Rs-422 - ProSoft Technology inRax MVI69-101M User Manual

MVI69-101M ♦ CompactLogix or MicroLogix Platform
IEC 60870-5-101 Master Communication Module

5.4.3 RS-422

5.4.4 RS-485
The RS-485 interface requires a single two or three wire cable. The Common
connection is optional and dependent on the RS-485 network. The cable required
for this interface is shown below:
RS-485 and RS-422 Tip
If communication in the RS-422/RS-485 mode does not work at first, despite all
attempts, try switching termination polarities. Some manufacturers interpret +/-
and A/B polarities differently.
Page 102 of 133
Reference
ProSoft Technology, Inc.
February 4, 2008