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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