Can an Arduino PLC talk the same language as a Beckhoff PLC? Absolutely yes! In this video we will make an Arduino PLC talk to a Beckhoff PLC using Modbus TCP. The Arduino PLC will act as a Modbus TCP client, and the Beckhoff PLC will act as a Modbus TCP server. By utilizing two function blocks, we will make the Arduino both read and write registers in the Beckhoff PLC.