Glossary · Distributed automation and IEC 61499
Function block network
Also known as: FB network
German: Funktionsbausteinnetzwerk
In IEC 61499, a function block network is a set of function block instances interconnected by event connections and data connections; it forms the content of applications, subapplications, composite function blocks and resources.
- IEC 61499
- Standards
In one sentence
An IEC 61499 function block network is a set of function block instances linked by event and data connections.
Example
The network of a filling application links a level sensor block, a control block and a valve block with event connections for sequencing and data connections for values.
How it applies
- Engineering: Networks express both control flow (event connections) and data flow (data connections). Reading an IEC 61499 network means following events to see what happens when, and data to see which values are used.
- Structure: Networks appear at several levels: inside composite function blocks, inside subapplications, as applications and as the content of resources after mapping.
- Review: Large flat networks are hard to review. Grouping into subapplications or composite blocks keeps each network readable.
- Documentation: Network diagrams are useful functional documentation. Add a short description of the event flow, because event order is not always obvious from the diagram.
IEC 61499 network vs. IEC 61131-3 FBD network
An FBD network in IEC 61131-3 has only data connections and executes in a fixed order each cycle. An IEC 61499 function block network has separate event connections that determine execution. See Function block diagram (FBD).