On Wed, 2010-12-08 at 15:56 +0200, Roland Jollivet wrote: > I have looked at these. The linearity is quite poor, see pg. 6 and 7 > It looks like you might be up to 10 counts out at any position with an > optimally placed magnet. > > Slotted encoders are usually out by a % of less than one count. > > The parameters will also change as the bearings wear over time. I think they > are great for something like a butterfly valve or accelerator pedal where > lots of discrete steps are required, but their relative accuracy is not > important. > > Regards > Roland
I have played with a similar device, the AEAT6010: http://wallacecompany.com/machine_shop/EMC2/AEAT-6010/ My plan is to use it with my tool changer carousel as an absolute pocket encoder. This allows me to know the pocket position without going through an initializing motion to find an index on an incremental encoder. One issue, for an absolute encoder, is the data link to EMC2. There is only a digital bit input so far. My AEAT6010 application uses an SPI link for which I created a halcomponent that bit-bangs the serial bits into a few parallel port pins. http://wallacecompany.com/machine_shop/EMC2/AEAT-6010/ This can work well for a tool changer, but not for realtime motion control. I suspect anywhere a potentiometer can be used, these Hall sensors would be an appropriate replacement, plus there is no or less mechanical wear and dirt issues. Now if I would just get off my behind and finish the project, you could see it work. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ This SF Dev2Dev email is sponsored by: WikiLeaks The End of the Free Internet http://p.sf.net/sfu/therealnews-com _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
