I did roll my own - let me know if you want me to send the Eagle PCB files and BOM.
DougM On Tue, Jun 14, 2011 at 1:20 PM, Peter Loron <pet...@standingwave.org>wrote: > On 06/14/2011 08:53 AM, Kirk Wallace wrote: > > On Mon, 2011-06-13 at 13:47 -0700, Peter Loron wrote: > >> Hello, folks. Can anybody comment on using hall effect switches on a 3 > >> axis mill for limit / home switches? Seems like they would have some > >> possible advantages over physical contact switches. > >> > >> Thanks. > >> > >> -Pete > > My Hardinge lathe uses Hall limit and home sensors. The Z axis target > > magnet is small and mounted such that there is minor protection from > > chips. There is a small gap between the magnet and sensors when aligned. > > If chips are in the magnet area, they get wiped off, but not too small > > such that small chips don't bind in the gap. the magnets are weak enough > > to have largesh chips fall off. The trip location accuracy only needs to > > be within about 2 or 3mm because, in my case, the home sensor is used in > > conjunction with the screw encoder index, which should be accurate > > to .002mm or better. What I like about Hall sensors is that they are > > machining fluid proof and will practically never wear out or change the > > trip point or behavior over time. I tend to think using mechanical > > micro-switches is silly, but a lot people use them to good effect. The > > Hardinge Z axis uses a Hall sensor with magnet in a micro-switch > > housing: > > > http://sensing.honeywell.com/index.cfm?ci_id=154286&la_id=1&Ne=7&sid=1308EB555700&ci_id=154286&N=3591+4294966517&la_id=1 > > Short URL: http://alturl.com/v2jzu > > > > These are mounted in a location well protected from chips, but the area > > is not sealed from coolant, which is fine because the sensors don't mind > > fluids. > > > > The Z sensors are in an aluminum threaded barrel similar to this one: > > > http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=480-3256-ND > > Short URL: http://alturl.com/netsd > > > > They tend to be expensive, but it should not be too difficult to machine > > a barrel and pot an IC sensor with leads into it > > Yeah, I'm going to roll my own...I have a pile of Allegro sensors here. > Also, retail on the Honeywell sensors is probably more that I've got > invested into the whole mill... :-) > > -Pete > > > ------------------------------------------------------------------------------ > EditLive Enterprise is the world's most technically advanced content > authoring tool. Experience the power of Track Changes, Inline Image > Editing and ensure content is compliant with Accessibility Checking. > http://p.sf.net/sfu/ephox-dev2dev > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ EditLive Enterprise is the world's most technically advanced content authoring tool. Experience the power of Track Changes, Inline Image Editing and ensure content is compliant with Accessibility Checking. http://p.sf.net/sfu/ephox-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
