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15.31
Date Code 20171006
Instruction Manual
SEL-400 Series Relays
Communications Interfaces
SEL M
IRRORED
B
ITS
Communication
SEL M
IRRORED
B
ITS
Communication
With SEL-patented M
IRRORED
B
ITS
communications protocol, protective relays
and other devices can directly exchange information quickly, securely, and with
minimal cost. Use M
IRRORED
B
ITS
communications for remote control, remote
sensing, or communications-assisted protection schemes such as POTT and DCB.
SEL products support several variations of M
IRRORED
B
ITS
communications pro-
tocols. Through port settings, you can set the relay for compatible operation with
SEL-300 series relays, the SEL-2505 or SEL-2506 Remote I/O Modules, and the
SEL-2100 Protection Logic Processors. These devices use M
IRRORED
B
ITS
com-
munications to exchange the states of eight logic bits. You can also use settings to
select extensions of the M
IRRORED
B
ITS
communications protocols, available
only in SEL-400 series relays, to exchange analog values, synchronize clocks,
and engage in virtual terminal dialogs.
summarizes M
IRRORED
B
ITS
communications features.
Communications Channels and Logical Data Channels
The 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
commu-
nications channels to a serial port: PROTO := MBA or MBGA for M
IRRORED
B
ITS
communications Channel A or PROTO := MBB or MBGB for M
IRRORED
B
ITS
communications Channel B.
Transmitted bits include TMB1A–TMB8A and TMB1B–TMB8B. The last letter
(A or B) designates with which channel the bits are associated. These bits are
controlled by SEL
OGIC
control equations. Received bits include RMB1A–
RMB8A and RMB1B–RMB8B. You can use received bits as arguments in
SEL
OGIC
control equations. The channel status bits are ROKA, RBADA,
CBADA, LBOKA, ROKB, RBADB, CBADB, LBOKB, DOKA, ANOKA,
DOKB, and ANOKB. You can also use these bits as arguments in SEL
OGIC
con-
trol equations. Use the
COM
command for additional channel status information.
Within each M
IRRORED
B
ITS
communications message for a given channel (A or
B), there are eight logical data channels (1–8). In operation compatible with other
SEL products, you can use the eight logical data channels for TMB1–TMB8. If
you use fewer than eight transmit bits, Data Channel 8 is reserved to support data
framing and time synchronization features. You can assign the eight logical data
channels as follows:
Table 15.23
M
IRRORED
B
ITS
Communications Features
Feature
Compatibility
Transmit and receive logic bits
SEL-300 series relays, SEL-2505, SEL-2506,
SEL-2100, SEL-400 series relays
Transmit and receive analog values
SEL-400 series relays
Synchronize time
SEL-400 series relays
Send and receive virtual serial port characters
SEL-400 series relays
Support synchronous communications channel
SEL-400 series relays
Summary of Contents for SEL-421-4
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