Schweitzer Engineering Laboratories SEL-2020 - Page 368

G-16 Appendix G Date Code 20010518
SEL-2020 Instruction Manual
Received message:
11
03
F8
00
00
0C
xx
xx
Response message:
11
03
18
00
14
00
15
...
xx
xx
xx
xx
Table G.1: Register Maps for Meter Data, Floating-Point Type
The METER command provides up-to-date meter information. However, for different SEL
relays, the meter data have different formats. Therefore, the register map will depend on the type
of relay. The meter data will always start at register address 100.
The first eight registers of Modbus meter data are the date and time stamp. This is the closest
time known to the SEL-2020; for all SEL-300 and SEL-500 series relays that use Fast Meter, it is
the time to the nearest millisecond that the data were sampled. For other relays, it is the time the
SEL-2020 received the meter data. The data types of currents, voltages, and power are IEEE
single-precision floating-point numbers; all other data are integers. All of these registers are
read-only, as indicated by the (R) following the register addresses. The following are meter
maps for all current SEL relays: Group I for ASCII meter data format and Group II for binary
meter data format.
The meter data the SEL-2020 retrieves may be in ASCII or binary format. Use the MAP n
command to determine the data types on a port. It will show an A for ASCII or a B for binary
data preceding the meter data type. The meter data retrieved with ASCII message format are
address 17
function code 3
startin
g
re
g
ister address F800h
read 12 registers
CRC-16 code
from address 17
successful function code 3 response
24 bytes of data following
SEL-121F IA data
SEL-121F IB data
SEL-501 ICY data
CRC-16 code