Glossary · Industrial communication
CAN bus
Also known as: Controller Area Network, CAN
German: CAN-Bus
In industrial and vehicle communication, the CAN bus (Controller Area Network) is a serial bus in which nodes send short messages identified by an identifier; bitwise arbitration on the identifier gives the message with the highest priority access without data loss. The data link layer is standardized in ISO 11898-1.
- Industrial communication
- Standards
In one sentence
The CAN bus is a serial, message-based bus with priority arbitration by identifier, standardized in ISO 11898 and used in vehicles and machines.
Example
On a mobile crane, the engine control unit, the load moment limiter and the joystick modules exchange data over a CAN bus.
How it applies
- Engineering: CAN itself defines the physical and data link layers. Higher-layer protocols such as CANopen, DeviceNet or J1939 define how devices, objects and services are addressed. Designers choose the higher-layer protocol first, then the Baud rate, which limits the bus length.
- Commissioning: Every node needs a unique node ID in the higher-layer protocol, the bus needs termination at both ends, and all nodes must use the same bit timing.
- Operation: CAN has built-in error detection and fault confinement: a node that produces too many errors goes into error-passive and eventually bus-off state. Status counters help to diagnose wiring problems.
- Documentation: The documentation team specifies which higher-layer protocol and which message identifiers or objects a device uses. "CAN interface" alone doesn't tell an integrator enough.
CAN vs. CAN FD
Classical CAN carries up to 8 data bytes per frame. CAN FD, also covered by ISO 11898-1, allows larger payloads and a faster data phase. Devices must support CAN FD explicitly to coexist on such a bus.