Siemens RUGGEDCOM RX1500

RUGGEDCOM RX1500
Installation Guide
Chapter 3
Communication Ports
Connecting Multiple RS485 Devices 37
• 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 53: Recommended RS485 Wiring
1. RX1500 Device 2. Common (Isolated Ground) 3. Negative 4. Positive 5. Shield to Earth (Connected At a Single Point)
6. RS485 Devices (32 Total)
NOTE
A 15 kΩ pull-up resistor is present on board for the positive terminal.
In noisy environments, additional pull-down resistors may be required for the negative terminal.