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3 Modbus protocol description
3.6.3 Writing n words
This function is used to write n words starting at a specific address.
Instruction
Response
Example
Write value 25.0 to the external analog input 1 (from word address 0x3700, 4 bytes = 2 words):
chapter 3.7.2 "Float values", Page 20
chapter 3.8 "Checksum (CRC16)", Page 22
Slave address Function
0x10
Address of
first word
Number of
words
Number of
bytes
Word val-
ue(s)
Checksum
CRC
1 byte 1 byte 2 bytes 2 bytes 1 byte x bytes 2 bytes
Slave address Function
0x10
Address of
first word
Number of
words
Checksum
CRC
1 byte 1 byte 2 bytes 2 bytes 2 bytes
Instruction (value in Modbus floating-point format):
01 10 37 00 00 02 04 00 00 41 C8 B0 58
Slave Function Address of
first word
Number of
words
Number of
bytes
Value CRC
Response:
01 10 37 00 00 02 4F BC
Slave Function Address of
first word
Number of
words
CRC