7.8
SEL-787 Relay Instruction Manual Date Code 20081022
Communications
Communications Protocols
SEL Communications Protocols
SEL ASCII. This protocol is described in SEL ASCII Protocol and
Commands on page 7.10.
SEL Compressed ASCII. This protocol provides compressed versions of
some of the ASCII commands. The compressed commands are
described in SEL ASCII Protocol and Commands, and the protocol is
described in Appendix C: SEL Communications Processors.
SEL Fast Meter. This protocol supports binary messages to transfer
metering and digital element messages. Compressed ASCII commands
that support Fast Meter are described in SEL ASCII Protocol and
Commands, and the protocol is described in Appendix C: SEL
Communications Processors.
SEL Fast Operate. This protocol supports binary messages to transfer
operation messages. The protocol is described in Appendix C: SEL
Communications Processors.
SEL Fast SER. This protocol is used to receive binary Sequential Events
Record unsolicited responses. The protocol is described in
Appendix C: SEL Communications Processors.
SEL Event Messenger. This is an SEL ASCII protocol with 8 data bits, no
parity, and 1 stop bit for transmitting data to SEL-3010 Event
Messenger. Only the communications speed is user settable to match
the settings in the SEL-3010.
MIRRORED BITS Protocol
The SEL-787 supports two MIRRORED BITS communications channels,
designated A and B. Within each M
IRRORED BITS communications message
for a given channel (A or B), there are eight logical data channels (1–8). You
can, for example, set MBA on Port 3 of the base unit and MBB on Port 4A of
the optional communications card. Attempting to set the PROTO setting to
MBA, MB8A, or MBTA when channel A is already assigned to another port
(or MBB, MB8B, or MBTB when channel B is already assigned on another
port) results in the following error message:
This Mirrored Bits channel
is assigned to another port.
After displaying the error message, the
device returns to the PROTO setting for reentry.
C37.118 Protocol
The SEL-787 provides C37.118 protocol (synchrophasor data) support at one
of the serial ports F, 2, 3, or 4. The protocol is described in Appendix H:
Synchrophasors.
Modbus RTU Protocol
The SEL-787 provides Modbus RTU support. Modbus is a protocol described
in Appendix E: Modbus RTU Communications.
DNP3 (Distributed Network Protocol)
The SEL-787 provides DNP3 protocol support if the option is selected. The
DNP3 protocol is described in Appendix D: DNP3 Communications.
DeviceNet
The SEL-787 provides DeviceNet support. DeviceNet is an optional protocol
described in Appendix G: DeviceNet Communications.
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