Inductive Proximity Sensors-what are they?

[Splint]

Hi,
I saw the term inductive proximity sensor on this page http://www.campbelldesigns.com/breakout_board_plus.htm but I'm not sure what one is or where it's used, are they limit switches? Please enlighten me...
Thanks
Splint

[Al_The_Man]

Proximity switches can be used as limit switches, there are types available in different kinds of physical shapes and also types that can detect a ferrous or non-ferrous metal 'flag'.
The sensing distance is dependant on the diameter of the sensing face, typically .2 to .5 cm. One down side is you cannot use them in a environment with a lot of metalic chips and dust etc.
Al

[ESjaavik]

Be sure you use the right type of metal for the flag. A collegue of mine told me that one place he worked before, someone had mounted a flag of another metal than specified for the end stop of a gantry crane. They obviously did not know how it worked. During the test run one test was of course testing the end stops. It didn't, and the gantry went through the wall and ended up on the parking lot outside. Ouchh!

[owhite]

I've been wondering if proximity switches would work to keep a laser's cutting head from coming in direct contact with the sheet metal its cutting. I havent taken a really in depth look at the spec sheets that are available for the capacitive sensors that are digikey. If anyone knows of a good circuit diagram for really precise positioning please let me know.

owen