RS485 (serial)
An RS485 connection supports Modbus RTU protocol. Using this connection type, the
Gateway is wired to an RS485 bus which typically leads to a serial I/O card or Modbus I/O
card (
see Figure 5-2
). Up to 31 Gateways can be connected to a single I/O card in this
manner.
Figure 5-2: RS485 Architecture
A. Engineering station
B. Primary control network
C. Controller and I/O
D. Secondary control network
E. Serial I/O card
F. RS485 bus
G. Wireless Gateway
5.3
Modbus
®
The Gateway supports both Modbus RTU over the RS-485 serial port and Modbus TCP over
Ethernet. It functions as a sub device on the Modbus network and must be polled by a
Modbus master or client (host system).
Communication settings
It is import that the Modbus communication settings in the Gateway match the settings in
the Modbus master or client. Please refer to host system documentation for more
information on how to configure these settings. The Modbus communication settings can
be found by navigating to
System Settings
→
Protocols
→
Modbus
.
Operation and maintenance
Reference Manual
May 2020
00809-0600-4410
40
Emerson.com
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 ...