128 Chapter 8 - Modbus RTU Protocol User Manual
8.4.2 Read Input Registers (04)
This function is similar to the previous one.
8.4.3 Preset Single Register (06)
This function allows to set the value of a single 16-bit register. The broadcast mode is allowed.
Request
Together with the Drive address and the function code (06), the message contains the register address (parameter)
on two bytes and the value to be allocated. The numbering system of the register addresses starts from zero (word1
= 0) for the MODBUS and from one (word1 = 1) for the JBUS.
Example: Modbus
Drive address 38 (26
hex
)
Register 26 (001A
hex
)
Value 926 (039E
hex
)
ADDR FUNC DATA DATA DATA DATA CRC CRC
bit# bit# WORD WORD
HI LO HI LO HI LO
26 06 00 19 03 9E DF 82
Response
The response is given by transmitting again the received message after the register has been modified.
Example: Response to the above mentioned request.
ADDR FUNC DATA DATA DATA DATA CRC CRC
bit# bit# WORD WORD
HI LO HI LO HI LO
26 06 00 19 03 9E DF 82
8.4.4 Read Status (07)
This function allows to read the status of eight predefined bits with a compact message. The broadcast mode is not
allowed.
Request
The message contains only the Drive address and the function code (07).
Example: Modbus
Drive address 25 (19
hex
)
ADDR FUNC CRC CRC
HI LO
19 07 4B E2
Response
Together with the Drive address and the function code (07), the message includes a character containing the status
bits.
Example: Response to the above mentioned request.
ADDR FUNC DATA CRC CRC
status
byte HI LO
19 07 6D 63 DA
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