LS iP5A - Inverter Communication Address; Modbus;Tcp Frame

iP5A Modbus/TCP Manual
8
8. Inverter communication address
Refer to iP5A manual appendix C - built-in comm. Parameter list
9. Modbus/TCP Frame
(1) Modbus/TCP Frame structure
Generally, Ethernet uses Ethernet II Frame.
MODBUS Application Protocol Header (MBAP Header)
MBAP Header structure is as below.
Protocol Data Unit (PDU)
AS an actual Data of Modbus TCP, consists of Function Code and Data.
Detail information will be given at “(2) Function Code Description.”
MBAP Header( 7 bytes)
PDU (5 bytes ~)
Region
Length
Description
Transaction Identifier
2 Bytes
As an identified transmitting number,
is increased by 1 each time Data Frame
is send to Server from Client.
Protocol Identifier
2 Bytes
Fixed as 0.
Length
2 Bytes
Modbus Data Frame length.
From MBAP Header to Unit Identifier,
Byte-unit length can be expressed.
Unit Identifier
1 Bytes
When Modbus TCP and Modbus RTU
are connected with Gate, Slave number
is written. When Modbus TCP is only used,
it is fixed as 0xFF.