Alois Zoitl

Appendix E: Exchange formats

The article gives a brief overview of the main keywords and structure used in the IEC 61499 Textual Syntax and XML format. It is provided to assist with the understanding of the examples of Textual Syntax and XML format given in the book. For a full description and the full and formal production rules of the Textual Syntax, the reader is advised to read Annex B of IEC 61499-1. For a full description of the XML format and the associated Document Type Definition, the reader is advised to read Annex A of IEC 61499-2.

Appendix C: Frequently Asked Questions (IEC 61499 FAQs)

The article is a compendium of frequently asked questions with answers concerning the development and application of the IEC 61499 function block standard. The answers have been provided by international experts working in the IEC working group for IEC 61499 (at that time IEC TC65/WG6). The authors have restructured and added additional comments to some of the answers. Furthermore the authors have updated the comments to be consistent with the current version of the IEC 61499 standard and also provided some additional questions with answers.

Industrial application examples

In this chapter, we will consider how the IEC 61499 concepts and standard function blocks can be applied to modelling some examples of industrial control systems. Specifically we will: model a simple temperature control system and its main function blocks; consider how to design a function block model for a conveyor belt control system; consider issues related to modelling systems running on Fieldbus devices; and explore some of the special requirements for function blocks used in process control.

Event function blocks

As discussed in Chapters 1 and 2, a fundamental property of IEC 61499 function block networks is that the execution of all software within every function block is, in some way, event triggered. In this chapter, we will review a special set of standard function blocks that are provided for event behaviour. These function blocks can be used to model the control, generation and detection of events. This chapter describes the standard event function blocks that: allow events to be split to produce new events; allow events to be merged; permit the propagation of particular events; select between two or more events; delay an event by a given period; generate streams of events; create events from Boolean edge detection; and count the number of event occurrences.