1. Socket Services Lunch & Learn Presented by: Eric Paquette Automation Specialist Kendall Electric

2. Copyright © 2012 Kendall Electric, Inc. All rights reserved.
Agenda
What Is It?
Understanding Basic Socket Services
How is it Different from Standard Ethernet Communications
Explanation of New Hardware Capable of Socket Comms
Socket Services Hints
Setting it Up
Review of Error Codes – Common and Others
Some Examples
Reference Tools
Setting Up and Using Logging with the EWEB
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3. Copyright © 2012 Kendall Electric, Inc. All rights reserved.
What is a socket?
A socket is one of the most fundamental technologies of computer networking.
Sockets allow applications to communicate using standard mechanisms built into network hardware and operating systems.
Although socket technology may seem to be a relatively new topic, socket technology actually has been around for roughly two decades.
Sockets are bidirectional, meaning that either side of the connection is capable of both sending (writing) and receiving (reading) data.
The application that initiates communication is termed the “client” and the other application the “server”.
Sockets are created using an IP address and a port number.
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4. Who uses socket interfaces?
Almost all networked hardware and software.
Historically sockets have been of interest mainly to computer programmers.
Most, if not all, programming languages use libraries that implement application programming interfaces (API’s) to access socket communications. Microsoft uses Windows Sockets (Winsock).
Since the widespread growth of Ethernet in factory floor automation, a need was created to make a more generic socket interface. Not all products speak EtherNet/IP.
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Types of sockets
Sockets are divided into three categories: Stream, Datagram and Raw
Stream
TCP/IP
Connection Oriented
Most Common
Requires two devices to establish a connection in advance
Datagram
UDP
Connectionless
Implicit
More efficient data transfer
Raw
Custom low-level programming
Not common
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6. EtherNet/IP vs. Open-Socket Interface
EtherNet/IP is a protocol and does in fact use sockets to communicate between devices.
EtherNet/IP products from Rockwell set up the socket connections automatically. No user programming is needed
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7. What can I use Sockets for?
Non-Windows Based Workstations
Control data can be easily consumed by an external application using the XML data markup (Data Views)
Standard XML data presentation provides a platform neutral environment (works on all Operating Systems)
w/ EWEB support
Any Standard Ethernet Devices (ie: Robots)
XML Data
(via Data Views)
Sockets Connection (using the MSG Instruction)
RFID Readers
The EWEB modules support both TCP and UDP socket types. Up to 20 Socket connections per module.
The MSG instruction in RSLogix 5000 is used to setup and pass data thru Socket connections to other devices
Printers
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8. Which Rockwell Products Support an Open-Socket Services?
1756-EWEB
1768-EWEB
1756-EN2xx
1769-L30ER, 1769-L30ERM, 1769-L30ER-NSE, 1769-L33ER, 1769-L33ERM, and 1769-L36ERM CompactLogix controllers
1769-L24ER-QB1B, 1769-L24ER-QBFC1B, 1769-L27ERM-QBFC1B CompactLogix controllers
1769-L16ER, 1769-L18ER, 1769-L18ERM CompactLogix controllers
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How is it implemented?
Rockwell Products that support open-socket services contain a socket object that is available for creating connection instances.
Socket Instances are created in the EWEB using Message (MSG) Instructions in the PAC.
The MSG instructions use a CIP Generic messages manage the Socket Instances. This is similar to the socket API function calls in most programming languages.
Each MSG Instruction is configured to perform one of the many different Socket Services. (Create, Open, Read, Write, Delete, etc.)
To communicate with another device you must understand the other devices application protocol. For example: the Socket Write must send the data in the proper format for the end device to understand it.
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10. Socket Object Services
Create Socket
Delete Socket
Delete All Sockets
Open Connection (Client)
Accept Connection (Listen)
Read Data
Write Data
Clear Log
Join Multicast Address
Drop Multicast Address
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Typical TCP Client
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Typical TCP Server
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13. Using MSG Instructions
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Socket Attributes
Socket Attributes can also be obtained using message instructions.
These are divided into two catergories:
Class Attributes (apply to the Socket Object)
Instance Attributes (apply to each Socket Instance)
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15. Timeouts! Timeouts! Timeouts!
There are three types of timeouts to be concerned with:
Service Timeouts
Should be less than the MSG timeout
Set in the Source Tag of the MSG
MSG Instruction Timeouts
30 Sec is Default, can be up to 35 minutes
Set in the MSG Configuration Tab
Socket Instance Timeouts
5 minutes is default
Set by accessing the Socket Instance Attributes
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Socket Object Logging
The EWEB cards are capable of logging activity and errors and are stored in RAM of the module
Logging is viewed on the Web Pages of EWEB module
Items logged can be selectively chosen
The log can be enabled, disabled, or cleared from within the controller using a Socket Class Attribute MSG
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17. Socket Object Logging (cont’d)
Logging can be enabled for the following:
Socket Create Requests
Open Connection Requests
Accept Connection Requests
Read Requests
Write Requests
Delete Socket and Delete All Socket Requests
Get / Set Attribute Requests
Log All Service Errors
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18. Socket Object Logging (cont’d)
A view of the EWEB Log Web Page
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Errors
Message Instruction Errors contain two parts:
Error Code
Extended Error Code
Error Codes 0 to FE are MSG Errors
See page 165 of 1756-RM003N-EN-P
Socket Service Errors Codes are generally FF
When evaluating errors from Socket Service Messages, we typically look at the Extended Error Code
See page 155 of ENET-UM527-EN-P
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20. Knowledgebase Articles
48879 – Summary of EWEB socket Information
32962 – Sample Application in Ladder
40626 – Socket Service Hints
– List of Hardware with Socket Support
66505 – Basic Socket Code in Structured Text
33240 – Using EWEB with Ethernet Printers
33672 – EWEB TCP Server application sample
34357 – Send UDP multicast messages
Copyright © 2012 Kendall Electric, Inc. All rights reserved.

21. Copyright © 2012 Kendall Electric, Inc. All rights reserved.
Let’s see it in action!
Demo
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22. Thank you for attending this Lunch & Learn session! Questions?
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