Limit Switch help

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Posts: 2
Joined: Tue Jan 19, 2021 1:54 pm

Limit Switch help

Post by carlopetrolo » Fri Jan 29, 2021 12:27 pm

I need a help to undestand how setup the limit switch.

which limit switch i can use? how I connect with the DB25 I/O port

May i have some example of products and cable setup.


bor MC
Posts: 17
Joined: Wed Mar 04, 2020 2:03 pm

Re: Limit Switch help

Post by bor MC » Sat Jan 30, 2021 1:01 pm

The most basic type of switch is a lever arm, micro limit ... 467011_1_7. Most of these come with 3 wire points labeled NO [normally open], NC [normally closed], and COM [common]. Run a wire from the COM post to one of the ground terminals on your DB25 breakout board [pins 7,19, or 25]. Run another wire from either the NO or NC post to the correct axis terminal and designate the setting on the control screen.

For example; Motor 0 is your X axis, and it homes to the minimum travel location. The switch is wired from COM to pin 7 and NO to pin 3 on the breakout board. On the buildbotics control screen under Motor 0 in the limits section, min-soft-limit is set to 0, max-soft-limit is set to your specific travel extent, min-switch is set to normally open, and max-switch to disabled.

Doug from buildbotics also has a link to some magnetic proximity sensors that he uses in a post in the FAQ section of this forum.

Currently I'm using Xtension limit switch kits from OpenBuilds ... witch-kit/. These are labeled GND, V+, SIG. My X switch is wired GND to pin 7 and SIG to pin 3 [the V+ wire isn't needed here].

There is other info in the "Docs" section at [url][/url ]if you want to use a 5v proximity sensor.

I hope this helps you some.


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