serial port error

Hi,

I have a problem with my serial port.
I have a rostock with ramps 1.4 + GEN7 extension board (rewire to the ramps) and a mega 2560 clone with the ch340 chip.
My baudrate is 115200.
I use repetier firmware and repetier host.

When I connect my desktop computer to the printer everything is fine, I can control the printer perfectly. But when I start a print, in less than a minute I have a bunch of

system.io.ports.serialport errorreceived

in repetier console, and the printer stops.
The printer can't be controlled from repetier anymore, but can be control from the LCD.
I can't reconnect to the printer without closing repetier host, resetting the printer, and pluging the rpinter on a different usb port

I have done those test :
I have tried to print directly from the SD card. The print is ok but repetier catch the same error and freeze.
I have done a print (from the sd card), and tried sending M105 command in the serial monitor of the arduino ide. The print was ok, but the printer stopped answering 1 minute after the print started.
I have tried different usb port : same issue
I have tried a baudrate of 9600 : same issue
I have tried with my laptop instead of my desktop computer. Same repetier host version, and I was able to do a 20min print directly from my laptop (no sd transfer). No problem at all.
I can make this error happen by sending a lot of manual command quickly (for example, by quickly changing the hotbed temp)
I let my printer idle (and plugged to the computer) for like an hour, and i got no problem, but as soon as i started a print, got the error again.

Other information that might be useful :
Sd tansfer works with my laptop and my desktop, but I have some "wrong checksum" error on my desktop and not with my laptop.
I thought of windows related issue, so i reinstalled windows completely on my desktop computer, but no success, same error.

I am running out of idea to figure out what is causing me this communication error. My printer is usuable as i can send gcode to the sd card, but, well, it's annoying...

Thanks for your help

Stupid question but have you tried different cables? Have you tried heavily shielded cables? Have you tried keeping the cable away from any mains voltage wiring etc... I get a lot of "checksum error resending " etc... if my usb cables are in close proximity to power cables, even heavily shielded ones?

Well... No.
In fact as it's working on my laptop, qith the same cable, I have guessed that it couldn't come from the cable. However I might be wrong. What do you think ?
I don't have another cable right now, that's why I didn't test that solution.

Edit : for the usb/power proximity, I have tried my best but, on ramps, the usb cable is right under the power cables...

Edited 1 time(s). Last edit at 01/25/2016 04:55PM by Repier37.

No I don't mean DC power cables they produce very little EMI, I mean mains voltage power cables are to be avoided.

Quote
DjDemonD
No I don't mean DC power cables they produce very little EMI, I mean mains voltage power cables are to be avoided.

Good to know.
But the answer is no.
But I found another usb cable, not shieldied either, but shorter (1m vs 3m). and ... IT WORKED. Like a charm...

After all, that was just the thing I eliminate at first.

Anyway, thanks a lot !!!

Edited 1 time(s). Last edit at 01/27/2016 09:58AM by Repier37.

You're welcome, common problems occur commonly.