Mitsubishi PLCs use several communication protocols to connect and exchange data with other devices and systems. The primary protocol is the MELSEC Communication Protocol (MC protocol), which is proprietary and allows reliable communication between a PLC’s CPU and external devices like PCs, HMIs, or other PLCs. For Ethernet-based connections, especially in modern iQ-R and iQ-F series PLCs, Mitsubishi uses SLMP (Seamless Message Protocol). SLMP enables fast, seamless communication over Ethernet, making it ideal for connecting PLCs to computers, HMIs, or industrial networks.
Other protocols include MELSEC-CNET, which is used for data exchange between Mitsubishi PLCs, and MELSEC-MEDEX, an Ethernet-based protocol for communication with host computers. Mitsubishi also supports CC-Link, including CC-Link IE, which is used for industrial networking and data communication across multiple devices. The choice of protocol depends on your PLC model and the type of connection you need. For modern Ethernet systems, SLMP is the standard. For older PLCs or PLC-to-PLC communication, MC protocol or MELSEC-CNET is commonly used. Understanding these protocols ensures efficient data exchange, smooth integration, and reliable operation in Mitsubishi PLC-based automation systems. Always check your PLC’s manual to confirm the supported protocols and configuration details.