C.2
SEL-2414 Transformer Monitor Instruction Manual Date Code 20130214
SEL Communications Processors
SEL Communications Protocols
Table C.2 lists the Compressed ASCII commands and contents of the command
responses.
Interleaved ASCII and
Binary Messages
SEL devices have two separate data streams that share the same physical serial
port. Human data communications with the device consist of ASCII character
commands and reports that you view through use of a terminal or terminal emula-
tion package. The binary data streams can interrupt the ASCII data stream to
obtain information; the ASCII data stream continues after the interruption. This
mechanism uses a single communications channel for ASCII communication
(transmission of an event report, for example) interleaved with short bursts of
binary data to support fast acquisition of metering data. The device connected to
the other end of the link requires software that uses the separate data streams to
exploit this feature. However, you do not need a device to interleave data streams
to use the binary or ASCII commands. Note that XON, XOFF, and CAN opera-
tions operate on only the ASCII data stream.
An example of using these interleaved data streams is when the SEL-2414 com-
municates with an SEL communications processor. These SEL communications
processors perform autoconfiguration by using a single data stream and SEL
Compressed ASCII and binary messages. In subsequent operations, the SEL
communications processor uses the binary data stream for Fast Meter and Fast
Operate messages to populate a local database and to perform SCADA opera-
tions. At the same time, you can use the binary data stream to connect transpar-
ently to the SEL-2414 and use the ASCII data stream for commands and
responses.
SEL Fast Meter, Fast
Operate, Fast SER,
and Unsolicited Write
SEL Fast Meter is a binary message that you solicit with binary commands. Fast
Operate is a binary message for control. The device can also send unsolicited
SEL Fast Message (used in the SEL-2414 for Remote Analogs) and Fast SER
messages automatically. If the device is connected to an SEL communications
processor, these messages provide the mechanism that the communications pro-
cessor uses for SCADA or DCS functions that occur simultaneously with ASCII
interaction.
Table C.2 Compressed ASCII Commands
Command Response Access Level
BNAME ASCII names of Fast Meter status bits 0
CASCII Configuration data of all Compressed ASCII
commands available at access level 1 and above
1
CEVENT Event report 1
CHISTORY List of events 1
CMETER Metering data, including fundamental, analog inputs,
math variables, remote analogs, and signal profile data
1
CSTATUS Device status 1
CSUMMARY Summary of event report 1
DNAME ASCII names of digital I/O reported in Fast Meter 0
ID Device identification 0
SNS ASCII names for SER data reported in Fast Meter 0
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