Hi guys, i'm ordering parts for my first cnc build and the thing that confuses me the most by now is the proximity switches. I want to know what kind of sensors should i order first and than what is the best way to connect them. I want to order 6 pcs connect them in series NC type, 3 wires, inductive proximity switches and they say they work on 6-36v.

q1- what is the difference between supplying them with 6-12-24-36v will the sensors behave different on different voltage or it doesn't matter? (i plan to run them on 12v)

q2- i have seen many different ways to connect them, what is the most reliable way? (i plan to do it in series with 12to5v relay on the signal)
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correct me if i'm wrong

extra question what do you think about the idea of using step down on the signal instead of using resistors or relay ?

i will use DB25 bob like that in the attachment, if that is even the name for the bob :/