Installation, Operation and Maintenance Manual
MAN712 Rev. 9
June 2021
Modbus RTU Interface
Section 8: Modbus RTU Interface
73
8.4.2
Function Code 06 (0x06) Write Single Register
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References 4x
This function code is used to write a value of a single holding register in a remote device.
The ELBS-20 Modbus RTU Interface has implemented 315 holding registers.
If address of register is more than 314, Exception Code 02 (0x02) is generated.
If value of register is out of range (see Section 8.5 for details), Exception Code 03 (0x03)
is generated.
If an error occurs while the slave device is performing the action requested in the query,
Exception Code 04 (0x04) is generated.
Only read register discharges new value without generating Exception Codes.
Broadcast messages are allowed, no response is generated after a broadcast request.
Example of a request to write Holding Register with address 0 in the field device 15:
Table 14.
Request
Field Name
Value (HEX)
Address
0F
Function Code
06
Register address Hi
00
Register address Lo
00
Register Value Hi
00
Register Value Lo
02
CRC
-
Table 15.
Response
Field Name
Value (HEX)
Address
0F
Function Code
06
Register Address Hi
00
Register Address Lo
00
Register Value Hi
00
Register Value Lo
02
CRC
-