Date Code 20130214 Instruction Manual SEL-2414 Transformer Monitor
Appendix G
Instruction Manual
MIRRORED BITS Communications
Overview
MIRRORED BITS
®
is a direct device-to-device communications protocol that
allows IEDs to exchange information quickly, securely, and with minimal
expense. Use M
IRRORED BITS for functions such as remote control and remote
sensing. The SEL-2414 Transformer Monitor supports two M
IRRORED BITS com-
munications channels, designated A and B. Use the port setting PROTO to assign
one of the M
IRRORED BITS communications channels to a serial port; PROTO :=
MBA for M
IRRORED BITS communications Channel A or PROTO := MBB for
M
IRRORED BITS communications Channel B. MIRRORED BITS are either Trans-
mit M
IRRORED BITS (TMB) or Received MIRRORED BITS (RMB). Transmit MIR-
RORED BITS 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. Con-
trol the transmit M
IRRORED BITS in SELOGIC
®
control equations. Use the
received M
IRRORED BITS as arguments in SELOGIC control equations. The chan-
nel 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: Communi-
cations) for additional channel status information.
Because of different applications, the SEL product range supports several varia-
tions of the M
IRRORED BITS communications protocol. Through port settings,
you can set the SEL-2414 for compatible operation with SEL-300 series devices,
SEL-2505 Remote I/O Modules, and SEL-2100 Logic Processors. When com-
municating 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-2414, the MIRRORED BITS transmission rate is a function of both the
baud rate and the power system cycle. At baud rates below 9600, the SEL-2414
transmits M
IRRORED BITS as fast as possible for the given baud. At rates at and
above 9600 baud the SEL-2414 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-2414 automatically enters the self-pacing mode at baud
rates of 9600, 19200, and 38400. Table G.1 shows the transmission rates of the
M
IRRORED BITS messages at different baud.
IMPORTANT: Be sure to configure
the port before connecting to a
M
IRRORED BITS device. If you connect
an unconfigured port to a M
IRRORED
B
ITS device, the device will appear to
be locked up.
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