3 Modbus protocol description
18
3.6.2 Writing one word
This function is used to write one word to a specific address.
The data blocks are identical for the instruction and response.
Instruction
Response
Example
Write binary value 1 to the external digital input 1 (word address 0x37A1):
chapter 3.8 "Checksum (CRC16)", Page 22
Slave address Function
0x06
Word address Word value Checksum CRC
1 byte 1 byte 2 bytes 2 bytes 2 bytes
Slave address Function
0x06
Word address Word value Checksum
CRC
1 byte 1 byte 2 bytes 2 bytes 2 bytes
Instruction:
01 06 37 A1 00 01 17 9C
Slave Function Word address Value CRC
Response:
01 06 37 A1 00 01 17 9C
Slave Function Word address Value CRC