Schweitzer Engineering Laboratories SEL-421-4 - Figure 2.47 SEL-421 to Computer-D-Subminiature 9-Pin Connector

2.47
Date Code 20171021 Instruction Manual SEL-421 Relay
Installation
Connection
Communications Ports Connections
The SEL-421 has three rear-panel EIA-232 serial communications ports labeled
PORT 1, PORT 2, and PORT 3 and one front-panel port, PORT F. For information on
serial communication, see Establishing Communication on page 3.3, Serial Com-
munication on page 15.2, and Serial Port Hardware Protocol on page 15.5 in the
SEL-400 Series Relays Instruction Manual.
In addition, the rear panel features a PORT 5 for an optional Ethernet card. For
additional information about communications topologies and standard protocols
that are available in the SEL-421, see Section 15: Communications Interfaces,
Section 16: DNP3 Communication, and Section 17: IEC 61850 Communication
in the SEL-400 Series Relays Instruction Manual and Section 10: Communica-
tions Interfaces in this manual.
Serial Ports
The SEL-421 serial communications ports use EIA-232 standard signal levels in
a D-subminiature 9-pin (DB-9) connector. To establish communication between
the relay and a DTE device (a computer terminal, for example) with a DB-9 con-
nector, use an SEL-C234A cable. Alternatively, you can use a SEL-C662 cable to
connect to a USB port.
Figure 2.47 shows the configuration of SEL-C234A cable that you can use for
basic ASCII and binary communication with the relay. A properly configured
ASCII terminal, terminal emulation program, or QuickSet along with the
SEL-C234A cable provide communication with the relay in most cases.
Serial Cables
Using an improper cable can cause numerous problems or failure to operate, so
you must be sure to specify the proper cable for application of your SEL-421.
Several standard SEL communications cables are available for use with the relay.
Figure 2.47 SEL-421 to Computer—D-Subminiature 9-Pin Connector
SEL-421 Relay
23
3
5
8
2
5
8
7
RXD TXD
TXD RXD
GND GND
CTS CTS
RTS
DCD
DTR
DSR
1
4
Pin
Func.
Pin
Func.
Pin
#
Pin
#
9-Pin DTE
Device
*
*DTE = Data Terminal Equipment (Computer, Terminal, etc.)
6
SHIELD
NO CONNECTION
SHELL
CAUTION
Severe power and ground problems
can occur on the communications
ports of this equipment as a result of
using non-SEL cables. Never use stan-
dard null-modem cables with this
equipment.