Data Reception Processing - Omron Sysmac NJ-series User Manual

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Data Reception Processing

This section describes data reception processing for TCP and UDP.
 TCP Receive Processing
With TCP communications, the receive data that is stored in the receive buffer can be separated
and received. (The receive buffer holds up to 9,000 bytes.) This can be used to receive data that
exceeds the size that can be received with one data request (2,000 bytes), i.e., more than one
receive request is used to receive all of the data. Also, all of the receive data can be received if there
is less data in the receive buffer than the size of the variable that was specified in the receive
request.
Example: Receiving 3,000 Bytes of Receive Data in Two Sections
1. The data that was sent from the sending node in two sends is stored in the receive buffer.
2. Two receive requests are used to receive all of the send data.
Sending node (host computer)
User program
1,000 bytes
2,000 bytes
NJ/NX-series CPU Unit Built-in EtherNet/IP Port User's Manual (W506)
Ethernet line
1st send
request
Data A
Data B
2nd send
request
Receiving node (Controller)
Built-in EtherNet/IP port
(1) Data received to
receive buffer.
(2) The data is received in
two sections.
Receive buffer
(9,000 bytes)
Data A
Data B
3,000 bytes
9 Socket Service
User program
1st receive request
(Request for 1,000 bytes)
1,000 bytes
Data A
2nd receive request
(request for 2,000 bytes)
Data B 2,000 bytes
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