Hitachi WJ C1 Series User Manual

Chapter 11 RS485 Communication
11-2-3
11.2.2 Read Holding Registers [03h]
 How to read multiple holding register data on Modbus communication?
 Reads the specified number of consecutive holding registers from the specified holding register
number.
 Examples of readings of the latest trip information (holding register number =0012h to 0017h)
from the inverter at slave address 1 are shown below.
Query
No.
Field name
Example
(HEX)
1
Slave address
*1
01
2
Function code
03
3
Register start No. (High)
*2
00
Register start No. = (Register No.)-1
4
Register start No. (Low)
*2
11
5
Number of holding registers (High)
*3
00
6 registers
6
Number of holding registers (Low)
*3
06
7
CRC-16 (High)
95
8
CRC-16 (Low)
CD
Response
No.
Field name
Example
(HEX)
1
Slave address
01
2
Function code
03
3
Number of data bytes
*4
0C
4
Register data 1 (High)
00
0003h → 03d → E03 (Trip factor =
Overcurrent)
5
Register data 1 (Low)
03
6
Register data 2 (High)
00
0004h → 4 (Inverter status =
during acceleration).
7
Register data 2 (Low)
04
8
Register data 3 (High)
00
0000 04D2h → 1234d → 12.34 (Hz)
(Frequency)
9
Register data 3 (Low)
00
10
Register data 4 (High)
04
11
Register data 4 (Low)
D2
12
Register data 5 (High)
00
001Eh → 30d → 3.0 (A) (Output current)
13
Register data 5 (Low)
1E
14
Register data 6 (High)
01
011Ch → 284d → 284 (VDC) (DC bus Voltage)
15
Register data 6 (Low)
1C
16
CRC-16 (High)
77
17
CRC-16 (Low)
3D
"h" = Hexadecimal "d" = Decimal
*1. Broadcasting is disabled.
*2. Note that the starting number is 1 less than the actual register number. Specify a number of
"(Register No.) - 1".
*3. The maximum number of data that can be read is 16 registers (32 bytes). If it is exceeded,
an exceptional response of exception code "03h" is returned.
*4. Data of the number of data bytes is transferred. In this example, it is 12 bytes because of
the six holding registers.
 If the command cannot be executed successfully, an exceptional response is returned. For
details, refer to "11.2.9 Exceptional Responses".
A
!
Q

Hitachi WJ C1 Series Specifications

General

Brand	Hitachi
Model	WJ C1 Series
Category	Inverter
Language	English