Data Receive Processing - Omron NJ Series User Manual

9 Socket Service
2. The built-in EtherNet/IP port separates the send data into 1,472 bytes as data A and 528 bytes as
data B.
3. Data A and data B are sent in sequence by the sending node.
4. Data A and data B are joined and restored as the original send data, and the data is passed to the
user program.
Sending node (Controller)
User program
(1) Send request
2,000 bytes
Original data
Since UDP communications are performed in datagram units as shown above, send data is re-
stored in the original data format before it is passed to the user program.
9-2-3

Data Receive Processing

This section describes data receive processing for TCP and UDP.
TCP Receive Processing
In TCP communications, receive data stored in the receive buffer (a maximum of 9,000 bytes) can be
divided to be received.
Thus, if received data is larger than the maximum size of data that can be received with one data re-
quest (2,000 bytes), more than one receive request can be sent to receive all of the data.
If the data in the receive buffer is smaller than the size of the variable specified by the receive request,
the entire receive data is received.
Example) Receiving 3,000 Bytes of Receive Data in Two Sections
1. The data is divided to be sent in two sends from the sending node, and is stored in the receive
buffer.
2. More than one receive request is used to receive all of the send data.
9-6
Built-in
EtherNet/IP port
Ethernet line
(3)
(2) Fragmenting
Data A and
data B are
1,472 bytes
separated
and sent.
Data A
Data B
528 bytes
NJ/NX-series CPU Unit Built-in EtherNet/IP Port User's Manual (W506)
Receiving node (host computer)
User program
Receiving node
(4) Receive request
2,000 bytes
Data A Data B