Instruction Manual

6. Modbus ASCII
188
Modbus
(3) Query format
In a query message, specify the address of the register from which to start reading data, and
number of bytes in registers to be read.
1 register = 2 bytes = 16-bit data
Field Number of characters
(Number of bytes)
ASCII mode
fixed character string
Remarks
Header 1 ‘:’
Slave address [H] 2 Arbitrary Axis number + 1 (01
H
to 10
H
)
Function code [H] 2 ‘0’, ‘3’ Register reading code
Start address [H]
4
Arbitrary Refer to 6.4.1 (2), “Start
address list.”
Number of registers [H] 4 Arbitrary Refer to “Start address list.”
Error check [H]
2
LRC calculation
result
Trailer 2 ‘CR’, ‘LF’
Total number of bytes 17 17
(4) Response format
Field Number of characters
(Number of bytes)
ASCII mode
fixed character string
Remarks
Header 1 ‘:’
Slave address [H] 2 Arbitrary Axis number + 1 (01
H
to 10
H
)
Function code [H]
2 ‘0’, ‘3’
“Read Holding Registers”
code
Number of data bytes [H]
2
Number of specified registers
in a query format x 2
Data 1 [H] 4
Data 2 [H] 4
Data 3 [H] 4
Data 4 [H] 4
: :
: :
Error check [H]
2
LRC calculation
result
Trailer 2 ‘CR’, ‘LF’
Total number of bytes