Constant motor noise after a move, since firmware update

jwilo

In an attempt to resolve the issue in https://forum.duet3d.com/topic/35452/reading-general-purpose-inputs-in-duet-mini-5-returns-null, I upgraded the firmware on my new Duet Mini5+ from 3.0.something (not actually sure) to 3.4.6.

After a machine move, the steppers now make a loud continuous noise, but not continuous in the sense they're buzzing continuously, but the pitch and volume appears to randomly change.

I thought this must be because my configuration format was for an older firmware version, so I refreshed it using RRF config tool, but no change.

The axes still move and function correctly, but this is a significant difference in behaviour, so would really appreciate any input in getting to the bottom of it. Thanks!

EDIT - not sure how to post a response to my own question to show it as an answer... so just edited here instead. Issue resolved.

So, in config.g, in the M569 lines I've enabled stealthChop using the D3 flag, where previously the D3 flag was not provided. Presumably stealthChop was enabled by default in older firmware, and not in current firmware?

; Drives
M569 P0.0 D3 S1                   ; physical drive 0.0 goes forwards

o_lampe

@jwilo IIRC there was a speed threshold where the driver automatically switched from stealthChop to spreadCycle and vice versa.
When I updated to 3.4.6, I've made no changes to M569 and it still behaves the same.

droftarts

@jwilo said in Constant motor noise after a move, since firmware update:

Presumably stealthChop was enabled by default in older firmware, and not in current firmware?

Yes, that's correct. See https://docs.duet3d.com/en/User_manual/Reference/Gcodes#m569-set-motor-driver-direction-enable-polarity-mode-and-step-pulse-timing

The default is spreadCycle for all drivers from RRF 3.4, and stealthChop2 for TMC22xx in RRF 3.3 and earlier.

Duet 3 Mini 5+ uses TMC2209 drivers, so the default was stealthChop before. Generally, it is advisable to use spreadcycle, as missed steps are more likely with stealthChop.

For the quietness of stealthChop mode when motors are stationary, coupled with the performance of spreadCycle when moving, set the M569 V parameter to switch over at a speed that is greater than zero, but less than your M566 jerk/allowable instantaneous speed change.

Ian

jwilo

@droftarts Thanks Ian, this is really good information - I'll make sure to add that to my reading list.