The future of CAN and CANopen

The future of CAN and CANopen

Friday, July 01, 2011

Guest columnist Holger Zeltwanger gives his views on current trends within CAN and CANopen.

It is now more than 24 years years ago since Bosch and Intel invented the CAN (Controller Area Network) technology. Even after this relatively long time, CAN is far from reaching its peak market penetration. With some 800 million CAN controllers sold per year, CAN is one of the worlds most used real-time communication technologies.

Moreover, CAN is still showing impressive growths rates: In 2015, market researchers expect annual sales figures of 2 billion CAN chips of which 80% will be used in passenger cars. The remaining 400 Million nodes will be used in a wide range of applications such as medical equipment, heavy vehicles, trains, door control systems and all kind of devices in industrial automation.

The key to success in the automotive industry

The internationally standardized CAN data link layer was, is, and will be the dominating in-vehicle network for passenger cars. The robustness of the physical layer (ISO 11898-2 and ISO 11898-3) as well as the reliability of the CAN protocol (ISO 11898-1) with a Hamming distance of six are the key features of the success of this network technology.

However, the standardized data link layer does not provide interoperability. This could be achieved with a standardized application layer and related profiles for devices or applications.

Many standardized CAN-based applications

Besides CANopen (mainly for embedded control systems including machine control) and DeviceNet (dedicated for factory automation), there are standardized CAN-based application layers for heavy-duty vehicles (J1939-based solutions), agriculture machinery (ISO 11783, also known as Isobus), and aviation systems (Arinc 825/6).

CANopen is the most widely spread application layer in non-automotive applications. It is standardized as EN 50325-4 and extended by the EN 50325-5 standard for safety-related communication (CANopen Safety). Beside the above mentioned standardized application protocols, there are numerous proprietary application protocols.

Increasing demand on CANopen connectivity

The CANopen application layer is very flexible regarding the communication functions, and the CANopen device, interface, and application profiles guarantee interoperability and partly exchangeability of devices. Nobody knows how many CANopen nodes are installed per year, but the number is larger than visible by means of devices on the market. This is because many OEMs use CANopen as an embedded technology within their machines.

There is also an increasing demand on CANopen gateways to Ethernet-based networks. Ethernet is often used as backbone, while CANopen is the sub-layered network linking the price-sensitive devices into the Ethernet networks. The CANopen protocol has been adopted by several industrial Ethernet systems including EtherCAT and Powerlink. This simplifies the migration from CAN-based fieldbusses towards industrial Ethernet networks and safeguards the investments in PLCs and control systems.

Holger Zeltwanger

Managing Director of of CAN in Automation e.V (CiA)

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