Schweitzer Engineering Laboratories SEL-421-4 - Page 1296

15.26
SEL-400 Series Relays Instruction Manual Date Code 20171006
Communications Interfaces
SEL Protocol
CASCII Configuration Message for Compressed ASCII Commands
The CASCII message provides a block of data for each of the Compressed ASCII
commands supported by an SEL device. The block of data for each command
provides message description information to allow automatic data extraction. The
relay arranges items in the Compressed ASCII configuration message in a pre-
defined order. For the purpose of improving products and services, SEL some-
times changes the items and item order. The information presented below
explains the message and serves as a guide to the items in Compressed ASCII
configuration messages.
NOTE: Compressed ASCII is self-
describing and may vary with the
firmware version of your relay. Before
you program a master device to send
and parse Compressed ASCII
commands and responses, you should
perform a CASCII command on your
relay or contact SEL for more detailed
information.
A Compressed ASCII command can require multiple header and data configura-
tion lines. The general format of a Compressed ASCII configuration message is
the following:
Definitions for the items and fields in a Compressed ASCII configuration mes-
sage are the following:
➤ n is the number of Compressed ASCII command descriptions to
follow.
➤ COMMAND is the ASCII name for the Compressed ASCII command
that the requesting device (terminal or external software) sends. The
naming convention for the Compressed ASCII commands is a C
character preceding the typical command. For example, CSTATUS,
abbreviated to CST, is the Compressed ASCII STATUS command.
➤ #H identifies a header line to precede one or more data lines; the #
character represents the number of subsequent ASCII names. For
example, 21H identifies a header line with 21 ASCII labels.
➤ xxxxx is an ASCII name for corresponding data on following data
lines. Maximum ASCII name width is ten characters.
➤ #D identifies a data format line; the # character represents the
maximum number of data lines in command response.
➤ ddd identifies a format field containing one of the following type
designators:
➢ I—Integer data
➢ F—Floating point data
➢ zS—String of maximum z characters (for example, enter 10S for
a 10-character string)
➤ yyyy is the 4-byte hex ASCII representation of the checksum. Every
checksum is followed by a new line indication (<CR><LF>).
ID Relay identification 0
SNS ASCII names for SER data reported in Fast Meter 0
Table 15.18 Typical Compressed ASCII Commands (Sheet 2 of 2)
Command Response Access Level
<STX>"CAS",n,"yyyy"<CR><LF>
"COMMAND 1",ll,"yyyy"<CR><LF>
"#H","xxxxx","xxxxx",......,"xxxxx","yyyy"<CR><LF>
"#D","ddd","ddd","ddd","ddd",......,"ddd","yyyy"<CR><LF>
•
•
•
"COMMAND n",ll,"yyyy"<CR><LF>
"#H","xxxxx","xxxxx",......,"xxxxx","yyyy"<CR><LF>
"#D","ddd","ddd","ddd","ddd",......,"ddd","yyyy"<CR><LF><ETX>