Sorry, I don’t have LabVIEW accessible right now, but I also used the latest vipm package. The code on GitHub definitely shows it to be there: https://github.com/rfporter/Modbus-Master/tree/master/MB_Master
Look in the MB_Master class under Properties>Slave ID.
Since it’s in a property definition folder, you could also use a property node instead of the VI.
The VI from the NI Modbus Library won’t do you any good since it belongs to a different class.
The password for the NI library is bestbus. It is only applied in the vip build and is listed in the VI package build spec on GitHub: https://github.com/NISystemsEngineering/LabVIEW-Modbus-API/blob/master/.vipb
