Message routing in control area network (CAN) protocol
US5854454A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1996 |
| Grant date | Dec 29, 1998 |
| Priority date | — |
| Expiry date | Sep 16, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2012/40215
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A hierarchial elevator control system (FIG. 2) utilizes standard Control Area Network (CAN) hardware and message protocols. A broadcast message format includes priority bits and source address bits in subfields within the standard CAN message identifier field, to separate priority levels from message type information, while maintaining collision avoidance by means of the source addresses. In a unicast message format, message response by individual receiving nodes is accomplished with simple standard CAN hardware filtering by providing, within the standard CAN message identifier field, a multi-bit destination address field to identify a unique receiving node to which the message is directed. In the unicast format, remote transmission requests are identified by a control bit in the standard CAN data field, and responded to utilizing a message-type field that is also in the data field portion of the message.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.