Which communication protocol is commonly used for industrial networking with PLCs?

The communication protocol commonly used for industrial networking with PLCs is Modbus. This protocol was specifically designed for industrial applications, which makes it highly suitable for communication between PLCs and other devices in a manufacturing environment. Modbus allows multiple devices to communicate on the same network, enabling efficient data exchange and command signaling necessary for automation systems.

Modbus operates in a master/slave architecture, which simplifies communication setup and allows a central control device (the master) to initiate requests while the other devices (slaves) respond accordingly. This flexibility and interoperability across different manufacturers and devices make Modbus a popular choice in industrial settings where PLCs play a central role.

While TCP/IP, Ethernet, and Profibus are also important in industrial networking, they serve broader or different contexts. TCP/IP is a suite of protocols used mainly in computer networks and can be applied to industrial settings but is not specifically designed for PLCs. Ethernet refers to a physical and data link layer technology and, while it can support Modbus TCP, is not a protocol in itself for PLC communication. Profibus, though widely used, is more specific to certain types of networks, particularly in Europe. Therefore, considering the context of PLC communication, Modbus stands out as the appropriate choice.