MK3S/MMU2S - Prints Fail and log shows errors: FULL RX BUFFER  

RE: MK3S/MMU2S - Prints Fail and log shows errors: FULL RX BUFFER

Haven't seen such an error message yet. Looks like data transfer issue to me. Are you using Octopi or any other USB kind printing?

If yes, try to print from SD card and see if you have still same issues.

RE: MK3S/MMU2S - Prints Fail and log shows errors: FULL RX BUFFER

Using USB, yeah I was thinking that it was some sort of USB transfer flow issue.  Only seems to happen when using the MMU2S for multicolor objects, so far no issues on single or low change material prints so i didn't know if it was some sort of bug from the MMU2S or something else.  I'm gonna start the print over from the SD card tomorrow and see how it does.

Thanks,

I'll update with progress, and hopefully and finally a successful print.

RE: MK3S/MMU2S - Prints Fail and log shows errors: FULL RX BUFFER

Are you using a Raspberry Pi? If so, what model?

RE: MK3S/MMU2S - Prints Fail and log shows errors: FULL RX BUFFER

Hello, thanks for this info. I can see the problem with my printers as well, as soon as a MMU2S is connected.
Printer is MK3 / S - FW 3.7.1 / MMU2S - FW 1.0.5 with current Octoprint on RPi 3B +. Connected via GPIO or USB.

This leads to occasional breaks in printing and missing layers at the end. At first I also suspected an error in the data transfer, but after removing the MMU connection the error had disappeared.

greetings Holger

serial.log:

2019-07-12 01:01:34,375 - Recv: ok
2019-07-12 01:01:34,382 - Send: N75774 G1 X143.989 Y92.170 E0.6644*103
2019-07-12 01:01:34,385 - Recv: ok
2019-07-12 01:01:34,390 - Send: N75775 G1 X144.367 Y91.830 E0.6734*99
2019-07-12 01:01:34,391 - Recv: ok
2019-07-12 01:01:34,394 - Send: N75776 G1 X144.601 Y91.396 E0.6822*106
2019-07-12 01:01:34,396 - Recv: ok
2019-07-12 01:01:34,399 - Send: N75777 G1 X144.665 Y91.010 E0.6892*111
2019-07-12 01:01:34,400 - Recv: ok
2019-07-12 01:01:34,403 - Send: N75778 G1 X144.665 Y83.683 E0.8194*110
2019-07-12 01:01:34,473 - Recv: ok
2019-07-12 01:01:34,476 - Send: N75779 G1 X144.768 Y83.435 E0.8242*100
2019-07-12 01:01:34,477 - Recv: Full RX Buffer
2019-07-12 01:01:34,486 - Recv: Error:Line Number is not Last Line Number+1, Last Line: 75774
2019-07-12 01:01:34,487 - Recv: Resend: 75775
2019-07-12 01:01:34,491 - Recv: ok
2019-07-12 01:01:34,492 - Send: N75775 G1 X144.367 Y91.830 E0.6734*99

RE: MK3S/MMU2S - Prints Fail and log shows errors: FULL RX BUFFER

After some searching, I found the cause of the error in my case. Occasional invalid G-codes in the .gcode file lead to an overflow of the cmd-buffer. Neither the Slicer nor Octoprint nor the MK3 firmware notice these invalid G-codes and let the G-code pass into the cmd-buffer of the printer until the buffer overflows and then is discarded even with the loss of valid data to gain new free space in the printer buffer. The firmware accepts the wrong G-code as correct instead of ignoring it with an error message. As a 1st error the slicer should not bring this g-code into the .gcode file! As a second error Octoprint should never send this G-code to the printer! The 3rd error happens last in the MK3 firmware. This problem does not occur with every print but only under certain circumstances.
I call this problem: The "G" Error
I have corrected the firmware 3.7.1 so that the printer ignores invalid G-codes, as in my case, with a hint in the .log file. This fix fixes the problem with the overflow of the buffer in my case. There may be a similar problem at the printer of myoung. This error is probably synonymous when printing from the SD card, but there is no .log file that logs the error.
I consider this issue to be security-relevant, since the printer can be corrupted by G-codes, which means that it is potentially unsafe for the received data. Therefore I do not give further information in public.

To fix this problem with your printer, look closely at the G-codes files.

greetings

Holger

RE: MK3S/MMU2S - Prints Fail and log shows errors: FULL RX BUFFER

@holger-s3

I'm seeing this now with my 3.8.1 MK3S with MMU2S.  But my gcodes are just the gcodes generated by PrusaSlicer 2.1.0 and sent down via octoprint.  Do you happen to have a git patch you can point me to for your firmware change to properly detect invalid gcodes?  I'd like to use it in my investigation.

RE: MK3S/MMU2S - Prints Fail and log shows errors: FULL RX BUFFER

@kevinh

Thank you for your hint. A problem related to this has also been posted on Github. I hope Prusa takes this problem seriously.

https://github.com/prusa3d/Prusa-Firmware/issues/2388

greetings

Holger

RE: MK3S/MMU2S - Prints Fail and log shows errors: FULL RX BUFFER

@holger-s3

Hi Holger, that was me 😉 (I found your post when googling).  I think the error is in the one line code_seen() function - if Prusa wants a PR I'll make one and send it in.

RE: MK3S/MMU2S - Prints Fail and log shows errors: FULL RX BUFFER

@kevinh

Yes, I already thought it. The issue you described is very similar but just the tip of an iceberg. I am therefore modifying the ori. Firmware for months (since 3.4.x) and I never use the original firmware.

RE: MK3S/MMU2S - Prints Fail and log shows errors: FULL RX BUFFER

@kevinh

There are certainly a variety of solutions to fix this issue. My changes to the topic can be found primarily in cmdqueue.cpp -> get_command () function.