Emerson 1420 - Simplex RS-485; D.4.3 Simplex RS-485

Reference Manual
00809-0200-4420, Rev HC
Appendix D: Redundancy
July 2015
74
Redundancy
D.4.3 Simplex RS-485
A simplex RS-485 host connection supports Modbus RTU protocol. When using this
architecture, connect the secondary Ethernet port on Gateway A directly to the secondary
Ethernet port on Gateway B. Then wire the RS-485 ports for both Gateways in parallel to a single
serial card at the host system. See Figure D-5 Simplex RS-485 Architecture.
Figure D-5. Simplex RS-485 Architecture
Note
In either a simplex or dual RS-485 architecture, the primary Ethernet ports can be connected to
an asset management network to provide connectivity to AMS Device Manager or AMS Wireless
Configurator.
A. Engineering Station
B. Process Control Network
C. Controller and I/O
D. Serial Card
E. RS-485 Bus
F. Secondar y Ethernet
A
B
C
D
E
F