Schweitzer Engineering Laboratories SEL-421-4 - Page 1271

Date Code 20171006 Instruction Manual SEL-400 Series Relays
Instruction ManualInstruction Manual
SECTION 15
Communications Interfaces
This section provides information on communications interface options for
SEL-400 series relays. The following topics are discussed:
➤ Serial Communication on page 15.2
➤ Serial Port Hardware Protocol on page 15.5
➤ Ethernet Communications on page 15.6
➤ Virtual File Interface on page 15.18
➤ Software Protocol Selections on page 15.22
➤ SEL Protocol on page 15.23
➤ SEL MIRRORED BITS Communication on page 15.31
➤ SEL Distributed Port Switch Protocol (LMD) on page 15.37
➤ SEL-2600A RTD Module Operation on page 15.39
➤ Direct Networking Example on page 15.40
The relay collects, stores, and calculates a variety of data. These include electri-
cal power system measurements, calculated quantities, diagnostic data, equip-
ment monitoring data, fault oscillography, and sequential event reports. You must
enter settings to configure the relay to protect and monitor your power system
properly. A communications interface is the physical connection on the relay that
you can use to collect data from the relay, set the relay, and perform relay test and
diagnostic functions.
The relay has three rear-panel serial ports and one front-panel serial port. These
serial ports conform to the EIA-232 standard (often called RS-232). Several
optional SEL devices are available to provide alternative physical interfaces,
including EIA-485 and fiber-optic cable. The relay also has a Ethernet card slot
for the optional Ethernet card.
Once you have established a physical connection, you must use a communica-
tions protocol to interact with the relay. A communications protocol is a language
that you can use to perform relay operations and collect data. For information on
protocols that you can use with the relay, see the instruction manual sections
listed in Table 15.1.
Table 15.1 Relay Communications Protocols (Sheet 1 of 2)
Communications Protocol Communications Interface For More Information See
ASCII Commands EIA-232
a
or Telnet using
Ethernet
Section 14: ASCII Command
Reference
Distributed Port Switch
(LMD)
SEL-2885 EIA-232 to EIA-485
transceiver on an EIA-232 port
SEL Distributed Port Switch
Protocol (LMD) on page 15.37
DNP3 EIA-232
a
or Ethernet Section 16: DNP3
Communication
FTP Ethernet FTP on page 15.12
HTTP Ethernet HTTP (Hypertext Transfer Pro-
tocol) Server on page 15.17