Emerson 1410S Reference Manual page 29

Reference Manual
00809-0600-4410
Figure 3-7: 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. 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
3.5.7 Power over Ethernet (PoE)
This Gateway is equipped with PoE technology to derive its power from another PoE
device via the Ethernet connection (PD mode). This device complies with the IEEE
802.3af-2003 or IEEE 802.3at -2009 for PD operation.
These standards require the use of Category 5 Ethernet cable or higher. In the operation of
IEEE 802.3a, PoE power is only transmitted from one device to another when the proper
impedance match is made. This prevents damage to non PoE devices on the network.
Emerson 1410S/781S
Installing the Gateway
(Figure 3-7).
September 2020
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