Am 30.06.2009 um 17:09 schrieb Andy Pugh: > 2009/6/30 Haberler Michael <mai...@mah.priv.at>: > >> The code rings are printed on plain paper with an inkjet printer, and >> laminated into a plastic pouch > > Interesting. When I tried a similar approach using clear tape I found > that the reflectivity of the tape in the frequency range of the > detectors was so high that the underlying colour was irrelevant.
I didnt try different colours but tried b/w on paper versus black stripes on a transparent slide, so the reflection would come from the aluminum pulley. The latter gave somewhat higher voltage swings on the coupler's collector, but the glue used to attach the ring would deteriorate things again (and dissolve the ink if glued onto the pulley without laminating), so I settled for the paper variant. Laser printers do give worse results than inkjet. The pouches came with the laminator. I mounted the sensors quite close so they'd "focus" on the paper and not the reflective surface (and due to lack of space :-). Angular displacement turned out to be fairly uncritical. > > Is there any sign of interference from your VFD on the sensor pulses? > I am finding that a bit of a problem. no, actually not. In fact the cable is unshielded but I'm going to change that in the final setup. -Michael btw - there are two flavours of CNY70 in the wild, and some have collector and emitter reversed - make sure to identify the manufacturer and get the proper data sheet. ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
