MCU randomly disconnecting

General Discussion
1

Printer Model: CR10S Pro
MCU / Printer board: Creality 4.2.7 main board
Host / SBC: Raspberry Pi3B+
klippy (5).log (3.9 MB)

So I’ve been stuck trying to figure out this issue for about a week and I cannot figure it out. I really need help interpreting my Klippy log. At first, I thought it was narrowed down to my webcam drawing too much bandwidth, so I switched it to camera-streamer and lowered the resolution. This made the print I was working on go about 90% done but then again it just randomly shut off. When my camera was on its previous settings it wouldn’t make it through the first layer without mcu disconnecting so I thought I had fixed it. The only other thing I can think of is my raspberry pi getting too hot and causing it to stop. Thanks for the help.

2

Welcome JimSchorts,

I think your klippy.log doesn’t show any unusual behavior.

Usually the first idea is the best. You could add the RPi temperature to your klippy.log see Klippy.log adding CPU Temperature of the host device - #2 by mykepredko

Good luck, hcet14

3

When I get a chance, I will set it up to do that. Between that post and now it actually did the same thing. Would you be able to see if it is any different? Also, could it be my usb cable because I assume if the usb cable is faulty and randomly disconnects it wouldn’t show anything in the log?

Here’s the next klippy log (compressed because it was too big)
klippy.zip (2.4 MB)

4

I couldn’t find any difference. The only thing I found outstanding was the time mark when Klipper restarted. “Stats 9524.8” in both klippy.logs. Did you try a print with a different model (gcode)?

Yes, it could be your USB connection, but I would expect “Timer too close” or “Timeout with MCU / Lost communication with MCU”. Have a look at Sineos excellent Knowledge Base - Klipper. There is nothing in your klippy.log.

5

Yes, it was a different file than what I had previously printed. Based on what you saw in my klippy log, what would be the most likely causes you would troubleshoot first?

6

Do i understand that right?

was printing a different file as

?

7

Yes that’s correct.

8

This is the “usual”

Lost communication with MCU 'mcu'

error. It is right in both logs. See Timeout with MCU / Lost communication with MCU

Since you’ve already identified the cam as a potential source, have you tried disconnecting it completely?
If this doesn’t work, take a look at the other sources listed in the provided link.

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9

When I had the camera initially setup, it was failing on the first layer of the print. I tried disconnecting it, and it seemed to work fine. But then I plugged it back in and turned down my fps and resolution and it made it about 75% through before failing which is why I’m not sure.

10

Now we’ve isolated the cause of the issue. :+1:

How far did you tune down your resolution and FPS? On my more powerful Pi4 connected to Ethernet, I run only 640x480 at 5fps.

11

I have it at 1280x720 @ 15 fps i think. I turned it to camera-streamer as well.

12

I would try 854x480 @ 5fps then try a print.

13

So here’s what I tried:

  1. I turned the res down to 640x480 @ 5fps
  2. I got a power supply that is a bit nicer and runs at slightly over 5 volts (I was getting undervoltage errors before at one point too)
  3. I put a fan on my raspberry pi case

I’m not sure which one of these fixed the issue, but I did a successful full print using this. I did turn my res back up to 1280x720 @ 5 fps and actually had a successful print with that, so I think my issue was the raspberry pi overheating. Before, it was having constant overheating notifications and running at 65 + degrees, now it runs at 45 under load. Fingers crossed its fixed now!

14

One question. How do you cool your raspberry pi?

15

I bought a 30 mm fan and plugged it in and there’s a heat sink as well that came with the pi. I didn’t have one before and it was at 65+ but now it’s running around 45 ish with the fan.

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