I have done this successfully with a 1747-KE and 1761-NET-ENI. It only works for a SLC-5/01 or /02 controller at Node 1 of the DH485 network.
Similarly, you could use a 1747-KE and a third party Serial/Ethernet converter and give RSLinx DF1 Full Duplex driver access to the 1747-KE serial port as a "virtual serial port".
A direct RS-485 to Ethernet converter will not work because it does not handle the timing and token-passing of the DH-485 network protocol.