DeviceNet

DeviceNet is a fieldbus standard for factory automation that uses the CAN (Controller Area Network) bus to connect field devices such as sensors, actuators, and controllers. Developed by Allen-Bradley in the 1990s and standardized by ODVA, it combines a robust physical layer with a common application layer to enable simple device addressing, I/O data exchange, and diagnostics in industrial environments.

Physical layer and topology: DeviceNet runs on shielded twisted-pair cabling and typically uses a trunk-and-drop topology with powered drops to devices. The network ends are terminated with resistors to minimize reflections. A separate 24-volt supply powers devices on the network, and data are transferred over CAN high and CAN low lines.

Protocol and data model: DeviceNet uses CIP (Common Industrial Protocol) on top of CAN, enabling standardized object types and services for I/O devices, sensors, and actuators. It supports two main communication patterns: I/O messaging for cyclic data exchange and explicit messaging for configuration, diagnostics, and parameter access.

Device classes and operation: In typical DeviceNet setups, devices act as talkers (producing data) or listeners (consuming data) in the I/O exchange. Profiles define common capabilities for categories of devices, aiding integration with PLCs and other control equipment.

Status and legacy: DeviceNet peaked in the 1990s and 2000s as a widely used automation network. With the growth of EtherNet/IP and other CIP networks offering higher speeds and IT integration, DeviceNet usage has declined, though many installations remain in operation.