While I agree that a hall sensor would be a better choice, I believe reed switches can be quite reliable as they have seen use as sensors for bicycle speedometers for some time.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ "Anyone who believes exponential growth can go on forever in a finite world is either a madman or an economist." -Kenneth Boulding, economist >________________________________ > From: Bruce Layne <linux...@thinkingdevices.com> >To: Enhanced Machine Controller (EMC) <emc-users@lists.sourceforge.net> >Sent: Sunday, November 11, 2012 6:34 PM >Subject: Re: [Emc-users] Sieg SC2518 CNC lathe conversion questions > > >On 11/11/2012 03:00 PM, Scott Hasse wrote: > >> ...plus a magnetic reed switch that triggers once per chuck revolution. > >I wouldn't use any mechanical switch in that application. There's a >chance it won't be able to respond fast enough at the faster spindle >speeds, but I'd be much more concerned about reliability. Most >mechanical switches are rated for mechanical life, independent of >contact wear from making and breaking current. Even with no current >flowing through the switch, most switches are rated for something in the >ballpark of 100,000 to 1,000,000 switch activations. That's a lot if >you're pushing a button, but if you're racking up 2000 switch >activations per minute for the spindle index pulse, you'll reach 100,000 >in 50 minutes of spindle time. > >I'd be looking at a solid state switch with no moving parts... either a >Hall effect switch for that magnet, or I'd use a slot or a hole in an >opaque disk with an optical interrupter. > > > >------------------------------------------------------------------------------ >Everyone hates slow websites. So do we. >Make your web apps faster with AppDynamics >Download AppDynamics Lite for free today: >http://p.sf.net/sfu/appdyn_d2d_nov >_______________________________________________ >Emc-users mailing list >Emc-users@lists.sourceforge.net >https://lists.sourceforge.net/lists/listinfo/emc-users > > > ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
