A major advantage of the inductively coupled probes is that there is no need for a battery in the probe. Also, there is no possible interference from other probes in the same shop (not a problem here!). The real driver for me is that they appear to be considerably more common on the used market than either the direct connect or the optically coupled flavours. The bad news is that an IMM plus MI5 interface unit costs more than a probe. I don't know what they do in the MP3 with IMM but WO 1995007521 A1 issued to Renishaw in 1995 describes a little of one system: Power is transmitted from the interface to the probe in the form of a 60kHz carrier. Data from the probe back to the interface is transmitted in a data band extending from approximately 500kHz to 5MHz. Commands are transmitted in a command band which is narrower than the data band and is centred around a 210kHz carrier.
I have no idea if this is the actual scheme used with the MP3. > -----Original Message----- > From: Gene Heskett [mailto:ghesk...@shentel.net] > Sent: Tuesday, September 27, 2016 11:37 AM > To: emc-users@lists.sourceforge.net > Subject: Re: [Emc-users] snagged touch probe on eBay - anybody know how to > interface ? > > On Tuesday 27 September 2016 09:29:47 Ken Strauss wrote: > > > The discussion has been regarding the optically coupled probe. Has > > anyone had success with the inductively coupled ones? Is it feasible > > to make your own IMM module? > > I'd have to say you could, but these machines are generators of a large amount > of magnetic noise. So I'd say not magnetically coupled, but radio coupled just to > get above the frequency of the machines own noises. I'd have to assume > something that used a very high carrier frequency just to get above all the > harmonics of the pwm and stepper pulsing noises. Any great amount of power > would require it be put, frequency-wise, is some band the fcc or whatever > control agency is governing your locale, has allocated for that. That wants to > point at bluetooth. Bluetooth stuff has a range of 10 feet or so, but thats so > noisy it would require you to invent your own protocol just so nearby computer > mice and keyboards wouldn't have the right checksums of their packets to > register. But it is by now a well developed, cheap technology. And I've no clue > what the latency would be, but quite likely much more than a direct electrical > contact would have. > > I debounce 2 servo cycles, so thats a 3 millisecond lag worst case which means I > double touch, the second at low feed speed. > > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > Genes Web page <http://geneslinuxbox.net:6309/gene> > > ---------------------------------------------------------------------------- -- > _______________________________________________ > 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
