Hi, new (potential) user here wanting to upgrade from Mach3. After 14 years using that venerable and unsupported CNC application on Windows machines I am finally thinking about an upgrade to my mill. At the moment I have a Windows NUC with USB to a UC100 to a BoB, thinking of replacing the BoB with a suitable board running grblHAL. One nice option would be to replace the NUC with a Pi 3B+ of which I have two spares. As far as I can see the latest version for the RPi is 1.6.1 which I have downloaded on a Pi500 desktop and it seems at least to load and open fine. Two questions if I may (and I didn’t find clear answers on the megathread).
Will the latest RPi image run on the 3B (assuming its OS is upgraded to 64-bit)?
A side issue - any recommendations for a processor board to run grblHAL?
@JohnHaine Since I don’t work for “the company” as @KGN does, I do not have any reservations about suggesting that you look at the SLB from Sienci. I switched from the original LM controller as soon as the SLB became available and it has been solid from day one.
Thanks for that. It does look a good solution, but as I understand it (though the description isn’t absolutely clear) it includes integral stepper drivers. I already have a chassis with 4 quite reasonable drivers and a PSU, all I really need is a motion controller to replace the UC100/BoB so I rather favour using an OTS processor card running grblHAL - I can sort out the interfacing etc myself.
The way I read this thread, the OP has open loop stepper motors. Is the output of the SLB-EXT suitable for open loop steppers as long as external drivers are used?
@Jens Good question. I don’t see anything in @JohnHaine posts that describe the steppers as open loop or closed loop. I don’t know if the SLB-EXT can be used to control open loop steppers, either. You could write books about what I don’t know.
Correct, I have open loop steppers. They also run from a 36v supply.
I’m confused about the SLB-EXT, the description is ambiguous. The -EXT suffix might indicate it uses external drives but then it needs a 48V 10A supply! Not having a clear specification is putting me off a bit!
The FAQs section for the SLB-EXT states it only works with closed-loop Nema 23s.
It requires the 48V 10A supply because if you get an AltMill all the data and power for the motors are connected directly to the SLB-EXT with single set of cables. This makes it cleaner/easier. You do not need to use the 48V power supply provided on the SLB-EXT and can use some external power source for motors and only need the data lines for the motors.
OK, thanks for that clarification. But I understand that it doesn’t have the actual stepper drivers on board, just outputs step and direction pulses, so what makes it only work with closed loop motors?
The device that makes it go, the driver, is hanging off the back end of the motor. I assume that the output of the SLB-EXT is power (presumably DC straight from the power supply) and the four individual phase signals (probably straight TTL output). A position decoder is part of the driver. The part that I don’t quite understand is how the SLB-EXT gets notified of a motor fault.
Edit: Looking at the ‘data’ connector from the SLB-EXT to the individual motors, there are eight conductors so there is obviously more than just step and direction involved. I did not look at the detailed schematics.
, maybe the SLB-EXT would be a better fit. It does not have the drive motors on the board.