RS-485 communication—the communication function used for controllers—is also the standard communication modality for industrial products. However, broadly speaking, this function has many limitations including a maximum total number of connections of thirty-one, and a maximum extension distance of 1.2 km. There are several other available protocols, but each have their own weaknesses.

At Yokogawa we began focusing on Ethernet communications, and we subsequently were the first to include it on controllers in Japan. Using the Ethernet communication function, we solved the problems of the limited number of connected units, the connection method, connection distance, and other issues, thus making dramatic improvements in connectivity. Naturally, we also considered that this would have the advantage of reducing wiring costs. Now PLC has even been adopted as a standard feature of Ethernet communication functions, and these modules and controllers can also easily be connected via Ethernet. We definitely encourage you to try out an Ethernet-enabled controller!