Siemens Argus 7SR21 - Optional Rear RS485 (COM3)

Chapter 4 - Data Communications Definitions
© 2017 Siemens Protection Devices Limited Chapter 4 - Page 13 of 96
Rx
Rx
Tx
Tx
RS232 to Fibre
Optic Converter
RS232 straight
through cable
Tx
Rx
Computer or
Control System
Rx
Tx
USB or 9 pin male
D connector
25 pin male
D connector
62.5/125µm fibre optic with ST
connectors
Fig. 2-3 Communication to Multiple Devices using Fibre-optic Ring Network
To
Control
System
7SG24 Sigma 1
Tx
Master
Rx
Rx
Rx
Tx
Tx
Tx
Rx
Tx
Rx
Tx
Rx
RS232 straight
through cable
Tx Rx
Computer or
Control System
Rx
Tx
62.5/125µm fibre optic
with ST connectors
USB or 9 pin male
D connector
25 pin male
D connector
Fig. 2-4 Communication to Multiple Devices from Control System and Laptop using Fibre-optic Star Network
2.5 Optional Rear RS485 (COM3)
The following settings, on the COMMUNICATIONS MENU, must be configured when using the electrical 2-wire RS485
Com3 interface.