J.5
Date Code 20080213 Instruction Manual SEL-351A Relay
SEL-351A Fast SER Protocol
Functions and Function Codes
02-Function Code:
Disable Unsolicited
Fast SER Data
Transfer, Sent From
Master to Relay
This function disables the SEL-351A from transferring unsolicited data. The
message format for function code 02 is shown Tab le J.2.
The SEL-351A verifies the message by checking the header, length, function
code, and disabled function code against the expected values, and checks the
entire message against the CRC-16 field. If any of the checks fail, except the
function code or the function to disable, the message is ignored.
If an acknowledge is requested as indicated by the least significant bit of the
status byte, the relay transmits an acknowledge message with the same
response number received in the enable message.
If the function to disable is not 18 or the function code is not recognized, the
relay responds with an acknowledge message containing the response code 01
(function code unrecognized) and no functions are disabled.
18-Function:
Unsolicited Fast SER
Response, Sent From
Relay to Master
The function 18 is used for the transmission of unsolicited Fast Sequential
Events Recorder (SER) data from the SEL-351A. This function code is also
passed as data in the “Enable Unsolicited Data Transfer” and the “Disable
Unsolicited Data Transfer” messages to indicate which type of unsolicited
data should be enabled or disabled. The message format for function code 18
is in Table J.3.
Table J.2 Message Format for Function Code 02
Data Description
A546 Message header
10 Message length (16 decimal)
0000000000 Five bytes reserved for future use as a routing address.
YY Status byte (LSB = 1 indicates an acknowledge is requested)
02 Function code
C0 Sequence byte (Always C0.
Other values are reserved for future use in multiple frame messages.)
XX Response number (XX = 00, 01, 02, 03, 01, 02...)
18 Function to disable (18 = Unsolicited SER)
00 Reserved for future use as function code data
cccc Two byte CRC-16 check code for message
Table J.3 Message Format for Function Code 18 (Sheet 1 of 2)
Data Description
A546 Message header
ZZ Message length (Up to 34 + 4 • nn decimal, where nn is the maximum
number of SER records allowed per message as indicated in the
“Enable Unsolicited Data Transfer” message.)
0000000000 Five bytes reserved for future use as a routing address.
YY Status Byte
01 = need acknowledgment
03 = settings changed and need acknowledgment
If YY = 03, the master should re-read the SNS data
because the element index list may have changed
18 Function code
C0 Sequence byte (Always C0.
Other values are reserved for future use in multiple frame messages.)
Courtesy of NationalSwitchgear.com
To Next Page
Loading...