Modbus Write Multiple Registers (FC16)

Function Code 16

Request

This command is writing the contents of two analog output holding registers # 40002 & 40003 to the slave device with address 17.

11 10 0001 0002 04 000A 0102 C6F0

11: The SlaveID (11 hex = address 17 )
10: The Function Code 16 (Preset Multiple Registers, 10 hex - 16 )
0001: The Data Address of the first register.
            ( 0001 hex = 1 , + 40001 offset = register #40002 )
0002: The number of registers to write
04: The number of data bytes to follow (2 registers x 2 bytes each = 4 bytes)
000A: The value to write to register 40002
0102: The value to write to register 40003
C6F0: The CRC (cyclic redundancy check) for error checking.

Response

11 10 0001 0002 1298

11: The SlaveID (11 hex = address 17 )
10: The Function Code 16 (Preset Multiple Registers, 10 hex - 16 )
0001: The Data Address of the first register. (# 40002 - 40001 = 1 )
0002: The number of registers written.
1298: The CRC (cyclic redundancy check) for error checking.