Question Multiple Toolhead CAN

[JudoJeff]

I am working on a Voron Trident build and would like to get multiple toolheads talking through CAN. I have read that the "first" and "last" boards in the chain have to have the 120 ohm termination resistors. However, I can't see any examples related to 3DP that show toolheads tied together. I do see that the BTT EBB42 toolhead boards do have a label for a "120R" which makes me believe these are already terminated. Does anyone have an example of how to connect multiple CAN toolhead boards? Do I need a separate USB-to-CAN for each? (BTT U2C) Currently I am trying to get just 2 extruders, but my goal is 3 total. Any help would be appreciated.

My hardware:

• LDO Voron Trident Kit
• BTT Octopus 1.1
• Raspberry Pi 4B, 4GB
• BTT U2C V2.1 (USB to CAN board)
• BTT EBB42 CAN V1.2 (Toolhead board) x2

 

[JudoJeff]

I found some info. Quick and easy answer for typical 3D printing applications: If you have the U2C board and 3 toolheads, just put the jumper on 2 of the 3 devices and make sure all the CAN High and CAN Lows are connected. For more details check out Old Guy Melts Plastic's videos:

 

[JudoJeff]

Update, Official response from BIQU:

Can a single U2C V2.1 CAN board communicate with multiple EBB42? -----It should be ok

 

[Maddog]

The only right way to connect 2 or 3 toolheads to CAN would be run a cable to and from each toolhead so you create a single bus and terminate the last one as well as the host controller.
As Old Guy Melts Plastic explained, While CAN is very robust it "works" when poorly configured or terminated, it should be avoided by design.