there are actually 4 coils. Each head has 2 shielded cables coming from the head - each cable has 4 conductors + shield. At the controller - the 2 coils on each cable are hooked together to form a center tapped setup. (agian - if I have it right - they excite the 2 outside connections of the 2 center tapped hookups - then the center taps get summed together and shaped. this from trying to read the desciption on the schematic I scanned - plus you can see the coil hookups) :)
thanks sam Jon Elson wrote: > Andy Pugh wrote: > >> Thinking about this some more, I think it is a quadrature LVDT. >> As we discussed on IRC it is a lot like an LVDT with multiple >> armatures. The thing is, if you only have that then you can't infer >> direction. By having two offset read-heads in quadrature you can tell >> direction. >> >> > Well, a classic LVDT is a non-repeating position measuring device. > > The Farrand Inductosyn can be run like this, but the difference is that > the pattern of exciting windings repeats periodically. > The Inductosyn has no pole teeth, and the long scale has a continuous > zig zag of traces on a ceramic or PCB substrate. > Obviously, the scale has low resistance and inductance, therefore it > requires a lot of drive current. The pick-up sensor is usually a short > length of identical zig zags, with the sin and cos sensor 90 degrees out > of phase relative to the long scale. > > The GE and other sensors were made to offer a similar device but get > around the Farrand patents, which were quite well written and precluded > any closely similar scheme. Having slots and no coils on the long scale > was different enough to not infringe on Farrand. These could be made > with 3 coils, and the variation of magnetic coupling between the teeth > and the coils changes the amount of excitation that gets to the sense > coils. I don't know how you do this with only 2 coils, and it probably > restricts the excitation and sense circuits quite a bit. > > Jon > > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.437 / Virus Database: 271.1.1/2804 - Release Date: 04/11/10 > 06:32:00 > > ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
