J.7
Date Code 20080213 Instruction Manual SEL-351A Relay
SEL-351A Fast SER Protocol
Functions and Function Codes
Acknowledge
Message Sent from
Master to Relay, and
From Relay to Master
The acknowledge message is constructed and transmitted for every received
message which contains a status byte with the LSB set (except another
acknowledge message), and which passes all other checks, including the CRC.
The acknowledge message format is shown in Tabl e J.5.
The SEL-351A supports the following response codes:
Examples
1. Successful acknowledge for “Enable Unsolicited Fast SER
Data Transfer” message from a relay with at least one of SER1,
SER2, or SER3 not set to NA:
A5 46 0E 00 00 00 00 00 00 81 00 XX cc cc
(XX is as same as the Response Number in the “Enable
Unsolicited Data Transfer” message to which it responds)
2. Unsuccessful acknowledge for “Enable Unsolicited Fast SER
Data Transfer” message from a relay with all of SER1, SER2,
and SER3 set to NA:
A5 46 0E 00 00 00 00 00 00 81 02 XX cc cc
(XX is as same as the response number in the “Enable
Unsolicited Data Transfer” message to which it responds)
3. Disable Unsolicited Fast SER Data Transfer message,
acknowledge requested:
A5 46 10 00 00 00 00 00 01 02 C0 XX 18 00 cc cc
(XX = 0, 1, 2, 3)
00000000 Element status (unused)
cccc Two byte CRC-16 checkcode for message
Table J.4 Message if SER Records Are Lost (Sheet 2 of 2)
Data Description
Table J.5 Acknowledge Message Format
Data Description
A546 Message header
0E Message length (14 decimal)
0000000000 Five bytes reserved for future use as a routing address
00 Status byte (always 00)
XX Function code, echo of acknowledged function code with MSB set
RR Response code (see below)
XX Response number (XX = 00, 01, 02, 03, 00, 01, ...) must match
response number from message being acknowledged
cccc Two byte CRC-16 checkcode for message
RR Response
00 Success
01 Function code not recognized
Courtesy of NationalSwitchgear.com
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