Mitsubishi Electric FR-D720S SC EC, Instruction Manual

Page: 378 / 512

Communication operation and settings Parameter
6 - 228
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
Response message
Slave
Address
Function Starting Address No. of Points CRC Check
(8 bits)
H03
(8 bits)
H
(8 bits)
L
(8 bits)
H
(8 bits)
L
(8 bits)
L
(8 bits)
H
(8 bits)
Slave
Address
Function
Byte
Count
Data CRC Check
(8 bits)
H03
(8 bits)
(8 bits)
H
(8 bits)
L
(8 bits)
...
n
×
16 bits
L
(8 bits)
H
(8 bits)
Message Description
Slave Address
Set the address to which the message will be sent. Broadcast communica-
tion cannot be made (0 is invalid)
Function Set H03.
Starting Address
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.
No. of Points
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.
Tab. 6-69: Description of the query message
Message Description
Byte Count
The setting range is H02 to HFA (2 to 250).
Twice greater than the No. of Points specified at
is set.
Data
The number of data specified at is set. Data are read in order of Hi byte
and Lo byte, and set in order of starting address data, starting a 1
data, starting a 2 data, ...
Tab. 6-70: Description of normal response