Yes, I know. Even things like a servo loop where you have to read an encoder is bi-directional but I think it matters where the loop is closed If the loop close inside the micro controller or the FPGA there would be very little latency. Different if the data has to flow all the way up to a user space Linux Process.
On the z-axis of my mill i'm using a closed loop stepper motor and the loop is closed inside the driver, they say it is a 32-bit DSP chip. The optical encoder connects directly to the DSP But for vision based robot it is a pretty long loop that goes through multiple Linux user space processes. The Linux PC is an 18-core Xeon and my goal is "better then 1Hz" and it still remains to be seen. I assume thing like spindle sync'd move have the control loop running at a very high rate on a process that is logically very close to the encoder signals. On Mon, Apr 23, 2018 at 12:49 AM, andy pugh <[email protected]> wrote: > On 23 April 2018 at 03:29, Chris Albertson <[email protected]> > wrote: > > Look at the example of streaming music. As long > > as the buffer never goes empty there are no dropouts. > > This is OK so long as the information flow is purely one-way. Add a > conductor to your musical example and it breaks down. > (probing, spindle-synched moves etc) > > -- > atp > "A motorcycle is a bicycle with a pandemonium attachment and is > designed for the especial use of mechanical geniuses, daredevils and > lunatics." > — George Fitch, Atlanta Constitution Newspaper, 1916 > > ------------------------------------------------------------ > ------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
