Rockwell Automation 1770-KF3 DH-485 Communication Interface User Manual - Manual (Page 46)

Troubleshooting the KF3
Chapter 5
5Ć3
Once you initiate active communication on the DF1 link, the RS-232
Activity LED will light up. If this fails to happen, check your RS-232C
parameters (Table 3.B, Parameters 3-8).
If you are unable to save new configurations successfully, the left display
will display hardware fault 6, and the Fault LED on the front will light
up. This indicates a malfunction in the module. Contact your A-B
representative.