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RS232 Connection

The RS232 standard interface (also known as EIA RS-232) is one of the commonly used serial communication interface standards, widely used for data transmission between various devices. Its stability and reliability make it the preferred communication method for many devices. This protocol uses signal levels different from the standard 5V to transmit wire data, which can minimize signal interference to the greatest extent. In the 3D printer system, compared to CAN, RS232 has a higher data transmission rate, better stability, simpler configuration, and better compatibility with the host computer.

Tool Board Connecting to Main Board Using RS232​

  • Please note that the tool board power cord is not connected to the RS232 signal line, but to the 12V-24v power line

  • D8 main board firmware does not need to be recompiled

Search for RS232 ID​

Precautions Before Searching for the Device​

  • Before searching for the RS232 ID, please first connect to SSH
  • Please note that you need to ensure that you are logging in to SSH via the network rather than through a serial port
  • Please ensure that UTOR is connected and that the data cable connecting to the host computer has data transfer capability
  • If using G2T, please determine whether the system supports UART connection

Search for the Device​

  • Now that you have successfully logged into the host computer, you can enter lsusb to search for devices. It will result in one of the following scenarios:
    • If entering lsusb prompts that the ls command cannot be found, you can enter the following command to install the command: 
      sudo apt-get install usbutils
    • If entering lsusb results in no reaction, this is a system issue and beyond our control. You will need to change the system or use a confirmed normal system
    • If the information shown below appears, please note that this is just a reference. You only need to confirm the characters after the ID.
  • 1a86:7523 belongs to the device you need to use. The subsequent prompt does not need to be managed as the system issue may cause it to display incompletely or not at all.
  • If not, please check if the data cable is properly connected and if the firmware has been correctly flashed.
Precautions

You can only use the following command to search for the RS232 ID when there is 1a86:7523.

Search for RS232 ID​

ls /dev/serial/by-path/*
  • If there is no ID output after entering ls /dev/serial/by-path/*, but lsusb shows a device, please replace the host computer or the host computer system
  • Please note that UTOR will output three IDs, and if you have used another UTOR system, it will record it and cause multiple IDs to appear during the search
  • Please ensure that the ID ends with -port0 otherwise it cannot be used.
Precautions

Please make sure that the tool board and UTOR are grounded!!! Otherwise, you cannot connect to the tool board!!!

Fill in the RS232 ID into the Configuration​

  • Open the printer web interface, find printer.cfg under the configuration option on the left sidebar; for fluidd it is {...}, and for mainsail it is machine, click in to find printer.cfg

  • Copy the blue ID and fill it into the serial: field in the [mcu SHT36] section of the printer.cfg configuration. After saving and restarting, you can connect to the mainboard. If Klipper prompts ADC out of range, it is a normal phenomenon. Connect the hot bed and thermistor well, configure the thermistor pins and output pins for the nozzle and hot bed, then save and restart.

Precautions
  • The RS232 ID needs to configure baud: and restart_method:command
  • Below is a reference configuration
[mcu SHT36]
serial: /dev/serial/by-path/platform-1c1c000.usb-usb-0:1.2:1.0-port0
baud: 250000
restart_method:command
dangerous

Note: All IDs appearing in the document are examples. Each mainboard's ID is different, so please modify and fill in according to the actual obtained ID.

dangerous

Please note that the following ID cannot be used!!!!

serial: /dev/serial/by-id/usb-1a86_USB_Serial-if00-port0