Glossary · System coordination, integration and orchestration
Decentralized control
Also known as: decentralized control architecture
German: Dezentrale Steuerung
In control system architecture, decentralized control is an approach in which control decisions are made by several local controllers, each responsible for its own section of a machine or plant, with limited coordination between them.
- System integration
In one sentence
In decentralized control several local controllers each decide for their own section of a machine or plant, with limited coordination.
Example
Each conveyor module of an intralogistics system has its own small controller that decides locally when to accept a tote from its neighbor.
How it applies
- Engineering: Decentralized control supports modular machines: modules can be tested, replaced and extended independently. The price is well-defined interfaces between modules and careful handling of situations that need a global view.
- Availability: The failure of one local controller affects its section, not the whole plant, if the neighbors detect the failure and react in a defined way.
- Documentation: Documentation should describe each module's responsibility and the interfaces between modules. Troubleshooting guides must say which controller owns which decision, because there is no single program to look at.
Decentralized vs. distributed control
The terms overlap. Decentralized control stresses local decision-making with little central coordination. Distributed control stresses that control functions run on several networked nodes, which may still be coordinated centrally, as in a distributed control system (DCS).