Schweitzer Engineering Laboratories SEL-734 - Table 7.3 SEL Fast Message Protocol Format; Table 7.4 Unsolicited Write Message Transmission Rates

7.6
SEL-734 Meter Instruction Manual Date Code 20090730
Time-Synchronized Measurements
Synchrophasor Measurements
Decide the Rate at Which You Want to Receive Fast Messages
The SEL-734 can transmit Unsolicited Fast Messages at the rate of 1, 2, 4, 5,
10, or 20 times per second. For Fnom = 50, the maximum rate is 10 times per
second. The packet sent to enable unsolicited synchrophasor data contains a
byte that defines the rate at which the SEL-734 will transmit synchrophasor
data. Use Table 7.4 to determine the correct value to insert in the enable
message.
Table 7.3 SEL Fast Message Protocol Format
Field Description Hex Data
Header Synchrophasor Fast Message A546
Frame Size 40 bytes for PMDATA = V1
a
a
When PMDATA=V1, size is 28h. When PMDATA=V, size is 40h. When PMDATA=A, size is 60h.
28
Routing Must be 0000000000 for this application 0000000000
Status Byte Must be 00 for this application 00
Function Code 20h Code for unsolicited write messages 20
Sequence C0 for single frame message C0
Maximum frame size
255 bytes
C0
Response Number XX = 00, 01, 02, 03 00
PM Data Address Address of Synchrophasor
Measurement Data (PMADDR setting)
00000000
Register Count
b
b
Register Count V1 = 0009h, V = 0016h, A = 0026h.
Data size in registers (1 Register = 2 Bytes) XXXX
Sample Number 0-based index into SOC of this packet XXXX
SOC Second of century XXXXXXXX
Frequency IEEE 32-bit floating point
c
c
From ANSI/IEEE Std. 754–1985, The IEEE Standard for Binary Floating-Point Arithmetic.
XXXXXXXX
Phasor Mag. V1 Magnitude (IEEE 32-bit floating point) XXXXXXXX
Phasor Angle V1 Angle ± 180° (IEEE 32-bit floating point) XXXXXXXX
Digital Data SV16–SV03
TSOK (Time Synchronization OK)
PMDOK (Phasor Measurement Data OK)
XXXX
Check Word 2-byte CRC-16 check code for message XXXX
Table 7.4 Unsolicited Write Message Transmission Rates
Number of
Packets Per Second
Frequency of
Packets in Milliseconds
Data Transmission Rate
(nn–hexadecimal)
20 50 00h
20 50 05h
10 100 0Ah
5 200 16h
4 250 19h
2 500 32h
1 1000 64h
Courtesy of NationalSwitchgear.com