Execute Command - GE D90 Plus Communications Manual

MODBUS FUNCTION CODES

Execute command

6
The following tables show the format of the master and slave packets. The example shows
a master device requesting three register values starting at address 4050h from slave
device 11h (17 decimal); the slave device responds with the values 40, 300, and 0 from
registers 4050h, 4051h, and 4052h, respectively.
Table 3: Master transmission packet example, function code 04h
Packet format
Slave address
Function code
Data starting address - high order byte
Data starting address - low order byte
Number of registers - high order byte
Number of registers - low order byte
CRC - low order byte
CRC - high order byte
Table 4: Slave response packet example, function code 04h
Packet format
Slave address
Function code
Byte count
Data byte 1 - high order byte
Data byte 1 - low order byte
Data byte 2 - high order byte
Data byte 2 - low order byte
Data byte 3 - high order byte
Data byte 3 - low order byte
CRC - low order byte
CRC - high order byte
The execute command function allows the master to perform operations in the relay. The
following table outlines the operations available.
Table 5: Summary of operation codes for function 05h
Operation code Definition
0000h NO OPERATION
0001h RESET
0005h CLEAR EVENT RECORDS
0006h CLEAR OSCILLOGRAPHY
1000h to 103Fh VIRTUAL IN 1 to 64 ON/OFF
The following tables illustrate the format of the master and slave packets for function code
05h. 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.
Example (hex)
11
04
40
50
00
03
A7
4A
Example (hex)
11
04
06
00
28
01
2C
00
00
0D
60
Description
Does not do anything
Performs the same function as the Reset command
Performs the same function as the Clear Event
Records command
Clears all oscillography records
Sets the states of virtual inputs 1 to 64 either "ON"
or "OFF"
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – COMMUNICATIONS GUIDE
CHAPTER 2: MODBUS COMMUNICATION