Mitsubishi Electric 700 Series, Instruction Manual

Page: 247 / 416

236
Communication operation and setting
(5) Message format types
The message formats corresponding to the function codes in Table 1 on page 235 will be explained.
z Read holding register data (H03 or 03)
Can read the description of 1) system environment variables, 2) real-time monitor, 3) faults history, and 4)
inverter parameters assigned to the holding register area (refer to the register list
(page 241) ).
Query Message
Response message
⋅
Query message setting
⋅
Description of normal response
1) Slave Address 2) Function 3) Starting Address 4) No. of Points CRC Check
(8bit)
H03
(8bit)
H
(8bit)
L
(8bit)
H
(8bit)
L
(8bit)
L
(8bit)
H
(8bit)
1) Slave Address 2) Function 5) Byte Count 6) Data CRC Check
(8bit)
H03
(8bit)
(8bit)
H
(8bit)
L
(8bit)
...
(n
×
16bit)
L
(8bit)
H
(8bit)
Message Setting Description
1)Slave Address
Set the address to which the message will be sent. Broadcast
communication cannot be made (0 is invalid)
2) Function Set H03.
3)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.
4)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.
Message Setting Description
5)Byte Count
The setting range is H02 to HFA (2 to 250).
Twice greater than the No. of Points specified at 4) is set.
6)Data
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 a 1
data, starting a 2 data, ...
Example) To read the register values of 41004 (Pr. 4) to 41006 (Pr. 6) from the slave address 17 (H11)
Query message
Normal response (Response message)
Read value
Register 41004
(Pr. 4) : H1770 (60.00Hz)
Register 41005 (Pr. 5) : H0BB8 (30.00Hz)
Register 41006 (Pr. 6) : H03E8 (10.00Hz)
Slave Address Function Starting Address No. of Points CRC Check
H11
(8bit)
H03
(8bit)
H03
(8bit)
HEB
(8bit)
H00
(8bit)
H03
(8bit)
H77
(8bit)
H2B
(8bit)
Slave Address Function Byte Count Data CRC Check
H11
(8bit)
H03
(8bit)
H06
(8bit)
H17
(8bit)
H70
(8bit)
H0B
(8bit)
HB8
(8bit)
H03
(8bit)
HE8
(8bit)
H2C
(8bit)
HE6
(8bit)