Analysis of Availability and Safety Considerations in EM-Diverse Systems

This paper analyses the availability and safety performance of non-EM-diverse and EM-diverse systems, represented as redundant traces on a PCB. The paper compares one trace as a non-redundant system with redundant systems comprising two and three traces to which different comparison and voting mechanisms are applied. Systems with two traces allow for comparison and the comparator can decide to initiate a safe action when appropriate. Introducing inversion on one of the traces results in an EM-diverse system. Adding a third trace enables majority voting, which is non-EM-diverse in its most basic form. By introducing time diversity between the traces, the system becomes EM-diverse. For the redundant system with three traces, a last method is introduced where two pairs are created with a shared trace in the middle, on which the signal is inverted. This results in two outputs with more possibilities to decide upon the final output or action. All these presented EM-diverse systems allow the designer to make an impartial decision considering availability and safety. Optimizing the system for safety has the drawback of performing a safe action even when the smallest anomaly is detected. Optimizing the system for availability has the advantage to allow fault-tolerant operation, however, with an increased risk of undetectable dangerous failures.

ISBN:978-1-7281-0594-9

Jaar van publicatie:2019

Toegankelijkheid:Open