The modbus unit module was already done for a lot of equipments (e.g. temperature controllers, vacuum controllers, intelligent sensors) and includes build-in commands. The user should export/import only the variables and device address.
All my projects are based on Dejan Crnila's TCom open library without any inconvenience or error with positive experience through many years of service.
The configuration are .ini format file for parameters and registry for software registering. Regards, Stephan