Rescheduled timer in the past - MKS Gen V1.4

General Discussion
1

Basic Information:

Printer Model: Modified Folger Tech FT-5 (CoreXY)
MCU / Printerboard: MKS Gen V1.4
klippy.log
klippy 2.log (371.4 KB)

Describe your issue:

Looking for some assistance with the “Rescheduled timer in the past” error. Currently running 1/16 microstepping on all axes (including extruder) with TMC2209’s. Max velocity in printer.cfg is 300 and max acceleration is 3000. Mainsail/Klipper are running on a Raspberry Pi Zero W.

Print sequence is Bed preheat, then hot end preheat, then send the file to print, home all axes, drops the bed, and the moves the toolhead to the start of the print. This is where I continuously get this error. Please also note that this issue was not happening prior to the most recent Klipper update. I’ve also tried re-installing the Klipper image on the Raspberry Pi and re-flashing the board but the problem persists.

I’ve sliced and resliced my models over and over with the most conservative (default) settings in Superslicer and continue to get this error. It appears to be tied to the extruder steps, because as soon as I change it to 1/8 microstepping, the printer runs but with poor quality.

Any help is greatly appreciated!

2

Interesting. How did you arrive at all these driver_* values for the TCMs?

3

They are all the default values given in the klipper configuration reference for tmc2209 drivers.

4

Quite small chested that tiny guy…

1 Like
5

:joy: Sure is… Planning on an upgrade very soon but it was just peculiar to me that it was working fine before the update.

1 Like
6

Well, in the context of this error the ATMEGA board could be considered overloaded but with your settings, it would be strange.

Try setting stealthchop_threshold to either 0 or 999999

7

Gave this one a go, but no luck. I’ve had stealthchop turned off for the extruder stepper driver since the TMC2209’s were installed, but I tried both (turning it off with “0” and turning it on all the time with “999999”) and still getting the same error message. This one has me puzzled…

8

Got my hands on a pi 3b in hopes that may help. Installed a fresh klipper/mainsail image on the pi, did a fresh flash on the board, still have the same error in the same exact fashion. It just seems that for some reason the board is no longer keeping up with klipper. On the bright side I have an octopus board arriving tomorrow. Hopefully that will be the ticket.

9

The error is the result of trying to move the extruder stepper motor too fast. As a guess, something in your recent print is causing it? It does not seem to be related to any recent software changes in Klipper.

From your log:

Dumping stepper 'extruder' (mcu) 77 queue_step:
...
queue_step 36: t=9260875973 p=1832 i=85 c=79 a=0
queue_step 37: t=9260882687 p=1911 i=84 c=147 a=0
queue_step 38: t=9260895034 p=2058 i=83 c=51 a=0

An interval of 83 ticks is 192K steps per second on an AVR (16000000/83). That is higher than the documented AVR step rate benchmarks.

Your pressure_advance setting is very high - try a print without pressure_advance to check if that is the culprit.

Note that a Rescheduled timer in the past error does not have similar causes as a Timer too close error. The former indicates mcu processing overhead, while the latter indicates host processing (or host to mcu communication) issues.

-Kevin

1 Like
10

It did not occur to me that pressure advance may have been putting the excess strain on the board. I disabled it entirely and it seems to be running well for the moment. Still puzzled why it worked in the past but I guess I must have just been dancing on the line of the mcu’s capabilities. Hopefully that won’t be a problem with a more modern board. It’s due for an upgrade! Thanks for the help!