ModBus Mode Communications
Append
ix
B
B–26
Read Holding Register [03h]:
This function reads the contents of the specified number of consecutive holding registers (of
specified register addresses). An example follows below.
• Reading previous three trip factors from an inverter having a slave address “5”
• This example assumes the previous three trip factors are as follows:
The data set in the response is as follows:
When the Read Holding Register command cannot be executed normally, refer to the exception
response.
SJ700
2
Command
D081 (N)
D082 (N-1
Register number
0012h
0013h
Trib factor (upper digit)
Over-voltage (E07)
Decelerating (02)
Response Buffer
4
5
6
7
Starting register
number
+0 (high order)
+0 (low order)
+1 (high order)
+1 (low order)
Register status
00h
07h
00h
02h
Trip data
Over-voltage trip
Decelerating
Query:
Note 1:
Broadcasting is disabled.
Note 2:
The starting coil number is one
less than the number of the coil to
be read first.
Response:
Note 3:
Data is transferred by the specified
number of data bytes (data size). In
this case, 4 bytes are used to return
the content of two holding
registers.
No.
Field Name
Example
(hex)
1
Slave address *1
05
2
Function code
03
3
Register start number
(high order)
00
4
Register start number
(low order)
11
5
Number of registers
(high order) *2
00
6
Number of registers
(low order) *2
02
7
CRC-16 (high order)
95
8
CRC-16 (low order)
8A
No.
Field Name
Example
(hex)
1
Slave address
05
2
Function code
03
3
Data size (in bytes) *3
04
4
Register start number
(high order)
00
5
Register start number
(low order)
07
6
Register start 1
(high order)
00
7
Register start 1
(low order)
02
8
CRC-16 (high order)
36
9
CRC-16 (low order)
37
