Residual error handling in CAN

Critical control applications require “determinism”, the certainty that a given set of inputs will produce the same set of outputs.  Nature intrudes upon our designed determinism by imtroducing various kinds of noise, which may alter the inputs and outputs in ways that are difficult to detect.

This patent application addressed the nondeterminism remaining after other aspects of CAN and CANOpen behavior were accounted for.

Rather than trying to ensure perfection, an estimate is maintained of the confidence in the current state.  If the confidence is above the currently configured threshold, then we continue with the assumption that all is well.

In this way the likelihood of error is bounded, and the threshold of acceptance is a tunable parameter of the system. 

Because many applications are continuously refreshed, any fleeting error will quickly get corrected.  It is possible to design many real-world applications to be immune to such glitches, as long as the glitch is corrected in real time.