iS7 Ethernet Option Manual
14
(9) Para Control (COM-50~58)
This parameter is not used in case of Modbus TCP.
This parameter appears only when the set value of the Output Instance
(COM-18) in the Ethernet IP is 4 or above.
COM-50 Para Ctrl Num cannot be set up but the number of the set up
parameters of the instance is shown. Enter the address of the inverter
data, which will make use of the reference data of the Client (Originator),
at the same number as that of the said parameters in the COM-51~58.
(10) Comm UpDate (COM-94)
At power on, the Option Parameters are expressed by the values set up
in the Option, however, not reflected immediately when set up.
If the Comm Update is set to ‘Yes,’ this value is reflected on the
Modbus/TCP communication card and only this card will be restarted.
9.
Inverter Communication Address
See Chapter 11. Communication Function, Inverter IS-7 Manual.
10.
Modbus/TCP Frame
(1) Modbus/TCP Frame Composition
Generally, Ethernet uses Ethernet II Frame.
MODBUS Application Protocol Header (MBAP Header)
MBAP Header constitution is presented below
.
MBAP Header( 7 bytes)
PDU (5 bytes ~)
Section
Length
Description
Transaction
Identifier
2 Bytes
Unique transmission number, which is
increased by 1 each time the Client sends
Data Frame to the Server.
Protocol Identifier
2 Bytes Fixed at 0.
Length
2 Bytes
The Data Frame length of the Modbus,
representing the length (in byte unit) from
the Unit Identifier in the MBAP Header.
Unit Identifier
1 Bytes
When the Modbus TCP and Modbus RTU
are connected via gate, Slave number is
indicated. If Modbus TCP only is used, this
is fixed to 0xFF.
