Mitsubishi Electric 800 Series Instruction Manual page 146

Read/
Function name
write
Write single register Write H06
Diagnostics Read H08
Write multiple
Write H10
registers
Read holding
Read H46
register access log
 Read holding registers (reading data of holding registers) (H03 or 03)
• Query message
a. Slave address b. Function code
H03
(8 bits)
(8 bits)
• Normal response (Response message)
a. Slave address b. Function code
H03
(8 bits)
(8 bits)
• Query message setting
Message
a Slave address
b Function code
c Starting address
d Quantity of registers
• Content of normal response
Message
e Byte count
f Register value
 Example) Read the register values of 41004 (Pr.4) to 41006 (Pr.6) from slave address 17 (H11).
Query message
Slave address Function code
H11 H03
(8 bits) (8 bits)
Code
Data is written to a holding register.
Data can be written to MODBUS registers to output instructions to
the inverter or set parameters.
System environmental variable (Refer to
Inverter parameters (Refer to
Functions are diagnosed. (communication check only)
A communication check can be made since the query message is
sent and the query message is returned as it is as the return
message (subfunction code H00 function).
Subfunction code H00 (Return query data).
Data is written to multiple consecutive holding registers.
Data can be written to consecutive multiple MODBUS registers to
output instructions to the inverter or set parameters.
System environmental variable (Refer to
Inverter parameters (Refer to
The number of registers that were successfully accessed by the
previous communication is read.
Queries by function codes H03, H06, and H10 are supported.
The number and start address of holding registers successfully
accessed by the previous communication are returned.
"0" is returned for both the number and start address for queries
other than function code H03, H06, and H10.
c. Starting address
H L
(8 bits) (8 bits)
e. Byte count
H
(8 bits)
(8 bits)
Set the address to send messages to. Broadcast communication is not possible. (Invalid when "0"
is set.)
Set H03.
Set the holding register address from which to start reading the data.
Starting address = start register address (decimal) - 40001
For example, when starting register address 0001 is set, the data of holding register address 40002
is read.
Set the number of holding registers for reading data. Data can be read from up to 125 registers.
The setting range is H02 to HFA (2 to 250).
Twice the number of reads specified by (d) is set.
The amount of data specified by (d) is set. Read data is output Hi bytes first followed by Lo bytes,
and is arranged as follows: data of start address, data of start address+1, data of start address+2,
and so forth.
Starting address
H03 HEB
(8 bits) (8 bits)
Outline
page 150.)
page 151.)
page 150.)
page 151.)
d. Quantity of registers
H L
(8 bits) (8 bits)
f. Register value
L ...
(8 bits) (n × 16 bits)
Description
Description
Quantity of registers
H00 H03
(8 bits) (8 bits)
Message
Broadcast format
communication reference
page
Available page 146
Not available page 146
Available page 147
Not available page 148
CRC check
L H
(8 bits) (8 bits)
CRC check
L H
(8 bits) (8 bits)
CRC check
H77 H2B
(8 bits) (8 bits)
3. RS-485 Communication
3.5 MODBUS RTU
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