Suddenly "Timer too close" canbus errors?

General Discussion
1

Basic Information:

Printer Model: VZBot
MCU / Printerboard: SKR 1.4 Turbo + Fly-SHT36
klippy.log
klippy(1).log (307.0 KB)

Describe your issue:

After printing perfectly fine several times yesterday (and several weeks before), I swapped to PLA from ASA today and attempted a print… every time, it aborts during the skirt now with a Timer too close error. Log also shows a bunch of stepcompress errors.
Klipper version is v0.10.0-631-g8a065287, I believe I updated last night after the last print from 627.

For testing purposes, I also ran an input shaper resonance test, which taxes the CAN bus pretty well as far as I know, and that ran through perfectly fine. Manual extrusion etc also does with no issues whatsoever.

2

Use ifconfig to check for error counts on the CAN bus. Dropped frames and errors

Run before and note current numbers, then run again after failures to see if they grow in numbers.

3

Hi,

I am getting the same error (see https://klipper.discourse.group/t/timer-too-close-on-voron-2-4)

@NAPCAL thank you for that hint, I got some dropped RX frames, but what should I do against it? I am using the BTT U2C v2.1 and the EBB2209 board.

Here is the output of ifconfig:

can0: flags=193<UP,RUNNING,NOARP> mtu 16
unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 1024 (UNSPEC)
RX packets 165216 bytes 1056406 (1.0 MiB)
RX errors 0 dropped 291 overruns 0 frame 0
TX packets 283127 bytes 2120877 (2.0 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

4

Lower the speed to 500K and check for errors.
If none the bump it up to 750K
If still high number lower it to 250K

If you still get errors there might be a connection problem, CAN bus wires too close to stepper wires.

1 Like
5

Thank you! I just reduced the speed to 500k and started a 5h print.

I have another question: The CAN cable (the one, which came with the EBB2209) and the wires for A and B stepper motors are all in the cable cain for the z-axis. Is it worth a try to use shielded cables for the stepper motors?

6

The better would be to add a braided shield to the cable with the CAN bus wiring.

I have been planning to do this but my spool of braided shield has gone missing!

7

PXL_20230830_172017127~2
PXL_20230830_172017127~21920×1446 194 KB

“Timer too close” again …

But this time, there were no errors or dropped packages.

However I noticed, that the print failed 2 times at the same spot (see image)

8

As described in the other discussion, probably I fixed my issue

1 Like
9

I have the feeling that UART connection requires short and not too thin cables that do not interfere with other cables and of course a good connection.

10

I totally agree with you. However, I had no troubles using the UART connection with the stock cables. Some days ago I got this error the first time.

This is the stock cable, which I was using.

2000×1730 735 KB