Inverted limit switches

Community Discussion 📄 General
1

hi everyone
sorry for the dumb questions.
I’m just after some advice with regards to a limit switch problem I have.
Im using the V3 Arduino CNC shield
I read somewhere with NC switches, you need to invert the pins i.e. $5 to 1
I did that, but the switches still Trigger immediately without any stepper movement.
I replaced the cable with a shielded one, but still NBG
I’m wondering if I misunderstood how to enable NC switches.

i also came across this ‘NOTE: If you invert your probe pin, you will need an external pull-down resistor wired in to the probe pin to prevent overloading it with current and frying it.’
is there any sampe wher eI can see how to do this? is the pull-down resister on the ground pin?

2

Hey Sammy,

Here’s info on limit switches and settings for them for the slb.

Screenshot_20250311-122246_Chrome
Screenshot_20250311-122246_Chrome1722×5396 695 KB

Found here:

Here’s info on limit switches on the older long board that is arduino based:

I believe the older lb boards needed a cap added to work, found here:

You can find a handy diagnostic tool within g-sender that shows activity on your switches (and some), this way you can look if gsender sees your switches correctly, found here:

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