Siemens RUGGEDCOM RMC30 - Page 25

RUGGEDCOM RMC30
Installation Guide
Chapter 3
Communication Ports
RS485/422 Data Ports 17
NOTE
Transient protection is provided on all terminals. Lightning strikes and ground surge currents can cause
large momentary voltage differences between ends of communication links. For maximum reliability of
the entire link, all equipment should have similar transient protection installed.
The following shows the recommended RS485 wiring.
< 1219 m (4000 ft)
120Ω 10nF
1
2
3
5
5
6
4
Figure10:Recommended RS485 Wiring
1. RUGGEDCOM RMC30 Device With Built-In Termination 2.Common (Isolated Ground) 3.Negative 4.Positive 5.Shield to Earth
(Connected At a Single Point) 6.RS485 Devices (32 Total)