MCU shutdown: Rescheduled timer in the past w/ RPi 0 and Ramps/Mega

General Discussion
1

Basic Information:

Printer Model: Voron v1.6
MCU / Printerboard: Ramps 1.4/Mega 2560
klippy.log
klippy.log (3.0 MB)

Fill out above information and in all cases attach your klippy.log file. Pasting your printer.cfg is not needed

Describe your issue:

Please could I get some assistance with MCU shutdown: Rescheduled timer in the past

Currently:
X,Y set to 16 with TMC2208s, jumpers on MS1, MS2
Z,Z1,E set to 32 with DRV8825, jumpers on MS1, MS2, MS3

I recently upgraded Klipper, Mainsail and Fluidd to the latest versions.

Edit - I forgot to mention that I’m using a RPi Zero for Klipper, Mainsail and Fluidd.

Re-flashed the MCU (Ramps 1.4/Mega 2560) and tested movements through Fluidd dashboard.

Print sequence is I preheat the Bed and HotEnd, then send the file to print (Gcode start print command homes x,y,z then drops the bed 10mm and moves the toolhead to the centre of the bed, zeroes the extruder. If correct temps reached, print begins)…

Then immediately shuts down with ‘Rescheduled timer in the past’ message.

I understand that the error essentially says to reduce microsteps, but I have not changed this from what was previously working (albeit on a very outdated version of Klipper - 1 year+ without updating…)

On the Klipper Discourse, it has been suggested to set all drivers to 16 steps.

Searching here, Google and Discord channels does not really provide any answers. Some similar setups and supposing maybe extruder steps or pressure advance settings… (??) Really, I would like to chase down the problem definitively.

…and I might need a bit of hand holding - there are many gaps in my understanding of all this.

My thanks for any assistance offered.

2

The issue is likely your Z axis. At a max Z velocity of 25, you would need 160k steps a second which is more than the 2560 can handle. I would start by reducing max Z velocity to 5 and see if the problem goes away.

1 Like
3

Thank you - I’ll try in the morning and update the thread with results.

4

Thanks J,

As an update:

I formatted the sd card on the RPi and reinstalled everything again. I double checked my vref’s for each driver/motor. I left the jumper settings as per previously stated.

Following the fresh install and uploading the printer.cfg for my printer, I set max Z velocity to 5 as per your suggestion. Print successfully started.

I then set max Z velocity to 15, print immediately failed on start movement.

On reading through my log file, you can see that I have z/z1 homing_speed = 8
I updated max_z_velocity = 8, print running successfully.

I still find it strange that it ran successfully with the previous settings (?)

Anyway, it seems that I have a functional printer again, so my thanks for your assistance.