Industrial Engineer · phase 5 of 16
Device Level Ring (DLR)
ODVA ring topology that provides rapid recovery from a single network break on supported EtherNet/IP devices.
The Explain card
- Plain English
- DLR is an EtherNet/IP ring topology with a supervisor that watches for a break. Devices with two ports are daisy chained into a loop, and if any cable fails the ring heals in a few milliseconds.
- Example
- Twelve I/O blocks along a conveyor are wired in a ring back to the controller. A forklift cuts one cable and the machine never notices.
- Why it matters
- A plain daisy chain loses every device past the break, and a ring keeps them all. The supervisor has to be configured, and a ring with no supervisor is a loop that floods the network the moment it closes.
- Hook
- A chain with both ends held.
Where it sits in the deck
Phase 5: PLC Industrial Communications
The protocols that let controllers, drives and operator panels talk, plus the addressing and description files that make them agree on what was said.
