On Tue, 22 Dec 2015, Marius Alksnys wrote: > Date: Tue, 22 Dec 2015 05:06:43 +0200 > From: Marius Alksnys <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: [email protected] > Subject: [Emc-users] Mesa 7i77 encoder max count rate > > In my current linuxcnc, 5i25 and 7i77 setup I get 1MHz maximum encoder > count rate. Is it possible to increase it? > > I want to run a spindle up to 10k RPM with resolver. There is a resolver > to quadrature converter, giving 16384 counts per revolution. That's > 5.461 MHz. > > Encoder velocity output goes crazy above 4000 RPM roughly. That's about > 1 M counts / s. > > It might be not possible for Mesa 7i77 while using 4 channels. I will > try to reduce output scale of the converter, but would like to get more > from 7i77. Can't find how. > > Another approach would be to look at the index pulse width and if it is > wide enough, count it with another encoder channel in count mode and > make custom HAL component to switch between feedback devices. I need > accuracy for slow moves and spindle orientation and velocity at higher > speeds. > > Using probably the latest firmware for Mesa cards and updated LinuxCNC 2.7. >
Did you try turning off the encoder filter bit? The limitation is because the 7I77 encoders are muxed. You can push up the mux rate with rev 4 encoders because they allow adjusting the multiplexing skew (from cable delays and switching times) > > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
