Welcome to the SeeMeCNC Community

I saw a lot of good feedback about the Repetier firmware so I decided to give it a try. Overall I love it, it's much smoother. The problem is that since I made the switch, during my prints I'm getting quite a few errors like this...

12:35:02.193 : Printing layer 1 of 25
12:35:17.345 : Unknown command:
12:35:17.550 : Resend:588
12:35:17.569 : Error:Binary cmd wrong checksum.
12:35:17.569 : Resend:597
12:35:17.796 : Resend:609
12:35:18.054 : Resend:647
12:40:09.696 : Printing layer 2 of 25

During one 5 hour print, I got 3 hours into it and although I didn't see this error, the printer just came to a halt and wouldn't accept anymore commands. Repetier host was not frozen but appeared to be waiting to be able to send more data to the printer which makes me suspect a communications failure.

The only thing I've found via web search was to make sure the receive cache size is set to 63, which it is. I can see that in the printer settings dialog in Repetier Host. I don't see anywhere in the EEPROM settings that it would be overridden. The other tips were to check parity and stop bits. My baud rate is showing correct in EEPROM and the firmware but I don't see anywhere to set or check parity or stop bits except in the printer settings dialog. I'm currently set to 250,000 baud, 1 stop bit, no parity and auto detect for transfer protocol and 63 bytes for the receive cache size.

Anyone else ever get weird com errors?

The longest print I've made so far was about 9 hours with the Repetier firmware... I've never seen this error... interesting... maybe something with your computer? Do you have the LCD screen and SD card? Maybe try printing from the SD card and see if you get the same problem...

Tony

I don't have the LCD and SD card yet unfortunately. I just had another print stop after about 2 hours. This time there were no errors but it froze the same way it did before. Repetier Host was still hapily running but no communication activity. I pressed the reset button on the Rambo and then Repetier Host immediately started updating temperatures again. Even though it had sat there for 15 minutes before I realized it was stopped, the controller still maintained the hotend and heated bed temps so it's like the controller was doing its job, the PC was too but they weren't talking to each other. This is frustrating since I can't see anything wrong to even begin to troubleshoot. I guess I'll go back to old firmware and try the same print to see what happens.

These types of errors are usually cable related, USB is a crappy interface for the way printers are run, it's very sensitive to noise especially on the ground wires.
You might want to try moving the 5V jumper on the RAMBO board, so it's only getting 5V from the PC USB port.
Try a shorter USB cable, preferably one with ferrite cores on either end.
Sometimes it can be noise on the power line, turning something specific on or off might cause the issue.
You can also try dropping the baud rate in the firmware and see if that reduces the errors.

Getting the same errors about an hour into the print. Turning off the visualization seemed to help...maybe just wishful thinking. I do know that when the errors were happening, I opened Windows Task Manager and the performance tab was showing 100% CPU usage.... Hmmmm.


The errors caused the the hot end to just sit motionless and continue to make blobs....

UPDATE
After checking the Receive Cache Size" under printer setting, I found mine was set to 127 and not 63. After making the change, and this change alone, I ran the same part with no errors.....