479 Publication 1766-RM001A-EN-P - October 2008
Chapter
23
Socket Interface Using CIP Generic Messaging
Overview
The socket interface allows you use a MicroLogix controller to
communicate, via the Ethernet Subsystem, with Ethernet devices that do
not support the EtherNet/IP application protocol, such as bar code
scanners, RFID readers, or other standard Ethernet devices.
Before you use the socket interface, you should be familiar with the
following:
• basic TCP/IP, UDP, and socket programming concepts.
• how to write socket programs in a programming language, such as
C or Visual Basic.
• how to use diagnostic tools, such as a network sniffer.
• the application protocols of the devices and applications with which
the MicroLogix controller will communicate.
• how to write ladder logic for a MicroLogix controller.
Socket Interface
Architecture
The socket interface is implemented via the Socket Object in the Ethernet
Subsystem. MicroLogix controller programs communicate with the Socket
Object via MSG instructions. MSG requests to the Socket Object are similar
to socket API calls in most computer operating systems. The Socket
Object services let you open connections, accept incoming connections,
send data, and receive data.
To communicate with another device, you must understand the other
device's application protocol. The Ethernet Subsystem has no application
protocol knowledge — it simply makes the socket services available to
programs in MicroLogix controllers.
Number and Type of Sockets
You can create as many as 8 socket instances. Each socket instance can be
one of these socket types:
• UDP socket (to send/receive UDP datagrams)
• TCP client socket (RSLogix500 initiates the connection)
• TCP server socket (another device initiates the connection to
RSLogix500)
efesotomasyon.com - Allen Bradley,Rockwell,plc,servo,drive
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