I wouldn't waste my time adding tachs on an existing system. Tachs are not without their own problems. Brushes, noise, belts, couplings, etc.
Tachs were used because there was no way to determine velocity off of a position resolver way back when. No one is installing tachs these days. The standard is to derrive the velocity from an encoder. Heck, even Fanuc did that in your existing control, which you are ripping out. Adding tachs is just adding possible mechanical issues and going backwards. I didn't know that hostmot2 could output velocity, that is pretty slick. That would certainly be a low cost solution and that should be very reliable. But lets face it. That machine you have is probably worth an easy $40K or more if it is running right. What is $195 x 3 for a $40K machine. Insignificant. Dave On 3/20/2010 5:33 PM, Paul Keeton wrote: > I agree with you Chris. The drive can be setup for either a 3v/1000 or > 7v/1000 tach signal. This might be the simplest way to to do it. Servotek > makes really good tachs, May be just what I need. > > Dave > > ----- Original Message ----- > From: "Chris Radek"<ch...@timeguy.com> > To: "Enhanced Machine Controller (EMC)"<emc-users@lists.sourceforge.net> > Sent: Saturday, March 20, 2010 5:19 PM > Subject: Re: [Emc-users] G52 and Fanuc conversion to EMC > > > >> On Sat, Mar 20, 2010 at 03:57:02PM -0500, Jon Elson wrote: >> >> >>> If you look further, I think you will find there is NO tachometer in the >>> machine. The Fanuc controls synthesize this from the encoder signals. >>> >> The mesa hostmot2 driver has a good encoder velocity output that >> considers the time stamp of the last encoder event to give smoother >> output than d(counts)/dt. I'd just send that to a dac and see if it's >> good enough to keep the amp happy. If it is, you have a pretty >> cheap solution (just the cost of another 7i33). >> >> If that didn't just work, I'd quickly give up and fit real tachometers >> like some others have suggested, because I bet in the long run that >> is the best configuration. >> >> Chris >> >> ------------------------------------------------------------------------------ >> Download Intel® Parallel Studio Eval >> Try the new software tools for yourself. Speed compiling, find bugs >> proactively, and fine-tune applications for parallel performance. >> See why Intel Parallel Studio got high marks during beta. >> http://p.sf.net/sfu/intel-sw-dev >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> >> > > > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
