> >I cruised some of the Honeywell sensor pages and the Digikey catalog > >page with the 1GP4001 on it. I had studied the previous Digikey page > >because I was interested in the Honeywell 103SR13A-1 which are installed > >on my Hardinge lathe. I am guessing that for rigid tapping that the > >sensor will need the zero speed feature. It did not seem obvious to me > >which sensors where zero speed capable. What should I look for that > >would indicate this? > > > First rule of magnetics is that a coil as and inductance is a velocity > sensitive device, so there is a minimum speed below which it doesn't work.
Zero speed capability has to do with the signal conditioning circuit. Some sensors use an edge detect, some use a level comparator with hysterisis, and some actually have an A/D and digital processing to constantly calculate switch points. There are probably more that I am not thinking of right now. > As far as I know, all Hall and GMR devices are amplitude sensitive, not > velicity. Even a reed switch fits this category if one doesn't mind the > mechanical lag which could be in the milliseconds range. Be careful analyzing Magneto-resistive, it is amplitude sensitive until saturated, and it is sensitive to the angle of the flux vector. > I'm still puzzled by the 10 kilohertz response listed for this device. > WTH? The upper limit on frequency is most likely due to the signal processing circuit. I would bet that it has a low pass filter for noise immunity. You really don't want the sensor that sensitive to mechanical, magnetic or electrical noise. 10 kHz is pretty fast in mechanical terms. ------------------------------------------------------------------------- SF.Net email is sponsored by: Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
