197
3. RS-485 Communication
3.5 MODBUS RTU
1
2
3
4
5
6
7
8
9
10
Read holding registers (reading data of holding registers) (H03 or 03)
• Query message
• Normal response (Response message)
• Query message setting
• Content of normal response
Example) Read the register values of 41004 (Pr.4) to 41006 (Pr.6) from slave address 17 (H11).
Query message
Write single register Write
H06
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
Available
Diagnostics
Read
H08
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).
Not available
Write multiple
registers
Write
H10
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
Available
Read holding
register access log
Read
H46
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.
Not available
Function name
Read/
write
Code
Outline
Broadcast
communication
Message
format
reference
page
a. Slave address
b. Function code
c. Starting address
d. Quantity of registers
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)
a. Slave address
b. Function code
e. Byte count
f. Register value
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
a
Slave address
Set the address to send messages to. Broadcast communication is not possible. (Invalid when "0"
is set.)
b
Function code
Set H03.
c
Starting address
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.
d
Quantity of registers
Set the number of holding registers for reading data. Data can be read from up to 125 registers.
Message
Description
e
Byte count
The setting range is H02 to HFA (2 to 250).
Twice the number of reads specified by (d) is set.
f
Register value
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 1, data of start 2,
and so forth.
Slave address
Function code
Starting address
Quantity of registers
CRC check
H11
(8 bits)
H03
(8 bits)
H03
(8 bits)
HEB
(8 bits)
H00
(8 bits)
H03
(8 bits)
H77
(8 bits)
H2B
(8 bits)
Summary of Contents for E820S
Page 5: ...4 ...
Page 177: ...176 2 Ethernet Communication 2 15 Ethernet communication parameters MEMO ...
Page 207: ...206 3 RS 485 Communication 3 5 MODBUS RTU MEMO ...
Page 211: ...210 4 Other Communication Options 4 2 Automatic connection with GOT MEMO ...
Page 212: ...211 CHAPTER 5 CHAPTER 5 4 5 6 7 8 9 10 Common Settings ...
Page 219: ...218 5 Common Settings MEMO ...
Page 220: ...219 CHAPTER 6 CHAPTER 6 4 5 6 7 8 9 10 Appendix 6 1 How to check specification changes 220 ...