On Sunday, February 05, 2012 08:41:06 PM Jon Elson did opine: > gene heskett wrote: > > This board claims excellent speed, as in 10ns propagation delays thru > > the opto stuffs. That seems rather fast for opto's, and I haven't > > measured it although I have the scope to do it with. > > I don't believe it! If they are really opto-isolators and not some > other technology like magnetic, then anything less than 100 ns is > almost impossible. I use some expensive optos with amplifiers in them, > and they swallow pulses less than 250 ns wide. I don't particularly > worry about the propagation delay, but the minimum pulse width is a > concern. > > Jon
Frankly, neither do I Jon, in fact when I read that, I immediately ordered up a whole trainload of skepticism. I didn't want to run out. In my present setup, I have the step pulse reset time at 4 u-secs, creeping down about .5 u-secs at a time when I think of it, which isn't often, till I see skip problems. I was cheerfully using about 1 microsecond with direct drive into a xylotex board. Stepconfig originally set it at 5 u-secs. All of those timing specs for the MM542 drivers seem to be a proprietary secret. They seem to be working well, but who knows when one of those specs has been pushed too far? Unless the machine does wild & crazy things that are obvious. Then you'll finally know but likely not which one you violated unless keeping notes. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> I believe a little incompatibility is the spice of life, particularly if he has income and she is pattable. -- Ogden Nash ------------------------------------------------------------------------------ Try before you buy = See our experts in action! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-dev2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
