2. MODBUS/TCP PROTOCOL
2 - 3
2.3 Function Codes
2.3.1 List of function codes
The MR-JE-_C servo amplifier supports the following function codes.
Code Function
name
Description
03h
Read Holding Registers
Reading data in holding registers
The data in the registered holding registers can be read from the client.
08h Diagnostics
Function
diagnostics
When this function code is sent from the client to a server, the server returns the
received data to the client without any changes.
Communication checks can be performed.
10h
Preset Multiple Registers
Writing data in multiple holding registers
Consecutive multiple data sets can be written in the registered holding registers from
the client.
2.3.2 Read Holding Registers (Reading data in holding registers: 03h)
Data in consecutive registers is read for the specified number of data points starting from the specified
register address.
(1) Message frame
Query Message
Transaction
Identifier
Protocol
Identifier
Length Field
Unit
Identifier
Function
Starting Address
No. of Points
H L H L
16 bits
0000h
0006h
FFh
03h
8 bits
8 bits
8 bits
8 bits
Message field
Size
Description
Transaction Identifier
(Transaction identifier)
16 bits
Set any value.
Protocol Identifier
(Protocol identifier)
16 bits
Set "0000h".
Length Field (Message length)
16 bits
Set "0006h".
Unit Identifier (Unit identifier)
8 bits
Set "FFh".
Function (Function field)
8 bits
Set "03h".
Starting Address (Start address)
(Note 1)
16 bits
Set a start address of the holding registers to read.
No. of Points
(Number of read points)
16 bits
Set the number of points of data to read starting from the start address of the
holding registers from which data is read.
Set the number of read points described in the list of holding registers.
To read the data in continuous registers, set a value obtained by adding the
number of read points of the target registers to this number.
Содержание MELSERVO-JE MR-JE-C
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