FAQs

FAQ's in general

FAQ's on using CORFU FBDK

FAQ's in General

What is CORFU ESS?

CORFU ESS is an IEC61499-compliant Engineering Support System for the development of distributed control systems or Industrial Process Measurement and Control Systems (IPMCSs) to use the term of the IEC61499 standard.

CORFU ESS is an integrated Engineering Support System. It is composed of:

        a general purpose CASE tool and

        the CORFU FBDK.

The current version supports collaboration with IBM’s ROSE however any other UML CASE tool can be utilized with minimum effort.

Should I have the IBM’s ROSE installed in order to run CORFU ESS?

No. If IBM’s ROSE is not available you can still use CORFU ESS. However in this case the integration of the Function Block concept with the UML diagrams is not supported and CORFU ESS can be used as a conventional Function Block development tool as Rockwell’s FBDK.

What can I do with CORFU ESS?

CORFU ESS can be used under two different approaches:

        A Function Block based approach.

        A hybrid approach

A) A Function Block based approach.

This is the one proposed by the IEC61499 standard. The control engineer starts from the definition of Function Block types and proceeds to the definition of Function Block Networks.

The control engineer can:

        Define new Function Block types (basic and composite),

        Edit existing Function Block types (basic and composite),

        Import Function Block types that are created by other IEC-compliant tools such as Rockwell’s FBDK.

        Export Function Block types to be used by other IEC-compliant tools

        Create Function Block networks

        Define the system layer models

        Execute the Function Block network

        Assign FB network components to system layer components

        Download the application to the execution environment

A more detailed description of the functionality of the tool can be found in the related publications or the on-line documentation.

B) A hybrid approach

This approach integrates the UML notation with the Function Block one to include in the development process the requirements elicitation that is supported using a general purpose UML-based CASE tool (in the current version IBM’s Rose is supported).

In this case all the above functionality is supported plus

        the possibility to utilize Rose for the requirements specifications of the control application using the widely known use case technique supported by UML.

        The possibility to automatically transform UML specifications from IBM’s Rose to CORFU FBDK.

For more information on this approach you can refer to related publications. For the use of UML in control and automation you can refer to the INDIN’04 paper.

Where can I execute the applications developed with CORFU ESS?

There are two options:

1)      Execute the FB network for verification purposes

2)      Execute the application on a real device

For the first case the built-in run-time environment of CORFU ESS can be used. You can have an idea of how it works by opening and running  the sistep project under the directory CORFU\projects.

For the second case the Archimedes System Platform Execution Environments (RTAI-AXE, RTSJ-AXE, CMM-AXE) can be used. This is the case of the SISTEP case study.

Is there any example application that I can use for start up?

There are two example applications included in the setup. These can be found in the directory corfu\projects.

What is SISTEP?

SISTEP is an example application that demonstrates the applicability of the CORFU development process that is supported by the CORFU ESS.

The SISTEP system was developed entirely with CORFU ESS and was executed on the RTAI-AXE an Archimedes Execution Environment based on RTAI Linux. The system was developed in the context of Chris Tranoris PhD thesis. RTAI-AXE was developed by George Doukas in the context of his PhD thesis.

top

FAQ's on using CORFU FBDK

Is there any real example application that I can use for start up?

The control application for the modular didactic system of FESTO is provided on request. This is an excellent real word application example to start with IEC 61499 and CORFU FBDK.

What files constitute a CORFU project?

A Corfu project is composed of the following files:

<project name>.crf : the main projects file stored in the projects directory that is defined by the user.

<FB type name>.fbt : For each FB type there is separate file that contains the XML specification of the FB type. All .fbt files of a project are stored in the \corfu\library\<project name>  directory. The function block type name is unique in the context of the FBType library.

<FBNetwork name>.fbn : For each FB network diagram there is a separate .fbn file that contains the XML specification of the FB network diagram.

<file name>. dfb : For each internal FB network there is a .dfb file. All .dfb files are stored in the

Where is the system layer diagram stored?

Only one System layer Diagram is supported per project. The XML specification of the projects System Layer Diagram is included in the main project file, i.e. in the .crf file.

Can I modify a FB type while working with a project?

If the specific FB type has been already used in FB network diagrams the following allpy:

a) There is no problem when the interface of the FBtype is not changed.

b) There is also no problem in the case of adding new elements in the interface.

c) In any other case the FB instances of the specific FB type should be deleted before the FB types modification.

Can I define the icons of Industrial Process Terminators (IPTs) in system layer diagram?

Yes. You can select from the IPT icons the one named Custom. Right click on the created instance and select from the pop up menu  Properties of and next change picture.

 Are event function blocks of IEC 61499 supported?

Yes. You can either use the Corfu representation to simplify the FB network diagram or toggle to the IEC61499 representation by selecting the Toggle Events Stereotypes icon at the FB network editor menu.

How can I execute a FB network diagram?

For the proper execution of the FB network diagrams in the FBNetRTE the complete specification of the FB types is required. (for a detailed reference see related MED 06 paper). This specification includes the detailed definition of ECC diagrams and the specification of FBs algorithms in Pascal. The Context Scripting Suite for Delphi v.1 by Context Software Inc. (http://www.contextsoft.com/products/ctxscript/docu-mentation.jsp) is utilized for the execution of the FB algorithms by the FBNetRTE.

  According to the defined for the step by step execution of FB network diagrams, the engineer has first of all to define the input events he has selected to trigger the specific scenario as well as to define the initial values for the appropriate data inputs and define the output data that he wants to monitor. By pressing the step button FBNetRTE triggers the specific FB instance, executes the ECC and the corresponding algorithms and displays the target state, the internal variable values as well as the generated output events and the values of selected for monitoring output data. Between steps the user can activate selected events, specify data values to the related data inputs in order to simulate the scenario of his choice. Any event generated by the FB instances is added to the event list; the daemon thread is resumed to route the events with the associated data to the target FB instance. On the left side of the window, information about the executed FB threads and issued events are given to better understand the behaviour of the executed FB network. In the left bottom corner debugging information for the FB network is provided to help the designer to identify bugs in his model.

top