Instruction Manual

6. Modbus ASCII
277
Modbus
(3) Query format
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
)
00
H
if broadcast is specified
Function code [H] 2 ‘1’, ‘0’ Numerical value specification
Start address [H] 4 Arbitrary Refer to 6.7.1. (2), “Start
address list”
Number of registers [H] 4 Arbitrary Refer to 6.7.1 (2), “Start
address list”
Number of bytes [H] 2 In accordance with
the number of
registers above
Enter the value twice as large
as the number of registers
specified above
Changed data 1 [H] 4 Refer to 6.7.1 (2), “Start
address list”
Changed data 2 [H] 4 Refer to 6.7.1 (2), “Start
address list”
Changed data 3 [H] 4 Refer to 6.7.1 (2), “Start
address list”
: :
Error check [H] 2 LRC calculation
result
Trailer 2 ‘CR’, ‘LF’
Total number of bytes Up to 256
(4) Response format
When normally changed, the response message responds with a copy of the query message
excluding the number of bytes and changed 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
)
00
H
if broadcast is specified
Function code [H] 2 ‘1’, ‘0’ Numerical value specification
Start address [H] 4 Arbitrary Refer to 6.7.1 (2), “Start
address list”
Number of registers [H] 4 Arbitrary Refer to 6.7.1 (2), “Start
address list”
Error check [H] 2 LRC calculation
result
Trailer 2 ‘CR’, ‘LF’
Total number of bytes Up to 256