Mitsubishi Electric FR-D720S SC EC Instruction Manual page 378

Communication operation and settings
Message format types
The message formats corresponding to the function codes in Tab. 6-68 will be explained.
● Read holding register data (H03 or 03)
Can read the description of system environment variables, real-time monitor, alarm history,
and inverter parameters assigned to the holding register area. (Refer to the register list on
page 6-236.)
Query Message
Slave
Address
(8 bits)
Response message
Slave
Address
(8 bits)
Message
Slave Address
Function
Starting Address
No. of Points
Tab. 6-69: Description of the query message
Message
Byte Count
Data
Tab. 6-70: Description of normal response
6 - 228
Function Starting Address
H03 H
(8 bits) (8 bits) (8 bits)
Byte
Function
Count
H03
(8 bits)
(8 bits) (8 bits)
Description
Set the address to which the message will be sent. Broadcast communica-
tion 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.
Description
The setting range is H02 to HFA (2 to 250).
Twice greater than the No. of Points specified at
The number of data specified at
and Lo byte, and set in order of starting address data, starting address + 1
data, starting address + 2 data, ...
No. of Points
L H
(8 bits) (8 bits)
Data
H L
n × 16 bits
(8 bits)
is set. Data are read in order of Hi byte
Parameter
CRC Check
L L
(8 bits) (8 bits)
CRC Check
... L
(8 bits) (8 bits)
is set.
H
H