Mitsubishi Electric FR-A740-00023 Instruction Manual page 346

Communication operation and setting
(5) Message format types
The message formats corresponding to the function codes in Table 1 on page 335 will be explained.
Read holding register data (H03 or 03)
Can read the description of 1) system environment variables, 2) real-time monitor, 3) alarm history, and 4)
inverter parameters assigned to the holding register area (refer to the register list (page 341)).
Query Message
1) Slave Address
(8bit)
Normal response (Response message)
1) Slave Address
(8bit)
⋅ Query message setting
Message
1)Slave Address
2)Function
3)Starting Address
4)No. of Points
⋅ Description of normal response
Message
5)Byte Count
6)Data
Example) To read the register values of 41004 (Pr. 4) to 41006 (Pr. 6) from the slave address 17 (H11)
Query message
Slave Address Function
H11
(8bit)
Normal response (Response message)
Slave Address Function Byte Count
H11
(8bit)
Read value
Register 41004 (Pr. 4): H1770 (60.00Hz)
Register 41005 (Pr. 5): H0BB8 (30.00Hz)
Register 41006 (Pr. 6): H03E8 (10.00Hz)
336
2) Function 3) Starting Address
H03 H
(8bit) (8bit)
2) Function 5) Byte Count
H03
(8bit)
(8bit)
Set the address to which the message will be sent. Broadcast
communication cannot be made (0 is invalid).
Set H03.
Set the address at which holding register data read will be started.
Starting address = starting register address (decimal) − 40001
For example, setting of the starting address 0001 reads the data of the
holding register 40002.
Set the number of holding registers from which data will be read. The
number of registers from which data can be read is a maximum of 125.
The setting range is H02 to H14 (2 to 20).
Twice greater than the No. of Points specified at 4) is set.
The number of data specified at 4) is set. Data are read in order of Hi byte
and Lo byte, and set in order of starting address data, starting address + 1
data, starting address + 2 data, ...
Starting Address
H03 H03
(8bit) (8bit)
H03 H06 H17
(8bit) (8bit) (8bit)
4) No. of Points
L H L
(8bit) (8bit) (8bit)
6) Data
H L
(8bit) (8bit)
Setting Description
Setting Description
No. of Points
HEB H00
(8bit) (8bit)
Data
H70 H0B HB8
(8bit) (8bit) (8bit)
CRC Check
L H
(8bit) (8bit)
CRC Check
... L
(n × 16bit)
(8bit) (8bit)
CRC Check
H03 H77
(8bit) (8bit)
CRC Check
H03 HE8 H2C
(8bit) (8bit) (8bit)
H
H2B
(8bit)
HE6
(8bit)