Add canbus support to the Sovol SV08

Introduction

On the road to converting one of my SV08 to multi-toolhead using dragonburner, I had to add CAN support to it. I decided to document my process.

Other can to USB adapters can work in the same way, you would need to adapt if you are using another adapter.

Pre-requisites

• Your SV08 needs to be connected to your local network (either wired or wifi)
• You need to know your printer ip address
• You need to know how to ssh into your printer

Bill of material

• Sovol SV08 3d printer
• Canable USB to CAN adapter (I use this one from aliexpress and programm it with candleligth firmware.
• USB cable to connect the Canable to your printer's USB port. I use these ones from amazon

And if you want to mount your canable on the 2020 extrusion under your SV08 you can use my small housing:

• 2 x M3x8mm Socket Head Cap Screws
• 2 x M3 Sliding T Slot Nut for 2020 Extrusion
• 1 x 3d printed bottomHousing (see stl folder)
• 1 x 3d printed TopHousing (see stl folder)

Procedure

Hardware setup

• Install the m3 bolts and the tnuts to the bottomHousing.
• Install the bottomHousing in the 2020 extrusion and screw it tigth, make sure the cap screws head are well inside the counterbore.
• Clip the canable in the bottomHousing.
• Clip the topHousing over the bottomHousing.
• Connect the USB cable on the free SV08 USB port (underneath the camera usb cable).
• Connect the Type-C end of the cable to the canable.

Software setup

ssh to your printer and follow the steps in these sections

Setting up a daemon to configure CAN at boot

create a systemD daemon file /etc/systemd/system/can0.service.

sovol@SPI-XI:~$ sudo nano /etc/systemd/system/can0.service

Add the following content to the file and save, you can use your prefered bitrate and txqueuelen, klipper recommends 128 but more doesn't hurt.

[Unit]
Description=Setup CAN interface can0
Wants=network.target
After=network.target

[Service]
Type=oneshot
ExecStartPre=/bin/sh -c "until ip link show can0; do sleep 1; done"
ExecStart=/sbin/ip link set can0 type can bitrate 1000000
ExecStartPost=/sbin/ip link set can0 txqueuelen 128
ExecStartPost=/sbin/ip link set up can0
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target

Enable your daemon

sovol@SPI-XI:~$ sudo systemctl enable can0.service

Setting up a udev rule to allow hotplug (in case you disconnect/reconnect your canable usb to can adapter)

create a udev rule file to init your canable /etc/udev/rules.d/90-canable.rules.

sovol@SPI-XI:~$ sudo nano /etc/udev/rules.d/90-canable.rules

Add the following content to your udev rule file and save.

ACTION=="add", ATTRS{idVendor}=="1d50", ATTRS{idProduct}=="606f", RUN+="/sbin/ip link set can0 type can bitrate 1000000", RUN+="/sbin/ip link set can0 txqueuelen 128", RUN+="/sbin/ip link set up can0"

Reload the udev rules.

sovol@SPI-XI:~$ sudo udevadm control --reload-rules

Test your setup

Reboot your printer

sovol@SPI-XI:~$ sudo reboot

ssh back into your printer and execute this command to show your can interface details

sovol@SPI-XI:~$ ip -details link show can0

the result should look like this, I currently have ERROR-ACTIVE because there is only one node to my CAN bus, CAN requires to have 2 nodes to work properly.

4: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UP mode DEFAULT group default qlen 128
    link/can  promiscuity 0 minmtu 0 maxmtu 0
    can state ERROR-ACTIVE restart-ms 0
          bitrate 1000000 sample-point 0.750
          tq 62 prop-seg 5 phase-seg1 6 phase-seg2 4 sjw 1
          gs_usb: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..1024 brp-inc 1
          clock 48000000 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535

Conclusion

You can now use CAN to add more klipper slaves mcu. Refer to the Klipper documentation.