On Friday 03 August 2007, John Kasunich wrote: >Gene Heskett wrote: >> The other possibility is that its a resolver, where one set of wires would >> be power, probably 5 volts, The next set, possibly the green one is an >> index at 0 output, and the other 3 would divide the full rotation in 1/2 >> turn, 1/4 turn, and 1/8 turn. But that on the face of it, would need >> about 4 or 5 more divisions to achieve sufficient accuracy. But one could >> make an educated guess as to that particular signal from a resolver by >> using the std nema color code sequence. The Bad Boys etc phrase comes to >> mind. :) If its all externally powered, then 5 sets of wires would let >> the resolution be divided further to 1/16th and 1/32nd of a turn, which >> with decent ballistics would allow thread cutting. As for an index, the >> MSB's 0-1 transition would suffice if that's the case. > >That's not a resolver. Sounds like you are describing a parallel >absolute encoder. Such things exist but are rare.
They exist, I've seen them with 13 active wires, but they were also wiper switches on copper commutator patterns. But they only had to work once, for about 20 minutes max. Something in the steering gimbels of a titan one IIRC. Yonks ago now, that was 1961 IIRC. Thanks for clearing up the terminology. >A resolver is a rotary transformer, similar to the old synchros and >selsyns that were used in the 40's and 50's. See >http://en.wikipedia.org/wiki/Resolver_%28electrical%29 for more details. > There is no electronics or optics in a resolver, only copper windings >and iron laminations. It does not use a DC power supply voltage. One >winding is excited by an AC sine wave (typically a few volts at 2500 or >5000Hz), and the magnitude and/or phase of the signals on two other >windings are decoded to get the position. > >The nice thing about resolvers is that they are very rugged - with no >electronics in the resolver itself, they can handle high temperatures, >coolant, and other abuse that would kill an optical encoder in short >order. The bad thing about resolvers is that the circuitry to generate >the sine wave reference and interpret the resulting signals is usually >complex and expensive. And could now be put in one IC. >Usually if you are retrofitting a machine with >resolvers the best approach is to remove them and replace them with >encoders. Which is at the end of the day, probably the best idea. I expect, unless he can acquire the original stuff, faster by quite a bit too in terms of making for profit swarf. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) The graveyards are full of indispensable men. -- Charles de Gaulle ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
