User's Manual

SEL-3031 Instruction Manual Date Code 20091009
Installation
Communications
2.12
Communications
Serial Ports
Table 2.8 shows the physical interfaces of the SEL-3031. Several options are provided
for Port 1 physical interfaces, including EIA-232, EIA-485, and fiber.
Serial (EIA-232 and EIA-485)
Use the EIA-232 port for communications distances of 15 meters (50 feet) in
low-noise environments. Use the optional EIA-485 Port 1 for communications of
1200 meters (4000 feet) maximum distance (to achieve this performance, ensure
proper line termination at the receiver).
If Port 1 is an EIA-485 connection, there are two types of connections that will work on
multidrop systems. Ta ble 2 .9 shows the standard pinout of a recommended four-wire
EIA-485 connection. If your system only works on a two-wire EIA-485 connection,
then you will need to connect Pins 1 and 3 together and Pins 2 and 4 together.
Figure 2.4 shows how to wire this configuration.
Figure 2.4 Two-Wire EIA-485 Connections
Table 2.8 SEL-3031 Port Description
Port Communications Interface Location
Port 1 EIA-232, EIA-485, or fiber Rear (Port 1 has three ordering options)
Port 2 EIA-232 Rear
Port 3 EIA-232 Rear
USB USB 1.1 Front (management port)
Port 1 EIA-485
9-Pin Male
D Subconnector
2-Wire EIA-485
2-Wire EIA-485
Tinned Wires
1
3
2
4
5
1
2
3
TX+
RX+
TX–
RX–
GND
Pin # Pin #