthchop can be turned off, if that is what is desired.

I believe setting stealthchop_threshold: 0 would also turn it off, as would excluding the setting from the config.

Hello @hyperphonic0, we have stealthchop 0 by default for a reason--Stealthchop can cause skips and other strange behavior that are more difficult to diagnose. During initial setup, we like to keep configurations in a more reliable state so that physical assembly issues can get identified. Stealthchop also can be louder than Spreadcycle at the higher speeds/higher travel speeds that we commonly use.

[hyperphonic0]

Erm, but Stealthchop is enabled in the default configuration! It is set to 500, which I believe is a value that may well cause the drivers to switch between Stealthchop and Spreadcycle during a print (which in turn can cause skipping and more noise).

[samtny]

lol, i put a PR in for the extruder one, didn't see this issue:

127

PR turns off stealthchop on the extruder only. I have personally troubleshot this with at least five people in the discord since I built my V0.1, July-ish.

[hyperphonic0]

Hi, @nemgrea. Not sure why this was closed, PR #127 doesn't resolve this issue, it turns Stealthchop off for the extruder but does nothing the A/B drives or Z axis.

I think my original suggestion is still correct. I can create a pull request if you’d prefer, but thought an initial discussion here would be a better point of reference; It can be a bit difficult to discuss this kind of issue on Discord!

Thanks for making the V0!