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« on: May 09, 2018, 08:24:17 AM »
^ Great reply from Joe as usual. It looks like your actual limit switch inputs are currently disabled so you'll need to activate that and run something into that pin.
Inductive proximity sensors are usual for home switches, and sealed NC microswitches are usual for limits. My machine is set up like this with the homes almost at the maximum + direction of each axis - The limits are at the absolute maxima.
I've used a series loop for all six limit switches so that all the switches trigger one pin. It makes very little difference operationally speaking and uses less wire.
Noise can be a problem on home and limit circuits so it's worth letting a nominal current through the loop (say 50mA) by fitting a decent pulldown resistor to the pin and 0V. This ensures that when the pin is held high by the power supply to the switch loop there is little enough loop resistance that any noise trying to pull the pin voltage down will make no difference, and when the limits are triggered the pin falls to 0V promptly and can't float up or be driven high by spurious signals. It's a common strategy in antenna controllers where long wiring systems may be subject to electrical interference, noise, microwave pulses and other mischief. How you implement this on the home switches will really depend on the sensor you use but it's just as important.