Proximity sensor hardware debounce?

Hi ! I struggle with a failure with my toolchanger.
i use the latest carousel.comp.

the atc is controlled by 3 proximity sensors.
the proximity sensors are npn normaly open.
i connect them to my mesa 7i92t.
on the mesa 7i92t i have the pullup jumper selected.

If i connect the sensor to 24v,gnd from mesa (on the idc connector) together with gnd of the 24v supply and the signal cable to a input on the mesa i see the pin change the state if i hold the sensor to a screw or something metallic.


original on this machine the signal cable goes to a 22k ohm resistor which is connected to ground. Then it goes to another 22k resistor in series.. which haves a ceramic cap 1nf to gnd. and then to a 74c14 schmitttrigger.. from there it goes to the mcu.

i will draw a small sketch later.

in linuxcnc i debounce the pin with the value 3.
the sensor cables ate not shielded.. and are near to the main drive and maindrive cables.. main drive becomes a 280v pwm signal up to 5amps.

so sometimes the atc stops turning anywhere .. i think it get count signal.. but thete is no count signal.

should i clean the signals like original controller it do?

thanks

I would use an RC filter if in a high noise environment

Also not sure from your description,  whats 24V and whats 5V
no 24V signal should be anywhere near 7I92T I/O pins

I make a drawing in few hours.
Its 5v i measured but later with the drawing it would be better to understand

Here i am again.. this shows us the original circuit of the original controller . the proximity sensor switching gnd. Its a npn normaly open proximity sensor without shielded cables.
Sensor is powered with 24v.

my now setup is:

the output cable from the sensor goes direct to my mesa 7i92t. i see the gpio toggles if i bring the sensor to some metal. it works. the mesa 7i92t is jumpered to pullup.


if i use this circuit i must set the jumper to pulldown. correct?
 

thanks for your help

On the bench it works.

Important is to know that the signal is inverted.
Option 1 use a second schmittriger to re invert. As example.. from 1Y to 2A and from 2Y to motion card.
Option 2 change signal in hal from in to in_not.

Either way will work, there is no technical advantage of using 2 external
inverters.

Pullups/pulldowns on the 7I92T don't really matter for this specific signal
since they are overdriven by the Schmitt trigger

(the pullup/pulldown mode may matter for other signals)
 

It works.
I use a second channel to re invert the signal.
Now no noise on the signal.