Re: [Emc-users] spindle index, once more
On Jun 30, 2009, at 3:26 PM, Haberler Michael wrote: > > Am 30.06.2009 um 17:09 schrieb Andy Pugh: > >> 2009/6/30 Haberler Michael : >> >>> 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. > Since you have an aluminum pulley you could anodize it then etch the lines on it much in the same manner you would etch a circuit board. IIRC HCl i.e hydrochloric acid works well if your resist will take it. I used to label aluminum panels by a deep etch of the letters then fill with colored epoxies. :-) HTH Dave > > > -- > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] spindle index, once more
2009/6/30 Steve Blackmore : > Andy - are you sure it's from the VFD? Yes, pretty much. The initial problem was with the limit switches nuisance-tripping, and that only happened with the lathe spindle turning, not with the milling spindle (which is on a DC motor). It even seems to only really be a problem at a certain small range of (lathe) spindle speeds too. -- atp -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] spindle index, once more
Am 30.06.2009 um 17:09 schrieb Andy Pugh: > 2009/6/30 Haberler Michael : > >> 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
Re: [Emc-users] spindle index, once more
On Tue, 30 Jun 2009 16:09:45 +0100, you wrote: >Is there any sign of interference from your VFD on the sensor pulses? >I am finding that a bit of a problem. Andy - are you sure it's from the VFD? I'm getting the some jitter even with the VFD powered off. Set up a spindle speed meter as per page 133 integrator manual, meter kicks randomly here with everything powered off? Steve Blackmore -- -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] spindle index, once more
2009/6/30 Haberler Michael : > 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. Is there any sign of interference from your VFD on the sensor pulses? I am finding that a bit of a problem. -- atp -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] spindle index, once more
my lathe was lacking a spindle index sensor and quadrature encoder, so I built one as follows: The code rings are printed on plain paper with an inkjet printer, and laminated into a plastic pouch; then cut with a scissor and glued to the spindle pulley (with some pressure so as to get a reasonably flat surface). The pulley on my lathe is 18cm in diameter and has about 2cms wide space for the code rings. Laminating the paper into the a plastic pouch protects the printout very well against oil and cooleant. The sensor are reflex couplers - I had CNY70's at hand, so I used those. The schematic is unspectacular: http://static.mah.priv.at/cnc/index.pdf . The couplers are mounted at about 1.5mm distance from the codewheel. - edit codewheel parameters in the Postscript source file to your liking: http://static.mah.priv.at/cnc/codewheel.ps - the parameters are reasonably documented. Pictures: http://mah.priv.at/gallery2/main.php?g2_itemId=68003 -Michael -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
