Partial network operation
Partial network operation refers to the state in which one part of a communication network is active while another part is not active. Such a state is currently not intended for all communication networks. If a CAN network is in partial network operation, the term CAN partial network is used in English. In German, the terms "Teilnetzbetrieb" and "CAN Partial Network" are often used on an equal footing.
Nodes that are not required and are only active because other nodes in the same network have to be active use electrical energy unnecessarily. This is why vehicle manufacturers are currently interested in introducing partial network operation in vehicles, as small amounts of energy can be saved in this way .
With (high-speed) CAN and partly with FlexRay , all network nodes become active when at least one starts communicating. In these cases, the solution is to disconnect individual network nodes from the supply voltage in order to make them inactive. Another possibility to generate a partial network operation is the collective waking up of all network nodes followed by a selective falling asleep of unnecessary network nodes, for example with the help of a network management .
With single-wire CAN it is possible to send messages with a higher than the normal voltage level. Only such messages activate (wake up) the inactive (sleeping) network nodes.
For high-speed CAN, the physical layer is specified in ISO 11898-5. It is provided that each node is activated (woken up) as soon as data is transmitted. In the new part of ISO11898, Part 6 (high-speed medium access unit with selective wake-up functionality), the wake-up is now specified by freely definable messages. In real products that correspond to this new standard, the wake-up message will be freely configurable via a Serial Peripheral Interface (SPI).
At the 15th specialist congress "Advances in Automotive Electronics" in Ludwigsburg in June 2011, the E / E managers (E / E: electrics / electronics) from the automobile manufacturers Audi, BMW, Daimler, Opel, Porsche and Volkswagen agreed on a common standard during partial network operation (CAN Partial Network) and presented the details to the public immediately (see link to the Ludwigsburg declaration). The right chips for CAN Partial Network are already available (see link).
Web links
Individual evidence
- ↑ VDI Conference Electronics in Automobiles, Baden-Baden 2009 ( ISBN 978-3-18-092075-7 )
- ↑ ISO 11898-5: 2007 Road vehicles - Controller area network - Part 5: High-speed medium access unit with low-power mode