Glossary · Distributed automation and IEC 61499
Distributed automation system
Also known as: Distributed control architecture
German: Verteiltes Automatisierungssystem
In industrial automation, a distributed automation system is a system in which control functions are spread across several networked devices that cooperate to control a machine or process, rather than being executed on one central controller.
- IEC 61499
In one sentence
A distributed automation system spreads control functions across several networked devices that cooperate instead of one central PLC.
Example
A modular assembly line has one small controller per station; the stations coordinate over the network, and new stations can be added without reprogramming a central PLC.
How it applies
- Engineering: Distribution supports modular machines, plug-and-produce concepts and scalability. IEC 61499 provides a standardized model for designing applications that run across devices; distributed control systems in process plants follow their own vendor architectures.
- Timing: Cooperation over a network adds Latency and possible message loss. Time-critical interactions need deterministic networks, Time synchronization and defined behavior when communication fails.
- Safety and security: More devices and connections mean more interfaces to secure and more failure modes to analyze. Safety functions across devices require safety-rated communication.
- Documentation: Documentation must show the system as a whole: which device performs which function, how they communicate and what happens when one fails. A system overview diagram is essential for operators and service staff.
Distributed vs. centralized automation
In centralized automation, one controller runs all logic and reads distributed I/O. In distributed automation, the logic itself is spread across devices. Distributed I/O alone does not make a system distributed in this sense.