A bit of both, but a man can dream and laugh at the same time ..... I have been trying to drive a laser diode ( pointer ), modulated at several frequencies to get absolute measurements, they have a feedback diode built in so it's possible, just filter out the multiple modulation frequencies, get the phase shifts, and viola ! the absolute distance, but not much precition, hard to get less than a micrometer. Its just for fun, and not working to well, if you try it, be sure to buy the diodes in bulk .... the feedback loop must be stable with the 250 - 500 MHz high frequency of the modulation signal .... :-D ....
It seemed like a good idea at the time :-D , the diodes were around $300 a piece at that time .... never got it right . It's hard to build phase detectors at these frequencies with discrete components. VARIAX used time of flight as I understand it. So a failed dream and a bit of pun for all the 'steppers are no good' folks ... :-D It was soo much easier n paper :-D What I'd really like is some netzler linear capacitive absoulte scales :-D ... simpler and available, but too expensive. I don't think linear drives are used except in EDM and ECM .... but I could be wrong, not enough holding tourque. / regards, Lars. 2012/8/29 EBo <[email protected]>: > On Wed, 29 Aug 2012 00:10:08 +0200, Lars Segerlund wrote: >> ... >> >> When it comes to hardware, no one can deny servos and encoders, but >> that's not necessary or the reality for many, for serious work only >> linear servos and absolute sensing lasers with interferrometric >> enhancement will do. > > Huh... are you serious with the linear servos and LDM? Or were you > just joking? > > EBo -- > > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
