Figure 3-7: RS-485 Resistor DIP Switches
A. Input terminal connection
B. Ethernet Port 1
C. Ethernet Port 2
D. Terminal connection 1
E. Terminal connection 2
F. DIP Switches
G. PoE disabled
H. Reset to defaults
I. 1.5 kΩ pull-down resistor
J. 120 Ω terminating resistor
K. 1.5 kΩ pull-up resistor
Switches 1 and 3 are connected to pull-up and pull-down resistors for Modbus connection.
Switch 1 is for the Tx + (A) line and Switch 3 is for the Rx – (B) line. These 1.5 kΩ resistors
are used to prevent noise from being interpreted as valid communications during periods
when no actual communications are occurring. Only one set of pull-up and pull-down
resistors should be active on the RS-485 data bus at time.
Switch 2 is connected to a 120 Ω terminating resistor for Modbus connection. This resistor
is used to dampen signal reflections on long cable runs. RS-485 specifications indicate that
the data bus should be terminated at both ends (
Installing the Gateway
Reference Manual
May 2020
00809-0600-4410
30
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 ...