MCU input for external switch with OVP and ESD protection?

[asrock70]

I need a universal input for MCU (STM32) for connecting external mechanical and magnetic sensors (HAL with open collector), and a universal output 0/5V (0/3.3V), all of which is resistant to connection of at least 24V and resistant to ESD in an industrial environment. With HW debouced mechanical switch , but with a short reaction time.
I came from the classics, everything important is in the picture
V+ for R1 and IC1 is derived from +V over isolation diode
supplemented with a capacitor and a 5V6 zener diode.
However, I'm not sure if 100uA is not enough for a mechanical button?
R1,C1 at least doubles the ESD protection of the 74HC to the input diodes
What do you think about that?
Isn't 100uA a little low for a mechanical switch?

 

[danadakk]

I have had mechanical P-B and lever switches bounce as high as 300 mS (really crappy
switch), but always did debounce in code/hw.

The HW approach an ARM series with many different analog and digital resources on chip,
multiple copies of each in most cases, see below. Its basically a system OnChip.

The debounce components in it just drag and drop...in this series of parts a "component" is on onchip
resource.

System on chip looks like -