The Siemens S7-1200 PLC mainly uses the PROFINET (Ethernet) communication protocol. This built-in interface allows the S7-1200 to exchange data with other Siemens PLCs like S7-300, S7-400, and S7-1500, as well as HMIs and SCADA systems. It supports S7 Communication using PUT and GET instructions, which help PLCs share data seamlessly without extra programming complexity. The S7-1200 also supports Modbus TCP for communication with third-party industrial devices that operate on TCP/IP networks. This flexibility makes it ideal for connecting automation systems in factories and process industries.
Besides Ethernet-based protocols, the S7-1200 can also handle serial communication using additional RS232 or RS485 modules. These modules allow point-to-point connections through protocols like Modbus RTU, USS, or ASCII in Freeport mode, enabling communication with drives, sensors, and legacy equipment. The PLC also supports TCP/IP, UDP, and HTTP for general networking and web applications, such as serving web pages or remote monitoring. Overall, the Siemens S7-1200 offers excellent communication versatility — from PROFINET for industrial automation to Modbus and Freeport for custom integration — ensuring seamless connectivity across modern and traditional systems.