I put a new CR-10s V2.1 MOBO in my CR-10 and added filament sensor. Everything fine except when the zstop is open it reads as triggered and vice-versa. X and Y stops read fine. What could cause this?
If you loaded Marlin, you can invert the signal in configuration.h.
Reverse the wires
Put the endstop at the top
[*]Leveling the bed is over-rated