G-12 Appendix G Date Code 20010518
SEL-2020 Instruction Manual
Response message:
06
04
C0
00
05
00
02
...
yy
yy
yy
yy
xx
xx
Example #2: Accessing Centralized Data
This example demonstrates the ability of the SEL-2020 to centralize data to reduce the number of
Modbus accesses necessary to collect data. This example uses an SEL-121F and an SEL-501 on
Ports 3 and 4 of the SEL-2020, respectively. The objective is to read the current and voltage
magnitudes from the relays with a single Modbus access. The following procedure explains how
to set the SEL-2020 and collect the data.
1. Connect the two relays to Ports 3 and 4 of the SEL-2020. Establish basic communications
settings to the first relay by auto-configuring using SET P 3. Use SET A 3 to set meter data
collection. Copy these settings to Port 4 using COPY 3 4. Auto-configure Port 4 while
copying.
2. Set Port 16 to be a Modbus port, as shown below:
*>>SET P 16<ENTER>
SET P 16<ENTER>SET P 16<ENTER>
SET P 16<ENTER>
Port communications settings for Port 16
Device Type (U=Unused, S=SEL IED, O=Other IED,
P=Printer, M=Master) DEVICE = U ? M<ENTER>
M<ENTER>M<ENTER>
M<ENTER>
Communications Type (S=SEL, L=LMD, M=MODBUS) PROTOCOL= S ? M<ENTER>
M<ENTER>M<ENTER>
M<ENTER>
Modbus Map Type (F=Float, I=Integer) MAP_TYPE= F ? <ENTER>
<ENTER><ENTER>
<ENTER>
Starting Code for ID List (0-255) START_ID= 0 ? <ENTER>
<ENTER><ENTER>
<ENTER>
Transmission delay from RTS assertion (0-30000 milliseconds) SETTLE1=0 ? <E
<E<E
<ENTER>
NTER>NTER>
NTER>
Post-transmit RTS de-assertion delay (0-30000 milliseconds) SETTLE2=0 ? <ENTER>
<ENTER> <ENTER>
<ENTER>
(continued on next page)
from address 6
successful function code 4 response
192 bytes of data following
first register
second register
CRC-16 code
last two registers
(IEEE float)
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