Rockwell Automation 1336T Wiring and Grounding Guide, (PWM) AC Drives - Manual (Page 24)

24 Rockwell Automation Publication DRIVES-IN001M-EN-P - March 2014
Chapter 1 Wire/Cable Types
Remote I/O and Data Highway Plus (DH+)
The maximum cable length depends on the baud rate.
All three connections (blue, shield, and clear) must be connected at each node.
Serial (RS-232 and RS-485)
Follow these recommended standard practices for serial communications wiring:
• One twisted pair and one signal common for RS-232.
• Two twisted pair, with each pair individually shielded, for RS-485.
IMPORTANT Only Allen-Bradley catalog number 1770-CD shielded twinaxial cabling is
tested and approved for remote I/O and DH+ installations.
Baud Rate Maximum Cable Length
57.6 Kbps 3048 m (10,000 ft)
115.2 Kbps 1524 m (5000 ft)
230.4 Kbps 762 m (2500 ft)
IMPORTANT Do not connect in a star topology. Only two cables can be connected at any
wiring point. Use either series or daisy chain topology at all points.