Running two Klipper instances on BTT pad. assigned the USB path to each machine. Only one will connect. Unable to open serial connect

General Discussion
1

Printer Model: Ender3v2 and Ender 3v3 SE
MCU / Printerboard: BTT Pad
Host / SBC- Mainsail
klippy.log

Describe your issue:

Running ls /dev/serial/by-path/* to see what USB are plugged in and assign them to each printer. however, regardless of what port I assign them after reboot, only one printer connects. sometimes its the v2, other times it’s the SE. I can’t find a rhyme or reason for it.

v2log.log (903.9 KB)

SElog.log (901.1 KB)

…

2

Are you sure the printer have different serials?

3

I assumed so, however, admittedly not sure. How would I check that. When I run by ID I get this

biqu@BTT-Pad7:~$ ls /dev/serial/by-id/* /dev/serial/by-id/usb-1a86_USB_Serial-if00-port0

only 1 response shows up.

4

Have you tried to get the id by just connecting one printer when running ls... and then the other one?

5

I unplugged, rebooted and ran the ls, then repeated with the other printer on a different USB, however, I ended with the same result

biqu@BTT-Pad7:~$ ls /dev/serial/by-id/* /dev/serial/by-id/usb-1a86_USB_Serial-if00-port0

6

Then you won’t be able to run them both with two Klipper instances on one SBC.
No instance can know to what printer it should connect.

7

Am I not able to identify them by-path instead, and assign them accordingly?

8

They also will have the same id by-path

9

When I run by path I get to entrys

biqu@BTT-Pad7:~$ ls /dev/serial/by-path/* /dev/serial/by-path/platform-5200000.usb-usb-0:1.2:1.0-port0 /dev/serial/by-path/platform-5200000.usb-usb-0:1.3:1.0-port0

If I unplug one and run it again it only shows 1 knowing one was unplugged.

Sorry, maybe I’m being dense here…

10

You may give it a try

11

I have it configured in my printer.cfg as

[mcu] serial: /dev/serial/by-path/platform-5200000.usb-usb-0:1.2:1.0-port0 restart_method: command

In the documents they mentioned flashing the micro controller with something like this

sudo service klipper stop make flash FLASH_DEVICE=/dev/serial/by-id/usb-1a86_USB2.0-Serial-if00-port0 sudo service klipper start

Should I run
sudo service klipper stop make flash **/dev/serial/by-path/platform-5200000.usb-usb-0:1.2:1.0-port0**=**/dev/serial/by-path/platform-5200000.usb-usb-0:1.2:1.0-port0** sudo service klipper start

I’m unsure what the printer’s unique serial port name would be.

12

Everything here is correct. My issue was there was another [mcu] section in my printer.cfg I did not see, causing issues. Once I deleted it worked like a charm