Timer too close and MCU shutdown

General Discussion
1

Basic Information:

Printer Model: Hypercube Evolution + klipper
MCU / Printerboard: MKS SKIPR
Host / SBC : MKS SKIPR
klippy.log
klippy.zip (2.1 MB)

My current configuration is using:

  • MKS Skipr as main board (klipper and MCU)
  • EBB 36 for the toolhead, connected through CAN

I have been running ok, just recently got three interrupted prints with one of two errors:

  • MCU timer too close for EBB_CAN
  • MCU shutdown (for the printer MCU)

I read the MCU timer too close, but I am still a bit at loss on where to start.

I attached the log and the MCU and host graphs. Host graph is basically not useful, shows a single peak. MCU graph shows loads always above 100% (which seems strange to me)

I have enclosed the printer, but the skipr board is outside the box. I have two 4010 fans running over the stepper motor drivers. Of course, the toolhead board is inside the box.

After the error, klipper won’t connect to the MCU, even with firmware restart command. The only way to connect to the MCU again is by performing a shutdown, turning the printer power off completely and turning it on again…

2

See Timer too close
Unfortunately, there is not much more guidance we can offer, except for carefully excluding each item mentioned in the above article.

3

I would check TransmitQueueLength for CAN interface (should be at least 1024) and double check CAN cables.

4

Without good reason, e.g. many CAN devices, it should not be bigger than 128. Also see CANBUS Troubleshooting - Klipper documentation

5

Ok… I thought the log might give a hint.

If not, I will:
-add a spacer or a fan to ensure the MCU is not heating due to being too close to the enclosure. Failures are happening when printing ABS one hour or so.
-Uninstalled Obico - it had been installed as default with mks image, but I never used it. Thought it might be using bandwidth for no reason.

  • check CAN cable (probably re-do one side)
  • check USB cable. Already tried two cables, I don’t believe this could be the issue though
  • go over both documents again

I would like to keep Crowsnest and the USB camera…

I am quite sure I have 1024 for txqueuelength. Only one CAN module (the EBB). Have been working like this for a while without issues… Is this number good ir bad?

Thanks
R.

6

I was able to complete the print that was halting. Printed two more parts after this (smaller items).

I did the following checks and changes:

  1. added spacers to create a small gap - 1 to 2mm- between my controller PCB enclosure and the printer enclosure.
  2. glued a small heat sink to the MCU chip
  3. changed txqueuelength for can0 to 128
  4. checked the CAN cable (did not find any problem)
  5. uninstalled OBICO (had been installed with MKS image, but never used)
  6. replaced the X-motor cable, since I found out that one of the terminals had overheated (this might be an old problem, not related to the current issue).

While printing, I monitored the temperature inside the chamber. Maximum is slightly below 50 degrees for long prints.

I don’t know which specific action solved the issue, but I am printing ABS now :slight_smile:
R.

7

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.