Stu's most recent post is correct: you can connect to an SLC-500 or MicroLogix controller's RS-232 port configured with DH485 protocol, using the 1747-UIC and an appropriate cable.
The appropriate cable, in this case, is the 1761-CBL-PM02. That's the standard programming cable that's been used for MicroLogix 1000 controllers since 1995.
If you know that the MicroLogix 1000 has been configured to make DH485 the "primary protocol", this arrangement should work right away.