@dc42 - The NEMA 17 stepper on my Bondtech extruder is p/n LDO-42STH25-1404MAC
The data sheet is specing' - " DC 1.4A /Phase ". (I can't post links in this forum yet)

It looks like the Duet 3 Roto Toolboard has a stepper driver current limit of 1.0Amps due to
thermal constraints. The TMC2240 stepper driver chip can Drive -
" Current Ratings per H-Bridge (Typical at 25°C):
* IMAX = 5.0A (Bridge Peak Current)
* IRMS = 2.1ARMS (3A Sine Wave Peak) "
Note 1 in the Duet 3 Roto Toolboard web data sheet states -
*1 Note further thermal testing may allow higher extruder current for Extruders other than the Revo Roto which should not exceed 600mA current.

So, do you think this would be a good combination for "further thermal testing" or is it bound to fail?

@droftarts - I am planning to finish my railcore build over Christmas this year. I have decided to use my previously purchased standard stepper motors on X and Y instead of the CAN connected M23CL's in the near term for simplicity sake. They consume 2.8Amps (Stepperonline pn 23HM22-2804S). The 3each Z-axis NEMA 17 motors (LDO pn LDO-42STH40-1684MAC) consume 1.68Amps. It looks like the the Duet 3 Mini 5+ is a little light on current for the X&Y so I am planning to purchase the Duet 3 Main Board 6HC to drive the 5 total X, Y and 3-Z steppers. Earlier you mentioned using the Duet 3 Roto Toolboard with my Bondtech BMG and Mosquito.

Is this a better solution than the Duet 3 Tool Board 1LC since the Roto Toolboard includes the accelerometer and Scanning Z-probe?
Are the connectors for the Roto Toolboard available easily or as a kit?
(I will look further into the docs)
Thanks for your help with this!
Frank Howard
Electrical Controls Engineer
Mitutoyo America Corp
Duet3D hat howardautomation dhot com

@Phaedrux , yes I have. There is some discussion of Duet 3 hardware, but not of wiring and configuring a total system of Duet 3 including the motors and other CAN I/O that I noticed.

Hello
I am just finishing my build of a RailCore II 300ZLT ( that I started in 2020). This is a personal Machine at my home. My printer build is mostly metal.
I have built up the mechanics with a NEMA 23 Halo and I am starting to look at the controls.
The kit was originally supplied with a Duet 2 combo, but I like the look of your DUET 3 board in combination with your NEMA 23 smart motors and the Duet 3 Toolboard as well as your scanning Z probe all on CAN bus.
I was hoping to keep and use the Bondtech BMG and Mosquito combo printhead, but I am open to changing the printhead if you feel there is major advantage to using your Duet 3 Roto toolboard with the E3D Roto extruder.

Do you have any example system configuration drawings (block diagrams?) vaguely like this –

using these latest Duet controls and their suggested interconnections that would suit my printer?

Regards

Frank Howard
Sr. Automation/Application Engineer
Addup Inc.
Cincinnati, Ohio, USA