Well Trying Hard, not as such but what VLT2800 do you have.
If you look at the type code there will be an F somewhere in the last part.
F00 is without Fieldbus
F10 is with Profibus DP 3 Mbit/s
F12 is with Profibus DP 12 Mbit7s
F30 is with DeviceNet
VLT2800 F00 will have ModbusRTU, Metasys N2 and FC-protocol (Danfoss own protocol)
And what RS485 is the Siemens Communication port capable of doing?
Best regards,
Michal_DK