On Mon, Nov 08, 2010 at 08:55:52AM -0800, Kirk Wallace wrote: > On Mon, 2010-11-08 at 10:30 +0000, Andy Pugh wrote: > > On 8 November 2010 01:16, Chris Radek <ch...@timeguy.com> wrote: > > > > > Jon, I have those same resolvers and I use your resolver converter > > > board. I am pretty sure there are two indexes per revolution. The > > > gearing is 1:1 so I don't think the original spindle resolver can be > > > used this way. > > > > That sounds like a fairly simple thing to fix with a bit of HAL > > though. A flip-flop based frequency divider maybe? > > It seems to me, making sure the flip-flop keyed on the same location of > the spindle, regardless of powering off or resets, might be a problem. I > would consider adding (anding, A & B) a Hall sensor (oil resistant, but > may not be fast enough) or opto-interrupter to the spindle shaft to > latch onto a single index. > > Or, I suppose one could home the flip-flop on power-up.
Index is tricky. With hardware assisted encoder counting like ppmc, HAL doesn't have the index directly. EMC can only tell at servo cycle time that the index happened some time since the last servo cycle, and the new count that is a result of the reset to zero at the index plus whatever additional motion has happened since then. Some mesa firmwares have an index mask ability that you could use to select one of the two indexes by having a sensor that is true for one and false for the other. I use index mask on my HNC because there are many (10? 12?) indexes per ballscrew revolution. A prox selects just one of them. If you don't have index mask in your firmware, your alternative would be to mask it yourself _in hardware_ before it gets to the encoder counter. I'm pretty sure this is something you just can't handle in HAL. Chris ------------------------------------------------------------------------------ The Next 800 Companies to Lead America's Growth: New Video Whitepaper David G. Thomson, author of the best-selling book "Blueprint to a Billion" shares his insights and actions to help propel your business during the next growth cycle. Listen Now! http://p.sf.net/sfu/SAP-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
