Omron V750 series, Network Connection Manual

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9. Program
31
9.1.1. Communications Data Flow
The following figure shows the data flow from when the Controller issues command data
with TCP socket communications to the destination device until when the Controller
receives the response data from the destination device. This program executes a series of
processing from the connect processing to the close processing continuously. The receive
processing is repeated when the response data is divided and multiple receive data are
sent.
1. Connect processing The Controller issues a TCP open request to the
destination device, and establishes a TCP
connection.
↓
2. Sending a command The Controller issues a send message (command
data), which is set in the program, to the destination
device.
↓
3. Receiving a response The Controller receives the receive message
(response data) from the destination device and
stores it in the specified internal variable.
↓
4. Close processing The Controller issues a close request to the
destination device, and terminates the TCP
connection.
*The response data is not sent after receiving command data or the response data is
sent immediately after a connection is established depending on the destination device
and command. With this program, the Send/Receive processing required/not required
setting can be set for the General-purpose Ethernet communications sequence setting
function block.
If Send only is set, the response data receive processing is not performed. If Receive
only is set, the command data send processing is not performed.