Update: Rail module repair = SUCCESS!

While I completely agree with you, in a pinch if I was forced to use that chip, it looks like the standalone mode could be as few as /8 microsteps. The main controller can comfortably run at a pulse count that would equal around 20mm/s at that microstep setting. If there was a huge desire to use that chip, testing might confirm the controllers ability to double or triple that speed. Not ideal for sure though.

If we’re redesigning the whole thing, let’s just go ahead and add the comms port from the linear module controller to that stepper driver and control it via CAN. So much work… I kid

Well as you mention CAN :smiley:
I think someone has to keep the autority on direction and such. waht ive seen, the step size can be varried, usualy, tell the “local” controller to switch step size, move to encoder pos for a rapid, then switch back to the stpper commands by the main controller?
I was looking for the mtotors today if soemoen had taken their linear module to bits to see what type, rating and size the motors are. having a maybe slightly thiner one with the option for a encoder might be an option? Dont know how far you want ti to take though on feedback, Like the local MCU is listening on the step infos and if the encoder suddenly shows a big movment let the printer e-stop and try to recover?

there is a really old post that i was in (don’t have time to look for it now) where the exact motor model and description was posted. as soon as i get my replacements i tend to fully tare down a rail and i can provide any specific information you would like at that time.

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That one I presume?

Seems like a super vanilla cheap stepper.


that would be the one i was thinking of… man seems like ages ago lol

I’ve been tracking SM specs as I find them, here:


I’ve been eyeballing the tmc2209. You can see here why I wouldn’t consider the tmc5160. This is from the tmc5160 datasheet.

This is from the tmc2209 datasheet.

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Yikes. 2209 it is…

Hello Geared, i know the difference between both IC, the TMC 2209 is up to 29V and 1,7A RMS (max. 2A) Single Chip design and the TMC5160 is diffrent with external MOSFET (multi Chip design) it is posible to use more then 50V and 4A. more like the specifications of the original motor driver of the SM2. I don’t know if the Tmc 2209 is powerfull enough for the replacement. Perheps it must be tested.
The only thing i know is the Powersupply has 24V and in the controller are Fuse for each rail about 5A, so it is possible to get 120W of power, this mean at 42V there is a teoretical max current of 2,8A. so my decision was to use the TMC 5160 with externel MOSFET an test it at 24V and later with 40V.

May I ask a question?

If I recall well, in order to use the ‘Silent/Stealth’ mode on the TMC drivers, they need to be ‘activated/programmed’ by one an MCU on the supported channels ( UART, SPI, … ) if not they just work in legacy compatibility mode which would be similar to the actual one, so not much benefit will be there on swapping them. I’m I missing something? Always keen to learn that we can manage with ‘just’ a HW swap :slight_smile:

If I’m reading the data sheet right Stealthchop is configured by tieing pin SPREAD to GND. The 2209 appears to have close to full functionality in standalone operation. The main limitation is 1/8 microstepping is as ‘fast’ as it’ll go in standalone mode.

Quick maths from something I saw staff posted: (18,000 mm/min max processor output @ 400steps/mm) -> 1/8 microstep = 2250mm/min (37.5mm/s) max travel, a pretty heavy limitation.

I run the 2209 drivers on my other printer and they are quiet, that’s for sure.


Really nice to know. Means that with HW mod we can already gain a bunch :smiley:
Thanks for sharing @brent113