10-8 Serial Port Communications and Commands Date Code 20001006
SEL-351 Instruction Manual
4. You can use the XON/XOFF protocol to control the relay during data transmission. When the
relay receives XOFF during transmission, it pauses until it receives an XON character. If
there is no message in progress when the relay receives XOFF, it blocks transmission of any
message presented to its buffer. Messages will be accepted after the relay receives XON.
The CAN character (ASCII hex 18) aborts a pending transmission. This is useful in termi-
nating an unwanted transmission.
Control characters can be sent from most keyboards with the following keystrokes:
XON: <CNTRL> Q (hold down the Control key and press Q)
XOFF: <CNTRL> S (hold down the Control key and press S)
CAN: <CNTRL> X (hold down the Control key and press X)
SEL Distributed Port Switch Protocol (LMD)
The SEL Distributed Port Switch Protocol (LMD) permits multiple SEL relays to share a common
communications channel. The protocol is selected by setting the port setting PROTO = LMD. See
Appendix C for more information on SEL Distributed Port Switch Protocol (LMD).
SEL Fast Meter Protocol
SEL Fast Meter protocol supports binary messages to transfer metering and control messages.
The protocol is described in Appendix D.
SEL Compressed ASCII Protocol
SEL Compressed ASCII protocol provides compressed versions of some of the relay ASCII
commands. The protocol is described in Appendix E.
Distributed Network Protocol (DNP) V3.00
The relay provides Distributed Network Protocol (DNP) V3.00 slave support. DNP is an optional
protocol and is described in Appendix H.
MIRRORED BITS Communications
The SEL-351 Relay supports MIRRORED BITS relay-to-relay communications on two ports
simultaneously (available in firmware versions 1, 2, 3, and 4 only). See Appendix I.
SERIAL PORT AUTOMATIC MESSAGES
When the serial port AUTO setting is Y, the relay sends automatic messages to indicate specific
conditions. The automatic messages are described in Table 10.5.
Courtesy of NationalSwitchgear.com
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