mechanical limits switches wiring for 7i96s MESA

hey i am having some trouble wiring switches to the board here is what I tried:
I am using pnc conf
I read that the inputs are opticallyisolated so I can put a lot of voltage on the input pins (haven't tried yet only 5v)

the mechanical switchers have NC NO and C

I tried connecting NC to 5V and V to pin1 doesn't stop during homing
inverting just began the turn on with an error about the switch limit


I tried connecting NC to GND and V to pin1 doesn't stop during homing
inverting just began the turn on with an error about the switch limit

I tried connecting NO to 5V and V to pin1 doesn't stop during homing
inverting just began the turn on with an error about the switch limit

I tried connecting NO to GNFand V to pin1 doesn't stop during homing
inverting just began the turn on with an error about the switch limit

FInally i tried attaching NC to 5V, NO to GND and C to pin one and it worked but then the mesa card would get restarted ( apparently its shorting something when i hold the button too long


i saw some other people connecting NC to 24V and then to pin 1, but it should work with 5V as well and it doesn't. i tried pin 0 as well in case the pin was not working. 

i am getting the 5V and gnd from the STEP 3 pins. 

I am very interested what exactly is it that I am doing wrong. 

THanks
 

If you use NC limit switch contacts and sinking inputs, wiring would be:

7I96S input common (TB3 pin 12) = GND (24V common)

+24V --> Limit-Switch C --> Limit-Switch NC --> 7I96S Input (TB3 pin 1 through 11)

In hal, the input must be inverted.

You can use 5V instead of 24V but it's not as reliable long term with mechanical switches

 

Thank you very much.

I don't understand how this is different from what I am trying. here is the setup:

Switch NC to 5V from one of the pins (would it be okay to plug it in the stepper motor DC 24 power supply?)

Switch C to PIN 1 TB3.

IN this case I am missing the TB3 common pin - will it work if I connect it to the GND from the MESA where I am getting the 5V will it work? It is not working as it is right now.

Eitherway if you say it is safe I will connect the DC power supply 24V to the limit switch NC then C switch to TB3 pin and I can connect the Common TB12 pin to the Power supply DC GND.

The isolated inputs will not work as expected unless you connect the
input common (TB3 pin 12)

For sinking inputs (pullup to a positive voltage to activate), input common should be
connected to  GND/power common. If you are using 5V from the 7I96S, this is the
stepgen connector GND.

And yes if you use a 24V supply and sinking inputs, the 7I96S input common would
connect to the 24V supply common (negative)
 

THANKS!!! WORKS!

Now i understand, because they are isolated you need to connect the common pin to a GND reference point to the voltage that will be applied to the input 1-11 pins. I connected everything as you said and it works flawlessly. !!!!

This feels like a bigger achievement than getting my Master's degree haha.