B-4
N60 Network Stability and Synchrophasor Measurement System
GE Multilin
B.2 MODBUS FUNCTION CODES
APPENDIX B
B
B.2.3 EXECUTE OPERATION (FUNCTION CODE 05H)
This function code allows the master to perform various operations in the relay. Available operations are shown in the
Sum-
mary of operation codes
table below.
The following table shows the format of the master and slave packets. The example shows a master device requesting the
slave device 11h (17 decimal) to perform a reset. The high and low code value bytes always have the values “FF” and “00”
respectively and are a remnant of the original Modbus definition of this function code.
B.2.4 STORE SINGLE SETTING (FUNCTION CODE 06H)
This function code allows the master to modify the contents of a single setting register in an relay. Setting registers are
always 16 bit (two byte) values transmitted high order byte first. The following table shows the format of the master and
slave packets. The example shows a master device storing the value 200 at memory map address 4051h to slave device
11h (17 dec).
Table B–4: MASTER AND SLAVE DEVICE PACKET TRANSMISSION EXAMPLE
MASTER TRANSMISSION
SLAVE RESPONSE
PACKET FORMAT
EXAMPLE (HEX)
PACKET FORMAT
EXAMPLE (HEX)
SLAVE ADDRESS
11
SLAVE ADDRESS
11
FUNCTION CODE
05
FUNCTION CODE
05
OPERATION CODE - high
00
OPERATION CODE - high
00
OPERATION CODE - low
01
OPERATION CODE - low
01
CODE VALUE - high
FF
CODE VALUE - high
FF
CODE VALUE - low
00
CODE VALUE - low
00
CRC - low
DF
CRC - low
DF
CRC - high
6A
CRC - high
6A
Table B–5: SUMMARY OF OPERATION CODES FOR FUNCTION 05H
OPERATION
CODE (HEX)
DEFINITION
DESCRIPTION
0000
NO OPERATION
Does not do anything.
0001
RESET
Performs the same function as the
faceplate
RESET key.
0005
CLEAR EVENT RECORDS
Performs the same function as the
faceplate
CLEAR EVENT RECORDS
menu
command.
0006
CLEAR OSCILLOGRAPHY
Clears all oscillography records.
1000 to 103F
VIRTUAL IN 1 to 64 ON/OFF
Sets the states of Virtual Inputs 1 to 64 either “ON” or “OFF”.
Table B–6: MASTER AND SLAVE DEVICE PACKET TRANSMISSION EXAMPLE
MASTER TRANSMISSION
SLAVE RESPONSE
PACKET FORMAT
EXAMPLE (HEX)
PACKET FORMAT
EXAMPLE (HEX)
SLAVE ADDRESS
11
SLAVE ADDRESS
11
FUNCTION CODE
06
FUNCTION CODE
06
DATA STARTING ADDRESS - high
40
DATA STARTING ADDRESS - high
40
DATA STARTING ADDRESS - low
51
DATA STARTING ADDRESS - low
51
DATA - high
00
DATA - high
00
DATA - low
C8
DATA - low
C8
CRC - low
CE
CRC - low
CE
CRC - high
DD
CRC - high
DD