Using Socket Services with CMND(490)

Section 6-8

6-8 Using Socket Services with CMND(490)

6-8-1 Using Socket Service

Each Ethernet Unit has eight TCP sockets and eight UDP sockets. Open, close, send, and receive processes are available for communications with sockets.

Open

Enables communications on a specified socket. A socket must be opened before it can be used for socket services. Opening a TCP socket establishes a connection.

Close

Ends use of the socket. Breaks the connection for a TCP socket.

Send

Sends data from a specified open socket.

Receive

Specifies an open socket and receives data from that socket.

These processes are carried out by sending FINS commands to the Ethernet Unit. The process from sending a request for processing to completion is shown in the following illustrations.

1,2,3... 1. Execute a socket service request command (MRC: 27) for the Ethernet Unit using CMND(490).

CPU

User program

CMND

END

Ethernet Unit

Socket service

Request command

2.CMND(490) ends normally when the socket service request command is received and a response is returned (response code: 0000).

CPU

User program

CMND

END

Ethernet Unit

Response

3.The Ethernet Unit starts the process requested by the parameters in the socket service request command.

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Omron CJ1W-ETN21 operation manual Using Socket Services with CMND490