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4. Modbus RTU
4.8.4 Preset Multiple Registers (Writing data in multiple holding registers: 10h)
Data is written to consecutive holding registers for the specified number of data points starting from the
specified register address.
(1) Message frame
Query Message
Starting Address
Slave
Function
Address
H
(8 bits)
10h
(8 bits)
Message
Slave Address
Function
Starting Address (Note 2)
No. of Registers
Byte Count
Data (Note 2)
CRC Check
Note 1. When the broadcast communication was performed, a Response Message is not returned from the slave. To send the next
Query Message continuously, send it considering the processing time of the slave. (Refer to section 4.6.)
2. Registers can be classified into two types: registers to which data can be continuously written and particular registers to which
data cannot be continuously written.
To write data in particular registers, write data in the target registers one by one.
For the details on whether data can be continuously written into the target registers or not, refer to chapter 7.
Response Message
Slave Address
Function
(8 bits)
10h
Message
Slave Address
Function
Starting Address
No. of Registers
CRC Check
No. of Registers
L
H
L
(8 bits)
(8 bits)
(8 bits)
Size
Set a station number to which the message is sent.
8 bits
When "0" (station number for broadcast sending) is set, this message is sent to
all axes. (Note 1)
8 bits
Set "10h".
16 bits
Set the start address of the holding registers to which data is written.
Set the number of points of data to write starting from the start address of the
holding registers to which data is written.
16 bits
Set the number of write points described in the list of holding registers.
To write data in continuous registers, set a value obtained by adding the number
of write points of the target registers to this number.
8 bits
Set the size of the data to write.
16 bits × n
Set the data to write.
Data for CRC error check
16 bits
This data is calculated automatically by a controller.
Starting Address
H
L
(8 bits)
(8 bits)
Size
8 bits
The station number of a slave (servo amplifier) is returned.
8 bits
When the Query Message was received without errors, "10h" is returned.
The start address of the holding registers to which the data was written is
16 bits
returned.
The number of points of written data starting from the start address of the holding
16 bits
registers to which the data was written is returned.
Data for CRC error check
16 bits
This data is calculated automatically by a servo amplifier, and the result of the
calculation is returned.
Byte
Count
H
L
(8 bits)
(8 bits)
(8 bits)
Description
No. of Registers
H
(8 bits)
Description
4 - 10
Data
to
H
L
to
(8 bits)
(8 bits)
(8 bits)
CRC Check
L
L
(8 bits)
(8 bits)
CRC Check
L
H
(8 bits)
H
(8 bits)
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