CAN Standard

For about two decades now, the automobile has undergone a genuine electronification process: Continually increasing numbers of electronic systems provide for a growing level of safety and convenience in car driving. Serial communication systems play a key role here. That is because many valuable electronic systems would not be feasible without data exchange.

The serial communication technology most frequently used in the motor vehicle is CAN (Controller Area Network). It is ideal for automotive applications, because it assures reliable data exchange even under very harsh environmental conditions.

CAN has been standardized since 1993 and is available as an ISO standard (International Standardization Organization): ISO 11898. While it initially consisted of three parts, today it has five parts. The first part describes the event-driven communication protocol. A time-triggered extension can be found in the fourth part.

The second and third parts cover information on the bus interface and physical data transmission: A distinction is made here between the High-Speed variant (data rates up to 1 MBit/s) and Low-Speed variant (data rates up to 125 KBit/s). The last part describes the behavior of a CAN node in the High-Speed network in “Low Power Mode”. The figure CAN Standard shows how the first three parts of the ISO standard 11898 - the most important parts in practice – would be classified in the OSI model (Open System Interconnection) published by ISO.

Specifically developed for use in the automobile, CAN is primarily used as High-Speed CAN in the powertrain and chassis areas, and as Low-Speed CAN in the convenience area.