# 2 instances of ender 3 s1 pro **URL:** \ **Category:** General Discussion\ **Created:** [February 15, 2024, 12:38am UTC](https://klipper.discourse.group/t/2-instances-of-ender-3-s1-pro/14118 "2024-02-15T00:38:55Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Crathen](https://avatars.discourse-cdn.com/v4/letter/c/e47c2d/32.png) [@Crathen](https://klipper.discourse.group/u/Crathen)\ **Post date:** [February 15, 2024, 12:38am UTC](https://klipper.discourse.group/t/2-instances-of-ender-3-s1-pro/14118/1 "2024-02-15T00:38:55Z")
### Basic Information: Printer Model: ender 3 s1 pro MCU / Printerboard:stm32f401 `klippy.log` _Fill out above information and_ **_in all cases attach your_ `klippy.log` _file_** (use zip to compress it, if too big). _Pasting your_ `printer.cfg` _is **not** needed_ _ **Be sure to check our “Knowledge Base” Category first. Most relevant items, e.g. error messages, are covered there** _ ### Describe your issue: MCU by-id only shows 1 printer. I’ve tried to change printer.cfg on both instances to the respective by-path values and still no success. I can run each printer alone if the other is unplugged using the by-id mcu. Any help? Running klipper, moonraker and mainsail off a laptop running lubuntu. ---
**Author:** ![JassMan23](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/jassman23/32/8238_2.png) [@JassMan23](https://klipper.discourse.group/u/JassMan23)\ **Post date:** [February 15, 2024, 5:55pm UTC](https://klipper.discourse.group/t/2-instances-of-ender-3-s1-pro/14118/2 "2024-02-15T17:55:30Z")
Welcome Crathen. Unfortunately no one will be able to help you unless you include your klippy.log. Having the check mark does not mean you have provided it. That said it sounds like you haven’t been through the install procedure correctly. You need to find the SERIAL address of each board. so you can have different references to each board eg: > [mcu] > serial = /dev/serial/by-id/usb-Klipper\_stm32g0b1xx\_49003D000E50415833323520-if00 > > [mcu] > serial = /dev/serial/by-id/usb-Klipper\_stm32g0b1xx\_49415833323520003D000E50-if00 > The Klippy docs about setting up your system explains how to find these serial numbers. /dev/serial/by-path is allocated each time a new serial device is detected and depends entirely on the order in which devices respond. It can not be relied on to be the same, the next time you change your plugging. ---
**Author:** ![Crathen](https://avatars.discourse-cdn.com/v4/letter/c/e47c2d/32.png) [@Crathen](https://klipper.discourse.group/u/Crathen)\ **Post date:** [February 15, 2024, 6:12pm UTC](https://klipper.discourse.group/t/2-instances-of-ender-3-s1-pro/14118/3 "2024-02-15T18:12:02Z")
Thanks I will give that a go, klippy.log I will upload today. ---
**Author:** ![Crathen](https://avatars.discourse-cdn.com/v4/letter/c/e47c2d/32.png) [@Crathen](https://klipper.discourse.group/u/Crathen)\ **Post date:** [February 15, 2024, 8:54pm UTC](https://klipper.discourse.group/t/2-instances-of-ender-3-s1-pro/14118/4 "2024-02-15T20:54:13Z")
ive done several reinstall of kiauh trying different combinations for an mcu output like the one you have shown. I still only have 1 port on by-id and 2 by-path. Neither board have a serial chipid to enter to be able to separate the identical boards. I haven’t uploaded the klippy.log yet because i haven’t been able to create 2 mcu id to add to the printer.cfg. Here is my output for dev/serial rinter@RicksPrinters:~$ ls /dev/serial/\* /dev/serial/by-id: usb-1a86\_USB\_Serial-if00-port0 /dev/serial/by-path: pci-0000:00:1d.0-usb-0:1.2.1:1.0-port0 pci-0000:00:1d.0-usb-0:1.2.2:1.0-port0 lsusb Bus 001 Device 006: ID 09da:2700 A4Tech Co., Ltd. W4DS Bus 001 Device 005: ID 09da:2700 A4Tech Co., Ltd. W4DS _ **Bus 001 Device 020: ID 1a86:7523 QinHeng Electronics CH340 serial converter** _ _ **Bus 001 Device 022: ID 1a86:7523 QinHeng Electronics CH340 serial converter** _ Bus 001 Device 004: ID 05e3:0610 Genesys Logic, Inc. Hub Bus 001 Device 003: ID 413c:3012 Dell Computer Corp. Optical Wheel Mouse Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 003 Device 002: ID 413c:2106 Dell Computer Corp. QuietKey Keyboard Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 004: ID 058f:a014 Alcor Micro Corp. Asus Integrated Webcam Bus 002 Device 003: ID 8087:07d6 Intel Corp. Intel(R) Centrino(R) Wireless-N + WiMAX 6150 Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub bold are the devices ---
**Author:** ![Sineos](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/sineos/32/18_2.png) [@Sineos](https://klipper.discourse.group/u/Sineos)\ **Post date:** [February 16, 2024, 7:31pm UTC](https://klipper.discourse.group/t/2-instances-of-ender-3-s1-pro/14118/5 "2024-02-16T19:31:10Z")
The boards are using the CH340 USB to serial chip. This chip does not expose a unique serial (see [Issues flashing the printer board](https://klipper.discourse.group/t/issues-flashing-the-printer-board/14015#obtaining-the-boards-serial-7) for a bit of detail). You will need to either - use by-path - use [UDEV rules](https://blog.oddbit.com/post/2022-02-13-wemos-udev-rules/) and try to create unique endpoints (not sure if it is even possible but it’s nerdy) ---
**Author:** ![Crathen](https://avatars.discourse-cdn.com/v4/letter/c/e47c2d/32.png) [@Crathen](https://klipper.discourse.group/u/Crathen)\ **Post date:** [February 17, 2024, 3:22am UTC](https://klipper.discourse.group/t/2-instances-of-ender-3-s1-pro/14118/6 "2024-02-17T03:22:33Z")
Perfect, thank you. Im thinking that i need to flash with the USB option in the menufile as the ender cfg file says to use the UART option. I will try again when i get a chance and will update with the results. ---
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/klipper/original/1X/64419bf2aac6639e6ef5cef200dcd456b0a01ac3.png) [@system](https://klipper.discourse.group/u/system)\ **Post date:** [April 17, 2024, 3:22am UTC](https://klipper.discourse.group/t/2-instances-of-ender-3-s1-pro/14118/7 "2024-04-17T03:22:47Z")
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