On 2/21/2015 6:27 PM, Kirk Wallace wrote: > On 02/21/2015 03:42 PM, Brent Loschen wrote: >> Greetings everyone! New guy here. I've been following the group for >> several weeks and feel it's time for an intro and to get some >> suggestions for a small project I'm working on. > Welcome to the world of LinuxCNC. > Thank you Andy P., Mark W., and Peter W. for your responses to my original post - most helpful!. My apologies for this delayed response.
I've been reading everything I can, and I'm weighing the various options for the desktop mill (to practice on with steppers) vs the Bridgeport (brushed DC servo ) conversion down the road. I'm not sure if some of the components used in CNC systems really do have multiple names for the same functionality, or if there are subtle differences between them. For instance is a motion controller the same as a PLC or FPGA? In certain contexts, I get the impression that they are the same, yet in others, a "motion controller" seems to be a programmable device used for fixed functionality i.e. robotic pick and place. In my world, PLC's and FPGA's are discrete semiconductor components, not complete boards controlled by them! Another question I can't seem to answer is, what's the fundamental difference between using a standard "bit banged" pport vs using something like 7i43 or a bus connected 5i25? In the default case (no special hardware), my understanding is that LCNC toggles the lines of the pport (step/direction signals?) which are connected to a stepper drive. What I've not been able to answer, is how the fundamentals change when using, say a 7i43, connected to the same port? Instead of sending pulses out the pport, LCNC must instead be sending some kind of higher level data stream (possibly lower bandwidth? ) to the 7i43 where it gets converted to precisely timed step/dir pulses - is that right? If so, what is that data and how is it different from step/dir signals in the default case? Can anyone comment on the differences or point me to documentation that explains it? Along the same lines, I've wondered how acceleration/deceleration is handled. Is it always manged by LCNC regardless of bit banging or additional hardware, or do FPGA/PLC based boards ever handle that too? Thanks, Brent ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
