Duet 3 an Nanotec CANOpen-Controllers

Sprenger

You wrote in your Duet 3 Mainboard description:

2 CAN-FD buses that support the next generation of Duet3D expansion boards, smart tools and custom addons. initial target is support for up to 8 x 3 channel expansion boards (another 24 stepper channels).

Would it be possible to connect Nanotec C5E/CLE4- Controllers with CANOpen to the mainboard?
Nanotec said that CAN-FD and CANOpen are compatible

Best Regards

dc42

What is the maximum rate at which they can process back-to-back accelerate-steady-decelerate command segments? It need to be very fast to support 3D printing (hundreds of segments per second).

When I looked at CANOpen at the start of the Duet 3 project in 2018, its bandwidth was hopelessly inadequate, and there was no FD version. I believe there is an FD version now but I haven't looked at it.

A Former User

@Sprenger said in Duet 3 an Nanotec CANOpen-Controllers:

Would it be possible to connect Nanotec C5E/CLE4- Controllers with CANOpen to the mainboard?

CANOpen is the high level protocol, which would have to be supported by the RepRap firmware.

CAN-FD is the physical layer so they could be connected, but that doesn't necessarily mean they'll work together.

Also, I think the 2 CAN-FD buses might be an oversight as I've seen the second CAN bus refered to as a vanilla CAN bus (this thread)

T3P3Tony

@bearer the hardware supports both as CAN-FD. It might make sense to put "slow" CAN devices on one and leave one for CAN-FD only. Not decided.

MaxGyver

Please excuse me for reheating this topic! I have the chance to get my hands on 3 PD2-C4118L1804-E-08 Closed loop stepper motors with integrated CAN-Open controllers.

Do you think it would be worth a try? I can send them back within 60days free of charge...

Cheers
Max

dc42

@maxgyver RRF does not support CanOpen protocol. I very much doubt that CanOpen would be fast enough to support the high movement rate required by 3D printing, especially as we are about to support input shaping on CAN-connected drivers, which will further increase the required bandwidth unless the drivers themselves support input shaping. It might be fast enough for slower applications such as laser cutting and some CNC applications.

A more practical approach is to configure CAN-connected closed loop motors over CAN, but to command motion using normal step and direction signals. One of our users is already doing this with Duet 3 and ODrives.

MaxGyver

@dc42 Okay, thank you for clearing this up for me.