SV06, after setting pressure advance, mcu shutdown: Rescheduled timer in the past

General Discussion
1

Basic Information:

Printer Model: Sovol SV06
MCU / Printerboard: ?
Host / SBC: Raspberry Pi Zero 2W
klippy.log: klippy (1).log.zip (195.0 KB)

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Describe your issue:

After setting pressure_advance: 0.025 I’m presented with the following error, after PRINT_START and PURGE_LINE from KAMP, as soon as the skirt needs to be printed.

MCU 'mcu' shutdown: Rescheduled timer in the past
This generally occurs when the micro-controller has been
requested to step at a rate higher than it is capable of
obtaining.

(If necessary I can attach gcode for the print, and config for OrcaSlicer)

Tried:

  • installing the v0.12.0 tag from git with building the bin myself. Installed, doesn’t prevent this issue
  • disabling pressure_advance altogether
  • compared the sv06-2022.cfg with mine, I saw there was one difference: in the section stepper_y the driver_... was set to 81 (in mine) and 82 in the one on github.
[tmc2209 stepper_y]
++ driver_SGTHRS: 82
-- driver_SGTHRS: 81

All of these things are tried, but none worked. I think somehow it’s trying to get too fast?

What can I do to deduct this issue???

2

See Rescheduled timer in the past
Likely a combination out of:

  • Quite high microstepping (128)
  • Pressure advance
  • Printing speed

that finally exceeds the board’s processing power.

3

How does this pop up suddenly, when I’ve not had this problem before?

Like I said, I removed pressure_advance and reduced the speed to only 120mm/s. What can be still the case if the microstepping was the same all along?

4

I do not know. Likely coming from some Macro or Slicer input. See your log:

KAMP purge is not using firmware retraction, it is recommended to configure it.
KAMP purge starting at 100.05199999999999, 101.872 and purging 30.0mm of filament, requested flow rate is 12.0mm3/s.
extruder: pressure_advance: 0.050000
pressure_advance_smooth_time: 0.040000
extruder: pressure_advance: 30.000000
pressure_advance_smooth_time: 0.040000
TMC 'extruder' reports GSTAT:      00000001 reset=1(Reset)
TMC 'extruder' reports GSTAT:      00000000
Stats 679.8: gcodein=0  mcu: mcu_awake=0.005 mcu_task_avg=0.000030 mcu_task_stddev=0.000088 bytes_write=89858 bytes_read=134307 bytes_retransmit=9 bytes_invalid=0 send_seq=4950 receive_seq=4949 retransmit_seq=2 srtt=0.003 rttvar=0.000 rto=0.025 ready_bytes=0 upcoming_bytes=0 freq=72003711 sd_pos=3698 heater_bed: target=60 temp=60.8 pwm=0.147 sysload=0.05 cputime=37.568 memavail=185144 print_time=734.429 buffer_time=15.992 print_stall=1 extruder: target=220 temp=220.6 pwm=0.476
# .... SOME LINES LATER ....
toolhead: max_velocity: 200.000000
max_accel: 800.000000
max_accel_to_decel: 400.000000
square_corner_velocity: 8.000000
Stats 696.8: gcodein=0  mcu: mcu_awake=0.013 mcu_task_avg=0.000032 mcu_task_stddev=0.000069 bytes_write=100857 bytes_read=140416 bytes_retransmit=9 bytes_invalid=0 send_seq=5299 receive_seq=5299 retransmit_seq=2 srtt=0.003 rttvar=0.001 rto=0.025 ready_bytes=11 upcoming_bytes=5517 freq=72003691 sd_pos=4301 heater_bed: target=60 temp=61.2 pwm=0.000 sysload=0.12 cputime=38.948 memavail=185180 print_time=737.471 buffer_time=2.023 print_stall=1 extruder: target=220 temp=222.1 pwm=0.188
MCU 'mcu' shutdown: Rescheduled timer in the past

extruder: pressure_advance: 30.000000 might be tiny tad too much

5

Ok. I found out what the issue is.

You’re right pressure_advance: 30.000000 ís a “bit” high.

I reinstalled MainsailOS and the whole bassamanator/Sovol-SV06-firmware that I used, and configured it again according to the steps.

Once that was done all prints went as planned.

Also, when that was done the following message popped up: Unknown command:"M900". That led me to investigate what it was, and lo and behold, it’s the linear advance of Orca Slicer. Apparently that’s setup for the MK3S profile for PLA that I’m using.

I do remember vaguely that I installed a shim macro for the M900 command.

So, all in all, I could’ve done with simply removing the M900 macro. This has lead me to a cleaner setup and config. It had become a little bit of a Frankenstein machine…

Now that hurdle is out of the way, AND I know the cause, I will continue on my journey to make my prints more efficient :smiley:

One question though: how to get rid of the M900 in the output gcode from Orca Slicer?

6

The PA value is a property of the used filament. As such, it makes sense for the slicer to have this value in its filament settings and pass it down into the Gcode.

Orca supports setting different Gcode “flavors” in the machine settings and if set to Klipper then it will emit SET_PRESSURE_ADVANCE ADVANCE=... instead of a M900 command.

7

Btw, a question on this. I’m calibrating now my steps with a calibration print and calculator.

Is it possible to set the microstepping to a different number? Will this give more fine-grained control?

8

I was expecting that too, but it’s not the case. When I switch to Klipper, nothing changes.

The only thing that’s been added is the M900 codes that are in the start-g-code in the filament section. I’m using the presets from Prusa MK3S with adaptation to SV06, that might be the issue.

However, I see that I have to enable Pressure Advance in the Filament Config. When I do that, it actually DOES output the SET_PRESSURE_ADVANCE macro

Thank you! I’ll change that when working with the filaments :slight_smile:

9

Microstepping reality:

  • In terms of accuracy, microstepping beyond 16 hardly yields any improvements in a typical printer setup
  • Microstepping improves:
    • Noise
    • Resonance
    • Smooth velocity transitions
  • Microstepping significantly reduces the torque of a single microstep, but NOT the overall torque.
  • X number of microsteps actually might pass “unnoticed” until enough torque is generated to overcome inertia or friction and something starts moving
10

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