The Application of Low Cost CAN Bus Load Transducer Technology 2001-01-0070

A low cost CAN bus load transducer, requiring only a few low cost components, has been developed. Traditionally, to ascertain CAN bus loading, an algorithm based upon a number of assumptions executed on a microcontroller is required. This has many disadvantages that include being potentially costly, inaccurate and can take up a significant amount of processing, especially under higher bus load situations causing a higher number of interrupts. However, the CAN bus load transducer developed, is connected to the CAN bus and outputs a varying signal proportional to bus loading. A microcontroller can then simply be used to read the bus load signal and covert it into percentage bus loading as often as is required. The method is inexpensive, accurate and provides a continuous signal for CAN bus loading measurement that does not become expensive in terms of processing under higher bus load conditions.

In this paper, the application of the CAN bus load transducer technology is explored. This includes applications using bus load such as data logging during control system development, on-line CAN bus diagnostics, CAN bus traffic control and distributed control system feedback confidence analysis. However, the same technology can be applied to additional applications not requiring bus load such as baud rate detection and frame scheduling analysis.