Schweitzer Engineering Laboratories SEL-700G Series, Instruction Manual

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Date Code 20170814 Instruction Manual SEL-700G Relay
Appendix I
M
IRRORED
B
ITS
Communications
Instruction Manual
Overview
M
IRRORED
B
ITS
is a direct relay-to-relay communications protocol that allows
IEDs to exchange information quickly, securely, and with minimal expense.
Use M
IRRORED
B
ITS
for functions such as remote control and remote sensing.
The SEL-700G Generator and Intertie Protection Relay supports two
M
IRRORED
B
ITS
communications channels, designated A and B. Use the port
setting PROTO to assign one of the M
IRRORED
B
ITS
communications
channels to a serial port; PROTO:=MBA for M
IRRORED
B
ITS
communications Channel A or PROTO:=MBB for M
IRRORED
B
ITS
communications Channel B. M
IRRORED
B
ITS
are either Transmit M
IRRORED
B
ITS
(TMB) or Received M
IRRORED
B
ITS
(RMB). Transmit M
IRRORED
B
ITS
include TMB1A–TMB8A (channel A) and TMB1B–TMB8B (channel B).
The last letter (A or B) designates with which channel the bits are associated.
Received bits include RMB1A–RMB8A and RMB1B–RMB8B. Control the
transmit M
IRRORED
B
ITS
in SEL
OGIC
control equations. Use the received
M
IRRORED
B
ITS
as arguments in SEL
OGIC
control equations. The channel
status bits are ROKA, RBADA, CBADA, LBOKA, ROKB, RBADB,
CBADB, and LBOKB. You can also use these channel status bits as
arguments in SEL
OGIC
control equations. Use the COM command (see
Section 7: Communications) for additional channel status information.
Because of different applications, the SEL product range supports several
variations of the M
IRRORED
B
ITS
communications protocol. Through port
settings, you can set the SEL-700G for compatible operation with SEL-300
series devices, SEL-2505 Remote I/O Modules, and SEL-2100 Logic
Processors. When communicating with an SEL-400 series relay, be sure to set
the transmission mode setting in the SEL-400 series relay to paced
transmission (TXMODE := P).
Operation
Message
Transmission
In the SEL-700G, the M
IRRORED
B
ITS
transmission rate is a function of both
the data rate and the power system cycle. At data rates below 9600, the
SEL-700G transmits M
IRRORED
B
ITS
as fast as possible for the given rate. At
rates at and above 9600 bps the SEL-700G self-paces, using a technique
similar to the SEL-400 series pacing mode. There are no settings to enable or
disable the self-pacing mode; the SEL-700G automatically enters the self-
pacing mode at data rates of 9600, 19200, and 38400. Table I.1 shows the
transmission rates of the M
IRRORED
B
ITS
messages at different rates.
IMPORTANT:
Be sure to configure
the port before connecting to a
M
IRRORED
B
ITS
device. If you connect
an unconfigured port to a M
IRRORED
B
ITS
device, the device will appear to
be locked up.
NOTE:
Complete all of the port
settings for a port that you use for
M
IRRORED
B
ITS
communications before
you connect an external M
IRRORED
B
ITS
communications device. If you
connect a M
IRRORED
B
ITS
communications device to a port that
is not set for M
IRRORED
B
ITS
communications operation, the port
will be continuously busy.