I am looking for an Arduino or compatible board that has:
- a serial RS232 port and a RS485 port (Modbus RTU) or
- a serial RS232 port and Ethernet port that can be used to program Modbus TCP.
The hardware can be Arduino or compatible boards with shield. The purpose is to build a gateway to a very old ABB PLC so that its internal data can be accessed.
Can you provide me with some recommendation of the parts so that I can make a purchase?