Re: Hello from a newbie (onstep)


Howard Dutton
 
Edited

On Mon, Nov 23, 2020 at 03:26 AM, JOAN wrote:
I use a MKS board with DRV8825 .
DRV8825's can often be really poor performers and so are not generally recommended.  Like most rules there are occasional exceptions (as in... I already have them and they work or using for focuser tin-can motor.)

According to you comment:

For example, the 3D printer boards (MKS Gen-L, FYSETC S6) and the CNC board (R32/CNCv3),
are not wired the same way as dedicated OnStep boards (Blue Pill, MiniPCB, MaxPCB), and
therefore the former will work fully only with two drivers (TMC2130 or TMC5160), while the
latter support more drivers (LV8729, S109).

Will I get problems with th drivers I use?
  • All supported 3D printer/CNCV3 boards provide shunts under the drivers to manually configure any micro-step mode you like for traditional StepStick drivers (LV8729, S109, etc.)  The slow Mega2560 based MKS Gen-L boards will be limited in goto speed with this kind of setup though since there is no ability to change the micro-step mode from within OnStep.
  • Most of our purpose designed OnStep boards (Bluepill, Mini2, Max2) allow the processor to do that same micro-step mode configuration.  They all have faster processors than the Mega2560 but they also allow changing the micro-step mode from within OnStep for fast gotos regardless.
  • Some 3D printer boards (S6, Mks Gen-L v2.0 v2.1) can also be configured for an SPI bus interface to the stepper drivers (so SPI controlled TMC2130 and 5160 drivers can plug right in and work.)  This allows changing the micro-step mode from within OnStep for fast gotos.
  • All of our purpose designed OnStep boards (Bluepill, Mini2, Max2, Max3) can be configured for an SPI bus interface to the stepper drivers (so SPI controlled TMC2130 and 5160 drivers can plug right in and work.)  They all have faster processors than the Mega2560 but they also allow changing the micro-step mode from within OnStep for fast gotos regardless.
There are "tricks" that would allow one to work around the MKS Gen-L limitations WRT to using mode switching with traditional StepStick drivers, like the LV8729 etc, it requires a little soldering (jumper wires or bridging driver mode control pins) and an understanding of how things work though... so I don't know of anyone who's actually done it.

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