DVP15MC11T Operation Manual
B.1 Modbus TCP Message Structure
Modbus TCP message structure
Byte NO. Name Explanation
Byte0
Transaction identifier
High byte
0
Byte1
Low byte
Byte2
Protocol identifier
High byte
0
Byte3
Low byte
Byte4
Modbus data length
High byte
The number of bytes of
Modbus address and the
data after it.
Byte5
Low byte
Byte6
Modbus ID
Single byte
0~0xFF
Byte7
Function code
Single byte
Byte8
Register address in
DVP15MC11T
High byte
0~0xFFFF
Byte9
Low byte
Byte10
Modbus data
High byte
Modbus data is
determined by function
B.2 Modbus Function Codes Supported in Modbus TCP
Modbus function codes which DVP15MC11T supports
Function
Function Register
0x02
Read bit register value; maximum 256 bits of data could
be read at a time.
%IX and %QX
0x03
Read one single or multiple word register values;
maximum 100 words of data could be read at a time.
%IW, %QW and %MW
Write one single bit register value.
Write one single word register value.
0x0F
Write multiple bit register values; maximum 256 bits of
data could be written at a time.
% QX
0x10
Write multiple word register values; maximum 100 words
of data could be written at a time.
%QW and %MW
B-2