User Manual

Chapter 8 Communication Functions
8 - 10
(B) 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 Trip monitor 1 factor and trip frequency, current, and voltage from an inverter having a
slave address “1”
 This example assumes the previous six trip factors are as follows:
NE-S1
Command
D081
(factor)
D081
(status)
D081
(frequency)
D081
(output
current)
D081
(DC-bus
Voltage)
Register Number 0012h 0013h 0014h 0016h 0017h
Trip factor Over-Current
(E03)
04h 9.9Hz 3.0A 284V
Query: Response:
No. Field Name
Example
(Hex)
No. Field Name
Example
(Hex)
1 Slave address *1 01 1 Slave address 01
2 Function code 03 2 Function code 03
3 Register start address *3
(high order)
00 3 Data size (in bytes) *2 0C
4 Register start address *3
(low order)
11 4 Register data 1 (high order) 00
5 Number of holding
registers (high order)
00 5 Register data 1 (high order) 03
6 Number of holding
registers(low order)
06 6 Register data 2 (high order) 00
7 CRC-16 (high order) 95 7 Register data 2 (low order) 04
8 CRC-16 (low order) CD 8 Register data 3 (high order) 00
9 Register data 3 (low order) 00
10 Register data 4 (high order) 00
11 Register data 4 (low order) 63
12 Register data 5 (high order) 00
13 Register data 5 (low order) 1E
14 Register data 6 (high order) 01
15 Register data 6 (low order) 1C
16 CRC-16 (high order) 0A
17 CRC-16 (low order) A3
Note 1: Broadcasting is disabled.
Note 2: Data is transferred by the specified number of data bytes (data size). In this case, 12
bytes are used to return the content of six holding registers.
Note 3: The PDU Register Number are addressed starting at zero. Therefore register numbered
“0012h” are addressed as “0011h”. Register address value (transmitted on Modbus line)
is 1 less than the Register Number.