Siemens RUGGEDCOM RS910 - Page 28

Chapter 3
Communication Ports
RUGGEDCOM RS910
Installation Guide
20 Connecting Multiple RS485 Devices
• The shield should be connected to earth ground at a single point to avoid loop currents.
• The twisted pair should be terminated at each end of the chain.
The following shows the recommended RS485 wiring.
< 1219 m (4000 in)
120Ω 10nF
120Ω 10nF
1
2
3
5
5
6
4
Figure19:Recommended RS485 Wiring
1. RUGGEDCOM RS910 Device 2.Common (Isolated Ground) 3.Negative 4.Positive 5.Shield to Earth (Connected At a Single
Point) 6.RS485 Devices (32 Total)