I have a small device based on an Arduino and I want to send some data to a PLC that has no RS232 port but can have an optional IO-Link master card. I looked around but found no info about Arduino and IO-Link, are there any projects using Arduino as a IO-Link slave device?
IO-Link is a communication protocol intended for industrial environments. It usually involves voltage levels of 24V. Apart for that, you will have to write your own communication stack on the Arduino (as far as I know there is no open source stack, although the standard is an open standard). This has implications both in HW and in FW.
If you are interested in learning IO-Link for the fun of it, go for it. Otherwise I would advise you to install a different communication module on your PLC, something like RS232 or RS485.
Perhaps this can be usefule to you
Disclaimer: I am the author of the repo.
Its a hardcoded IO-Link device stack but can be used as a starting point.