• The iTapestry Bean provides a simple interface to connect with industrial automation devices. Beans encapsulate the behavior of the device. The Bean also provides the device specific logic to retrieve data by encapsulating the logic and commands required to access data in the device. These are general logic tools, not specific to a particular information management application.
• The Bean is a communication tool. It retrieves data from the automation device in the native format of the device. Supporting the binary data format of the automation device reduces network traffic and increases data throughput.

• The Bean insures that the appropriate PLC tag is receiving the appropriate data type enforcing data consistency.
• The Bean translates the message to the native communication format that has to be provided to the connector.
• The Device Bean is actually a package of three beans comprising a main Entity Bean and two Session Beans which manage access to the Entity Bean.
• The Entity Bean contains all the tag information, location of the device, name of the device and the methods for accessing the data in the PLC. This is a local entity Bean and only things in the EJB Container can access the entity Bean.
• The Session Beans are facades to provide access to the Entity Bean inside the EJB Container from software components outside the Container. These forward calls to the Entity Beans. There is an Administration Session Bean which handles creation, removal, and various administrative commands including updating tag names and types, and updating the plc name. There is also a Tag Bean for accessing the PLC tag data within the PLC.

• Connectors encapsulates the behavior of the communications protocol used to communicate over an industrial Ethernet network with the automation device or PLC.
• A Connector handles the message and converts that message into the appropriate byte format for the industrial network protocol.
• The Connector takes the message and breaks it down to:
• schedule the message on the network
• place it on network
• wait for a response
• convert response from byte format into a higher level format the PLC EJB understands and returns it to the PLC EJB.

• The Connector converts a high level request from the PLC EJB into a byte array, in the native format of the industrial protocol, in the form of a message
• The Connector sends the message to the I/O Library where it is queued up. (I/O Library – Input and Output – for example writing and reading of the packets). The I/O library places the message on the network. When the message is returned, in raw byte format, the I/O Library passes it back to the Connector
• The connector takes the response and turns it into a higher level entity/construct which the PLC EJB can understand.
• A high level response is passed back to the PLC EJB which may perform further processing in order to provide the user the data they requested.
• The iTapestry EtherNet/IP (EIP) Connector is unique. It is the only java library written specifically for EIP. It supports the EIP standard including unconnected messaging (UCMM), explicit messaging and all the data types. Class 1 & 0 message will follow shortly.

Servlets are Java code used to generate dynamic web pages by using Java classes (server side). Servlets may also generate HTML pages. Servlets provide more functionality than Java Server Pages.

The HMI Builder is an Eclipse integrated development environment (IDE) plug-in. The HMI Builder can be used to develop code on any developer workstation with the Eclipse IDE installed.

The HMI Builder generates a combination of compiled code (java class files) plus other files such as html, .jar, JavaScript, JSP and SVG files, to form the HMI web application. These files are combined into a Web Archive (.war) file by the HMI Builder. The .war file is then added to an Enterprise Archive (.ear) file which is deployed on the J2EE application server. Full documentation is provided explaining how to deploy the web application on a variety of J2EE application servers including, WebSphere, WebLogic and JBoss. The running web application will dynamically serve the HMI Operator screens to any PC browser window in the plant.

The HMI web application communicates with the iTapestry EJB to provide dynamic information for the HMI client in a browser window.