Mod-rssim Registration Key
According to the software's source code and documentation, the registration key is totally free .
The key is generated based on the IDENT_CODE of your specific PLC. This ensures the license is tied to the physical hardware. modrssim/src/mod_RSsim/About.cpp at master - GitHub mod-rssim registration key
Simulates both Modbus RTU (Serial) and Modbus TCP/IP connections. According to the software's source code and documentation,