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890053-03-01
Connecting with Other Products
10.3.2 Function Codes
The Modbus TCP communication involves clients and a server. During
communication, clients send commands to the server, and the server responds to the
commands. In general, devices such as a PLC, HMI, and PC are used as the client,
and the inverter works as a server.
①
Read Holding registers
Read Input registers are functions used to read the server (inverter) data.
The following table explains the components of a request data frame from a client to a
server.
Request frame
Length
Value
Function code
1 byte
0x03
Comm. address
2 byte
0x0000
–0xFFFF
Number of data
requests
2 byte
1
–16 (Inverters)
The following table explains the components of a response data frame from a server to a
master.
Response frame
Length
Value
Function code
1 byte
0x03
Comm. address
1 byte
2 x the number of data requests
Number of data
requests
Number of data requests
x 2 bytes
Data value of the given number from
the comm. address
②
Read Input registers
Read Input registers are functions used to read the server (inverter) data.
The following table explains the components of a request data frame from a client to a
server.
Request frame
Length
Value
Function code
1 byte
0x04
Comm. address
2 byte
0x0000
–0xFFFF
Number of data
requests
2 byte
1
–16 (Inverters)
