On Friday 18 May 2018 22:15:37 Jon Elson wrote: > On 05/18/2018 07:57 AM, Maxime Lemonnier wrote: > > Well, from the halscope capture, the index signal looks quite clean. > > it is digitally generated anyways. > > That is misleading, it is only sampled by the PPMC driver > 1000 times a second, and is also sampled at > the encoder filter clock rate (1 - 10 MHz, selectable) by > the PWM controller board. But, if you don't get any > triggers except at the rate you are sending them, then maybe > it is fine. > > Jon
Jon is correct there. The sample rate of the halscope is the thread rate its running on. usually the 1 kilohertz floating point capable "servo-thread". Its incapable of registering or showing something that may change state at 500+ kilohertz. So this, to get an idea of whats going on, needs at least a dual trace triggered scope with a 100mhz bandwidth, or a digital sampler with a similar bandwidth. I have both. Likewise, the triggering logic being discussed here, also needs to be real, external IC's on a circuit board, the logic bits and pieces for linuxcnc are tied to the thread they are addf'd to in the hal file, with a maximum state change at the 1000 hz servo-thread rate. The external logic can generally keep up with state changes at a 20+ megacycle rate for the $0.25 parts when you buy them in tubes of 25 or so. But this is an interesting project, so please Maxime, keep us posted on progress and problems. -- Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
