Read Holding Register [03H] - Omron MX2 User Manual

Network Protocol Reference
Note 1
Note 2
Note 3

Read Holding Register [03h]:

This function reads the contents of the specified number of consecutive hold-
ing registers (of specified register addresses). An example follows below.
• Reading Trip monitor 1 factor and trip frequency, current, and voltage from
an inverter having a slave address "1"
• This example assumes the previous three trip factors are as follows:
MX2 D081
Command (factor)
Register 0012h
Number
Trip factor Over-Current
(E03)
Query:
No. Field Name
1 Slave address *1
2 Function code
3 Register start
address *3
(high order)
4 Register start
address *3
(low order)
5 Number of holding
registers (high order)
6 Number of holding
registers (low order)
7 CRC-16 (high order)
8 CRC-16 (low order)
Broadcasting is disabled.
Data is transferred by the specified number of data bytes (data size). In this
case, 6 bytes are used to return the content of three holding registers.
The PDU Register Number are addressed starting at zero. Therefore register
numbered "0012h" are addressed as "0011h". Register address value (trans-
mitted on Modbus line) is 1 less than the Register Number.
D081 D081
(frequency) (output current)
0014h 0016h
9.9Hz 3.0A
Response:
Example No.
(Hex)
01 1 Slave address
03 2 Function code
00 3 Data size (in bytes) *2 0C
11 4 Register data 1
(high order)
00 5 Register data 1
(high order)
06 6 Register data 2
(high order)
95 7 Register data 2
(low order)
CD 8 Register data 3
(high order)
9 Register data 3
(low order)
10 Register data 4
(high order)
11 Register data 4
(low order)
12 Register data 5
(high order)
13 Register data 5
(low order)
14 Register data 6
(high order)
15 Register data 6
(low order)
16 CRC-16 (high order)
17 CRC-16 (low order)
Section B-3
D081
(DC-bus Voltage)
0017h
284V
Field Name Example
(Hex)
01
03
00
03
00
00
00
63
00
00
00
1E
01
1C
AF
6D
269