@Leeuw123 Just so you understand what has changed, and the effect of that, see M569

The M569 D parameter lets you choose the mode of operation between stealthChop (D3) and spreadCycle (D2). stealthChop is a quiet mode of operation for stepper motors at standstill and at low velocities, but will struggle at higher speeds. While stealthChop is a voltage mode PWM controlled chopper, spreadCycle is a cycle-by-cycle current control. It can react extremely fast to changes in motor velocity or motor load. spreadCycle will give better performance in medium to high velocity range for motors and applications which tend to resonance.

spreadCycle is the default mode of operation, because printers have been getting faster, and reaching the limitations of stealthChop, causing missed steps. RepRapFirmware also allows you to switch over from stealthChop to spreadCycle, using the V parameter. However, this changeover needs to happen at a relatively low speed, as there is a jolt when the changeover happens. The higher the changeover speed, the worse the jolt.

The V parameter defines at what speed this happens, except V isn't the actual speed, it is the interval in clock cycles between 1/256 microsteps below which the drivers will switch from stealthChop to to spreadCycle mode. Low V means the changeover happens at high speed, high V means it happens at low speed.

We suggest the use of one of the following configurations:

stealthChop changing over to spreadCycle a very low speed. Compared to running in spreadCycle always, this reduces standstill noise with some motors. stealthChop changing over to spreadCycle at a little over your normal maximum printing speed. It will switch to spreadCycle for travel moves, except very short ones. This will only be viable if the jerk at switchover is tolerable. Limit your travel speed so that you can keep the printer in stealthChop mode always.

Send M569 P... to see the speed this changeover happens, and tune V to a sensible speed for your setup. eg On my machine, if I send

M569 P0.0 S0 D3 V40 18/12/2024, 13:53:56 M569 P0.0 Drive 0 runs in reverse, active low enable, timing fast, mode stealthChop, ccr 0x00053, toff 3, tblank 0, tpwmthrs 40 (117.2 mm/sec), pwmScaleSum 11, pwmScaleAuto 0, pwmOfsAuto 36, pwmGradAuto 14, pos 8

You can see the changeover speed is 117.2mm/s. I usually set the speed to be above 0mm/s, but below the jerk setting (M566, on my machine set to 5mm/s), so it's in spreadCycle for all movement, but stealthChop at standstill, like this:

M569 P0.0 S0 D3 V1000 18/12/2024, 14:24:59 M569 P0.0 Drive 0 runs in reverse, active low enable, timing fast, mode stealthChop, ccr 0x00053, toff 3, tblank 0, tpwmthrs 1000 (4.7 mm/sec), pwmScaleSum 11, pwmScaleAuto 0, pwmOfsAuto 36, pwmGradAuto 14, pos 8

Tune the V parameter to get the right balance of noise reduction and performance for your machine.

Ian