Emerson Rosemount 1410S Reference Manual page 29

Reference Manual
00809-0600-4410
3.5.5 Shield grounding
The shields of the twisted-pair cables need to be grounded using the grounding terminal
on the Emerson 1410S.
3.5.6 Terminating resistors
Three of the five DIP switches are provided to enable various terminating and biasing
resistors to the RS-485 (Modbus
housing, located in the square opening of the shroud on the upper left side
The switches number left to right going down from 5 to 1. The downward position on the
switch is ON.
Three DIP switches are provided to enable various terminating resistors to the RS-485
data bus. The terminating resistor on the Emerson 781S connection (120 ohm) is always
enabled.
Figure 3-8: DIP Switch Identification
A. DIP switches
B. PoE disabled
C. Reset to defaults
D. 1.5 kΩ pull-down resistor
E. 120 Ω terminating resistor
F. 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. Ensure that only one set of pull-up and
pull-down resistors is active on the RS-485 data bus at a time.
Emerson 1410S/781S
) data bus. The switches are found inside the electronics
®
Installing the Gateway
December 2023
(Figure 3-8).
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