Stealthchop Tuning Confusion

[jwebb4616]

So I am still learning and have tried to not be that person to not look but I am not understanding and seeing clear answers when I search.

I have an FL Sun Super Racer that I decided to convert over since I already had the Duet board. I have it running, and everything is working, but I do not understand what I am reading at the link below.

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

M569 P0
Drive 0 runs forwards, active low enable, timing fast, mode spreadCycle, ccr 0x00053, toff 3, tblank 0, hstart/hend/hdec 5/0/0, pos 210

This printer came with a MKS Nano V3 that had stealthchop enabled and it worked okay, but I had a driver die and a few other issues with the board. I know the documentation says its not recommended at higher printing speeds to use stealthchop but I used it with Klipper and Marlin without an issue so I'd like to at least try it.

How do I determine starting values? Example, This is set by the M569 V parameter. Lower values increase the speed at which the driver will switch over to spreadCycle. M569 with just a P parameter will translate the existing tpwmthrs to mm/sec belt speed for you.

I really don't want it to ever switch over to spread cycle but its not even clear what a good starting value is for tpwmthrs to tune from.

Is there another guide I've missed in searching, with klipper I just turned on the microstepping and then interpolation and used a 999999 threshold and it appears this will be a bit more involved.

[jwebb4616]

I figured this out after a couple days of pulling my hair out. On to pressure advance and input shaping.

[jumpedwithbothfeet]

@jwebb4616 your using the old documentation there maybe more info in the link below

https://docs.duet3d.com/en/User_manual/Connecting_hardware/Motors_tuning

[droftarts]

@jwebb4616 you don’t really need to ‘tune’ stealthchop if you aren’t using stall detection and/or sensorless homing. To set to stealthchop permanently (I do the same), set the M569 parameters for each motor to stealthchop, usually simply D3.

I need to update the driver tuning page, but it’s quite a complex subject!

Ian

[gloomyandy]

@droftarts Last time I checked the default tpwmthrs parameter was relatively high (2000 I think), which typically results in a switch to spreadcycle at a low (ish) speed. So if you want to keep the driver in stealthchop mode all of the time you may need a different V setting as well as D3.

[droftarts]

@gloomyandy good point!
@jwebb4616 Add D3 V0 to stay in stealthchop the whole time.

Ian

[jwebb4616]

@droftarts Ah I used v40 from another post, but V0 makes sense and I will update