On 2/22/2016 9:15 AM, andy pugh wrote: > On 17 February 2016 at 17:14, Dave Cole <[email protected]> wrote: >> Prox switches are just the opposite. Most are even waterproof. >> Prox switches are becoming very cheap. Someplace is trying to sell me >> some for about $10 each with a cable. >> I've used Prox switches on very expensive machines for homing and limits >> and they just work. No call backs. > Those must be the expensive ones :-) > http://www.ebay.co.uk/itm/390880485798 as a random example, that's about $5. > > NPN work better with parports and mesa cards (not sure about Pico). > They almost all need a >5V power supply, but NPN ones look like a > switch-to-gnd to 5V logic, so that isn't a problem. > I run mine at 12V because it is convenient. > > Note that they come in a variety of diameters and detection distances, > and that there are two types. The one in the link above will _not_ > work if embedded in an iron casting. This type, where the threaded > portion reaches right to the end (called "shielded") will work in that > situation. > http://www.ebay.co.uk/itm/121776227835 > These have a shorter detection distance. > I have recently been tending to use these embedded into the machine > out of harms way and picking up on drilled holes in the slideways as > targets. I do try to find non-bearing surfaces, of course. > There are two here: > https://picasaweb.google.com/108164504656404380542/HarrisonMill#5989135693933177186 > > There is also an alternative mounting style that might be very > convenient for an extruded-frame machine: > http://www.ebay.co.uk/itm/121766473917 >
>>Those must be the expensive ones :-) Yes, but the ones I buy are extra shiny. :-) Seriously, the 12 mm ones that I spec out most often are about $18 with a quick connect plug on the back end. The cord with the connector is another $9-$20 depending on length. All of the ones I have seen die have been due to customer tweaking or abuse, or extreme corrosion. In general, if the plastic projects from the end of the metal shell, it is an unshielded prox. Dave ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
