Probe connection. Direct or through optocoupler?

[flugzeug]

Should I connect the probe directly to an input on an UC300 board or should I connect the probe through an optocoupler? The optocouplers on the board I have are 20 kHz. Will that cause any issues?

P.S. I am aware that if I connect it directly I need a 5V PSU.

I have a wired probe from Vers: https://vers.by/en/blog/user-guides/vers-pr

Does my wiring diagram look fine?

[cncdrive]

You should not connect things directly to the UC300ETH pins which things are wired with long wires and on the machine body and could carry EMI charge which could damage the UC300ETH input pins. You should treat the UC300ETH pins just like as if it was an LPT port.
So, yes. you should use somekind of buffer between the probe sensor and the UC300ETH input, a buffer IC or even better to use an optocoupler as you've already pointed this out.

[flugzeug]

Thank you very much for the explanation.