First post here… so I guess I should start with a “Hi everyone!”…
tldr: With two 1.7amp nema 17 steppers driving my Z axis, is it better to use 1 or 2 drivers? And should I go for the LV8729s or the TMC2208s I have? If not 2 seperate steppers, how do I calculate the vref?
I’ve recently added a second Z lead screw to my printer, I brought 2 matching nema 17’s that, according to the advert, are rated at 1.7amp their part no is 17hs4401. I was using them with a single TCM2208, and have prepared both a parallel and series connection for them. I started with the parallel connection and confirmed it was working mechanically, and moving smoothly, etc. printed a marvin, wow - the results were soooo much better than my single lead screw…
However, I forgot to tweak the vrefs and, during the next print, the stepper for the Z died. In the process of identifying the cause and working through the rest of the drivers I also managed to short my MKS Gen L board. Now the USB isn’t working and the no matter what combination of drivers and steppers I use I can’t get either of the extruder channels to work.
So I’ve order a replacement board, as the 32bit SKRs v1.3 are only 3/4 “moneys” more than the MKS Gen L, I’ve opted for this. If I’m right I can set the vref using the firmware, and not the potentiometers.
Before I make the same mistake again, what are people’s opinion on the use of Dual Z with 2 steppers, is it better to use a seperate driver for each?
If I only use the one, how do I calculate the vref?
Also, I’ve read some notes on the TMC2208’s specification that state a max current of 1.4 amps. As these “17hs4401” steppers are rated at 1.7 amp, does this mean I shouldn’t use these steppers with the 2208s?
Anything else I should consider when swapping out a board?
I’m planning to use the LVs as I have enough, but I still have a couple of spare 2208’s that have always been good to me, on X & Y at least! So I’m considering using these on X & Y still.
Many thanks, and sorry it’s long!