Help needed with proximity switches

[Boyan Silyavski]

Hi,
I would need some help please with wiring correctly the proximity switches/LJ12A3-4-Z/BX Inductive Proximity Sensor Switch NPN DC6-36V/ to C23 board.

Now i read carefully all posts about that and thought that i understand it, but maybe i am making some basic mistake.





What i would like to achieve is all axis to have 2 switches at both ends each , one as a limit and one as a home. All limits in one pin, all homes at one pin and A home/ second long axis gantry motor/ separately, so be able to square the gantry by adjusting the switches.





I read carefully the manual of the board with the wiring diagrams, but maybe i am missing something.


First the manual of the board says: "Note. The bellow wiring diagrams require setting the inputs to use pull-down resistor."





Second the manual shows how to measure the internal resistance:



So i calculate its 11kOhm, so say roughly 10kOhm


These switches are supposed to be normally open. They have 3 wires brow blue black.



I supply them with 18VDC + at brown -at blue. There is 18v at black, measured between black and blue. I activate the switch with metal object and black goes to 0v.


I followed the corresponding diagram and what i read here at the forum, so wired them like this:
All blue together , all brown together. all black limits together, all black homes together + one black home separate for the long axis squaring.

Now the diagram says connect negative/blue/ to board ground.
I treat 18v as 24v so i connect 10kohm resistor between the input pin and corresponding wire.


So now inputs light but they can not detect triggering of switch. Whatever i change in mach3. I even changed the inputs of the board to high/what i read here on the forum/ but still nothing happens.

One by one the switches work but connected together nothing happens. I searched the web but could not find something better, they all refer C23 diagram in fact.


I am ignorant in electronics, but still wonder how this works, as when more than 1 switch blacks are connected there is always same voltage in the black measured to ground, how the board will detect something happens?

What am i missing here?