Limit switch wiring

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Limit switch wiring

Post by cornbrown » Thu Feb 18, 2021 7:43 am

I have a V3.51 shield w/ grbl 1.1. I'm using a 24v > 5v optocoupler and some npn proximity sensors. I'm trying to figure out if the X+ limit pin needs ground or if the ground from the shield will work. Or should I jump the limit pin grounds to the same ground pin going to one of the optocoupler's grounds?

Here is a pic to illustrate.

I can add the proximity sensor's wiring if needed. It's just npn
proto.png (266.75 KiB) Viewed 114 times

Bertus Kruger
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Re: Limit switch wiring

Post by Bertus Kruger » Mon Feb 22, 2021 6:41 pm

All GND pins are shared on the CNC Shield , so you only need one connected.

The CNC shield has builtin pull up resistors that will pull the line high at all time...
When the endstop gets shorted it will pull the pin to GND and GRBL will stop.

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