TABLE OF CONTENTS 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 will describe 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.
In the previous chapters we have reviewed several different ways to create function block type definitions, i.e. for basic, composite and service interface function blocks. In this chapter we will now review a special set of function block types that are defined in IEC 61499 specifically to handle events. Most of these function blocks are defined as basic blocks. A couple of blocks are defined as a form of service interface as they require some interaction with the containing resource. There are also some more complex event blocks which are built as composites from the elementary event blocks.
All the standard event function blocks are designed to be used within the definitions of larger user composite function blocks and applications and provide many of the common operations required...
