What does "event-driven" mean?

[Rodrigo_Garcia]

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[JohnConway · Accepted solution]

Today, in most control applications that use embedded controllers, logic and control algorithms are processed using a cyclic or scanning-based solving mechanism. This means that CPU cycles are wasted processing logic and algorithms even if some things have not changed. In an event-driven processing method, logic is solved based on the firing of an initiating event. This is very useful when time critical logic that needs to be solved can be accomplished in a predictable fashion, particularly if logic resides and is executed in multiple CPUs. This allows IEC 61499 control strategies to be shifted across multiple CPUs without negatively impacting control behavior.

It is also a very good strategy for interfacing with IT systems (design tools, simulation, business systems) which are generally transactional, i.e., event-driven. The control system responds to a request from the IT system when the corresponding event is triggered.

For these reasons IEC 61499 is well-suited for implementing Industry 4.0 use cases like the digital twin, where one needs to be able to easily combine real-time control with IT systems like 3D simulation.

For more information on IEC 61499, download the whitepaper "IEC 61499: The Industrial Automation Standard for Portability that Unleashes Industry 4.0".