Usually, there are two options to establish communication with S7-1200 and S7-1500 PLCs through a computer: a LAN cable is used directly or through a network switch device. In this method, it is necessary to have a regular or industrial network card installed on the computer. However, on the PLC side, there is no need for a network card as you can utilize the Profinet port on the CPU. For a visual representation and a better understanding of the communication principles between the computer and S7-1500 PLC, refer to Figure 1.1.
This is a companion discussion topic for the original entry at https://www.solisplc.com/tutorials/exploring-the-power-of-online-and-diagnostics-mode-for-siemens-plcs-in-tia-portal