In attachment you can see a project on how to make a keyboard.

The RS232 output displays the ASCII value.

The characters on keys can be changed by adjusting the values in the LUT instructions.

You don't have to place all the keys, you can just leave the lines open.

The shift-key is separate because it was too complicated to integrate it into the scan cycle.

'r' means that they are in reserve and you can assign them yourself.

Everything has been tested and works well, but if you have any questions, just ask.

You must use ldmicro5411b and you can get it here LDmicro5411b.zip

https://cq.cx/ladder-forum.pl?...parent=11445&tt=1681945891

Learn from it ;)