I needed an extra driver channel on my big CoreXY. I had been using an external driver but it was starting to annoy me having to control it with jumpers and the voltage put rather than the Duet configs.
So, I looked at adding a Duex5 expansion but then decided to get a Duet 3 Mini 5+ with the additional 2 driver addon board. This gives me seven TMC2209 drivers.
Here it is all mounted up. The wire hanging down the middle is for an accelerometer I haven't wired up yet.
Decided to stick an accelerometer on my extruder carriage to take advantage on input shaping.
The CoreXY is running at 200mm/sec and 10,000mm/sec^2 but I've got a fair bit of ringing I'd like to get rid of.