Figure B-7: Dual RS-485 Architecture
A. Engineering station
B. Process control network
C. Controller and I/O
D. Dual serial card
E. RS-485 bus
F. Secondary Ethernet
Note
By default, only the active Gateway in a redundant system will respond to Modbus polling
requests. If simultaneous polling is desired, login to the Gateway web interface, navigate
to
Setup
→
Modbus
→
Communications
and set
Respond when running as redundant
standby?
to
Yes
. Only use this setting in a dual RS-485 architecture.
Power
Power for the redundant Gateways should be applied after all primary and secondary
Ethernet and RS-485 connections have been made. Using separate uninterruptable power
supplies (UPS) is recommended to ensure availability of the redundant Gateway system.
B.4
Diagnostics
The redundant system will perform many diagnostic checks to verify the health and
connectivity of the system. In the event of a failure, it can take up to 30 seconds for the
Gateway to trade positions.
These diagnostics can also be mapped to Modbus
®
registers or OPC tags. The following
table covers what diagnostics are included on the
Redundancy Status
page as well as how
they can be mapped as parameters in Modbus or OPC.
Reference Manual
Redundant Gateway systems
00809-0600-4410
May 2020
Emerson 1410S/781S
61
Summary of Contents for 781S
Page 2: ...2 ...
Page 6: ...Introduction Reference Manual May 2020 00809 0600 4410 6 Emerson com ...
Page 20: ...Configuration Reference Manual May 2020 00809 0600 4410 20 Emerson com ...
Page 34: ...Installing the Gateway Reference Manual May 2020 00809 0600 4410 34 Emerson com ...
Page 44: ...Operation and maintenance Reference Manual May 2020 00809 0600 4410 44 Emerson com ...
Page 67: ...Reference data Reference Manual May 2020 00809 0600 4410 54 Emerson com ...
Page 68: ...Quick Start Guide 00825 0600 4410 Rev AA March 2020 Emerson Wireless 1410S Gateway ...
Page 93: ...7 5 Declaration of Conformity Quick Start Guide March 2020 26 Emerson com ...
Page 94: ...March 2020 Quick Start Guide Quick Start Guide 27 ...
Page 95: ...Quick Start Guide March 2020 28 Emerson com ...
Page 98: ...Quick Start Guide 00825 0700 4410 Rev AA March 2020 Emerson Wireless 781S Smart Antenna ...
Page 112: ...Quick Start Guide March 2020 16 Emerson com ...
Page 113: ...March 2020 Quick Start Guide Quick Start Guide 17 ...
Page 115: ...March 2020 Quick Start Guide Quick Start Guide 19 ...
Page 116: ...Quick Start Guide March 2020 20 Emerson com ...
Page 118: ...Quick Start Guide March 2020 22 Emerson com ...
Page 119: ...March 2020 Quick Start Guide Quick Start Guide 23 ...
Page 130: ...Redundant Gateway systems Reference Manual May 2020 00809 0600 4410 64 Emerson com ...