Introduction

This appendix presents a reliability and safety analysis of a number of programmable controller architectures. The architectures chosen represent a majority of those implemented. The architectures are listed in Table F-1.

The architectures modeled in this appendix are the "generic" architectures. Actual commercial implementations may vary. While the architecture concepts are presented with programmable electronic controllers the concepts apply to sensor subsystems and final element subsystems.

This appendix uses material from Chapter 14 of the book Control System Safety Evaluation and Reliability by one of the authors (Ref. ^[1]).