> -----Original Message----- > From: andy pugh [mailto:bodge...@gmail.com] > On Mon, 25 May 2020 at 10:42, Chris Albertson <albertson.ch...@gmail.com> > wrote: > > > Ideally you have just one thin cable going from controller to the machine. > > If you like those chips just glue on on each encoder and turn then encoder > > into a serial interfaced device. Or use a serial buss so 6 encoders can > > share one cable. > > There are elements of this to the STMBL servo drive, in that it uses > the STM32 to count encoder (and resolver and SSI) encoders then > reports back to LinuxCNC using the Mesa smart-serial protocol. > This is a neat choice, as Smart-Serial is self-configuring. Plug in > the device and all the appropriate HAL pins appear as if by magic. > > Smart-serial is still one cable per node, though. It's a star topology. > > But if it will work for you, then the smart-serial STMBL code for > STM32 is there on the STMBL Github. >
There are two options for distributed. Either CAN bus or EtherCAT. For closed loop motor control CAN bus just isn't fast enough although the new CAN-FD has possibilities. EtherCAT is seeing more use in industry. All those solutions are generally more expensive than LinuxMESA for a home/small_shop/hobby system. And that you can get full 3 or 4 Axis CNC systems with LCD displays from China for under $300US for basic CNC operations (internally they have 32 bit ARM processors I believe) the reality is one has to now look at the market. The days of replacing the FANUC or whatever industrial controller on the surplus mill with only a PC c/w parallel port are over. For those systems I'm seeing either MACH4 with Ethernet type Smooth Stepper or LinuxMESA. Most users of Linux do not recommend LinuxCNC with a parallel port. Some users are experimenting quite successfully with Raspberry Pi LinuxMESA. And the BeagleBone with MachineKit is somewhat dead because MachineKit itself is somewhat dead end. Certainly Andy is right. The STM32 as used on our STMBL drives is a good solution for motor control and what Rene and company have done with the STMBL drive is really quite good. I happen to have the Microchip ICD-4 for programming and debugging code. And lots of other Microchip stuff so I am pulled in that direction rather than text based make files and terminal interfaces for all debugging. And it's where my work is. My clients refuse to use Linux for development so it's a no brainer that I'm using MPLAB-X etc. Meanwhile, I've still not completely figured out how LinuxCNC decides how far/fast it should move the Z axis based on the items read back from the quadrature encoder. Or how starting G95 will, I'm told, result in the Z axis tracking the spindle as it's rocked back and forth by hand. John Dammeyer _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
